Identification of Microsporidian Genera (Protozoa, Microspora) - a Guide with Comments on the Taxonomy

Arch. P rotisten kd . 136 (1 988) : 1-37 VE E G us t a v Fischer Verlag .I en a

D ep a r t m ent of Zool og y , U n iversity of Lu n d , Lu nd , S we d e n

Identification of Microsporidian Genera (Protozoa, Microspora) a Guide with Comments on the Taxonomy By J. I. R ONNY LARSSON Wi th 8 F ig ure s K ey wor ds: Microspor id ia ; Ident if ica tion of g ene ra ; Cho ice of character s ; Taxono my

Summary T h e paper t rea ts practice a n d problem s with t he id entifica tion of ge ne ra of mi crosporidia. After a b rief r evi ew o f t he tech n iq ues, characters u se ful for the id entifica t ion of genera a re t re a ted i n more d etail: light -microscopic or elec t ro n -m icros co p ic char acters; the b asic t erminolo gy fo r t he m or pholog y a nd lif e cy cle stages of m icrospor idia ; t he sh a pe a n d size of t he sp ores ; t he co nstruction of t he spo re wa ll, pol ar filament a nd pol a ropl a st; t h e in it iatio n, co nst r uct io n a nd in cl usions o f t he s poro p horo us ve s icl e; t he p a tholo gi cal ch a nges ind uced in t h e h ost ; a nd t he verteb rate or inver t ebrate h ost . A dichotomous k ey distingui shes bet ween 83 micr osporidian gener a . The tax ono m ic ch a r a cterist ics of 87 genera, in a lp h a b et ical order, a re compared in a tabl e. Genera omit t ed fr o m t he key a nd genera wit h speci al problem s for identi fication an d tax o no ai y a re co m m ented o n se pa ra t ely .

Introduction The taxonomy of mi crosporidia has been trea ted in monographs by AUERBACH (1910) ; K UDO (1924) and SPRAGUE (1977), and in taxonomic reviews by WEISER (1977, 1985) ; SPRAGUE (1982); ISSI (1986) and CANNING (1987), but for the id entification few guides exist. WEISER (1961) in cluded id entification keys t o species in the mon ograph on ins ect-parasitic microsporidia, and WEISER a nd BRIGGS (1971) and HAZARD et al. (1980) publish ed keys to the genera of microsporid ia found in in sect s and mites. 'Vithout doubts in sect s are the most important hosts to mi crosporidia , and approximately half t he number of spec ies a re pa rasit es of insec t s. Nevertheless several mi crospo ridian genera are not known to be present in insects, and keys restrict ed to microsporidia of in sects are naturally of limited value when dealing with microsporidia of other invertebrate groups, and useless for mi crosporidia of vertebrates. The review by WEISER (1985) has keys t o families, but cove rs onl y a pproximately 1/3of t he genera. The class ifica ti on follow s that of WEISER (1977), without considering lat er publication s. Microsporidiology dev elop s rapidly, new species and gen era appear in a continuous flow, and new information cha nge s the conce ption of exist ing taxa. In a few years monographs and reviews are out of date , and it is therefore necessary at fairly short intervals to revi ew the taxonomy and bring identification keys up to date. It is not of much value to try t o cover all microsporidian sp ecies in the same identifi ca tion guide. The number is now so gr eat that it would creat e a big publication, useful only for a short time. Sp ecies are best treated in revisions of gen era and fami1

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lies and in reviews of microsporidia of particular host groups, like the recent monograph on microsporidia of vertebrates by CANNING and LOM (1986). Identification keys to genera are more suitable. Such a key takes only a small number of printed pages, and will therefore be simple to renew. It is also a suitable taxonomic level for identification, as a key to genera to a great extent can be based on simple characters, often visible with the light microscope. It is not a great problem for a general parasitologist to identify a microsporidium to genus, but to identify the species is difficult as in many cases characters only visible with electron microscopy must be used, and for the reason that a great number of species have been classified provisionally it is often necessary to have an overview of the taxonomy of microsporidia. The genus level is not free from problems. Experimental studies of life cycles and the increased use of electron microscopy in later years have provided substantial characters for identification, and many genera are now defined with precision. However, in addition to these strictly .defined genera there is still a number of genera where no species has been investigated by modern methods, clear diagnostic characters are lacking, and it is doubtful if the genera can be recognized as valid. There are also genera which nowadays for good reasons are interpreted in a more strict sense than in earlier days. This excludes a number of species, which for a period must remain home-less. Some years ago a simple key for identification of microsporidian genera was compiled, which intended to cover all genera with distinctive characters, without limitation to certain groups of hosts (LARSSON 1983b). It was written in Swedish and intended for Scandinavian users. However, two years later Canada Institute for Scientific and Technical Information published an English translation (LARSSON 1985a), which shows the interest for identification of microsporidia and the lack of suitable literature. Even jf a short time has passed since the key was compiled, so much has happened that it is of practically no use today, and it cannot easily be modified to accomodate new genera and observations. As to my knowledge no alternative key has appeared in the meantime, a new key is presented here. It does not cover all named genera for the simple reason that some of them have no distinctive characters. Omitted genera, and some other genera with special problems for taxonomy and identification are discussed separately. As a complement to the key the genera are listed in alphabetical order in a table, where the most important taxonomic characters can be compared. A key is based on a selection of characters, and the same type of characters are not used for all genera. Therefore a table with the same sets of characters for all genera is a useful tool when dealing with a microsporidium that for some or other reason does not agree well with the characters used in the key.

Techniques for the study of microsporidia VAVRA and MADDOX (1976); HAZARD et al, (1980) described in detail the techniques for making light- and electron-microscopic preparations of microsporidia and there is no need to recapitulate them here. In most cases conventional histological techniques can be used. BOUIN'S or SCHAUDINN'S fixatives are suitable, and staining with HEIDENHAIN'S iron haematoxylin or GIEMSA solution is sufficient for routine work. For the study of fresh smears the modified agar cushion method by HOSTOUNSKY and ZIZKA (1979) is excellent. Standard fixations for electron microscopy, using glutaraldehyde and osmium tetroxide, give acceptable results, but spores of microsporidia need prolonged fixation times. When making light microscopic preparations the smearing technique is of importance. The smears must be made so carefully that they reveal modes of division and the presence of sporophorous vesicles (visible as grouped spores). If the smear is made like a bacteriological smear, spore

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F ig. I. T o h n iq ues for mll ki llg <'1I111,1t pr up urut iou- ,

grou ps a r e d estroyed , unless t he e nve lope of t he s po ro p ho ro us v esic le is u n usu all y per sisten t . T o make sq uas h prepara tio ns is b et t er wa y to pr eser ve t hese charact ers. T h e follo wing procedure has proven useful. A s mall p iece o f mi er os pori di a-filled tissue is p ut i nto a s ma ll d rop of water clo se to t he edge of a microsco pe slide . Ano t he r slide is pl a ced on t h e top, a nd the two slides are ge n t ly pressed against each other (Fig. 1). If too str ong pressure is ex er ted , the shape of the spor e phor ous ves icles is destroy ed. T he slides a re se parat ed by gentl e t ur n in g , a v oid ing them to glide.

Characters used for identification 1. Light micros c opic and ultrastructural c h a r ac t e r s

In later years the use of elect ron mi croscopy for the st ud y of mi crosporidia has gre atly in creased , and nowadays we meet des criptions of new t axa, on different lev els, whi ch ent irely have been ba sed on t he ultrastructural cy t ology. It cannot be deni ed that ligh t mi croscop y is of limited valu e, as the size of many micros porid ia is close to t he limits of resolution for ligh t microscopy using white ligh t. It is difficult, or often impossibl e, to define a new spec ies using light mi croscopi c characters alone, unl ess t hey are coupled t o presumed or verified host specificity. For taxonomic levels above the spec ies charact er s visible with light mi croscop y migh t be useful. There is no reason t o a void the use of ult ra structural charact ers in taxo no my, if they allow a clear and precise delimitation of a t axon , bu t it is valuable, and to be rec omme nde d , t ha t both t he ligh t mi croscopi c and ultrastructural aspect s are covered in de script ions of new microsporidia. The ultrastructure of mi crosp oridi a has been revi ewed by VAVRA (1976) and LARSSON (1986c). The key presented here, like the key of 1983, has been constr ucte d for maximum us e of characte rs visible with t he ligh t microscop e. Many genera can be id entified fr om the appearance in st aine d smears, at least if the prep arations are carefully made, or in paraffin sections. In other cases light mi croscopic cha ract ers alone deli mit a small group of genera, and for the final identification it might be necessary to use additional charac te rs, not visible with light microscopy . 2. S om e basic terminolo gy When microsporidia are isolated from a naturally infect ed host the spore stage is domi nant . The spore is an unicellula r, thick-walled body, usu ally of regular sha pe (Figs. 2-3). With rare ex ception s t he wall has three layers : an internal pla sm a mem b ra ne (plasmalemma), a median struc t ure-less e n dos po re, and a surface layer of mo re or less complex cons truct ion , t he e xos pore (Fig. 5 E). The t erminology for the layers of the spore wa ll used here is ide nt ica l to the t ermin ology by VAVRA (1976), whi ch is gen erall y a ccepted by mi crosp oridiologist s. WEISER (1985) used t he same terminology differen tl y. In t he interior of t he spore (Fi g. 5 B ) is a t hread-like structure, the polar fil a m en t , whi ch is attac hed t o an a nc horing appa rat us at the l*

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ant erior pole, and usually coiled in t he po st er ior half of the spore. A syst em of membrane-lined sa c-like or lamella r st r uct ures, the pol aropl ast., surro un ds the a nterio r p art of t he polar filam en t. At t he posterior pole is u su ally a membrane-lined poste rio r vac u o le . In the wid est pa rt of the spore are one or t wo nuc lei. Two coup led nu clei a re known as a diplok ar y on , a sing le nucleu s as a mon ok ar yon. The spore is filled with a granular cy t op lasm wit h prominent stra nds of endo plas mic reticulum. The spore , like all st ages in the lif e cyc le of mi cro sporidia , la cks mi t och ondria. The new host is eit he r infected by spo res or the mi crosp oridium is transm itted th roug h t he eggs. If spores are ingeste d by the food , t he polar fila ment is ext ru de d in t he gut, wh er e it forms a tu be-like st ruc t ure (F ig. 5A ), wh ich pe netrates the wa ll of a g ut cell. The infectiou s cell, t he s po r o p las m (whi ch is t he nuclear a pparat us of t he spore, a p art of t he cytoplas m a n d a surro und ing unit membrane), is inject ed t hroug h t he .p ola r filam ent in t o the cell. The mi cro sporidium reproduces in this or in other cells of the body, differ ent for differ ent mi cro sp oridia. All mi crosporidia a re in tracellu la r parasites, usu ally in t he cy toplasm , but so meti mes a lso in the nucleus. Ther e are usually two di stinct phases of reprodu ction: vegetative reproduction, m er o g ony, and production of spo re s, sporogony. The mo t he r cell for merogony is called m e r o n t , for sporogony s p o r o n t . The final daughter cells produced in the sp orogony are the sporobla st s , whi ch without further division directly mature to spores . Bot h reproductions ca n proceed as binary fissi on , frag me nt a t ion of a rounded 0 1' cylind ric al plasmodium, pl a smotomy, or as multip le budding from a r osettelike plasmodium, s chizo g on y (Fig. 6 A-C). Daughter cells may remain united as cha ins. All de velopmental stages ma y have isolated nuclei or d ipl okaryotic nuclei, or t he veget ative reproduct ion is d ipl ok aryotic, followed by sp orogonial stages with isola t ed nu clei. Sexual processes a re known from a small number of mi cr osp oridia ( HAZARD a nd BROOKBANK 1984 ; H AZAR D et a l. 1985 ), with p roduction of ga me t e nuclei or ga me tes, zygote form ati on , an d subseq uen t re d uctiona l di vision. The m eiotic di vision starts t he sporo gonial re prod uc tion . Sp orogon y ca n p ro ceed in a sac-like struct ure, t he s p o r o p h o ro us ve s icle (or in older literature pansp oroblast) (F ig. 8), wh ere t he en velope usually is formed by the sporogo nial pl asmodium , or rarely during me rogo ny, 01' sp ores a re p roduced free in the cytop las m of t he host cell. 3. Th e s ha pe a n d s i z e of t he s pores Most micr osporidi a have oval o r py riform spores, bu t sp herical a nd rod-sh aped spores a re n ot unusual (Fig. 2). A small number of ge nera, like Amblyospora (F ig. 21), Cougourdella (F ig . 2N-O ), Cylindrospora (F ig. 3K), Golberqia (Fig. 4E ), Parathelohania (F ig. 4F), 'I'oxoqluqea (F ig. 2L ) and Weiseria (Fig. 4.D), have unique spo re shapes, whi ch have been u sed t o defin e the genera. All spore s may be of approxi mately the same size (vary cont inuously in a small size range) 0 1' the spores may be divided into two or more easily identified size classes, In that case spores are referred t o as micro- and ma cro sp or es (Figs. 3D1, 80). It is of particular interest that so me genera have proven t o have dimorphic, or eve n polymorphic, sporogony, producing sp ores of at least two morphological types

F ig . 2. S po r es o f microspori d ia i n fr esh s me a rs a nd scan n ing elec t ro n mi croscopy. A-B , Alfvenia nuda ; C-D. E p isep tu m i nvel'sum; E -F. Ghapma nium dispersus ; G- H . Bo huslonia as terias ; I. Amblyospora s p ., octospore; K. A mblyosp om callosa , octospores and fr ee s p or es ; L. T oxoglu gea oari abilis i M. H elmichia aggregata; N - O. Oouqou rdella sp.; P. Bacillidium sp . ; Q. R es iomeria odona tae. (Bars . : A, D, E, G , I , L , ~I , 0, P. I 111ll; B , C, H, K, N, Q . 5 pm ; F. 10 pm).

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(Fig. 2K). The different morphs may occur together, or be present in different generations of the same host, or even appear in different host species. For the moment we have no idea of how wide-spread this phenomenon is, and it is of fundamental importance for microsporidian taxonomy to solve the problems with polymorphism and alternating hosts. The possible presence of polymorphism has greatly increased the problems with the handling of a previously undescribed microsporidium. It is now always necessary to question if the miorosporidium is a new species or only an unknown part of a polymorphic life cycle of an existing species. The practical consequences for identification are that a genus known to be polymorphic must appear in more than one position in an identification key. It should be remembered, however, that mixed infection of two or more microsporidia, or microsporidia and other protozoa, are not unusual. 4, The spore wall While the structure-less endospore only varies in thickness, the exospore varies also in construction. In most genera it is uniformly electron-dense (Fig. 5E). A few genera, like Auraspora and Episeptum (Fig. 5F), have unique, complex exospores. Microsporidia of Thelohaniidae and Amblyosporidae have stratified exospores, where the basic organisation (an internal moderately dense layer, a median double-layer resembling a unit membrane, and a less dense surface layer) is shared by all genera (Fig. 5G). In Amblyospora (Fig. 5H) and Parathelohania the dense layer internal to the double layer is thick and fibrous. Chapmanium has two prominent layers internal to the double layer (Fig. 51). Most genera have smooth exospores without surface sculpture. Striatospora has longitudinal ridges. In microsporidia with sporophorous vesicles fibrillar or tubular material of the cavity may be attached to the exospore. Exospores of Ameson and Spraguea have a fringe-like surface coat of fine fibrils or tubules. A few genera have exospore projections longer than the spores. Caudospora (Fig. 4A) and Jirovecia (Fig. 3 R) have one long terminal projection, Lnodoeporus has 3-4 posterior tubules and a small forked anterior projection (Fig. 4B). Hirsuiosporos has an equatorial band and a posterior tuft of tubules (Fig. 4C). These genera are recognized by their exospore projections. The gelatinous coat present in many microsporidia of aquatic hosts has not proven useful for identification at the genus level.

Fig. 3. Spores of microsporidia in fixed and stained preparations. A. Aljvenia nuda; B. Amblyospora callosa, octospores and free spores( *); C. Amblyospora undulata, octospores; D. Bacillidium sp.; E. Berwaldia singularis, arrow-heads indicate coupled spores; F. Bohuslavia asterias, spore groups with 8 and 16 spores; G. Buxtehudea scaniae; H. Chapmanium dispersus ; 1. Cougourdella sp.; K. Cylindrospora jasciculata; L. Encephalitozoon cuniculi; M. Episeptum inversum ; N. Glugea anomalo; O. Gurleya sp.; P. Helmichia aggregata; Q. Janacekia debaisieuxi; R. Jirovecia limnodrili, arrow-head indicates the tail-like prolongation; S. Nosema tractabile; T. Octosporea chironomi; U. Pegmetheca lamellata; V. Polydispyrenia simulii; W. Resiomeria odonatae; X. Systenostrema candida; Y. Telomyxa glugeijormis, spores indicated by arrow-heads; Z. Thelohania sp.; AI. Toxoglugea variabilis; B1. Tuzetia skuldae; C1. Vairimorpha sp.; octospores and free spores (*); D1. Vavraia holocentropi; microspores and macrospores (*). (Stainings: R. Dominici; T, Y. Giemsa; all the other Heidenhain's iron haematoxylin. Bars: A, B, K, P, S, T, AI, D1. 5 pm; the other, including inset on AI, with a common scale bar on W, 10 pm).

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L Fig. 4. Schematic drawings of spores (A-H) a nd sporophorous v esi cles (I-M) of the following gener a : A. Oaudospora : B. Lnodosp orue ; C. H i rsut osp oros ; D. W ei 8eri a; E. Golbergia ; F . Parathe lohania ; G. Onmpanulosporo ; H . No rleoinea; 1. Amphi(~m blY8; K . Metchnikovelln ; L. Amphiacantha ; ~I. 'I'richoduboscqia . (Bar: A-H. 5 I'm ; I -M. 10 I'm).

Identification of Microsporidian Genera

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5. The polar filament A few genera, like Cylindrospora, Helmichia and Striatospora, have a straight or bent polar filament, not longer than the spore. In most microsporidia the filament is considerably longer than the spore and coiled in the posterior part of the spore (Fig. 5B). In older descriptions great importance has been paid to the length of the extruded filament. The presence of ejected filaments gives light microscopic evidence for the organism investigated being a microsporidium, but measuring the length of the extruded filament in a light microscopic preparation has no practical use. There is no way to check if the ejection is complete, and most measurements published indicate that incompletely ejected filaments have been measured. If the length of the filament is used as a taxonomic character in the diagnosis of a genus, the evaluation must be based on the appearance in ultrathin sections. The polar filament is attached to the anchoring disc by a pad-like or cylindrical attachment section, wider than the rest of the filament. The filament proper is either uniformly thick from the attachment section to the tip, isofilar (Fig. 5A-B), or abruptly constricted at some point, having a wide anterior and a narrow posterior portion, anisofilar (Fig. 5C). In a typical anisofilar filament both the wide and narrow part are coiled. An anterior stiff, wide uncoiled anterior filament part has been called a manubrium, present in Bacillidium, Jirovecia and Ormieresia. In Desportesia, Metchnikovella and other Rudimicrosporea, the unique short, uncoiled filament, with a terminal swollen part, suggested to be a gland, and a posterior lamellar projection, has also been called a manubrium. The polar filament has normally a smooth surface, but in a few genera with spherical spores, like Buxtehudea (Fig. 5D) and Chytridiopsis, tubular projections from the filament give the transversely sectioned filament a star-like or honeycomb-like appearance. 6. The polaroplast A few genera, like Buxtehudea, Chytridiopsis and Baculea have only a few polaroplast lamellae or lack entirely the polaroplast. In most microsporidia the polaroplast is voluminous, occupying approximately 1/3_1/2 of the spore volume. In a stained smear the polaroplast is visible as an unstained area with clear-cut or oblique posterior border (Fig. 3P). At the ultrastructural level different types of polaroplasts can be dinstinguished. The polaroplast is the organelle of the spore most sensitive to fixation and embedding, and when interpreting the construction it is especially important to be observant on the risk of artifacts and to be aware that the appearance of the sectioned polaroplast is affected by the plane of sectioning. The construction of the polaroplast must be studied in a longitudinal section through the mid-line of the spore. Usually the polaroplast has two lamellar parts, with narrow and regularly arranged lamellae anteriorly and wider and less regularly arranged lamellae posteriorly (Fig. 7 A). An inverted arrangement of the two lamellar parts is present in Episeptum (Fig. 7 B). The genus Chapmanium has a uniform polaroplast, with identical sac-like compartments from the anterior to the posterior pole (Fig. 7 C). The microsporidia with the most elongate pyriform spores have chambered polaroplasts with wide compartments, of uniform appearance in Culicospora, Culicosporella and the copepod morph of Amblyospora, more closely compressed in posterior direction in Bohuslavia (Fig.7D). 7. The sporophorous vesicle With few exceptions the envelope of the sporophorous vesicle is produced at the beginning of sporogony. In Pleistophora, Vavraia and Pegmatheca the envelope is

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formed during the merogon y. Normall y the envelop e en closes a ll spores produced by t he spo ro nt. In T'uzeiia a nd related ge ne ra, the spo ro p horous vesicle divides with it s content during the sporogony, enclosing ea ch spo re in a vesicle of it s own (Fig. 8 V-X). The en velope of the sporop horous vesi cle is often fragil e, som etimes disappearing already in the host wh en the spores m ature, or is easily destroyed when smears are made. The en velop e is ra rely seen with the light mi croscope and the presence of spo rophorous vesi cles is normally revealed by spores occurring in gr oups (Figs. 2 C, 8 0 ). Most mi crosporidia have s phe rical or ova l spo rop horo us vesicl es. Fusiform (spindles ha ped) vesicles are characte rist ic for Ohapmanium (F ig. 8H). lWetchni kovella a nd t he other gene ra of R udimicro sp orea have lon g, almost cylind rica l vesicles (F ig. 4I-K ). The sp orop ho rous ves icles of P egmatheca re main attach ed to ea ch othe r, forming gro ups with 4 vcs icles or more (F ig. 8D-E). Sporop horo us vesicles of Trichoduboscqia (Fig. 4l\I) a n d .Mitoplistoph ora have long filamentous proj ections. The en velope is usu ally a thin uniform la yer, seldo m more t han 10 nm thick (F ig. 8S). Pleistoph ora and V avraia (Fig. 8T) have thick en velopes , > 30 nm, permeated by channels or divided into layered st ru ct ures. The en velope of B erwaldia appears two-layered in that the tubular inclusion s of the episporont al sp a ce form a closely packed layer internal to the envelope (Fig. 8R). In Aljoenia (Fig. 8 D ) and N elliemelba the extern al layer s of the ex osp or e partially or complete ly are given off a s a n extras pora l coat between the exospore a nd the envelop e of the spo rop horous vesicle. Inclusion s are common in the ca vity of the sporop ho rous vesicl e, t he e p i s p o r o nt a I spa c e, eit her appearing as granular or fibrou s secret ory products or as tubular projections from the dividing cells . Inclu sions are most numerous at the b eginning of spo rogo ny a nd di sappear suc cessi vely . Vesicles with mature spo res are sometimes devoid of in clu sions. In gene ra with uniform electron-de nse exospo res t ubules have uniform electron-dense wall s, in mi crosp orldia of Theloh aniidae a n d Am blyosporidae the tubules display the exos pore-layers (Fig. 8P). Normally the const ruct ion of the tubules is modified during maturation of the spores. The tubules of Tuzetia often form a characteri sti c net-work below the envelope (Fig. 8X). Tubular or fibrous inclusions a re not rev ealed by light mi croscopy. Amorphous or crystal-like agg regat es of secreto ry products a re revealed in st ained smears (F ig. 8 I -K) . Ambluoepora (F ig. 8L), Cryp fosporina a nd Parathelohania ha ve almost uniform inclusion s, Chap manium has in clu sion s where the cent re an d the p eriphery have d iffer ent electron den sities (Fi g. 8 J). The num ber of sp or es in t he sp or ophorou s vesicles is a widely used characte r for t he id en tificat ion of mi crosp oridian ge nera .

Fig. 5. A. E ject ed pol ar fila m en t of Nosema tra cta bile ; B. L on gi tudinall y sectio ned fr ee spore of Amblyospora callosa , w ith iso fila r p ola r fila m e nt; C. An iso filar p olar fila m ent of A m bly osp ora callosa, octospore ; B . D ev eloping po la r fila m ent o f Buxt ehudea scaniae wit h tu b ula r proj ect ions; E. Sp ore wa ll of Vairi morpha sp., fr ee spo re ; F . Spore wall of Episep tum inversum , with a com plex exos p or e ; C. Spo re wa ll of Systemos trem a alba, with an exospore of t.he b a si c co nstr uctio n for T he loh aniida e, a rrow- head ind ica t es t he d ouble-la y er ; H. Spo re wa ll o f A mblyosp ora callosa , octospore, with a thick fibrous la y er internal to the do uble -layer ; I. Spore wa ll of Cha pmanium dispersus, octospore, with t wo la y ers internal to t he d oubl e-l ayer. (Bars : A. 5 tun ; B, D . 0. 5 pm; C, E - 1. 100 nm).

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13

8. Histopathology Histopathology and tissue affinity may provide taxonomic characters, but are usually more useful at the species than at the genus level. If the microsporidium is a parasite of invertebrates, the tissue affinity should always be evaluated in sections. Making smears from various tissues during dissection is unreliable, due to the great risk of contamination. A prominently enlarged host cell where the microsporidia and the organelles of the cell have been closely integrated is called a x e nom a, a host-parasite reaction characteristic for many fish-parasitic microsporidia. The xenoma is well delimited from other host cells, and the development is not controlled by the host. Parasites and host cell organelles may be characteristically stratified in a xenoma. In the Glugeaxenoma (Fig. 6C), with a unique laminar wall, immature stages of the microsporidium are found close to the periphery, mature spores in the centre. In the xenoma of Spraguea, one spore type develops in the centre the other at the periphery. Microgemma produces a xenoma where the microsporidia are concentrated to a distinct zone inter-

Fig. 6. Modes of division and histopathology. A. Binary fission, the daughter cells remain attached like a chain, Nosema mesnili; B. Plasmotomy, Vavraia holocentropi; C. Schizogony with rosette-like plasmodia, Janacekia undinarum; D. Infected cells are dispersed among uninfected, the cell walls remain intact, Systenostrema candida; E. Infection in the gut wall, microsporidiafilled cells are released in the gut lumen which erroneously can give the impression of sporogony in SV's, Nosema apis; F. Cell walls of infected c~tls are destroyed leaving back a syncytium, Amblyospora undulata; G. The Glugea xenoma, with mature spores in the centre, immature stages at the periphery, and a thick complex laminar celt wall, Glugea anomala. (Bars: A, B-C, with a common bar, 10!"m; D-F, with a common bar, G. 50 !"m). Fig. 7. The polaroplast. A. The most common type with narrow, regularly arranged lamellae anteriorly, wider and more irregularly arranged lamellae or sacs posteriorly, Vavraia holocentropi; B. Inverted lamellar polaroplast, with wide lamellae anteriorly, narrow lamellae posteriorly, Episeptum inversum; C. Polaroplast with uniform sac-like compartments, Ghapmanium diepersus ; D. Chambered polaroplast, where the chambers' are successively more compressed in posterior direction, Bohuslavia asterins, (Bars: 100 nrn). Fig. 8. The sporophorous vesicle. A-C. Polyspofous vesicles, A-B. Vavraia holocentropi, C. Polyd'ispyrenia simulii; D-E. The adherent octosporous vesicles of Pegmatheca lamellata; F -C. The spore-like SV's of Telomyxa glugeiformis, where two spores are embedded in an amorphous secretory material; H-J. Ghapmanium dispersus, H. Uncompressed fusiform vesicles, 1. Compressed vesicle with prominent crystalline inclusions (arrow-head), J. Inclusions have a more electrondense central part; K-L. Amblyospora undulata, K. SV with big crystalline inclusions, L. Inclusions are made of a uniform material; M. SV's of Duboscqia sp. with 16 spores; N. The narrow SV's of Gylindrosporafasciculata collect the rod,shaped spores to closely packed bundles; 0. SV's of Hyalinocysta expilatoria with 2, 4 and 8 spores in three distinct size classes; P. Tubular inclusions of Systenostrema alba, displaying the layers of the exospore; Q-R. Berwaldia singularis, Q. Spores are coupled, each one enclosed in a folded and spot-wise attached vesicle of its own, R. The envelope is two-layered with an internal layer of closely arranged tubules; S. The uniform thin envelope of Systenostrema corethrae; T. The thick folded envelope of Vavraia holocentropi, which is divided by a central band of translucent material (white arrow-head); U. The external layers of the exospore of Alfvenia nuda are released as an extrasporal coat (arrow-head); V-X. Tuzetia lipotropha; V. Each spore is enclosed in a vesicle of its own, which can be seen in fresh preparations (arrow-heads); X. The tubular inclusions form a reticulum below the envelope of the SV. (Bars: A, M-N. 5!"m; B-F, H-I, K, 0, V. 10 !"m; G, L, Q. l!"m; J, S, X. 0.5!"m; P, T-U. 100 nm; R 50 nm).

14

J .1. R .

LARSSON

7

Identification of sIicrosporidian Genera

8

15

16

J. 1. R.

LARSSON

nally to the aggregated mitochondria of the host cell. Xenomas of vertebrates are treated in detail in the monograph by CANNING and LOM (1986), and invertebrate xeno-parasitic associations as discussed by WEISER (1976). In invertebrates, and sometimes also in vertebrates, the cells of infected organs are hypertrophied. The increase in volume is partly a distension caused by the reproducing parasites, partly an answer to the demands of the parasite for an increased supply of nutriments and energy. All cells of an organ, or of a part of an organ, may be hypertrophied and microsporidia-filled, or the infected cells are distributed in a characteristic way in the organ, at least in initial stages of infection (Fig. 6D). Some microsporidia destroy the cell walls of infected organs, creating syncytia where the developmental stages of the microsporidium are floating among organelles and nuclei of the destroyed host cells (Fig. 6F). Spores enclosed by the cell membrane of the host cells might erroneously suggest the presence of sporophorous vesicles. This is frequently seen in infections of the gut epithelium, where microsporidia-filled cells are shed into the gut lumen (Fig. 6E). 9. Vertebrate or invertebrate host In a few positions in the key it has been necessary to use development in vertebrates or invertebrates as distinguishing characters. Little is known about the distribution of microsporidia in different animal groups, and therefore host characters should be avoided as far as possible. However, we have no clear evidence of a genus appearing both in vertebrate and invertebrate hosts. Of the vertebrate-parasitic genera Encephalitozoon, Glugea and Pleistophora have also been used for microsporidia of invertebrates. SPRAGUE (1977), in the annotated list of species of microsporidia, did not acknowledge any Glugea or Encephalitozoon species from invertebrates. A few years later a parasite of springtails was named Encephalitozoon jtaoeecens, provisionally classified in the genus by the monokaryotic spores alone (WEISER and PURRINI 1980). The microsporidium is insufficiently known and the description does not tell us to what genus the species belongs. After the re-examination of the type species of Pleisiophora the diagnosis for the genus was emended (CANNING and NICHOLAS 1980). No microsporidium of invertebrates has been shown to belong in the genus. As the genus Pleistophora has not been revised a number of dubious or clearly wrongly classified species remain there, and new invertebrate-parasitic species are still described in the genus, although they do not agree with the distinctive characters. The problem with the old Pleistophora species is discussed separately. Numerous microsporidia of vertebrates have been classified in invertebrate-parasitic genera, most of them in Nosema. Some have found new positions in the classification, others are temporarily treated as Microsporidium species. In the recent monograph on the microsporidia of vertebrates by CANNING and LOM (1986) only five vertebrate-parasitic microsporidia remain in invertebrate-parasitic genera: Thelohania apodemi, T. baueri, T. ovicola, Nosema connori and Mrazekia piscicola, For all of them the classification is an unsolved problem. The variable number of spores produced by T. baueri and T. ovicola speaks directly against a classification in Thelohania. SPRAGUE (1977) was of the opinion that N. connori probably must be transferred to another genus. Mrazekia piscila has the spore shape characteristic for the invertebrate-parasitic genus Jirovecia. The parasite was found in the gastric caeca of Gadus merlangus (GEJP:EDE 1924). The host tissue was badly preserved and it is not clear that the organism was a parasite of fish tissue. It is probably an invertebrate parasite ingested by the food and found in the lumen of the caeca.

Identification of Microsporidian Genera

17

10. Abbreviations used in the key, table and figures AA

DK EM EN ES

EX LM

PF

PM PP

PV

anchoring apparatus diplokaryon electron microscopy endospore envelope of the sporophorous vesicle exospore light microscopy polar filament; abbreviations used in column 10: a anisofilar 1 isofilar m l - manubrium with swollen posterior end m2 - manubrium-like straight, wide anterior part r reduced t external tubules plasma membrane (plasmalemma) polaroplast; abbreviations used III column 11: c chambered inverted lamellar lamellar r reduced u uniform posterior vacuole

SV

sporophorous vesicle; abbreviations used in column 7: associated A C cylindrical F fusiform I individual o oval P projections S spherical T triangular U unique Modes of division, column 8: B binary fission P plastotomy R schizogony by rosette-like budding R2 - rosette-like budding followed by binary fission Spore, abbreviations used in column 9: barrel-shaped b ep elongate pyriform h horse-shoe-shaped or spiralized o oval p pyriform r - rod-shaped s spherical u unique

Identification key Abbreviations are explained on p. 17 1. All spores have the same shape and are all grouped (enclosed in SV's) or all ungrouped; all are of uniform size (continuous variation in a slight size range) or of two or three distinct size classes (micro- and macrospores, Figs. 3 Dl, 8 0) . . . . . . . . . . . . . . 2 Two types of spores present, which differ not only in size but also in shape and/or arrangement, with one spore type occurring in groups (in SV's) the other type being ungrouped (not vesicle-bound spores or spores enclosed in individual SV's) (Figs. 2K, 3 B). . . . . . 77 2. Spores with long filamentous prolongations (Figs. 3 R, 4 A) or with long tubular projections (Fig. 4B-C), visible with LM 3 Spores different. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3. Spores with one tail-like prolongation, diplokaryotic . . . . . . . . . . . . . 4 Spores with a number of tubular or filamentous projections, mono- or diplokaryotic 5 4. Spores oval (Fig. 4 A) Caudoepora Spores rod-shaped (Fig. 3R)

. . . . . . . . . . . ..

Jirovecia

5. Spores oval, monokaryotic, with 4-5 long filamentous projections (Fig. 4B); III SV's with 8 spores . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . . I nodosporus Spores oval, diplokaryotic, with a posterior tuft and an equatorial girdle of tubules (Fig. 4 C); spores not grouped H irsutosporos 2

Arch. Protistenkd., Bd. 136

18

J. I. R.

LARSSON

6. Spores in SV's with lung filamentous projections( Fig. 4L-M) 7 SV's without projections or SV's absent. . . . . . . . . . 9 7. SV's long, fusiform, with thread-like ends (Fig. 4L); spores spherical · . . . . . . . . . . . . . . . . . . . . . .. ..... Amphiacantha SV's rounded or triangular, usually with more than 2 filamentous projections; spores pyriform '.' . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 8. SV's spherical with (2--)4(-6) long filamentous projections, the number correlated to the number of spores in the vesicles (Fig. 4M); SV's usually with 16 and 32 spores · . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 'I'richoduboscqia SV's triangular or fusiform with 2-3 filamentous projections; SV's with 8-48 spores · . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mitoplistophora 9. SV's long, cylindrical, usually with more than 8 spores (Fig. 4I-K); PF manubrium with a gland like terminal swelling, PP reduced or absent. 10 SV's different or absent 12 10. Spores long, rod-shaped, in SV's with 22 spores Desportesia Spores spherical . 11 II. SV's less than 10 times as long as wide (Fig. 4 K) M etchnikovella BV's more than 10 times as long as wide (Fig. 41) · . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Amphiamblys 12. All spores are coupled and embedded in a uniform substance to an oval, spore-like body with two spores (Figs. 3Y, 8F-G); spores oval, monokaryotic Telomyxa Spores not associated in this way . • . . . . . . . . . . . . . . . 13 13. Spores oval, diplokaryotic, with a girdle around the widest part of the spore; the presence of an extrasporal coat makes the spore bell-shaped (Fig. 4G); in SV's with 2 or rarely 4 spores Campanuloepora Spores of different shape . . . . . . . . . . . . . . . . . . 14 14. Spores calabash- or flask-shaped (Figs. 2N-O, 31), monokaryotic Couqourdella 15 Spores of different shape . . . . . . . . . . . . . . . . . . Spore wall with a small number of elevated ridges, visible with LM, the posterior end 16 15. projecting in a collar- or nail-like fashion (Fig. 4 D-E). . . . . . . . . . . . . . 17 Spore wall smooth or with sculpture only visible with EM . . . . . . . . . . . . 16. Posterior end of the spore extending like a collar (Fig. 4 D), monokaryotic, in polysporous groups in SV's Weiscria Posterior end with a nail-like prolongation (Fig. 4 E), diplokaryotic, SV's absent · . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Golbergia 17. Groups with 8 and 16 elongate pyriform spores of uniform size (Figs. 3 F) occur together Bohuslaoio 18 Spores ungrouped or differently grouped . . . . . . . . . . . . . . . . . . spores in SV's with 8 spores (Fig. 3 C), or octosporous SV's with microspores occur All 18. 19 together with a small number of SV's with 2 and 4 macrospores (Fig. 80). . . . . 35 Spores ungrouped or differently grouped . . . . . . . . . . . . . . . . . . 19. SV's stick to each other, forming groups of 4 vesicles or more (Fig. 8 D-E); spores oval, isofilar Pegmatheca · . 20 SV's free from each other. • . . . . . . . . . . . . . . . . . . . 20. Spores oval monokaryotic, with a posterior collar-like prolongation, in stained smears visible as an unstained area (Fig. 4F); exospore with an internal lamellar layer, PF anisofilar; SV's with granular, uniform inclusions Parathelohania · . . . . . . 21 Spores different; SV's with or without inclusions .

19

Identification of :\ficrosporidian Ge n er a

22 28

2 1. Spores rod -shaped . . . . . . . . . . . . . . . . . . . . . . . . . . Spores s phe rical, pyriform or b arrel-shaped . . . . . . . . . . . . . . . 22 . Spores diplokaryotic, sh or t, st r a ig ht or lightly b ent rods; PF isofilar (Fig. 3 T)

Spores monokaryotic . . . . . . . . . . . . . . . . . . . . . . . 23 . Spores horse-shoe-shaped, s -s h a p ed or spir alized (Figs. 2L, 3 AI ); 1'F isofilar

Octosporea 23

T oxoglugea Spor es straight or ligh t ly bent . . . . . . . . . . . . . . . . . . . . 24 . Spores sle nde r , lig h tly b ent, rods, at lea st 10 times as long as wide, in clo sely packed bundles (Fig. 8 N, 3 K); sp ores with thin s por o-wull a nd a str ongly r educed isofilar 1'F, approximately 1/4 of the spore length

· . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

24

Oyl indrosp ora

Spores stout rods, 3- 8 t imes a s long as wide (Fig. 2M) , u su ally irregul arly arranged in the SY's, s por es with thick wall, PF at lea st 2/3of the spore length 25 . 1'F longer than the s pore a nd coiled . . . . . . . . . . . . PF no t longer than the sp ore, uncoiled . . . . . . . • . . . 26. Anterior p art of the 1'F wid e, s t ra igh t a nd manubrium-like, the po sterior narrow parrt coiled

25 26 27

Orm ieresia 1'F anisofilar, both wide and narr ow parts coiled (Figs. 2 Q. 3 W)

· . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27. Exospore with longitudinal sc ulp t u re , vi sible with EM; PF a p pr ox im a tely length

2/3 of

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

R esiomeri a the spo re

Striatospo ra

Exospore wi thout sc ul p t ure ; PF approxim ately of the same length a s the s p ore (Figs. 2:\1, 31')

H elmichia 28 . Spores s p he rical, produced b y a cy lind r ical pl a smodium P ilosporella Spores b arrel -shaped or p yriform . . . . . . . . . 29 29. Spores barrel -shaped (Figs. 21, 3 C); exospore with a thick, la m ell ar internal la y er (Fig. 5H) , 1'F a n isofila r ; Sy's r ounded , init iall y with prom in e nt granular, uniform, inclusion s (F ig .8K-I.)

· . . . . . . . . .

. . . . . . . . . . . .

Amblyospor a

Spores pyriform (Fig. 2E-F) , exoflpore w it h out lamell ar internal la y er, SY's with or wit h out inclusions . . . . . . . . . . . . . . . . . . . . . 30. S Y's with gran ula r i nclus ions (Fig . 8 I - J); exosp ore o f t h e basi c Thelohaniidae-t ype (Fig. 5G) or with two intern al la y ers (Fig. 5) . . . . . . . . . . . . . . . . . . . . SY's wit h tubular (Fig. 8 P) or fib r ill a r incl usi on s or d evoid or in clusions ; ex osp or e of the 'I'hcloha.niid a e-t.ype (Fig. 5 G ) . . . . . . . . . . . . . . . . . . . . . . . . . . 31. SY's ov al; in fr esh s mears wi th amber-coloured big g ranular inclusi ons, which nearly obscure t he s pores ; e xos po re of t he Thelohaniidae-type; P F isofilar

· . . . . . . . . . . . . . . . . . . . . . . . . . . . .

30 31 32

Crupto sporina

SY's s pi nd le -sh a p ed (Fig. 8 H), with two-layer ed granular in clusio ns (F ig. 8 I-J) ; exospore with two layers inter n al to the Theloh a niid a e-exosp or e (Fig. 51); 1'F a n is ofila r (F igs. 2E- F, 3 H )

Ohapman ium 32 . PF isofila r (Fig. 2 Z) PF anisof ilar . . . . . . . . . . . . . . . . . . . . 33 . SY's with m ature s p ores h ave tubular inclusions (Fig. 3 X)

Thelohania 33 Systenostrema

SY's with m a ture sp ores d evoid of in clusion s . . . . . . . . . . . . 34. Sporobl asts not form ed by ro sette-like budding ; envelope of SY's not visible in stained smears

34

Agmasoma 2"

20

J.1. R .

LARSSON

S porob lasts usually form ed b y ro sett e -like budding ; en velope of SV's vi sible in st a in ed s mears (Fig. 80) H y alin ocysta 35 . Sp ores in groups with 4 m onokary oti c spo re s (Fig. 2 C) 36 S pores ungrouped or differently grouped; mono- or d iplokary ot ic 37 36. S pores lightly pyrifo rm (Figs. 2 C-- D, 3 ~I); e x os p ore thick, co m ple x (Fig. 5 F); PF a nis ofilar ; PP in v er t ed la m ella r (Fig. 7 B) · . . . . . . . . . . . . . . . . . . . . . . . . . . . Epis eptu m Spo re s elongat e p yriform (F ig . 30); exos po r e uniform or strat ified , PF isofilar; P P lam ell ar or cham be re d Gurlego. and Pyroth eca 37 . All s p ores in SV's with 16 s po r es (Fig. 8 ~1 )

· . . . . • . . . . . . . . . . . . 38. 39 .

40.

41.

42 .

43.

Dubo scqia

Spo res ungrouped or differently grouped 38 S pores sph er ica l . . . . . . . . . . . 39 Spor es of different shapes . . . . . . 44 Spores in multisp orous SV's; spores m ono - or di plokaryotic 40 S V's absent; sp or es mo n ok a r y ot ic . . . . . . . . . . . 42 All sp ore s en closed in elongate ov al SV's (Fig. 4K); spores monokaryotic ; PF manubri u m with gland -lik e p ost er ior sw elling • . . . . . . . . . . . . . . . . . . . . . . . . . • . • M etchn i kovella S V's sp he r ica l ; PF not manubrium- like, co iled. . . . . . . . . . . . . . 41 All sp ores in SV's with wall s a p pear ing a s a mosaic of polygonal pl a t es; no a ssociation wi th the nucleus of the ho st cell ; m ost s p ores monokaryotic; PF is ofil ar H ess ea Two kinds of SV's , with thin e nve lope a nd with thick la m ella r wall; d evelopment in cl ose a sso ciation with the nucleu s of t he h ost cell ; spores monokary otic; PF with a hon ey comb-like su r face la y er Ohytridiopsis In fected cell grows to a big xeno m a ; PF isofilar without su rface sp ecia lisat io ns Burkea · . . . . . . . . . . S poro go ny in vacuoles, n o x eno ma-for mat ion ; PF w it h tubular or honey comb-like sur fac e la y er . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 D ev el opment in close assoc iatio n wi th the nucleus of the host cell; PF w it h a honey comblike s ur face la yer · . . . . . . . . . _ . . . . . . . . . . . . . _ . . . . . . . . . Steinhausi a N o associa t io n with the nucleus o f the h ost cell ; P F with tubular s urfa ce proj ections (Figs. 5 D, 3 G)

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Buxt ebudea

44 . III one to sev er al mm wide xe no mas of unicellular nature or in wh ite , elo nga te multicellular le sions ; in poik ilothermic v ertebrates (fish, amp hibia, r eptiles) . . . . . . . . . . . 45 In more or less hyper t r ophied a nd d estroyed t iss u es , exceptionally x enomas ; in v a ri ou s invertebrates or verteb r a t es (m ammal s , birds, r arely r ept iles). . . . . . . . . . . . . 51 45 . Sp oro g ony in thick-walled SV's ; with micro - a n d macrospor es ; in x en ornas or multicellu la r lesions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 S V's thin-walled or a bse nt ; sp ores usually of uniform size ; in x enomas . . . . . . . . . 4 7 46. In great x enornas ; most SV's with 8 m acrospores, a smaller number with 16 microspores , s po re s pyriform; SV's with uniform env elope · . . . . . . . . . . . . . . . . . . . . . . . _ . . . . . . . H eterosporis In pluricellular, whitish lesions; mo st S V's wit h numerous mi crospores, a s malle r number with ~ 8 m a crospores, s pores ova l-l ightly p yriform; envelope of SV's initially p ermeated b y ch a n ne ls · . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pleistophora 47. S po res ov al, d iplokaryo tic, x en oma with projections interd igitating with the host tissue · . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. I chthyosporidium

Identifi cation of Mio rosporidian Genera

21

All stages monokar yotic, xenoma with mi crovill us- li ke projections or with smooth or fibrill a r wa ll . . . . . . . . . . . . _ _ . . . . . . . . . . • . . . . . . . . 48 48 . X enoma s with t hick la m i na t ed wa ll (Fig. 6G) ; immature stages lie peripher ally and the ova l s p or es li e centrally in t he x enom a; v eg etative reprod uc tion b y fr agmentation o f c y li nd ri cal plasmodia ; in po ly sporous BV' s (Fig. 3 N) Gluqeo X e n o m a s d ifferent . . . . . . . . . . . . . . . . . . . . . . . . . . 49 49 . X enornas with fi brous cover; d ev elopmental st ages m ixed in t he x enoma; v eg etative r eproduction b y fr a g m e nt a t io n of cy lin d r ical plasmodia ; sp ores oval in p ol y sporous BV's; m a cros pores may be present Loma X enomas with microvillus-like proj ections, BV 's absent . . . . . . . _ . . . 50 50. l\li crosporidia in t he ce ntre of t h e x enoma, mitocho ndria concentcated to a band b elo w t he mi crovill us-like la y er ; s p ores oval; polysporobla st.ic

· . . . . . . . . . . • . . . . .

5 1. 5 2.

53 .

54 .

55 . 56.

57 .

58.

50 . 60 .

. . . . . . .

M icroqemma

Xen oma not st r a t ified , mi cro sporid ia mixed in t he entire x enom a; s p ores oval-li g htly pyriform ; tetras POl'O bl a stic T etra m i cra Spores in po lys p or o us BV' s 52 Spores associa t ed pair-wise in SV 's or ungr o u p ed (devoid of SV's or in individ u al BV's) . . 55 Spores ligth tly rod-shaped, in SV 's with 4-60 spores; all stages with iso lated nuclei · . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cystospo rogen es S pores oval; m o n o- or d iploka r y o t ic . . . . . . . . . . . . . . • . . . . . . 53 S V's with t h ick e nvelope, divid ed into two la y er s by a translucent s p ace (Fig . 8 A- B , T) , formed d uri ng merogony; most SV's with n umerous m icrospores, a s mall number of BV' s wi th a reduced num b er of macr ospores (Fig. 3 D I); monokaryotic, PF a n isofila r • . _ _ _ .. . . . V avraia BV's with thin envelope, p roduced during s p or og o n y (Fig. 8 S) ; a ll s pores of uniform s ize ; PF iso fila r . . . . . . . . . 54 All stages diplo kar yotic Pseudopleis tophora. Presp or a l stages diplokaryot ic, s po re m onokaryotic (Figs . 3 V , 8 C) P olydi sp yr en ia Sp ore s coupled, in SV's. . . . . . . . . 56 Sp or es ungrouped, fr ee or in ind iv idua l SV 's 59 S pores diplokaryotic , pyriform I ssi a Spores monokaryotic, ova l or lig h tl y pyriform . . _ . . _ _ . . . . . . _ . 57 P r esporal s tages d iplokaryotic; BV's wide, s p her ica l, e nvelo pe no t a t t ached to t he exospo re . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N eop erezia All st a ge s mono k a ryotic . . . . . . . . . . . . . . . . . . . . . . 58 Spor es elongat e oval with pointed anterior en d , conn ect ed by a ce me n t ing su bs tance to a figure resemb ling the foo t -p r in t of an even-toed ungula t e (Fig. 4 H) ; SV 's wide, oval , e ncl osi ng o ne to four doublet s o f spores ; PF anisofilar · • . . • . . • . • . . . . . . . . . . . . . . . . . . . . . . .. "Norl euinea Spores oval, connected b y patches of ce m e n t ing material; SV 's with two -layered e n v elope, w h ich is fo lded and a ttached sp o t -w ide to the exos p ore (F ig . 8 Q-R) ; PF isof'ila r (Fig. 3 E) · . . . . . . . . Berwaldia S poro s r od·sh a p e:i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 S po res di fferent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1 Spores s m a ll , less t ha n 3'1m, monok aryot.ic, with a s h or t , st ra ig h t isofil ar PF; PP r ed uced , la t er al to the P F

· . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

B acul ea

S po r es big. 10-40 11m, diplokary o ti c; PF with wide manubrium· li k e ant erior p a r t a nd p osterior narrow coils; PP la m ell a r , s ur r o u nd ing the anterior part of t h e PF (Figs. 2 P ,3D) · . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B acill i diu m

22

J. 1. R.

LARSSON

61. Parasites of vertebrates . . . . . . . . . . . . . . . . . . . 62 Parasites of invertebrates. . . . . . . . . . . . . . . . . . . 63 62. All stages with isolated nuclei, disporoblastic, spores oval (Fig. 3L); In mammals, birds or rarely reptiles · . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Encephalitozoon Merogonial stages diplokaryotic; probably octosporoblastic; spore probably oval; in mammals Enterocytozoon 63. Spores oval, formed by fragmentation of cylindrical plasmodia 64 Sporogony different . . . . . . . . . . . . . . . . . . 65 64. Presporal stages diplokaryotic, spore monokaryotic, polysporoblastic Perezia All stages with isolated nuclei, 2-8 sporoblasts · . . . . . . . . . . . . . . . . . . . . . . . . . . . Orthosoma 65. Spores elongate, pyriform, in individual SV's produced by the sporoblasts, PP chambered . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 Spores oval-lightly pyriform, with or without SV's; SV's, if present, formed by the sporont; PP usually lamellar. . . . . . . . . . . . . . . . . . . . . . . . 67 66. Tetrasporoblastic; in microcrustaceans Amblyospora Polysporoblastic, spores formed by rosette-like budding; in mosquito larvae · . . . . . . . . . . . . . . . . . . . . . Culicospora 67. Macrosporesregularlypresent;SV'sabsent 68 Macrospores rare or absent; SV's present or absent 69 68. Spores oval-lightly pyriform; macros pores diplokaryotic, probably disporoblastic; microspores monokaryotic, 16-sporoblastic · . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Semenovia Spores pyriform, macrospores and microspores formed by rosette-like budding; both spore types monokaryotic, 8-12-sporoblastic Pleistosporidium 70 Spores in individual SV's(Fig. 8 V-X) . 73 . 69. SV's absent 71 70. Spores oval (Fig. 2 A-B), merogonial stages diplokaryotic, PF isofilar 72 Spores lightly pyriform (Fig. 8 V), all stages with isolated nuclei, PF iso- or anisofilar 71. Exospore uniform, thin, no extrasporal coat; SV's with wide tubular inclusions (Fig. 3 Q) · . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Janacekia Exospore initially layered, the external layers are partially released as an extrasporal coat (Fig. 8 U); SV's without inclusions(Figs. 2 A-B, 3A) · . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Alfvenia 72. SV's with narrow tubules, often forming a reticulum below the envelope (Fig. 8X); no extrasporal coat; PF isofilar (Figs. 3 Bl, 8 V) Tuzetia · . SV's devoid of tubules, extrasporal coat formed by exospore material; PF anisofilar N elliemelba 74 73. Spores diplokaryotic. . . . . . . . . . 76 Spores monokaryotic. . . . . . . . . .

74. Exospore covered with fine microtubules or fibrils, only visible with EM; polysporoblastic; PF isofilar . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ameson 75 Exospore smooth; disporoblastic; PF iso- or anisofilar. . . . . . . . . . . . . . Spores big, of uniform size, elongate oval-lightly pyriform; PF iso- or almost anisofilar; in oenocytes close to the ovaries of adult female mosquitoes · . • • . . . . . . . . .. Amblyospora, Culicospora, Parathelohania and Pilosporella 75. Spores small (macrospores may be present), oval; PF isofilar; in various hosts and tissues Figs. 3 S, 5 A). Nosema · .

Identification of Microsporidian Genera

23

76. Spores oval, polysporoblastic, formed by rosette-like budding; PF isofilar

Nosemoides Spores oval, disparablastic, PF isofilar · . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Unikaryon 77. Parasites of fish; in a stratified xenoma with oval monokaryotic spores (exospore with fringe-like surface) in the periphery and oval-cylindrical, diplokaryotic spores (exospore smooth) in the centre

Spraquea. Parasites of invertebrates. . . . . . . . . . . . . . . . . . . . . . 78 78. The greatest spores in SV's with four spores, octosporoblastic small spores free, both sporogonies equally frequent; monokaryotic; PF anisofilar Stempellia The great spores ungrouped; small spores grouped or ungrouped 79 79. Monokaryotic small spores in SV's with two spores; diplokaryotic great spores isolated; both spore types oval Evlachovaia Spores ungrouped or differently grouped . . . . . . . . . . . . . . . . 80 80. One sporogony sequence yields great ungrouped spores, the other sequence produces smaller spores in octosporous SV's (or sometimes also with a small number of SV's with 2 or 4 macrospores) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 Both spore types are ungrouped, or small spores occur in SV's with a reduced irregular number of mature spores, less than 8 . . . . . . . . . . . . . . . . . . . . . . . 83 81. The two spore types occur in different tissues; free great spores are elongate oval, diplokaryotic and disporoblastic; small spores are oval, monokaryotic, in SV's with 8 spores; PF of both spore types isof'ilar, long Burenella The two spore types occur together. . . . . . . . . . . . . . . . . . . . 82 82. Octospores barrel-shaped (Fig. 21), monokaryotic, PF anisofilar, exospore with a lamellar layer internal to the Thelohaniidae-exospore (Fig. 5 H); the other spore type elongate oval, diplokaryotic, disporoblastic, with isofilar or sligthly anifofilar PF, exospore uniform, thin (Figs. 2K, 3B, 5B) · . . . . . . . . . . . . . " Amblyospora Octospores oval, monokaryotic, with Thelohaniidae-exospore; free spores elongate oval, diplokaryotic, disporoblastic, with thin uniform exospore (Fig. 5E); both types with isofilar PF (Fig. 301) · . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Vairimorpha 83. One sequence yields elongate pyriform, big, ungrouped, diplokaryotic spores with chambered polaroplasts in individual SV's; the other sequence yields SV's with less than 8 fully developed monokaryotic, barrel-shaped spores together with a small number of rudimentary spores · . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Culicosporella Both spore types devoid of SV's; diplokaryotic spores have thick lamellar exospore, anisofilar PF and lamellar PP; monokaryotic spores have thin uniform exospore, isofilar PF and chambered PP Hazardia

Comments on some microsporidian genera Auraspora WEISER and PURRINI, 1980 The genus was reported to be dimorphic, but the two sporogonies could not be connected to a life cycle. Presporal stages were not described. One spore type (the normal series) was described as pyriform, thin-walled and diplokaryotic. The other sporogony (the anomalous series) yielded thick-walled monokaryotic spores in sporophorous vesicles. These spores had a foamy episporontal secretion, radiating from the

Table 1. Microsporidian genera in alphabetical order.

Culicosporella

Oampanulospora Oaudospora Ohapmanium Ohytridiopsis Oougourdella Oryptosporina Oulicospora

Burkea Buxtehsulea

Bacillidium Baculea Berwaldia Bohuslaoia Burenella

Ameson Amphiacantha Amphiamblys Auraspora

2 2

I)

2)

2?

2'!

2 2

2)

1

..

.)

21 2 1 I 1 1 I

21

1)

'?

2 I I I 1 2 I 1

I 1 I 2 1 2 1 I 2 1

3

2 1 1 2 1 21 1 1 2 2 i r I? 2 '!

~

't

2? ?

't

2? I? 1 2

't

2 2 ? 1 :! 1

I) 2)

I) 2)

1) 2) 3)

2'!

2'! 2 2 2 1 't 2'? 1 '! 2?

Agmasoma Alfvenia Amblyospora 2 :! 2 1 2 1 1 21 1

2

1

Genus

1

+

2'!

n 4-16 8 n 2 < 8

+

+

+

-I-

+ + +

+

2 (4) 8 8

-

-

+ + +

--

-

+

-

+

-I-

-

I

<

8

8 n 4-16 8 1

2 (4)

S I

-

0 I

0

F S

0

-

IA S S -

I 8/16 8

-

-

-

S

C -

«'

I

S I S

7

-

n ?

J1

-

8 I 8

+ + +

-

6

5

n

J1

2 2/4 2 8/16 8 2

't

41

J1

J1

8 n 8 2 4 n

4

13 R R l' R R1 It 13 R? B'!

1'? l'

13

13 13 13 R R

13 1'1 1'1 1 1

H,

1'1 R R2 13

8

b ep

0

P ep

II

P s

011

011

s s

0

0

ep

0

r r

P P

s s

0

ep

0

b

0

P

!J

a

'!

? i a it i i 1

i i i i i it

rr

In2

i 1111 III I i 1

1

a i a

10

c

't

c

I'!

c

?

II

1 1

I Ir I c I? I? Ie 1r

1 I 1

't

c I

? I I

II

WEISEH, 1977

ISSI et al., 1983 WEISER, 1946 HAZARD & OLDACRE, 1975 SCHNEIDER, 1884 HESSE, 1935 HAZARD & OLDACRE, 1975 \VEISEH, 1977

SPRAGUE, 1977 LARSSON, 1980b

,JANDA, 1928 LOUBES & AKABARIEH, 1978 LARSSON, 1981 b LARSSON, 1985b JOUVENAZ & HAZARD, 1978

SPRAGUE, 1977 CAULLERY & MESNIL, 1914 CAULLERY & MESNIL, 1914 WEISER & PURRINI, 1980

HAZARD & OLDACRE, 1975 LARSSON, 1983c HAZARD & OLDACKE, 1975

Authors, year

The columns denote: 1. Number of nuclei in the meront; 2. Number of nuclei in the sporont; 3. Number of nuclei in the spore; 4. Number of sporoblasts; 5. Presence (+) or absence (-) of sporophorous vesicle; 6. Number of spores in the sporophorous vesicle; 7. Shape of the sporophorous vesicle 8. Mode of division in the sporogony; 9. Spore shape; 10. Construction of the polar filament; II. Construction of the polaroplast, In columns 1-3 indicate: 1 monokaryotic, 2 diplokaryotic condition. In columns 4 and 6 indicates: n an irregular number. ? means that the character is unknown or the construction is postulated. Abbreviations used in columns 7-11 are explained in the list of abbreviations on p 17.

Z

0

00 00

~

i»

t-<

~

?J

~

~

t-:l

2

I I 'I

'/

I

I

'/

Lnna

M etclui ikroella M icrogem m a At it apl ist ophora

"

'2 ?

:2

"

:1 ~

"

" 'J

,I

"

"

'2 l '2

"

:)

,)

:2 y

-"

?

.,

I

:)

,)

.)

,)

I

I 21

t 1

2)

I)

l

~ O (

I

:!?

Lanai osp rra

Janacelsia J irooecia

Lssia

1cht hy osllOl"id i w n InJd?8p J1'l18

Hyal i n?cY 8/~1

H elm ich ia H essea H cte rosp oris H irsut lap 11')8 H ol Jbisp 11'(1

Hazardia

Gluqea GJlb erg ia Gurley a

~

2)

!

" "

I

1

1)

1

E n cephalit )ZJon Enteracyt JZ) on

1

Episept um

1

Du'r rscqia

I

Evlach ova ia

'/

D esp rrt esia

1

2t

1

OY8t )8]JH':J geI1-e8

'2

I :!

'2

Cylindr:Jap om

I 1 ?

I

y

"

'2

:)

'2 1

I I

ir 2

u:

I

:~

I

I

:)

I

n

II

II

II 'f

"

2

11

'2

8

:;

8

,)

,)

8 :2 S,'l G

t

II

·i -Ili ,I

)l

I!

,)

I I

2 81 4 2

IG

v-

01. )

11

8

I 1

I

I

I

I

:-;

.."-

f!

+

n

-

11

+ -

n

?

-

-I-

?

-

+

~

I

.

:2

._

I-

,)

--

8! ro

n '!

S

,- -

--

--I

--

n

C 1'1'

0 '/

?

-

I

0

,

.S ',

. --

". )

t

._-

S :J H

()

_..-

-.-

s

:-; ,- -

-

-

f;

". )

2

4

!-

_

-t-

iI-1-

--

t-

-

+ + -+.

-

-

-

- ,.

-

H

C

S

C

1(j

:J ~

11

8

~ f-

+ +

+

?

l'

RP

H 'I'

H. B

B

It '/

il

l'\" "

B

n

py

n

It

R t

R It H

'/

B

R

B R1

t

I'

P

P

P

0

s

0

01'

ru

0

p

011

0

I'

0 1'

ou

P

H

r

P

I'

P

1I

0

0

0

p

'/

0

0

l'

r

r

?

i

ml

i

'/

I H2

i

I ?

'/

I I

I I

'/

I

j '/

l?

I

I

I I

t

I I

('

t 11

I

t

~

i

1'/

I

t

~

1'/

I

i

:t

t

i.: i i i

It

i

i 'l

?

i

'/

~

j? a

i

'/

lid

t

it-

1977

CAULLERY & MESNII., 18!J7 HAI,PHS & MATTHEWS, 1986 CODREANU, 19 6 6

V ORONIN, 198 6 MOHIUSON & Sl'RAGU1';, 1!J8l

L xnsso», 1983 c ' VEI SER, 1977

C,\ ULLEHY & MESNlI " InOli OVI~H STREE T & WE1IJNI·; Jt, 1!J74 'VmsEH, 1977

LAH';SON, 1!J82 OR,IUERES & SPRAGUg, Ion S CHUBERT, 19 69 BATSON, 198:l V OHONIN, 198 6 H AZARD & OLDACHE, 197 5

'V~;I SER ,

'fHELOIIAN , 1891 W m sER,1 977 D OFLEI N, 189 8

L ~: vADrrI et a]" 1923 DE SPORTES et a]" 19 85 LARSSON, 1986 a V OHONIN & ISSI, 1986 in I s s I (1986)

I ss! a n d VORON1N, 198 6 iII I SSI (1986) PEREZ, 190 8

I SS1 & VORON1N, 1986 in I SS1 ( 198 6 ) CANNING et a]" 198 5

~,

t~

Ot

~

".,

:: '"

0

::

~

e:

::l,

"0 0

'"

0

s.,

!".;ll .....

0

...,

0' ::

e-

il'

C>

::l

::

'"

~

2 1 2 2 2 2 2 2 1 ? 2 2 ? 2

2 1

2 2 2 2 2 2 1 ?

2 2 ?

2

Ormieresia Orthosoma

Polydispyrenia Pseudopleist »phora Pyrotheca

Resiomeria

1) 2)

2? 1 2 1 ? ?

2? 1 2 ? ? ?

2) 1) 2)

Spraguea

Steinhausia Stempellia

?

?

1)

1) 2)

Semenovaia

Pleistophora Pleistoeporidium

Pegmatheca Perezia Pilosporella

1) 2)

2 1

2? 1

Octosporea Oligosporidium

Parathelohania

1 2 1 2 1 1

I? 2 1 2 1 1

N elliemelba Neoperezia Norlevinea Nosema Nosemoidee

1) 2)

2

1

Genus

Table I, continued

2 1 2 1 1 1

I

1

I 2 I'!

1 2 1 1 1 2 1 1

1 1

2 1

1 1 1 2 1 1

3

? n 2 n 4 8

16

8

8 n 4

8 2 8 n 8 2 n n

8 2-8

8 2

n 2 2/4 2 n n

4

8

-

-

+-

-

-

S

? ? B p R R

4 -

-

0

0

or s

0

P

P

r

P S

?

ep

R

-

0

0

P

0

R

P P P

S S 0

S

s 0

P B

0

P 0

ou

0

r

r op

r

0

0

op

0

P

9

R2 B R p

R? p

R B

? B B B R ?

8

-

8

8n n 4

-

-

0

-

SA

8 8 n

-

s

8

-

C

-

S

-

-

-

I S 0

7

-

++++-

-

-

++-

-

++-

-

+-

-

8

-

+-

-

-

1 2 2/4

+± +-

-

6

5

i i i it a? a?

i

a

i i i?

i?

a ? i i i i i

m2 ?

i i?

a i? a i i i

10

I? I I? ? I? I?

I?

I

I I c?

I ? I ? I I I I?

I I

I I?

I I? 1 I I I

11

SPRAGUE et al., 1972 LEGER & HESSE, 1910

WEISSENBERG, 1976

VORONIN & ISSI, 1986 in ISSI (1986)

LARSSON, 1986d

GURLEY, 1893 CODREANU-BALCESCU & CODREANU, 1982 CANNING & HAZARD, 1982 SPRAGUE, 1977 HESSE, 1935

HAZARD & OLDACRE, 1975 LEGER & DUBOSCQ, 1909 HAZARD & OLDACRE, 1975

CODREANU, 1966

FLU, 1911 CODREANU-BALCESCU et al., 1981 VIVARES et al., 1977 CANNING et al., 1983

LARSSON, 1983c ISSI & VORONIN, 1979 VAVRA,1984 NAEGELI, 1857 VINCKIER, 1975

Authors, year

Z

0

'J1 'J1

:0

t'" :>-

~

t-<

"-<

~

~

2

2 2 1

1

T'h eloluinia

'I'oxoqluqea

Trichadu boscqia

U nikaryon

2 2

1

1

1 2 1

1

1 1 1

1 1 1

1

1

2 32

n

n

8 2

2

n

8 16/32

2 4 8

8

8

+

+ + +

-

+ + + +

+

-

+ +

+

2 :1 2

n

n

-

0

0 S

R

8 -

-

8

S I'll' I

S

8 16/:l 2 1

8

-

OU

-

8

2

81

8

8

B 1'1

1

R B 1'R

B

R2 R R

B R R

R2

R1

+) T he PF is d esc ri b ed as anisofil a r, b u t the mi crograp h (F ig. 11) shows a n is ofil ar P F .

I

1

2

Ahelepora Ovaveei cula

?

1

2 2 1

1

2 2 1

1 1 2

2

21

W eiseria

Va vra ia

Vairimorpha

2 2 1

1 1

'l'elom y:l'a T'etramicra

1) 2)

2

8 y slen o,. tr ema

'l'uzetia

21

S tria tospora

so

0

u

0

0

0

op

P P

h

P

0

0

P

r

? i +) i

a a a

i

i 1 i

i i i

n.

ir

1 1

?

I I I

1

I I

1

I I I

1

1

1910

IlEN N~; GUY

Aze v n n o, 198 7 ANDlU:A DIS & RAN ULA, 19 87

DO BY & 8AGUEZ, 19 64

' VEISER, 19 77

P ILLEY, 19 76

CANNING et n l., 1974

L EGEU, 1926 MAUHAND et a l., 1971

& 'l'IlELOHAN (1 892 L EGER & H ESSE, 1924

H g NNEGUY i n

& MA'l'THEWS, 1980

H~:SSE ,

MATTH ~;WS

Lreo s u &

I ssr & VORONI N. 1!J86 in I ssr ( 1986) HA ZAUD & O LDA CltE, 1117 5

p..

'«-"

H

-:r

t:-:l

'It,.,"

g

0

:;

5: S;.

'0

'0,.,"

0

Q

,.,

~

0 ....

«-

'" g"

Q

~

:;

28

J . I. R .

LARSSON

exospore. It is unclear if t he spores were of identical shape . In the definition of the genus spores of the normal seri es are d escribed as pyriform, with thick walls and a surfa ce cover of episporo ntal secretions. It is unclear if it is a case of dimorphism or a mixed infection. Bacillidium .JANDA, 1928 The mi crosporidia with big rod-shaped, diplokaryotic spores without a posterior tail-like prolongation are here treated as Bacillidium species, like they were in .JfltoVEO'S revision (.JiROVEC 1936 ). A re-examination of slide s of B. criodrili , the type spe cies of the genus, collec te d by .JANDA from the t ype host and the type locali t y a nd therefore with a potential t o be design at ed as neotypes, reve aled tha t t he sporogony is not oct osporoblasti c a nd no sporop horo us vesicles a re formed (L ARSSON 1986 b). All octosporoblastic sp ecies, which for a period, and also in the recen t monograph by ISSI (1986) , wer e treated as Bac illidium spec ies are t he refore exclude d .

Cougourdella HESSE, 1935 The genus was inadequately described. The type spe cies, C. magna, had spo res resembling cala bashes, t he fruits of the bottle gourd , Lagenaria cougourda, occurring in pairs (HESSE 1935). L ater species have been assigned to the genus from the spore shape alone. WEI SER (1977) enlarged t he diagnosis and added: spo re thin-wall ed , with a largc helicoidal polaroplast with cha mbers filled with granular substance, sho rt pol ar filam ent, monokaryo tic, produced fr om plasmodia with 4, 8 or 16 nuclei . It is unclear from what species the additi onal cha rac ters wer e taken. Investigation of a te t rasporo blas t.ic species with the t ypical spore shape verified WEISER'S diagn osis, exc ept for the number of spores (LARSSON, unpublished) . Cougou rdella is probably closely related P yrotheca a nd Gu rleya.

Diffingeria ISSI, 1979 The genu s was erected for the sp ecies GOLBERG (1971) call ed W eiseria spinoea; and the nam e is a younger sy nony m of Golbergia WEI SElt, 1977.

Geusia R UllI, a nd KORN, 1979 The genus wa s erected for a mi crosp or idium of gregarines with ova l, monoka ryot ic, apparen t ly isofilar spores, and proba bly wit h thin exos pore . No unique cha rac te rs wer e reported a nd ther e is no diagnosis for the new gen us . The description d oes not satisfy Ar ticle 13 a of t he International Code of Zoologi cal Nomen clature (1985), and the genus ca nno t be cons ide red val id .

Gurleya D OFLEIN, 1898, and Pyrotheca HESSE, 1935 Both gen era have tetrasporoblasti c spo rogon y , probably in sporophorous vesicles. The type spec ies of Gurleya , G. tetraspora, has slightly pyriform spores . P. cyclopis, the t ype spec ies of Pyrotheca, ha s elongate pyriform spo res. Sp or es of both genera a re proba bly monoka ryoti c. Both species have micro crustaceans as type host s. SPRAGUE (1977) was of t he opinion t hat too little is known about t he t y pe species t o ena ble us to di st ingui sh between the genera . A further p roblem is t he copepod -mo rp hs of trimorphic A mbluospora spe cies, whi ch have mon okaryotic, elong ate p yriform , tetrasporo blastic spo res (SWEENEY et al. 1985). These spores are, however, enclosed in individual sporop horo us vesicles, produced by the sporoblas t, not in com mo n , t etrasporou s vesicles produced by t he sporont . As individual sporop horous vesicles cannot be re vealed withou t elect ron microscopy, id entification and t axonomic handl-

Identification of Microsporidian Genera

29

ing of tetrasporoblastic microsporidia, at least from microcrustaceans, are especially difficult. Gurleyides VORONIN, 1986 The genus (described on p. 152; VORONIN 1986), according to the description, shares characters with the genera H oiobispora, Lanatospora and Gurleya. Two types of spores are produced. One spore type is elongate oval (Table 3, p. 146 in the description). The spores are coupled permanently along their long axes, and two pairs of coupled spores are enclosed in a sporophorous vesicle. Spores of the second type are oval and isolated, with an additional cover like in Lanaiospora. The genus was compared to Glugea daphniae, the fine structure of which was described by VAVRA (1978), who created the new genus Norlevinea for the species (VAVRA 1984). VORONIN (1986) was of the opinion that the presence of two spore types legitimated the creation of a new genus. Micrographs of fresh smears and ultrathin sections (Fig. 5; VORONIN 1986) show clearly the similarities between the coupled spores of Gurleyides and spores of Norlevinea. The uncoupled spores (Fig. 5: 2), in my opinion, differ clearly from spores of Lanatospora (Fig. 4: 3), but resemble strikingly spores of the genus Tuzetia (for example as shown by LARSSON 1983c). The thin electron-dense envelope of the sporophorous vesicle is connected to the exospore by narrow tubules. Fig. 4: 3 shows clearly that the tubules form the characteristic net-work below the envelope. It seems fairly clear that VORONIN (1986) has investigated a mixed infection of a Norlevinea and a Tuzetia species. As VAVRA (1978, 1984) did not observe Tuzetia-spores in the Norlevinea species investigated, and LARSSON (1983c) did not find Norlevinea-spores in any of the five species of Tuzetia s. str. examined, it seems less probable that the dimorphic sporogony of Gurleyides is the complete version of a life cycle where the two parts previously have been described under the generic names Tuzetia and Norlevinea.

Holobispora

VORONIN,

1986

In the description (on p. 152; VORONIN 1986), the genus is characterized by having two permamently associated monokaryotic spores, which carry drop-shaped electrondense secretions. It is written that there is no sporophorous vesicle, which is the principal difference to the genera Telomyxa, Neoperezia and Berwaldia. In Table 4 (p. 150 in the description) spores of the type species H. thermocyclopis are characterized as oval with pointed anterior end, but the unfixed spores shown in Fig. 3: 1 (VORONIN 1986), could equally well be classified as pyriform. In Fig. 3: 4 a structure resembling the envelope of a sporophorous vesicle is indicated as pansporoblast cover, which contradicts the statement on p. 152. Also the tubule-like secretions shown in Figs. 4: 2-4 suggest the presence of a sporophorous vesicle. The coupled spores shown in Fig. 3: 1 resemble spores of Issia trichopterae, the type species of the genus Iseia, which however are diplokaryotic. For the present time it seems impossible to distinguish H olobispora from other genera with coupled spores. Jiroveciana

LARSSON,

1980b

The genus is insufficiently known, with no information on the mature spore.

Lanaioepora

VORONIN,

1986

The genus (described on p. 152; VORONIN 1986) is characterized by the presence of an additional cover on the spore wall, formed by secretory material, which appears as short intermingled filaments, and a surface layer. The complex is different from a

30

J .1. R.

LARSSON

pan spo robl astic cover of t he type characteristic for the genus Tuzetia , bu t resembles t he foamy secretions coveri ng mi crospore s of Auraspora, H owev er, Auraspora has dimorphic sporogony whi ch differs t he t wo gen era (VORO~'lN 1986). The type spec ies L. macrocuclopis (so indicated in t he foot-note on p. 152) has oval (although Fi g. 4: 1 shows pyriform) spores, anothe r spec ies , L. bosminae , ha s pyriform spores (Tables 3-4 ; VORONIN 1986). There is no information on t he vegetative reproduction and sporogony , and no statem ents on t he nuclear condit ions in t he differen t phases of developmen t , not even for the ma ture spore. The t wo spec ies are distinguished by characters of the polar filamen t , where formulas indicate three grou ps of coils. The criteria used for t he grouping are not ex plained . The spore wall of L . macrocqclopis resembles the spore wall of Episeptu m inversum, t he type spec ies of the genu s Episeptum. LARSSON, 1986 a, bu t t he scarce informati on on L anatospora makes it difficult t o compare the t wo mi crosporidia further. VORONIN (1986) was apparently of t he opinion that Lanatospora was devoid of sporophorous vesicles, which are presen t in Episeptum. It is impossibl e to decide if the two names are used for the same genus, but it can not be excluded. 'I'he name Lanatospora wa s probably published before Episeptum, and has priority if the two names denote the sam e t axon. As the pyriform spore shape is shared by many microsporidian genera, and episporont al secretions are present in at least five gen era , these characters alone are not sufficient to define t he genus Lanatospora. The la ck of important information, lik e t he number of nuclei in spo res and presporal stages and the number of sporoblasts produced , makes it doubtful if t he description of L anatospora sa t isfies the demands of Ar ti cle 13a of t he International Code of Zool ogical No menclat ure (1985).

L oma MORRISON and SPRAGUE, 1981

Lounss and colla borators described t he new spec ies L . dirnorpha , where spo res

were formed by t wo d ifferen t modes of division (LoUB:F.s et al. 1984). The two sequen ces yield ed identi cal spo res, however , and the spec ies did not display real di morp his m. The conce pt ion of L orna as bein g monomorphic is t he refore unchanged.

M icrosporidiu m BALBIMi'I , 1884 The gene ric name M icrosporidium , which is a ctually a syn onym t o No sema, was used in t he mo nogra ph by SPRAGUE (1977) as a collective and unclassified gen us for existing spec ies of mi crospor idia which were to o in complet ely known t o b e in cluded in an existing genus or to allow the creation of a new gen us. I n t.he last 10 yea rs se vera l new miorosporidia have or iginally been described as named M icrosporidium spec ies. In t he present sit uation, with t he unsolved problem of polymorphism , it is easy t o feel unhappy about describing new genera, and species. H owever, it will probably create greater taxonomic probl ems if an increasing nu mb er of Microsporidium sp ecies are reported, an opinion alread y expressed by SPRAGm, (1977). Microsporidium spec ies a re in fact hidden away and oft en forgotten in com pa risons , while new genera and spec ies attributed t entatively to exist ing genera are more a va ilable for comparison. It is probably better t o take t he risk of creating a fu ture synony m than t o increase t he amorp hous mass of Microsporidium species. M razekia L EGER and HE SSE, 1916 The type species, AI . arqoisi , was described very briefly and t he present conce ption of t he spec ies is based on lat er in vesti gations by D EBAISIEUX (1931) and JiROVEC (1936). DEBAISIEUX and JiROVJ
Identification of

~Iicrosporidian

Genera

31

C. DEGRANGE, person al com munication) . A re-exa minat ion of slides in ColI. O. JiROVEC (Cha rles University, Prague) showed t hat t he microsporidi um DEBAISIEUX ident ified as 111. arqoisi is not related to t he 111razekia sp ecies of Oligochae ta, and apparentl y not a mie rosporidium at all (I"ARssoN 1986 b) . 111razek ia must be rest rict ed t o M . arqoisi, and the gen us is here exc luded from the microspo ri dia.

Nosemoides VINCKIER, 1975 It is unclea r if all spores a re unif orm or if spores of two types are produced. The descri pt ion of t he type species, N. vivieri, mentioned on ly oval, small spores (VINCKIER et al, 1970). A second paper on t he same spec ies described two spore types of ident ical cytology, but different in shape and size , called micro - and macro-spo res (VINCKIER et a1. 1971). In t he di agnosis of the genus only t he small, oval spores are me ntioned (VmcKIER 1975).

Oligosp ori di u m CODREANU-E ALCESCU, CODREANU and TRACIUC, 1981 The morphology and dev elopmen t of t he genus are identical to Uni karyon and Encephalit ozoon. The reason for erect ing a new gen us was that t he host (a spi der) is so phylogeneti cally and ecologica lly distant from digeneans and verte brates, the hosts of Un ikaryon a nd Enc ephalitozoon. Pl eisiophora GURLEY, 1893, The genus Pl eistophora has bee n u sed as a reposit ory for microsporidia with mo nokaryotic spores in po lysporous sporophorous ves icles. CANNING and NICHOLAS (1980) re-investigated the t ype species, P. typicalis, and fou nd that t he sporophorous vesicle had a chara ct erist ic thick envelope, produc ed by the merogonial plasmodium. The genus is at presen t time onl y known from fishes, amp hibia and re ptiles. The polyeporoblastic species of insects, for merly treated as Pleisiophora spe cies, are ex cluded from the genus. T hree new genera (Vavraia, Polydisp yrenia and Cystosp orogenes) ha ve been erected for old Pleisiophora species of insects (WEISER 1977 ; CANNING and HAZARD 1982; CANNING et a1. 1985). Still most Pleistop hora species of invertebrates ha ve an unp roven generic affiliation. Pseudothelohania CODREANU and CODREANU-BALCESCU, 1982 The genu s was established for an octosporoblastic mi crosporidium of bla ckfly larvae, where t he spores wer e not enclosed in sporophorous vesicles. The new genus was me ntioned in a cong ress a bst ra ct , without statement on the type spe cies. To my knowledge no valid des cription has appeared . According to Article 13 b of t he Intern at ional Code of Zoological Nomenclature (1985) t he genus is not valid. S temp ellia LEGER and H EssE, 1910 T he genus S temp ellia has for a long time bee n used to collect microsporidia with spores produced in groups wit h more t han one nu mber of spo res. A modern investigation of a miorosporid ium id entified as t he type spe cies, S. mutabilis, by DEsPoRTEs (1976), led SRPAGUE (1977) to rest ri ct S tempellia to t his species. WEISER(1977) created the three new gene ra Oulicospora, Oulicosporella and 1Iazardia for t hree old Stempellia spec ies, and S . simulii was transferred to Bo husla oia by LARSSON (1985b). There is still a nu mber of S tempellia species which have no t found their genu s yet.

32

J.1. R.

LARSSON

Telomyxa LEGER and HESSE, 1910 HAZARD and FEDERICI (1985) described the new species Telomyxa orae and commented on the genus. Two ultrastructural investigations (CODREANU and VAVRA 1970; LARSSON 1981a) claimed to have investigated the type species, T. glugeijormis, and CODREANU and VAVRA used microsporidia collected in France, where the species originally was found. However, as none of these investigations used microsporidia isolated from the type host, Ephemera vulgata, but from the related species E. danica, HAZARD and FEDERICI (1985) refused to accept that the type species has been investigated, and that the results obtained were diagnostic for the genus Telomyxa. The description by LEGER and HESSE (1910) was very brief without illustrations. Some years later, line drawings of the characteristically coupled spores were published (LEGER and HESSE 1922), which probably was overlooked by HAZARD and FEDERICI (1985). These drawings together with the description make it clear that both CODREANU and VAVRA (1970) and LARSSON (1981a) investigated a Telomyxa species, probably the type species, T. glugeijormis. The species described by HAZARD and FEDERICI (1985) does not resemble the drawings by LEGERand HESSE (1922) and has no similarities with the Telomyxa species treated by CODREANU and VAVRA (1970) and LARSSON (1981a), which so far is the only Telomyxa species that agrees with the illustrations of LEGER and HESSE (1922). Telomyxa orae resembles Norlevinea daphniae, the type species of Norlevinea. The two species have coupled spores of similar shape and an anisofilar polar filament (the filament of Telomyxa is isofilar). The species investigated by CODREANU and V.~VRA (1970) and LARSSON (1981a) is here accepted to be a Telomyxa species, and results from these investigations are used for the identification of the genus Telomyxa, while T. orae is considered to be a N orlevinea species.

Thelohania HENNEGUY, 1892 The type species, Thelohania giardi, is very superficially known and has not been investigated by modern methods. The present interpretation of the genus has been based on species from decapod crustaceane considered to be congeneric with the type species. The genus is not restricted to crustaceans, however, but also present in insects (LARSSON, unpublished observations). T. capillata, which was interpreted as a Thelohania species from the presence of an isofilar polar filament (LARSSON 1983a), shares so many characters with Amblyospora, that the short uniformly thick filament probably is a reduced anisofilar filament and the species should be included in Amblyospora. The revision of the Thelohania-like microsporidia by HAZARD and OLDACRE (1975) distributed a number of Thelohania species to new genera, and listed more than 50 old Thelohania species as species with unproven genus affiliation.

Toxoglugea LEGER and HESSE, 1924 SPRAGUE (1977) synonymised Spirillonema, Spiroglugea, Spironema, Spirospora, Toxonema and Toxospora with Toxoglugea, as the spiral shape or horse-shoe shape characteristic for respective genus showed so many intermediate forms that the shape alone seemed not sufficient to distinguish between the genera. Such variation was present in Toxoglugea variabilis, where s-shaped macrospores occurred together with horse-shoe shaped micro- and macrospores (LARSSON 1980a). As no new information has indicated that the action was wrong, SPRAGUE'S opinion on Toxoglugea is followed here, and the genus is accepted to contain both species with horse-shoe-shaped and s-shaped spores.

Identification of Microsporidian Genera

33

Acknowledgements I am greatly indebted to Mrs. LINA HANSEN, Mrs. INGA JOGBY, Mrs. IJS"GER NORLIJS"G and Mrs. INGA-LILL PALMQUIST, all at the Department of Zoology, University of Lund, for excellent technical assistance, to Fil. mag. VERA ULVER, Dept. of Zoology, Lund, for generous help with translation of Russian texts, to Dr. J. CHALUPSKY, Charles University, Prague, for loan of slides in CoIl. O.•JiROVEC, and to Prof. C. DEGRANGE, Scientific and Medical University of Grenoble, for information about the fate of CoIl. L. LEGER. The investigation was supported by research grants from the Swedish Natural Science Research Council.

Literature AUERBACH, M. (1910): Die Cnidosporidien (Myxosporidien, Actinomyxidien, Microaporidien), einc monographische Studio. Leipzig. BALBIANI, G. (1884): Lecons sur Ies Sporozoaires. 1-184. Paris. BATSON, B. (1983): A light and electron microscopic study of Hirsiuosporos austrosimulii gen. n. sp, n., (Microspora: Nosematidae), a parasite of Austroeimulium sp. (Diptera: Simuliidae) in New Zealand. Protistologica 19: 263-280. CANNING, E. U. (1987): Phylum Microspora. In: MARGULIS, L., CHAPMAN, D., CORLISS, J. D., (eds.). Handbook of Protoctists. - BARKER, R. J., NICHOLAS, .J. P., and PAGE, A. M. (1985): The ultrastructure of three microsporidia from winter moth, Operophtera brumata (L.), and the esta blishment of a new genus Cystosporoqenee n.g. for Pleistophora operophterae (CANNING, 1960). Syst. Parasitol. 7: 213-225. - and HAZARD, E. I. (1982): Genus Pleistophora GURLEY, 1893: An assemblage of at least three genera.• J. Protozool. 29: 39-49. .- LAI, P. F., and LIE, K .•J. (1974): Microsporidian parasites of trematode larvae from aquatic snails in West Malaysia. J. Protozool. 21: 19-25. - and LOM, J. (1986): The microsporidia of vertebrates. London. - and NICHOLAS, J. P. (1980): Genus Pleistophora (Phylum Microspora): redescription of the type species, Pleistophora typicalis GURLEY, 1893 and ultrastructural characterization of the genus. J. Fish Diseases 3: 317-338. WIGLEY, P. J., and BARKER, R .•J. (1983): The taxonomy of three species of microsporidia (Protozoa: Microspora) from an oakwood population of winter moths Operophtera brumata (L.) (Lepidoptera: Geometridae). Syst. Parasitol. 5: 147-159. CAULLERY, M., and MESNIL, F. (1897): Sur un type nouveau (Metchnikovella n.g.) d'organismes parasites des Gregarines. C. R. Acad. Sci., Paris 125: 787-790. - - (1905): Recherches sur Ies Haplosporidies. Arch. Zool. Exp. Gen. 4: 101-181, PI. 11-13. "- - (1905): Sur des Haplosporidies parasites de poissons marins. C. R. Soc. BioI. 58: 640-642. - - (1914): Sur les Metchnikovellidae et autres Protistes parasites des Gregarines d' Annelides. C. R. Soc. BioI. 77: 527-532. CEPEDE, C. (1924): Mrazekia piscicola n.sp., Microsporidie parasite du Merlan (Gadus merlangus LINNE). Bull. Soc. Zool. Fr. 49: 109-113. CODREAXU, R. (1966): On the occurrence of spore and sporont appendages in the microsporidia and their taxonomic significance. Proc. 1st Int. Congr. Parasitol., Roma 1964: 602-603. - and CODREANU-EALCESCU, D. (1982): Observations ultrastructurales sur une Microsporidie parasite de Simuliides. J. Protozool. 29: 301. - and VAVRA, J. (1970): The structure and ultrastructure of the microsporidian Telomyxa glugeiformis LEGER and HESSE, 1910, parasite of Ephemera danica (MULL.) nymphs. J. Protozool. 17: 374-384. CODREANU-EALCESCU, D., and CODREANU,R. (1982): Sur la position taxonomique dapres les caractores ultrastructucturaux d'une Microsporidie hyperpasite d'une Gregarine. J. Protozool. 29: 515. - - and TRACIUC, E. (1981): Ultrastructural data on a microsporidian infesting the ovaries of an araneid.•J. Invertebr. Pathol. 37: 28-33. DEBAISEUX, P. (1931): Etude cytologique de Mrazekia argoisi. La Cellule 40: 147-171, PI. I-II. 3

Arch. Protistenkd., Bd. 136

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D ESPOltTES, 1. (1976) : U ltrastr u ct ure d e S tenipellia mutabilie LEGElt et H ESSE, Microspor-idie parasite d e I'Ephemere E phem era vu lqato. L . Protistologica 12 : 121 -1 5l. LE CHARPENTIE R. Y., GALl AN, A ., B ERNARD, F., COCHAND-PRIOLLET, B. , LAVERGNE, A., R AVISSE, P., a nd MODIGLIANI, R. (1985) : Occurrence of a n ew m icrospo ri dian : Enterocylozoon bieneusi n.g., n. sp., in t h e enterocyt es of a human p a tient with AI D S. J . Prot ozo ol. 32: 25 0 to 25 4. D OllY, J.-1\1., a n d SAGUEZ, F. (196 4): Weis eria , genre nouv eau d e l\1icr osp or idies et W eiseria l a urenli n .sp ., para si t e d e la rves d e P rosi m uli u m i nf latum D AVIES, 1957 (Dipt er es Par- anern a t.oceres). C. R. Acad. Sci., P aris 259 : 3614-1617. D OFf,EIN, F . (1898): Studien zur Nanurgeschich t e del' Protozoon . II I. U eber My xosporid ie n. Zool. Jahrb. Abt. Ana t . ll: 281-350, T a r. 18-24. FLU, P. C. (1911) : St ud ie n tib er die i m Da rrn d el' St ube n fliege , M usca dom esti ca, v or ko m m en d en p rot o zoiir en Ge b ilde. Zentralbl. B akt eri ol. P arasitenk. Infekt ion skr. H yg. Abt. I , Orig . 57 : 52 2-535 . G OLBEltG, A. 1\1. (1971): 1\Iikrosporidi ozy k omarov Cu lex pipiens L. Med. P arazitol. P ara zit. B oleznio, Moskva 2: 204-207. GURLEY, R. R. (1893): Cla ssi fica t ion o f the Myxosporidia, a gr oup o f pr ot oz oan parasites infesting fishes. Bull. U. S. Fish Com. for 1891 11: 407-420. H AZAltD, E. 1., and BROOKBANK, J. W . (1984): Karyogamy a nd me iosis in an Amblyospora sp . (Micr ospora) in the mosquito Culex salinari us , J. Invertebr. Pathol. 44: 3-11. - EI,LIS, E . A., and .JOSLYN, D .•J. (1981): Identification of micr os poridia , In: H. D. BURGES (ed.), Mi crobial control of pests and pl ant d iseases 1970-1980, pp. 163-1 82, London. - a n d F EDERICI, B. A. (1985): Ultrast r uc t ure and d escription of a n ew species of Telomyxa (Mi cros p or a : T elom yxida e) from t h e s ernia quatic b eetl e, Ora tex ana CHAMP. (Col eop t era: H elodida e). J. Proto zo ol. 32: 189-1 94 . - F UKUDA, T . , a nd BE CNEL, .J. ,r. (1985) : Gamet oge nes is a nd pl a s m og am y in certain s pecies of Microspora .•r. Inv ertebr. P a thol. 46: 63 -69. - and OLDACRE, S. \V. (197 5) : R ev ision of mi cr osporida (Protozoa) clo se to T helohania , with d esc ri ptio ns of n ew family , eigh t n ew gener a , and t h irteen n ew sp ecies . U . S. D ept. Agric. 'I 'e c h n . Bull. N o. 1530: 1- 1 04. H ENNEGUY, F., a nd THELOHAN, P. (1892): Myxosporidies p a ra s it es d es muscles d es Cr ustac es d ecapod es. Ann. Mi crogr. 4 : 6 17- 641, PI. 4. H ESSE, E. (193 5): Sur quel qu es Micr op or idies p arasites d e M egaeyelops viridis Jurine. Arch. Zool. E xp. Ge n. 75: 651 - 66l. H OSTOUNSKY, Z., a n d ZIZKA, Z. (1 97 9) : A modifica t ion of t he " agar cus h io n meth od " for observ a tion a nd recording mi cr osp or id ian s p ores. J . Protozool. 26 : 41 A-42 A. Int ernation al Code of Zoologi cal N omencl ature, 3r d ed . (1985 ). I nterna ti on al Trust for Zool ogi cal Nomencla ture , London. I SSI, I. V. (1979) : Novil rod m ikro s poridii D iffingeria (= W eiseria) spinosa (GOLBERG, 1971) iz kor n arov Culex p ipins ( Diptera, Cu licidae). In: Sistema tika i eko lo g ia s por ov in k ov i knidosp or id ii, pp. 91-97 L eningra d. _ (1986): Microsporidia as a phylum of p arasitic protozoa. Protoz oolog y (L eningrad) 10: 6-136 (in Russian). _ RADISCHEVA, D. F" and DOLZHENKO, V. 1. (1983): Microsporidi a of flies of genus Delia (Diptera, Mu scidae), harmful to farm cr ops . Bjul. VIZR 55: 3-9 (in Russian). _ a nd VOltONIN, V. N. (1979): The co nt emp orar y state of the problem s on b isp ore genera of microspor id ia ns. Parazitologia 13: 150-1 58 (in R u ssian). J ANDA, V . (192 8): Dber Mikroorga nism en a u s d el' L eibeshohl e v on Oriodri lus laeuum H OFF],I. und eige nar t ige Neubildungen in d el' Korper wand di esos 'I'i eres , Arch. Protist enkd, 63: 84-93 , T a f.8 . J iROVEC, O . (1936) : Zur K enntnis VO Il in Oli go ch iiten p a ra siti ere nd e n Mikrosporidi en a us d el' F a m ilie Mr a zekidae. Ar ch. Proti st e nkd . 87 : 314-344, T aL 12-1 5. J OUVENAZ, D. P., a n d HAZARD, E . 1. (197 8): New family, g en us, a nd species of Mi cr osporida (Proto zoa: Microsporida) fr om t he t ro p ical fir e a nt, So lenopsie gem inata (Fabricius) (Insect a: F ormi cid a e) . .J. Protozool. 25: 24-29.

I dent ifi ca ti on of Mi crosporidian Gene r a

35

K UDO, R. R. (1924) : A biologic a nd t a x o nomic study of t he Mi er osporid ia. III. Biol, Monogr. 9: 1-268. L AItSSON, R. (1 980 a): U ltrastructural stu d y of Toxoglugea va ria bilis n .sp. (Micr osporida: Theloh a niida e) , a micr os po r id ia n p ar asit e of t he b iting midge B ezzia d p . (Dip t er a: Ceratopo g on idae). Protist olog ica 16: 17-32. _ (1980b) : I n sect pathological investigatio ns on Swed is h Thy sa nura: II. A new micr osporidi an p a rasite of P etrobius brevistyli s (Mi cr ocor yphia, Ma chili d a e); d escrip ti on of t he species a n d crea t ion of two n ew genera and a n ew fa mily. Protist ologica 16 : 85 - 10 1. _ (198 1 a ) : The ultrastr uctu re of t h e s pore a nd sp or ogo nic stages of T elomsjxa glugeijormis L EGER a nd H ESSE 1910 (Microspo rid a : T elomyxidae). Zool. A n z, (J ena) 206 : 137 -153. _ (1 981 b): A new micr osporid iu m B erioaldia s inqu laris ge n . et sp . n ov . from D aphn ia pulex a nd a su r vey of m icrosporidia desc r ib ed fr o m Cla d oeer a . P ara si t olog y 83 : 32 5-342. _ (1 982): Cytology a nd taxo nomy o f H elm ichia aggregata gen. et sp . nov . (Mi crospora, T'heloh ani id a e), a para site of Endochironomus larv a e (D iptera, Chi ro nomidae). Proti stologica 18: 355-370. (1 983 a ): T helohania capillato. n. sp. (Microspo ra, Theloha n iida e) - An u lt rastru ct ural stu dy wi t h r emar k s on the taxonom y of the genus Thelohania H ENNEGUY, 1892. Arch. Protistenkd. ]27: 21-46. (1 983 b): Identifikation av mi krospor idier (Protozoa, Microsporn). Mem. Soc. Fauna Flora Form. 59: 35-51. (198 3c) : A revisionary study of tho t a xon Tuzetia MAURAND, FIZ E, F ENWICK and MICHEL, 1971, and r elated forms (Micr os por a, Tuzetiidae). Protistologica 19 : 323-355. _ (1 985 a): Identification of m icro sporid ia . Ca nad ia n Translation of Fisheries and Aquatic Sciences N o. 5143: 1-49. _ (198 5 b ): On t he cyt ology, d evelo p m en t a nd system a t ic po sitio n o f Thelohan ia ast eria» W EISER, 1963, with creatio n of t he n ew genus Bohu slaoia (l\Ii crospora, Thelohaniida e). Protistologica 21 : 235-248 . - (1 986 a) : U lt ra cy t ology of a t etras po ro b last ic m icrosporidiu m o f t he cad d is fly Hol ocentrop us picicornis (T r icho ptera, P ol y centropod id a e), with d escription o f Episeptu m i n versu m gen. et s p . nov . (Microspora, Gurleyid a e). Arch. Protist enkd. 131 : 257-27 9. - (198 6 b ) : On t he t axonomy of Mr a zekida e: R esurrection of t he ge n u s Bacillulium JA NDA. 192 8. •T. Prot ozool. 33: 542-546. - (1986c) : U ltrastr u cture, fu n ct ion a nd classification of m icro p oridia. P rogr. Protistol. 1: 32 5 to 390 . (1 986 d): Ult.rasb r uct.u ral i nvest igatio n of two micr osporid ia with ro d-shape d spores, with d es cr iption of Gyli ndrospora fus ciculota s p . nov. a nd R esiomeria odonatae gen . et sp . nov. (M icr os pora , Thelohaniida e). Prost ist ologi ca 22: 379-398. LEGt;R, L. (1926) : U ne Mi crosporidie nouv ell e a s p oro ntes e p ineux . C. R . Acad. Sc i., P aris 182 : 727-729. - a n d D UBos cQ, O . (1909) : S ur u ne l\1icrosporidie p ara sit e d ' une Gregari n e. C. R . Acad. Sc i., Par is 148: 733-734. - a nd H ESSE, E. (1910): Cn idosp oridies d es larves d'Ephem eres . C. R . Ac ad. Sci., Paris 150: 411-414. - - (1916): Mrazekia, genre n ouveau d e Mi crosporidies it spores tubul eu ses. C. R. Soc. Biol, 79: 34 5-348. PI. I. - - (1922): l\ficrosporidies bact.erifor rnes et essai de systematique du groupe. C. R. Acad. Sci., P aris 174: 327-330. - - (1924): Mierosporidies nouvell es p ara sites des animaux d' ea u do uce, T rav . Lab. Hydrobiol. Pisc. Univ . Grenoble 14: 49 -56. L EVADITI, C. , NI COLAU, S. , a ncl SCHOEN, R. (19 23) : L'etiologi o d e I' encephalit e, C. R. Acacl . Sc i., P a r is 177: 985-988. L o unes , C., a ncl AKBARIEH, :i\1. (1 97 8) : Etude ultra structural e d e la Mi crosporidie B acul ea daphni ae n .g., n. sp., para site d e I'epithel iu m intestinale cle D aphnia p ul ex L EYDIG, 1860 [Crusta ce, Cladocere). Protist ologica 14 : 23-38. - MAURAND, J., GASC, C., B URON, 1. D E, and BARRAL, J . (1 984): Etud e ultrastr ucturale d e L orna dimorpha n .sp., Mi crospnr id ie p a ra sit e d e P oissons Gobiida e Languedocie ns . Proti st ol ogica 20: 579-589. 3"

36

J. 1. R. LARSSON

MATTHEWS, R. A., and MATTHEWS, B. F. (1980): Cell and tissue reactions of turbot Scophtholmu« maximus (L.) to Tetramicra brevifilum gen. n., sp. n. (Microspora). J. Fish Diseases 3: 495-515. MAURAND, J., FIZE, A., PENWICK, B., and MICHEL, R. (1971): Etudes au microscope eIectronique de Nosema infirmum KUDO, 1921, Microsporidie parasite d'un Copepode cyclopolde; Creation du genre nouveau Tuzetia a propos cette espece. Protistologica: 7: 221-225. MORRISON, C. M., and SPRAGUE, V. (1981): Electron microscopical study of a new genus and new species of microsporidia in the gills of Atlantic cod Gadus morhua L. J. Fish Diseases 4: 15-32. NAEGELI, C. (1857): Uber die neue Krankheit del' Seidenraupe und verwandte Organismen. Bot. Ztg. 15: 760-761. ORMIERES, R., and SPRAGUE, V. (1973): A new family, new genus, and new species allied to the microsporidia. J. Invertebr. PathoI. 21: 224-240. OVERSTREET, R., and WEIDNER, E. (1974): Differentiation of microsporidian spore-tails in Lnodoeporus spraquei gen. et sp. n. Z. Parasitenk. 44: 169-186. PEREZ, C. (1908): Sur Duboscqia leqeri, Microsporidie nouvelle parasite du 'I'ermes lucifugus, et sur la classification des Microsporidies. C. R. Soc. BioI. 65: 631-633. PILLEY, B. M. (1976): A new genus, Vairimorpha (Protozoa: Microsporida), for Nosema necatrix KRAMER, 1965: pathogenicity and life cycle in Spodoptera exempta (Lepidoptera: Noctuidae). ,J. Invertebr. PathoI. 28: 177-183. RALPHS, J. R., and MATTHEWS, R. A. (1986): Hepatic microsporidiosis of juvenile grey mullet, Chelon labrosus (RISSO), due to Microqemma hepaticus gen. nov. sp. nov. J. Fish Diseases 9: 225-242. RUHL, H., and KORN, H. (1979): Ein Mikrosporidier, Geueia. gamocysti, n. gen., n. sp., als Hyperparasit bei Gamocystis ephemerae. Arch. Protistenkd. 121: 249-355. SCHNEIDER, A. (1884): Sur Ie developpemcnt du Stylorhynchus lonqicollis, Arch. Zool. Exp. Gen. 2: 1-36. SCHUBERT, G. (1969): Ultracytologische Untersuchungen an del' Spore del' Mikrosporidienart, Heteroeporie finki, gen. n., sp. n. Z. Parasitenk. 32: 59-79. SPRAGUE, V. (1977): Systematics of the microsporidia. In: A.BuLLA .Ir, and T. C. CHENG (eds.), Comparative Pathobiology, Vol. 2, pp. 1-510. New York and London. - (1982): Microspora. In: PARKER, S. P. (ed.), Synopsis and classification of living organism, Vol. 1,589-594, New York. - ORMIERES, R., and MANIER, ,J.·F. (1972): Creation of a new genus and a new family in the Microsporida. J. Invertebr. Pathol. 20: 228-231. SWEENEY, A. W., HAZARD, E. I., and GRAHAM, M. F. (1985): Intermediate host for an Amblqoepora sp. (Microspora) infecting the mosquito, Culex annulirostrie . .J. Invertebr. Pathol. 46: 98-102. THELOHAN, P. (1891): Sur deux Sporozoaires nouveaux, parasites des muscles des Poissons. C. R. Soc. BioI. 112: 168-171. VAVRA, J. (1976): Structure of the microsporidia. In: BULLA, Jr., L. A., and CHENG, T. C. (eds.), Comparative Pathobiology, Vol. 1: 1-85. New York and London. _ (1978): The ultrastructure of the sporulation stages of a microsporidian forming spore doublets, "Glugea daphniae". Proc. Int. Coll. Inv. Pathol. Praha 1978: 227-228. _ (1984): Norleoinea n.g., a new genus for Glugea daphmiae (Protozoa: Microspora), a parasite of Daphnia longispina (Crustacea: Phyllopoda). J. Protozool. 31: 508-513. _ and MADDOX, J. V. (1976): Methods in microsporidiology. In: BULLA Jr., L. A., and CHENG, T. C. (eds.), Comparative Pathobiology, Vol. 1: 281-319. New York and London. VnwKIER, D. (1975): Nosemoides gen. n., N. vivieri (VINCKIER, DEVAUCHELLE & PRENSIER, 1970) comb. nov. (Microsporidia): Etude de la differcnoiation sporoblastique et genese des differentes structures de la spore.•J. Protozool. 22: 170-184. _ DEVAUCHELLE, G., and PRENSIER, G. (1970): Nosema vivieri n.sp. (Microsporidae, Nosematidae) hyperparasite d'une Gregarine vivant dans Ie caelome d'une Nemcrbe. C. R. Acad, Sci., Paris 270: 821-823. _ _ _ (1971): Etude ultrastructurale du developpcmenb de la Microsporidie Nosema vivieri (V. D. et P. 1970). Protistologica 7: 273-287. VIVARES, C. P., BOUIX, G., and MANIER, J.·F. (1977): Ormieresia carcini gen. ri., sp. n., Microsporidie du Crabe Mediterraneen Carcinus mediterraneus CZERNIAVSKY, 1884: Cycle evolutif et etude ultrastructurale. J. Protozool. 24: 83-94.

Identification of Microsporidian Genera

37

VORONIN, V. N. (1986): The microspiridia of crustaceans. Protozoology (Leningrad) 10: 137-166 (in Russian). WEISER, J. (1946): Studie 0 mikrosporidiich z hmyzu nasich vod. Vest. Cs. spol, zoo!. 10: 245-272. (1961): Die Mikrosporidien als Parasit en der Insekten. Monogr. Angew. Entomo!. 17: 1-149. (1976): Microspoi-idia in invertebrates: Host-parasite relations at the organismal level. In: BULLA Jr., L. A., and CHENG, T. C. (eds.), Comparative Pathobiology, Vo!. 1, pp. 163-201. New York and London. - (1977): Contribution to the classification of microsporidia. Vestn. Cs. spo!. zool. 41: 308-321, Figs. 1-5. - (1985): Phylum Microspora SPRAGUE, 1969. In: LEE, .J. .J., HUTNER, S. H., and BOVEE, E. C. (eds.), An illustrated guide to the protozoa, 375-383. Lawrence. - and BRIGGS, J. D. (1971): Identification of pathogens. In: BURGES, D., and HUSSEY, N. W., (eds.), Microbiol control of insects and mites, pp. 13-66. London and New York. - and PURRINI, K. (1980): Seven new microsporidian parasites of springtails (Collembola) in the Federal Republic of Germany. Z. Parasitenk. 62: 75-84. WEISSENBERG, R. (1976): Microsporidian interactions with host cells. In: BULLA Jr., C. A. and CHENG, T. C. (eds.), Comparative Pathobiology, Vol. 1, pp. 203-237. New York and London. Author's address: Dr. RONNY LARSSON, Department of Zoology, University of Lund, S - 22362 Lund, Sweden.

Added in Proof After the manuscript was finished two more genera have been described: Abelepora AZEVEDO, 1987 (J. Invertebr. Patho!. 49, 83-92) and Ovavesicula ANDREADIS and HANULA, 1987 (J. Protozoo!. 34, 15-21). The genera can be incorporated in the identification key with the following modifications: 40.

SV's oval (Fig. 4K); spores monokaryotic; PF normal or manubrium-like, coiled or . . . . . . . . . . . . . . . . . . 40 A or uncoiled Ovavesicula 40 A. SV's with 32 spores; PF not manubrium-like, coiled. . . . . . . . . . SV's with a variable number of spores; PF manubrium-like with a gland-like posterior swelling, uncoiled . . . . . . . . . . . . . . . . . . . . . . . Meich.nileooello. 53. SV's with thin or thick envelope, produced during sporogony (Fig. 8 S); all spores of uniform size; PF isofilar . . . . . . . . . . . . . . . . 53 A 53 A. SV's with thick envelope; 32 spores per SV. . . . . . . . . . Ouauesicula SV's with thin envelope; SV's with an irregular number of spores 54 58. Spores oval, not coupled to foot-print-like associations; PF isofilar . . . . . . . 58 A 58 A Spores connected by patches of cementing material; SV's with two-layered envelope, which is folded and attached spot-wise to the exospore (Fig. 8 Q-R) (Fig. 3 E) Berwaldia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Spores not connected by a cementing substance; SV's with uniform, thin envelope, not folded and attached to the exospore . . . . . . . . . . . . . . . . Abelspora