A Preliminary Account of the Tardigrades of Newfoundland

Zool. Anz. 240 (2001): 223–232 © by Urban & Fischer Verlag http://www.urbanfischer.de/journals/zoolanz

A Preliminary Account of the Tardigrades of Newfoundland* Lois BATEMAN1 and Michael COLLINS2 1

Science Division, Sir Wilfred Grenfell College, Memorial University of Newfoundland, Corner Brook, Newfoundland, Canada

2

Biology Department, Memorial University of Newfoundland, St. John’s, Newfoundland, Canada

Abstract. This is the first published report of tardigrades in Newfoundland and Labrador. Twenty-six species have been identified so far, including four new records for Canada and one new record for North America. Although there is some overlap of species with those found in earlier Canadian studies, there are some interesting discrepancies. The rare occurrence and restricted distribution of the very few heterotardigrades (three species and 30 specimens) found so far in Newfoundland is noteworthy, as is the occurrence of several tardigrade species whose former records have been mainly for Greenland. It appears the environmental conditions in Newfoundland can support a number of species that would normally be restricted to a more northerly distribution. A comparison of the species found in Newfoundland with those of a number of other northern countries suggests that the Newfoundland species are most similar to those found in Greenland and mainland Canada. Key words. Tardigrada, Newfoundland, Canada.

1. INTRODUCTION AND METHODS Newfoundland, the easternmost land mass of North America, is an island of 108,860 square kilometres situated in the northwest Atlantic. It was created when the continental plates Laurentia (which eventually formed North America) and Gondwana (which eventually formed Africa, South America, India, Australia and Antarctica) collided over 500 million years ago and then separated 300 million years later. This left an island with three geological origins (Fig. 1). The eastern portion is part of what is now the African plate and consists mainly of sandstones and shale, with some granite, ash and lava. The western portion, part of the North American plate, also contains some sandstone and shale, but has a great deal of limestone and a large area of granite and gneiss. The central portion originated as ancient oceanic floor from the Iapetus Ocean and contains a mixture of all the previously mentioned

*

Contribution to the 8th International Symposium on Tardigrada, Copenhagen, Denmark, 30 July–5 August 2000.

types of substrate. The most recent glaciation receded 8 to 10 thousand years ago, leaving table-topped and rounded mountains and numerous fjiords (some of them land-locked freshwater lakes) along the west and south coasts of the island. The western North American portion carries the northern extension of the Appalachian Mountains (highest point 815 m). The cool wet climate and relatively short time period since glaciation have produced a shallow organic soil layer, and resulted in a boreal forest of balsam fir (Abies balsamea (L.) Mill) and black and white spruce (Picea mariana (Mill) B.S.P., Picea glauca (Moench) Voss), with white birch (Betula papyrifera Marsh.) in the west. Many exposed areas at higher altitudes or in proximity to the ocean do not support tree growth and are characterized by subarctic and arctic/alpine shrub layers or peatlands. The present climate varies from cold maritime on the eastern and southern coasts to a temperate continental climate with a relatively short summer in the central and western areas. Cool or cold winter weather with frozen soil and ground vegetation lasts four to six months. In maritime climate areas there may be erratic periods of thawing during the winter months. 0044-5231/01/240/03–04-223 $ 15.00/0

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There have been few extensive surveys of tardigrades in Canada. The earliest records (RICHTERS 1908; MURRAY 1910) are from scientific exploratory expeditions. During the 1960’s and 1970’s central and southern New Brunswick were studied (ARGUE 1971, 1972, 1974) and species from Axel Heiberg Island (WEGLARSKA ˛ 1970; WEGLARSKA ˛ & KUC 1980) , Quebec (IHAROS 1973) and the Yukon Territory (PILATO 1977) were recorded. The late 1980’s and early 1990’s produced a study on Vancouver Island (KATHMAN 1989, 1990; KATHMAN & CROSS 1991; KATHMAN & DASTYCH 1990, KATHMAN & NELSON 1989) and added a few species from the Yukon Territory (DASTYCH 1987; MANICARDI 1989), several species from the Northwest Territories (VAN ROMPU et al. 1991, 1992) and one from New Brunswick (NELSON 1991). A complete listing of the 82 tardigrade species previously recorded from Canada is included in Tab. 1. In this preliminary survey of the tardigrades of Newfoundland, ground and rock mosses and lichens from a mixture of forested and non-forested areas across the island were sampled. Samples were taken during the summers (June to August) from 1995 to 1998. Extraction methods used were those developed by NELSON

(1999). The method of collection and extraction has produced specimens in numbers consistent with those reported by both DASTYCH (1988) and KATHMAN & CROSS (1991) for the same species collected in Poland and British Columbia respectively. Most species occurred in single digit numbers in the Newfoundland samples (Tab. 2) as well as in Poland and British Columbia. The 59 sites sampled are shown in Fig. 1. The sites are scattered widely over the island, and are categorized in one of three groups based on geological plate origin. Five sites were sampled from the Avalon Region, 12 sites from the Central Region, and 42 sites from the Western region. Each site has been described in terms of altitude, vegetation, geological substrate (using GIS technology) and susceptibility to dessication (to be published elsewhere).

2. RESULTS AND DISCUSSION From the tardigrades isolated in the present study, a total of 26 species have been identified (included in Tab. 1) and at least five more species are yet to be iden-

Fig. 1. Tardigrade sample sites and geologic zones for the island of Newfoundland.

Tardigrades of Newfoundland

225

Tab. 1. Tardigrade Species found in Canada (including present study). Heterotardigrada Species

Area Found

Distribution Pattern (According to RAMAZZOTTI and MAUCCI 1983, and MCINNES 1994)

Bryochoerus intermedius (Murray,1910) Bryodelphax parvulus Thulin,1928 Echiniscus bisetosus Heinis,1908 E. canadensis Murray, 1910 E. horningi Schuster & Grigarick, 1971 E. maucci Ramazzotti, 1956 E merokensis Richters, 1904 E. oihonnae Richters, 1903 E. quadrispinosis Richters, 1902 E. reymondi Marcus, 1928 E. spiniger Richters, 1904 E. sylvanus Murray, 1910 E. wendti Richters, 1903 Hypechiniscus gladiator (Murray, 1905) Proechiniscus hanneae (Petersen, 1951) Pseudechiniscus alberti Dastych, 1987 P.goedeni Grigarick, Mihelcic, & Schuster, 1964 P. suillus (Ehrenberg, 1853) Testechiniscus laterculus (Schuster, Grigarick, & Toftnei,1980) T. spinuloides (Murray, 1907) T. spitzbergensis (Scourfield, 1897)

BC (M) BC (M) BC (M) BC (M) BC (K&D) NB (A),BC (K&D) NF, NWT (W&K) BC (M) BC (K&D) BC (M-named by MARCUS) NB (A) ON (M) NF, BC (M, K&D) NB (A), BC (R, K&D) NF YU (D) BC (K&D)

rare widespread? holarctic, widespread N.Amer. N.Amer. widespread widespread cosmopolitan Can-BC widespread Can-Ont cosmopolitan widespread Grnlnd N.Amer.-Yukon cosmopolitan

NB (A),BC (K&D), NWT (W&K,VR2) BC (K&D)

cosmopolitan Can-BC

NB (A) NWT (W&K,VR1,2)

Eur, N.Amer. holarctic

Eutardigrada Species

Area Found

Distribution Pattern

Dactylobiotus ambiguus (Murray, 1907) D. dispar (Murray, 1907) Macrobiotus areolatus Murray, 1907 M. bondavilli Manicardi, 1989 M. crenulatus Richters,1904 (=M.dentatus Binda, 1974) M. echinogenitus Richters, 1904 M.furciger Murray, 1906 M. harmsworthi Murray, 1907 M. cf. hufelandi Shultze, 1833 M. montanus Murray, 1910 M. occidentalis Murray, 1910 M. richtersi Murray, 1911 M. tenuis Binda & Pilato, 1972 M. tonollii Ramazzotti, 1956 M. virgatus Murray, 1910 M. willardi Pilato, 1977 Minibiotus intermedius (Plate,1888) M. lazzaroi Maucci, 1986 Murrayon dianeae (Kristensen, 1982) M. hibernicus (Murray, 1911) M. pullari (Murray, 1907) Microhypsibius (Thulin, 1928) sp. Pseudodiphascon arrowsmithi Kathman &Nelson, 1989 Amphibolus smreczynskii (W˛eglarska, 1970) A. w˛eglarskae (Dastych, 1972)

NB (A) NWT (VR) NB (A),ON (M), SK (P), BC (M,K), RM (M) YU (MA) BC (K)

cosmopolitan cosmopolitan cosmopolitan Can. - Yukon Eur. N.Amer.

NB (A), ON (M), BC (M,K) NB (A) NF, NB (A), ON (M), BC (K), NWT (VR1) NF,NB (A), PQ (I), ON (M), BC (R,M,K), RM(M) NF, NB (A) BC (M) NB (A), PQ (I), BC (K) SA(P) NB (A) ON (M), BC (M) SA (P) NF, NB (A), ON (M), BC (K) BC (K) NF, NWT (VR1,2) NB (A), BC (K) NB (A) NF

cosmopolitan widespread cosmopolitan cosmopolitan cosmopolitan cosmopolitan Eur, N.Amer. Eur, N.Amer. Eur, N.Amer. Aust. Eur, N.Amer. cosmopolitan Eur, N.Amer. Grnlnd, NWT Eur, N.Amer. widespread Europe,Greenland, Japan

BC (K) NWT (W) BC (K), NWT (VR2)

Eur, Can-NWT Eur, N.Amer.

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L. BATEMAN and M. COLLINS

Tab. 1. (Continued). Eutardigrada Species

Area Found

Distribution Pattern

Calohypsibius ornatus* (Richters,1900) Hypsibius arcticus Murray, 1907 H. convergens (Urbanowicz, 1925) H. dujardini (Doyere, 1840) H. microps Thulin, 1928 H. pallidus Thulin, 1911 Isohypsibius bertolanii Manicardi, 1989 I. canadensis (Murray, 1910) I. granulifer (Thulin, 1928) I. lunulatus (Iharos, 1966) I. papillifer (Murray, 1905) I. papillifer bulbosus (Marcus, 1928) I. prosostomus (Thulin 1928) I. sattleri (Richters, 1902) (= I. bakonyensis (Iharos, 1964)) I. schaudinni (Richters, 1909) I. tetradactyloides (Richters, 1907) I. tuberculatus (Plate,1888) I. woodsae Kathman, 1989 Ramazzottius baumanni (Ramazzotti, 1962) R. oberhauseri (Doyere, 1840) R. sp Diphascon (Adropion) belgicae (Richters, 1911) D(A.) modestum Binda, Pilato & Dastych, 1984 D(A.) prorsirostre Thulin, 1928 D.(A.) scoticum Murray, 1905 D.(Diphascon) alpinum Murray, 1906 D.(D.) bullatum Murray, 1905 D.(D.) burti Nelson, 1991 D.(D.) chilenense Plate, 1888 D.(D.) iltisi (Schuster & Grigarick, 1965) D.(D.) nodulosum (Ramazzotti, 1957) D.(D.) oculatum vancouverense (Thulin, 1907) D.(D.) pingue (Marcus, 1936) (( including brunsvicensis) Argue, 1972) D.(D.) ramazzottii Robotti, 1970 D.(D.) recamieri Richters, 1911 D.(D.) rugosum (Bartos, 1935) D.(D.) tenue Thulin, 1928 D. behanae Dastych, 1987 Hebesuncus conjungens (Thulin, 1911) Itaquascon pawlowskii Weglarska, 1973 Mesocrista spitzbergense (Richters, 1903) Platicrista angustata (Murray, 1905) P. cheleusis Kathman, 1990 Milnesium tardigradum Doyere, 1840

NF, BC (K) WC (M), BC (M), ON (M) NF, NB (A), BC (K), NWT (VR1,2) NF, NB (A), NWT (VR1,2) NF NF, NB (A), PQ (I) YU (MA) BC (M), NWT (VR2), RM (M) NWT (VR1,2) NF, BC (K), YU (MA) NWT (VR1,2) NWT (VR1,2) NF NF, NB (A), BC (M,K), RM (M)

widespread cosmopolitan cosmopolitan cosmopolitan widespread cosmopolitan Can.-Yukon Asia, N.Amer. cosmopolitan widespread cosmopolitan cosmopolitan? widespread cosmopolitan

NF, PQ (I), NWT (VR 2) NWT (VR1,2) NB (A),BC (M) BC (K) BC (K) NB (A), PQ (I), BC (M,K) NF NB (A), BC (K) BC (K) NF, NB (A), BC (K) NF, NB (A), RM (M), BC (M,K) ON (M), RM (M) NB (A) NB (A- named by N) RM (M) BC (K) NF, NB (A), BC (K) BC (M) NF,NB (A), BC (K)

widespread, cosmopolitan cosmopolitan widespread Can-BC NZ, Amer. cosmopolitan

NF BC (K), NWT (VR 2) NB (A) PQ (I) YU (D) NF BC (K) NF, NB (A), BC (K) NF, NB (A) BC (K) NF, NB (A), BC (R, K) PQ (I), ON (M)

Europe widespread Eur., Can -NB Eur, Can-PQ Eur, Can-Yukon widespread Eur, N.&C.Amer. Eur, Afr, NA widespread Can-BC cosmopolitan

Locations:

Records From:

BC = NB = NF = ON = PQ = RM = NWT = SA = WC =

A D I K K&D MA M

British Columbia New Brunswick Newfoundland Ontario Province de Quebec Rocky Mountains Northwest Territories Saskatchewan West Coast

= = = = = = =

ARGUE (1971, 1972, 1974) DASTYCH (1987) IHAROS (1973) KATHMAN (1990) KATHMAN & DASTYCH (1990) MANICARDI (1989) MURRAY (1910)

widespread Eur, Can.-BC widespread cosmopolitan cosmopolitan widespread Can-NB cosmopolitan Eur, N.Amer., Asia NZ, N.&C.Amer. Eur, N.Amer. cosmopolitan

N = P = R = VR1 = VR2 = W = W&K =

NELSON (1991) PILATO (1977) RICHTERS (1908) VAN ROMPU et al. (1991) VAN ROMPU et al. (1992) W˛EGLARSKA (1970) W˛EGLARSKA & KUC (1980)

Tardigrades of Newfoundland

New Zealand and 74 from Venezuela, all labelled M. intermedius. Only two and 49 specimens respectively were confirmed as that species, with the others being assigned to several other Minibiotus species. However, although the Newfoundland specimens showed variation, mainly in presence and size of eyes, and several specimens were smaller than the range of sizes found by ARGUE (1971), all are M. intermedius (S. K. CLAXTON, pers. comm. 2000). Very few eggs were present in the extracted samples, and none were found for any of the macrobiotids. The lack of eggs prevents further identification of the two unknown macrobiotids and the Ramazzottius species (R. GUIDETTI & R. BERTOLANI, pers. comm. 2000) as well as further separation of the Macrobiotus cf. harmsworthi and M. cf. hufelandi complexes. Since

Echiniscus merokensis E. wendti Proechiniscus hanneae Macrobiotus cf. harmsworthi M. cf. hufelandi M. montanus Minibiotus intermedius Murrayon dianeae Microhypsibius sp. Calohypsibius ornatus Hypsibius convergens H. dujardini H. microps H. pallidus Isohypsibius lunulatus I. prosotomus I. sattleri (bakonyensis) I. schaudinni Ramazzottius sp. Diphascon (Adropion) prorsirostre D. (A.) scoticum D. (Diphascon) nodulosum D. (D.) pinque D. ramazzottius Hebesuncus conjungens Mesocrista spitzbergense Platicrista angustata Milnesium tardigradum

# specimens/site

Species Found In Newfoundland

Total # specimens found

Tab. 2. Number of tardigrade specimens found in Newfoundland sampling sites. # sites in which found

tified. The latter include a Ramazzottius sp., a Microhypsibius sp., two Macrobiotids and a Hypsibiid. Three of the identified species are heterotardigrades and the others are eutardigrades (six macrobiotids, 16 species from the family Hypsibiidae, and Milnesium tardigradum). Macrobiotus cf. hufelandi occurs in 64% of the sites and makes up 41% of the 597 specimens found. As shown in Tab. 2, only nine other species are represented by more than 10 specimens. With the few exceptions described here, specimens of most species showed characteristic features as described by RAMAZZOTTI & MAUCCI (1983) or DASTYCH (1988). The cosmopolitan species complexes of Macrobiotus cf. harmsworthi and M. cf. hufelandi are both represented in Newfoundland by specimens which show a wide range of structural variability. Tab. 3 illustrates the variability which occurs in macroplacoid size, microplacoid size and buccal tube width in both species; for M. cf. harmsworthi there is also great variability in the size of the satellite on the third macroplacoid and the appearance of the eyes when they are visible. Each complex may represent more than one species, as described by KINCHIN (1994) and RAMAZZOTTI & MAUCCO (1983). As pointed out for M. cf. hufelandi by BERTOLANI & REBECCHI (1993), until eggs are found it will not be possible to clarify the picture. However, it is possible that there is more than one species from each complex present in Newfoundland. Seven species of hypsibiids (Hypsibius dujardini, Isohypsibius prosostomus, I. schaudinni, Diphascon prorsiristre, D. pinque, D. scoticum, Mesocrista spitzbergensis) exhibit a smaller size range and/or mean in Newfoundland than specimens recorded by other authors (Tab. 4) (RAMAZZOTTI & MAUCCI 1983; ARGUE 1971, 1972, 1974). Conversely, the specimens of P. angustata found show a size range greater than that described by those authors. Two macrobiotid species showed structural peculiarities worthy of mention. All of the specimens of Murrayon dianeae from one of the sites (Burgeo) had unusual subcuticular swellings which could not be characterized using phase lighting. The form of Calohypsibius ornatus found was different from both forms reported by KATHMAN (1990) from British Columbia (BC). Most BC specimens were of the typical longspined form described by BARTOSˇ (1940), without conical protuberances on legs IV, but there were also some individuals of the carpaticus form, with conical protuberances on leg IV, and no long spines. The Newfoundland specimens are a long-spined version of the carpaticus form with the leg IV protuberances. Fifty-six specimens of Minibiotus were encountered in 14 sites during this study. In a revision of the genus Minibiotus, CLAXTON (1998) examined 44 slides from

227

2 1 1

3 1 32

1–3 1 32

9 38 1 14 4 1 1 8 2 1 2 1 5 1 1 4 3

15 243 1 56 17 1 4 16 6 1 2 2 35 1 2 27 3

1–6 1–14 1 1–11 1–7 1 4 1–7 2–4 1 1 2 2–19 1 2 3–15 1

5 3 10 1 1 2 3 4

18 5 38 2 8 5 9 8

1–9 1–3 1–9 2 8 1–4 1–5 1–2

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most of the Newfoundland samples were taken in the months of June, July and August, this may be later than the most common time of egg production. Although most studies reporting eggs do not provide sampling dates (ARGUE 1971, 1972; KATHMAN 1990) there is some indication that egg production occurs earlier than summer. KRISTENSEN (1980) found eggs in the middle of winter in Greenland and KENDALL-FITE (1993) found eggs in Minibiotus intermedius more frequently in December than at any other time in Tennessee. NICHOLS (1999) also mentions a lack of eggs in an Alabama study, with the few found occurring mainly in January and April (P. B. NICHOLS, pers. comm. 2000). Of the 26 named species reported from Newfoundland, ten are cosmopolitan (MCINNES 1994; RAMAZZOTTI & MAUCCI 1983) and the authors of this paper would designate 11 more to be widespread (defined as occurring on at least four continents, as recorded by MCINNES 1994) (Tab. 1). Ten of the resulting 21 cosmopolitan or widespread species occurring in Newfoundland have previously been found in at least two of the three major geographic areas of Canada (east – New Brunswick,

Quebec, Ontario; West – Saskatchewan, British Columbia, Rocky Mountains; north – NorthWest Territory, Yukon) for which tardigrade records exist (Tab. 1). Diphascon (Diphascon) nodulosum and Mesocrista spitzbergense, while not considered to have a cosmopolitan or widespread distribution on a world wide scale, have also been previously recorded from two or more geographical areas within Canada, from the east (ARGUE 1971, 1972) and from the west (KATHMAN 1990). On the other hand, nine species (one heterotardigrade and eight eutardigrades) which are considered cosmopolitan or widespread have previously been reported from at least two other geographic areas from within Canada, but have not appeared in the Newfoundland samples (Tab. 1). A further 17 cosmopolitan or widespread species reported from at least one other Canadian site are also missing from the Newfoundland samples. So although the majority of tardigrade species from Newfoundland are common elsewhere, many others which might be expected to be present, based on their general distribution patterns, have so far not been recorded.

Tab. 3. Comparison of Newfoundland specimens of Macrobiotus cf harmsworthi and Macrobiotus cf hufelandi with previous records. Body structure

Appearance or Size [given as range(mean)] (all measurements in µm) ––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– Macrobiotus cf harmsworthi Macrobiotus cf hufelandi –––––––––––––––––––––––––––––––––––––––––– –––––––––––––––––––––––––––––––––––––––––––––––––––– Nfld. specimens Other specimens Nfld. specimens Other specimens

Body length

206–549 (358)

400–500 R&M 280–480 A 220–300 K

110–555 (287)

300–450 R&M 320–520 A

Buccal tube width

5–10 (6.5)

20% of length R&M 6.5 A

1.5–10 (4.3) ≤10% of length (variable)

≤10% of length (notable variability) R&M 5–6 A

Buccal tube length

33–51(44.9)

32–35 A

20–71(40)

30–40 A (36.9) B&R

Macroplacoid size

1=2<3 4–9 < 5–10

1 ≥ 2 ≤ 3) R&M, A

1>2 1 > 2 R&M 5–19 (9.8) > 3–12 (6.2) 13.1 > 7.6 B&R

Microplacoid size

1–5

1

/2–1/3 of macro R&M ‘large’ K

1–6 (2.9)

3.8 B&R

Appearance of eyes

present in 50% small → large

sometimes lacking R&M

present in most

present in most R&M

3rd Macroplacoid satellite

varies in size

not mentioned

n/a

n/a

A – ARGUE (1971), B&R – BERTOLANI & REBECCHI (1993), K – KINCHIN (1994), R&M – RAMAZZOTTI & MAUCCI (1983).

Tardigrades of Newfoundland

Three widespread species found in Newfoundland (Hypsibius microps, Isohypsibius prosostomus, Hebesuncus conjungens) have not previously been recorded for Canada, although the last two are present in other continental North American sites (MCINNES 1994) and H. microps has one record for continental North America (KENDALL-FITE 1993). Diphascon ramazzotti is a new record for North America, while Proechiniscus hanneae and the Microhypsibius species are new records for continental North America. Proechiniscus hanneae was previously thought to be endemic to Greenland (MCINNES 1994; MAUCCI 1996), while the Microhypsibius specimen does not appear to be one of the four described species (RAMAZZOTTI & MAUCCI 1983; ITO 1991) and no species from this genus has been reported from any part of North America except Greenland (MCINNES 1994). Tab. 4. Body lengths of some hypsibiids found in Newfoundland. Species

Body Lengths [given as mean(range)] (all measurements in micrometers) –––––––––––––––––––––––––––––––––––––––––– Newfoundland Other Studies specimens

Hypsibius dujardini

150 (125–191)

500 R&M 220–300 D 210–460 A

Isohypsibius prosostomus

238.8 (129–378)

270–470 R&M 210–287 D

I. schaudinni

139 & 161 (2 specimens)

up to 368 R&M

Diphascon prorsirostre

155.3 (140–173)

245 R&M 275 (210–340) A

D. pingue

168.4 (87–268)

240 R&M 160–230 D 225 (160–280) A

D. scoticum

267 (195–440)

462 R&M 180–370 D 385 (240–500 )A

Mesocrista 294 (179–381) spitzbergensis

450 (240–600) R&M 253-650 D 350 (220 - 400) A

Platicrista angustata

485 (290–630) A (350-490) R&M

465.7 (343–750)

A – ARGUE (1971), D – DASTYCH (1988), R&M – RAMAZZOTTI & MAUCCI (1983).

229

Heterotardigrade species are often less numerous and less widely distributed than eutardigrade species, but in Newfoundland, in comparison to other subarctic northern locations, this situation seems to be exaggerated. KATHMAN & DASTYCH (1990) note that although most echiniscids are cosmopolitan, their British Columbia study and other Canadian studies (ARGUE 1971, 1972, 1974; MURRAY 1910), record only 20% of the species as heterotardigrades. In Newfoundland, only 10% of the species are heterotardigrades. Five of 27 species reported for Alaska are heterotardigrades (DASTYCH 1982) and in Poland, 21 of 95 species are heterotardigrades (DASTYCH 1988) with six occurring in several sites, often in numbers greater than 20. In both New Brunswick (NB) and British Columbia (BC), the number of specimens per sample recorded for single heterotardigrade species was frequently greater than 20 (four of the BC species occurred in several sites and three of the NB species occurred in either three or four sites). In contrast, the even smaller number of heterotardigrade species found so far in Newfoundland and their very localized distribution is noteworthy. Each of the three species occurs in a single geographic location, usually in a single site. Echiniscus merokensis and E. wendti were represented respectively by only three specimens (from two adjacent sites) and one specimen. MAUCCI (1996) considers these species to be ‘widely spread’ or ‘common’, but they have both also proven to be uncommon elsewhere. DASTYCH (1988) describes both Echiniscus species as rare in Poland considering both to be montane species. Neither was found by ARGUE (1972) in New Brunswick or MURRAY (1910) in Ontario, and KATHMAN & CROSS (1991) found only E. wendti, which occurred in small numbers in most of the British Columbia sites, although one site produced 38 specimens. The third heterotardigrade species found in this study, Proechiniscus hanneae, described as very common in West Greenland (KRISTENSEN 1987), was found at a single, rich (25 specimens) site in Newfoundland. However, heterotardigrade species found to date in Newfoundland can only be described as rare. This might be considered as surprising, as many areas of Newfoundland exhibit harsh environmental conditions relative to those expected from its latitude, and it is not uncommon for other alpine/tundra organisms to exhibit a southern or lower altitude range extension into Newfoundland. In addition, many heterotardigrade species are considered adapted to montane or tundra conditions eg. DASTYCH (1988) (14 of 22 heterotardigrade species from Poland including Echiniscus merokensis and E. wendti) and MAUCCI (1996) (15 heterotardigrade species cited as typical of arctic tundra conditions, including the three heterotardigrade species found in Newfoundland). Further study is required to

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Tab. 5. Number of tardigrade species (by family) found in Newfoundland, New Brunswick (ARGUE 1971, 1972, 1974; NELSON 1991),Greenland (MAUCCI 1996), and Iceland (MAUCCI 1996; MCINNES 1994). Family

Number of Species ( ) denotes number of species in common with 1 ––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– Newfoundland1 New Brunswick2 Greenland3 Iceland4

Echiniscidae Macrobiotidae Hypsibidae Milnesidae

3 6 16 1

5 (0) 11 (4) 16 (10) 1 (1)

13 (3) 17 (5) 19 (11) 2 (1)

14 (2) 16 (4) 24 (11) 1 (1)

0 3 7 1

0 3 6 1

Total spp.

26

33 (15)

51 (20)

55 (18)

11

10

broaden the habitat sampling to encompass a more extensive investigation of rock lichens and to include other microhabitats such as moss samples from the bark of trees (eg. ARGUE 1971, 1972), and leaf litter (eg. GUIDETTI et al. 1999). Such a study would be expected to discover some of the other sub Arctic species that might be expected from Newfoundland (see Tab. 1), for example Pseudechiniscus suillus, which also occurs in Greenland and Iceland and is considered cosmopolitan (RAMAZZOTTI & MAUCCI 1983), and Hypechiniscus gladiator, which has been reported from Europe, Greenland, New Zealand and Japan (MCINNES 1994). A similar, though less pronounced, pattern can be seen in the eutardigrades with ten species currently absent from the Newfoundland list (see Tab. 1). Six of these (Macrobiotus areolatus, M. echinogenitus, M. richtersi, Hypsibius arcticus, Ramazzottius oberhauseri, and Diphascon (Diphascon) alpinum) are considered cosmopolitan and three (Isohypsibius tuberculatus, Diphascon (Adropion) belgicae and D. (D.) recamieri) are widespread (MCINNES 1994). Tardigrade species recorded for other northern areas offer an interesting basis for comparison with Newfoundland (Tab. 5). The species assemblage found in Newfoundland would be expected to be similar to that found in New Brunswick, which is geographically close to Newfoundland, and shares a similar macroclimate. Indeed, a 50% overlap in species occurred in the two areas and a comparable number of total species were found (33 in New Brunswick, 31 in Newfoundland), while almost all the common species were eutardigrades and most were hysibiids. However, there was also an extensive overlap with Greenland (north of 60 oN), a much larger island situated to the northeast of Newfoundland (south of 52 oN). Greenland has a greater number of recorded species (Tab. V) and as with the New Brunswick records, the greatest overlap was within the hypsibiids. In contrast to New Brunswick, all three echiniscid species found in New-

Number of Common Species –––––––––––––––––––––––––––– 1, 2 & 3 1, 2, 3 & 4

foundland are also present in Greenland. Ten of the tardigrade species found on Newfoundland have not been recorded from New Brunswick, but only seven of the 26 named Newfoundland species were not present in Greenland. The species overlap between Newfoundland and Iceland (north of 60 oN) is similar to that between Newfoundland and Greenland (Tab. 5). Newfoundland lies southeast of Greenland and Iceland in the path of the westerly wind flow proposed by PUGH & MCINNES (1998) as the mechanism of distribution for arctic tardigrades.

3. CONCLUSIONS Preliminary studies of Newfoundland tardigrade species indicate a somewhat depauperate community in comparison with reports from other Canadian regions. This is especially true for heterotardigrades. The majority of species which are present can be considered cosmopolitan or widespread, but a number of ‘widespread’ species found in other Canadian sites were not present in this study. There are also a number of species common to Newfoundland and the more northern islands of Greenland and Iceland. It is anticipated that ongoing investigations of more habitats within the island and on Labrador, the neighbouring and more northern continental portion of the province, will help to furnish a more complete picture of the tardigrade fauna of this subarctic area and its affinities. Acknowledgements. We gratefully acknowledge the considerable assistance we have received from Dr. Diane Nelson, Department of Biological Sciences, East Tennessee State University, Johnson City, Tennessee, USA. We would also like to express our thanks for assistance with species identification to Mr. Nigel Marley, University of Plymouth, UK, Ms. Sandra Claxton, School of Biological Sciences, Macquarie University, Ryde, New South Wales,

Tardigrades of Newfoundland

Australia, and Dr. Roberto Bertolani and Dr. Roberto Guidetti, Department of Animal Biology, University of Modena, Italy. We also acknowledge the assistance of Mr. Roy Ficken of the Biology Department, Memorial University of Newfoundland, for his help with the operation of the departmental research microscope and the associated photography and Doug Piercey of the Corner Brook Division of the Canadian Forestry Service, Natural Resources Canada for obtaining and imaging the G.I.S. data. We would also like to express our considerable gratitude to three of our student assistants, Ms. Julianne Mayo and Ms. Lori Garland, who have spent many hours extracting, mounting, measuring and identifying our specimens and Mr. Jason Chaulk who has assisted with the compiling and formatting of the results. Without their help and enthusiasm we would not have progressed as rapidly as we have. The constructive comments provided by anonymous reviewers were much appreciated. This study was supported in part by a research contract to LEB from the Corner Brook Division, Canadian Forestry Services, Natural Resources Canada.

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Authors’ addresses: Lois BATEMAN, Science Division, Sir Wilfred Grenfell College, Memorial University of Newfoundland, Corner Brook, Newfoundland, Canada A2H 6P9 and Michael COLLINS, Biology Department, Memorial University of Newfoundland, St. John’s, Newfoundland, Canada A1B 3x9 Received: 26. 10. 2001 Reviewed: 17. 07. 2001 Accepted: 17. 09. 2001 Corresponding Editor: Reinhardt Møbjerg KRISTENSEN