- Email: [email protected]
Some British Phidoloporidae (Bryozoa: Cheilostomatida)
Zoological Journal of the Linnean Society (1996), 117, 103–112. With 3 figures
Some British Phidoloporidae (Bryozoa: Cheilostomatida) P. J. HAYWARD F.L.S. AND J. S. RYLAND F.L.S. Marine and Environmental Research Group, School of Biological Sciences, University of Wales, Swansea, Singleton Park, Swansea, SA2 8PP
Received April 1995, accepted for publication August 1995
Five British species of Reteporella Busk, 1884 are described and figured. A neotype specimen is selected for R. beaniana (King), and R. incognita sp. nov. is described, and distinguished from R. couchii (Hincks). ©1996 The Linnean Society of London
ADDITIONAL KEY WORDS: — Neotype – new species. CONTENTS Introduction . . . . . Systematic accounts . . . Reteporella beaniana (King) R. couchii (Hincks) . . . R. incognita sp. nov. R. septentrionalis (Harmer) . R. watersi (Nordgaard) . . Acknowledgements . . . References . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
103 104 104 107 107 109 111 111 112
INTRODUCTION
The fenestrate, or reteporiform, cheilostomate bryozoans popularly known as lace corals are represented in the Northeast Atlantic region by three genera and five described species. The taxonomy of this apparently uniform group has changed radically since the three species reported from the British Sea area were described and figured in the Linnean Society Synopsis, British Ascophoran Bryozoans (Hayward & Ryland, 1979). Gordon (1989) finally resolved the problem over the validity of the long-used genus Retepora Lamarck, 1801 by establishing that it is a junior homonym of Retepora Soldani, 1795 and thus unavailable for lace corals despite its much arguedover pre-Linnean usage. Further, he showed that Phidoloporidae Gabb and Horn, 1862 had taxonomic precedence over Sertellidae Jullien, 1903, which in recent years has been used by taxonomists in preference to Reteporidae Smitt, 1868. In the same work Gordon (1989) also suggested that Reteporella Busk, 1884 should be considered the senior synonym of Sertella Jullien, 1903, on the grounds that the only 0024–4082/96/050103 + 10 $18.00/0
103
©1996 The Linnean Society of London
104
P. J. HAYWARD AND J. S. RYLAND
distinguishing feature between the two genera was the form of the colony, which in Reteporella is generally freely branching or irregularly anastomosed, and in Sertella generally regularly anastomosed, or closely reticulate. Re-examination of the type species of Reteporella, R. flabellata Busk, 1884, vindicates Gordon’s (1989) view as its autozooidal morphology differs in no substantial way from any described species of Sertella. The Northeast Atlantic lace corals thus consist of the genera Phidolopora Gabb and Horn, 1862, represented by the single species P. elongata (Smitt), Reteporellina Harmer, 1933, for R. hyperborea Hayward, and Reteporella Busk, 1884, represented by R. septentrionalis (Harmer), R. beaniana (King) and R. couchii (Hincks), in the family Phidoloporidae Gabb and Horn, 1862. In preparing updated accounts of the species of Reteporella for a revised edition of the Linnean Society Synopsis, specimens of all three species, from a number of localities in the British sea area, have been examined by scanning electron microscopy, in comparison with specimens from the Faroe Islands and from several Mediterranean localities. Of especial interest is R. septentrionalis (Harmer), which in Britain is known only from a few localities in the extreme north, is apparently common further north, yet has also been widely reported from shallow coastal habitats throughout the Mediterranean (e.g. Gautier, 1962; Hayward, 1974). Comparison of specimens from the northern and southern limits of its range confirm that only a single species may be recognized, although some Mediterranean specimens, resembling those described by Calvet (1927) as Retepora cellulosa var. aquilina, show slight morphological differences from north European specimens. Nordgaard (1907) noted a distinctive ‘variety’ of R. beaniana (King) from Iceland which he named var. watersi. The only subsequent author to recognise this taxon was Kluge (1962), who also figured it for the first time; Hayward (1994) redescribed it and raised it to full specific ranking, noting that previous authors (e.g. Ryland, 1963) did not distinguish it from R. beaniana. Reteporella watersi was found to be common around the Faroe Islands and the Faroe Bank (Hayward, 1994); it occurs along the western coasts of Norway, and northwards to Spitzbergen, Franz Josef Land and the Barents Sea. Its southern limit is presently unknown but it may prove to occur in deep waters to the west of the Shetland Isles, where the bryozoan fauna has many similarities with that of the Faroe Islands. Examination of specimens of R. couchii from several British localities revealed a further, previously undescribed species, almost certainly overlooked because of its superficial resemblance to R. couchii. It is here described as R. incognita sp. nov.. All five species of Reteporella present in the British sea area are here described and figured, using scanning electron microscopy. Specimens deposited in the collections of The Natural History Museum, London are denoted by the prefix NHM, and their respective registration numbers.
SYSTEMATIC ACCOUNTS
Reteporella beaniana (King) (Fig. 1A–C) Retepora beaniana King, 1846: 237 Retepora beaniana: Hincks, 1880; 391, pl. 53, figs. 1–5 Sertella beaniana: Hayward & Ryland, 1979: 262, figs 112A, 113
SOME BRITISH PHIDOLOPORIDAE (BRYOZOA: CHEILOSTOMATIDA)
Figure 1. A–C, Reteporella beaniana. A, group of autozooids, 3 70. B, detail of ovicelled autozooids, 3 140. C, primary orifice, 3 388. [A,B: 1911.10.1.795, Northumberland. C: 1911.10.1.792, Shetland] D,E, Reteporella couchii [1911.10.1.804, Guernsey]. D, autozooids at a branch edge, 3 70. E, ovicelled autozooids with characteristic development of the peristome, 3 100.
105
106
P. J. HAYWARD AND J. S. RYLAND
Material. NEOTYPE (selected here): NHM 1911.10.1.795, Northumberland. Other material: NHM reg.nos. 1994.3.8.16, Norway; 1911.10.1.798, Flor¨o, Norway; 1911.10.1.792, 1361, 1362, Shetland; 1888.6.9.22, Loch Lorn; 1898.8.25.4, Rockall Bank; 1899.7.1.2916, Beadnell, Northumberland. Description. Colony 40–50 mm high, with an equivalent horizontal spread; developing an open fan, or a shallow cup-shape, but with the edges of the colony usually folded or enrolled to a varying degree. Trabeculae consisting of three to five alternating, longitudinal series of autozooids, doubled at points of trabecular fusion; fenestrulae oval, longer than wide, commonly 1.5 3 0.5 mm. Autozooids about 0.5 3 0.2 mm, separated by distinct, raised sutures in early ontogeny, which become obscured by later ontogenetic thickening of the frontal shields; calcification smooth, each autozooid with few (3–5) large, distinct marginal pores. Frontal shield predominantly cryptocystidean, but with a reduced umbonuloid fold immediately proximal to the orifice, bounded on its inner face by a distinct ring scar. Primary orifice broadly bellshaped, about 0.09 3 0.11 mm, slightly wider than long; distal border distinctly toothed, condyles rounded. A single stout spine present on each side of the orifice, level with the condyles (occasionally a second, smaller spine above each); cylindrical, blunt, to 0.2 mm long, typically persisting in late ontogeny. Peristome developed laterally and proximally, partly obscuring orifice in frontal view; a single oval avicularium present on its rim, mid-proximally, 0.6 mm long, proximally or proximo-laterally directed, slightly acute to frontal plane and projecting conspicuously. Distal rim of avicularium finely toothed, proximal edge developed as a bifid mucro projecting above the orifice of the autozooid. Rim of peristome deeply notched adjacent to avicularium, forming an open pseudosinus, which does not close over in later ontogeny. Additional oval avicularia sporadically developed on frontal walls of autozooids and on abfrontal colony surface, often frequent on older parts of colony. Ovicell slightly wider than long, flattened frontally, with an elongate median fissure; aperture arched, without a labellum; partly obscured in later ontogeny by secondary calcification. Remarks. Reteporella beaniana was originally described from specimens collected off the Northumberland coast (King, 1846) but these could not be traced in the collections of The Natural History Museum, London, University College, Galway, or Trinity College, Dublin, and are considered to be no longer extant. A neotype is here selected, from the Northumberland coast, in order to stabilize the taxon. It is common off the east coasts of Britain, from Yorkshire northwards, and has recently been collected from a gas-drilling rig in the southern North Sea (R. Hamond, pers. comm.); it ranges northeastwards to the Faroe Islands and West Norway. Ryland’s (1963) material from the Bergen area, and material collected earlier from the Hardangerfjord (NHM 1963.3.30.246) included specimens of both this species and R. watersi (Nordgaard), and in mixed collections from the Faroe Islands (Hayward, 1994), R. watersi was more abundant than R. beaniana. It is distributed from Shetland southwards along the western coasts of Britain and Ireland, and occurs below 200 m in the Bay of Biscay, but does not appear to reach the Mediterranean. This species is readily distinguished from R. watersi by its more delicate, folded colony form, by the smooth frontal calcification of the autozooids, and by its open peristomial pseudosinus.
SOME BRITISH PHIDOLOPORIDAE (BRYOZOA: CHEILOSTOMATIDA)
107
Reteporella couchii (Hincks) (Fig.1D,E) Retepora couchii Hincks, 1878: 355, pl.18, figs 1–6; 1880; 395, pl.53, figs 6–11 Sertella couchii: Hayward & Ryland, 1979: 264, figs 112B, 114 Material. HOLOTYPE: NHM 1899.5.1.1242, Lands End, Hincks colln. (ex. Couch) Other material: NHM 1879.4.25.69, Naples; 1899.5.1.;1008, Naples; 1899.7.1.3014, 3020, Madeira; 1899.7.1.3015–3018, Mediterranean; 1911.10.1.806, Madeira; 1911. 10.1.793, Finmark; 1911.10.1.804, 1938.11.26.1, Guernsey; 1963.8.2.22,23, Alexandria; 1965.8.20.24, La Chapelle Bank. Description. Colony 20–30 mm high, with equivalent horizontal spread; growing edge lobed and loosely convolute, forming a three-dimensional structure. Trabeculae consisting of two to four alternating, longitudinal series of autozooids, doubled at points of trabecular fusion; fenestrulae elongate oval, 0.5–1.0 mm long, as wide as the trabeculae. Autozooids elongate, convex, smoothly calcified, separated by raised sutures; commonly 0.5 3 0.2 mm. Primary orifice broader than long, proximal border straight or slightly convex; condyles indistinct, distal denticulations minute. Two to four delicate, distal oral spines present in earliest ontogeny only, obliterated by the development of a deep peristome, formed from two elongate proximo-lateral flaps fused medially except at the extreme proximal end, where they part to define a round pseudospiramen. One side of the peristome incorporates a slender cylindrical avicularian cystid,up to 0.3 mm long, projecting conspicuously from the colony surface; rostrum terminal, oval, 0.05 mm long, with complete, slender crossbar. Frontal avicularia sporadic; normal to frontal plane, proximally directed, 0.2 mm long; rostrum parallel-sided, distally rounded, with a complete, slender crossbar; palate with a small triangular or trilobed foramen just distal to crossbar. Similar avicularia present, often numerous, on abfrontal surface of colony, 0.1–0.2 mm long; also small, oval avicularia, 0.05 mm long. Ovicell prominent and conspicuous, twice as long as wide, with a narrow median fissure extending the whole of its length. Remarks. Reteporella couchii occurs offshore, on coarse grounds, and is apparently widespread throughout the Mediterranean. It ranges south to the Gulf of Guinea (Cook, 1968), and northwards to the Channel Isles and South Cornwall. There is a single specimen from northern Norway (NHM 1911.10.1.793), and one specimen has been collected recently from the Faroe Islands, but it has yet to be reported from off the western coasts of Britain. Reteporella incognita sp. nov. (Fig. 2A–C) Material. HOLOTYPE: NHM 1994.3.11.10, Shetland, A.M. Norman colln. PARATYPE: NHM 1911.10.1.805, off SW Ireland. Other material: BIOFAR Stn. 090; 1897.5.1.1241, W of Great Skellig Ireland; 1897.5.1.1240, no locality; 1899.7.1.77, NNW of Rona, 55 fms; 1963.2.12.150, W of Ireland. Description. Colony architecture incompletely known, but broadly fan-shaped, with a lobed, folded edge; exceeding 40 mm high, with an equivalent spread. Fenestrulae irregularly oval, commonly 1.0 3 0.5 mm; trabeculae stout, consisting of three or
108
P. J. HAYWARD AND J. S. RYLAND
Figure 2. A–C, Reteporella incognita sp. nov. A, portion of holotype colony (1994.3.11.10), 3 35. B, detail, showing ovicells and characteristic peristome, 3 60. C, primary orifice (1911.10.1.805), 3 400. D–F, Reteporella septentrionalis. D, ovicelled autozooids in frontal view, 3 70. E, lateral view, to show cusps on avicularium rostrum [1911.10.1.807, Finmark], 3 50. F, a specimen from Rovinj (F.K. McKinney), 3 70.
SOME BRITISH PHIDOLOPORIDAE (BRYOZOA: CHEILOSTOMATIDA)
109
four alternating, longitudinal autozooid series,doubled at points of trabecular fusion. Autozooids elongate, irregularly polygonal, bounded by raised sutures; commonly 0.5 3 0.25 mm. Primary orifice longer than wide, proximal edge gently concave; condyles small, rounded, mid-distal border indistinctly toothed. Two widely spaced distal oral spines present in newly developed autozooids, neither of which persists in later ontogeny. Frontal shield smooth, with few ( < 10) irregularly spaced marginal pores. Avicularia polymorphic: consistently one lateral-suboral, with a columnar cystid, the rostrum 0.08 mm long, oval, terminal, normal to frontal plane, usually orientated along a disto-proximal axis; rostrum finely denticulate distally, crossbar complete, with a small columella. The length of the columnar cystid varies, most often 0.15–0.3 mm; basally it fuses with one lateral lobe of the peristome; on the other side of the orifice the peristome is produced as a narrow lobe which arches proximo-medially to fuse with the avicularian cystid, thus defining a large, round mid-proximal foramen. Frontal avicularia sporadic, sometimes identical to lateral suboral type, or larger (0.13 mm) with tapered rostrum supporting a triangular mandible. Both types of avicularia present abundantly around edges of fenestrulae, and more sparsely on the basal surfaces of the colony. Ovicell about as broad as long; its aperture highly arched, without a labellum, the longitudinal frontal fissure extending most of its length. Remarks. This species has a superficial resemblance to R. couchii (Hincks), for which reason it has probably been overlooked. The most striking similarity between the two species is the tall, columnar, lateral suboral avicularium, which in both varies in length in different parts of the colony. In R. couchii the rostrum of the avicularium is tapered proximally while that of R. incognita is regularly rounded. The peristome of R. couchii is very much deeper than that of this new species and bears a distinctive channelled line of fusion between the two lobes, and a relatively small mid-proximal foramen, distinct from the rim of the peristome. The fused peristomial lobes of R. incognita are each smaller than the large foramen. Other major points of difference lie in the ovicell, which is much longer than broad in R. couchii; and the frontal avicularia, which are short and triangular in R. incognita but elongate and lingulate in R. couchii.
Reteporella septentrionalis (Harmer) (Figs 2D–F, 3A) Retepora cellulosa forma cellulosa Smitt 1868: 35, pl.28, figs 222–225 Retepora cellulosa: Kluge 1962: 526, fig. 367; 1975: 639 Sertella septentrionalis Harmer 1933: 620; Hayward and Ryland 1979: 266, figs 112C, 115 Material. Arctic specimens: NHM reg. nos. 1899.7.1.2992, Norway; 1899.7.1.2995, 2999, Spitzbergen; 1899.7.1.2998, Godthaab; 1911.10.1.807, 808, Finmark; 1921.5.23.5, Whales Beach, Iceland. Mediterranean specimens: 1843.3.6.137, ‘Mediterranean’; 1878.5.10.270, Malta; 1899.7.1.2991, Mediterranean coast of Spain; 1899.7.1.2965,2974,2980, 2981,2989,2997, ‘Mediterranean’; 1899.7.1.2977, Tenerife; 1963.8.2.24, Alexandria; 1965.9.2.26, Mediterranean Stn.187 (Gautier,
110
P. J. HAYWARD AND J. S. RYLAND
1962); 1965.9.2.;34, Mediterranean Stn.182 (Gautier, 1962); 1965.9.2.35, Mediterranean Stn.279 (Gautier, 1962); 1975.1.12.410, Chios; Rovinj, Adriatic (F.K. McKinney colln.). Description. Colony up to 40 mm high, 80 mm horizontal spread; initially a shallow cup-shape, but its rim lobed or folded in larger colonies, often forming anastomoses defining narrow tubes or funnels, and developing a compact, convoluted, threedimensional form. Fenestrulae elongate oval, 1.0–1.6 mm long, wider than the rather slender trabeculae, giving a delicate, open fenestration. Autozooids in two to four longitudinal series, or up to eight at points of trabecular fusion; elongate, 0.4–0.6 3 about 0.2 mm; convex, separated by distinct sutures in early ontogeny. Primary orifice wider than long; distal edge with few, minute denticulations, proximal edge very slightly concave; condyles short, rounded, indistinct. A pair of delicate, lateral oral spines present in early ontogeny, obscured by development of the peristome. Peristome consisting of two unequal-sized proximo-lateral flaps, fusing distally to define a rounded pseudospiramen below a long, proximo-lateral suture. Frontal shield smooth or finely nodular, with three to five widely spaced and conspicuous marginal pores. Avicularia polymorphic, numerous: most frequently oval, normal to frontal plane, 0.09–0.11 mm long, with complete, slender crossbar; one or two present on the frontal shield of every autozooid, with variable orientation. Rarely, similarly-sized avicularia with acute rostra also present. Commonly and characteristically a massively enlarged avicularium occupies much of the frontal shield of the autozooid, the rostrum projecting at a right angle to the frontal plane, its proximal portion partly obscuring the primary orifice of the autozooid; rostrum up to 0.35 mm long, narrowly triangular, with a sharp, abruptly hooked tip, and a sharp cusp on each side halfway along its length. Ovicell slightly longer than wide, with a short, rounded labellum projecting over its aperture, and a wide frontal fissure running about two-thirds of its length. Remarks. Specimens from Arctic Norway display the large, strongly hooked avicularium, with prominent lateral cusps, figured by Smitt (1868). In Mediterranean specimens the enlarged avicularia tend to be more slender, without pronounced lateral cusps. In these specimens, also, the lateral oral spines tend to persist into late ontogeny, visible above the rim of the peristome even in ovicelled autozooids; the ovicell tends to be shorter than in Arctic specimens, with a straight-edged labellum. Reteporella septentrionalis has a curious geographical distribution. It is widespread, and apparently common, in Arctic seas; it is rare around the Faroes, but has occurred in deep water off St. Kilda (Ryland, 1965) and in the Bay of Biscay (Hayward, 1978). What appears to be the same species is widely distributed in shallow waters throughout the Mediterranean; it was accurately described and figured by Calvet (1927), as Retepora cellulosa var. aquilina. The Mediterranean specimens listed above all conform closely to Calvet’s account, with the single exception of the Malta specimen (1878.5.10.270), in which the enlarged avicularia bear lateral cusps similar to those seen in the Arctic specimens.
SOME BRITISH PHIDOLOPORIDAE (BRYOZOA: CHEILOSTOMATIDA)
111
Figure 3. A, Reteporella septentrionalis, a specimen from Malta (1878.5.10.270), 3 100. B, Reteporella watersi, a specimen from Hardangerfjorden collected by S.F. Harmer (1963.3.30.246), 3 190.
Reteporella watersi (Nordgaard) (Fig. 3B) Retepora beaniana var. watersi Nordgaard 1907: 16 Retepora beaniana var. watersi: Kluge 1962: 529, fig. 370 Reteporella watersi: Hayward 1994: 195, fig.8A,B Material. NHM 1896.8.3.1, Rockall, 90 fm; 1911.10.1.798, Flor¨o, Norway; 1911.10.1.799, Faroe Channel; 1963.3.30.246, Hardangerfjorden, Norway. Remarks. This species was recently redescribed from the Faroe Islands (Hayward, 1994), where it appears to be very common. Examination of material in The Natural History Museum, London, indicated that it had previously been confused with R. beaniana. The colony of R. watersi forms a broadly open fan-shape, and it is generally much more robust, with heavier calcification and proportionately smaller fenestrulae, than that of R. beaniana. The frontal calcification of the autozooids is regularly dimpled, or shagreened, and becomes especially coarse in late ontogeny. A final point of distinction between the two is the peristome: in R. watersi the suboral avicularium is proportionately larger than in R. beaniana and the peristomial notch adjacent to it closes distally in early ontogeny to define a distinct, round pseudospiramen. Reteporella watersi ranges north from the Faroe Islands to northern Norway and into the Arctic Sea. Its presently known southern limit is Rockall but it is probable that the species extends further south along the West European continental shelf.
ACKNOWLEDGEMENTS
We are grateful to the NERC for financial support, to Mary E. Spencer Jones (The
112
P. J. HAYWARD AND J. S. RYLAND
Natural History Museum, London) for the loan of specimens, and to Dr M.R. Fordy (SBS, University of Wales, Swansea) for scanning electron microscopy.
REFERENCES Busk G. 1884. Report on the Polyzoa. Part 1. The Cheilostomata. Report of the Scientific Results of the Voyage of HMS Challenger, Zoology 10: 1–126. Calvet L. 1927. Bryozoaires de Monaco et environs. Bulletin de l’Institute Oc´eanographique Monaco 503: 1–46. Cook PL. 1968. Bryozoa (Polyzoa) from the coast of tropical West Africa. Atlantide Report 10: 115–262. Gabb WM, Horn GH. 1862. The fossil Polyzoa of the Secondary and Tertiary Formations of North America. Journal of the Academy of Natural Sciences of Philadelphia 5(2): 111–179. Gautier YV. 1962. Recherches e´ cologiques sur les Bryozoaires chilostomes en Mediterran´ee occidentale. Recueil des Travaux de la Station Marine d’Endoume, Facult´e des Sciences de Marseille 38: 1–434. Gordon DP. 1989. The marine fauna of New Zealand: Bryozoa: Gymnolaemata (Cheilostomida Ascophorina) from the western South Island Continental Shelf and Slope. Memoirs of the New Zealand Oceanographic Institute 97: 1–158. Harmer SF. 1933. The genera of Reteporidae. Proceedings of the Zoological Society of London 1933: 615–627. Hayward PJ. 1974. Studies on the cheilostome bryozoan fauna of the Aegean Island of Chios. Journal of Natural History 8: 369–402. Hayward PJ. 1978. Bryozoa from the west European continental slope. Journal of Zoology, London 184: 207–224. Hayward PJ. 1994. New species and new records of cheilostomatous Bryozoa from the Faroe Islands, collected by BIOFAR. Sarsia 79: 181–206. Hayward PJ, Ryland JS. 1979. British Ascophoran Bryozoans. Linnean Society Synopses of the British Fauna (n.s.) 14: 1–312. Hincks T. 1878. Notes on the genus Retepora, with descriptions of new species. Annals and Magazine of Natural History (5)1: 353–365. Hincks T. 1880. A history of the British marine Polyzoa. Van Voorst; London. Vol. 1, 601 pp. Vol. 2, 83 pls. Jullien, J. 1903. In: Jullien J, Calvet L. Bryozoaires provenant des campagnes de l’Hirondelle. R´esultats des campagnes scientifiques accompli par le Prince Albert I 23: 1–188. King W. 1846. An account of some shells and other invertebrate forms found on the coasts of Northumberland and Durham. Annals and Magazine of Natural History 18: 233–251. Kluge GA. 1962. Mshanki severnykh morei SSSR. Opredeliteli po faune SSSR, Izdavaemye Zoologicheskim Muzeem Akademii Nauk 76: 1–584. Lamarck, JBP, de M. 1801. Systˆeme des Animaux sans vert`ebres…pr´ec´ed´e du discours d’ouverture du Cours de Zoologie, donn´e dans le Mus´eum National d’Histoire Naturelle, l’an 8. Paris. Nordgaard O. 1907 Bryozoen von dem norwegischen Fischereidampfer “Michael Sars” in den Jahren 1900-1904 gesammelt. Bergens Museums Aarbog 1907 (2): 1–20. Ryland JS. 1963. Systematic and biological studies on Polyzoa (Bryozoa) from western Norway. Sarsia 14: 1–59. Ryland JS. 1965. Two polyzoans new to the British Fauna. Nature 206: 957. ¨ Smitt FA 1868. Kritisk F¨orteckning o¨ fver Skandinaviens Hafs-Bryozoer. IV. Ofversigt af Kongliga Vetenskaps-Akademiens F¨orhandlingar 25: 3–230. Soldani A. 1789-98. Testaceographiae ac Zoophytographiae parvae et microscopicae tomus primus (– secundus), etc. Senis. 2 vols.
Some British Phidoloporidae (Bryozoa: Cheilostomatida) P. J. HAYWARD F.L.S. AND J. S. RYLAND F.L.S. Marine and Environmental Research Group, School of Biological Sciences, University of Wales, Swansea, Singleton Park, Swansea, SA2 8PP
Received April 1995, accepted for publication August 1995
Five British species of Reteporella Busk, 1884 are described and figured. A neotype specimen is selected for R. beaniana (King), and R. incognita sp. nov. is described, and distinguished from R. couchii (Hincks). ©1996 The Linnean Society of London
ADDITIONAL KEY WORDS: — Neotype – new species. CONTENTS Introduction . . . . . Systematic accounts . . . Reteporella beaniana (King) R. couchii (Hincks) . . . R. incognita sp. nov. R. septentrionalis (Harmer) . R. watersi (Nordgaard) . . Acknowledgements . . . References . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
. . . . . . . . .
103 104 104 107 107 109 111 111 112
INTRODUCTION
The fenestrate, or reteporiform, cheilostomate bryozoans popularly known as lace corals are represented in the Northeast Atlantic region by three genera and five described species. The taxonomy of this apparently uniform group has changed radically since the three species reported from the British Sea area were described and figured in the Linnean Society Synopsis, British Ascophoran Bryozoans (Hayward & Ryland, 1979). Gordon (1989) finally resolved the problem over the validity of the long-used genus Retepora Lamarck, 1801 by establishing that it is a junior homonym of Retepora Soldani, 1795 and thus unavailable for lace corals despite its much arguedover pre-Linnean usage. Further, he showed that Phidoloporidae Gabb and Horn, 1862 had taxonomic precedence over Sertellidae Jullien, 1903, which in recent years has been used by taxonomists in preference to Reteporidae Smitt, 1868. In the same work Gordon (1989) also suggested that Reteporella Busk, 1884 should be considered the senior synonym of Sertella Jullien, 1903, on the grounds that the only 0024–4082/96/050103 + 10 $18.00/0
103
©1996 The Linnean Society of London
104
P. J. HAYWARD AND J. S. RYLAND
distinguishing feature between the two genera was the form of the colony, which in Reteporella is generally freely branching or irregularly anastomosed, and in Sertella generally regularly anastomosed, or closely reticulate. Re-examination of the type species of Reteporella, R. flabellata Busk, 1884, vindicates Gordon’s (1989) view as its autozooidal morphology differs in no substantial way from any described species of Sertella. The Northeast Atlantic lace corals thus consist of the genera Phidolopora Gabb and Horn, 1862, represented by the single species P. elongata (Smitt), Reteporellina Harmer, 1933, for R. hyperborea Hayward, and Reteporella Busk, 1884, represented by R. septentrionalis (Harmer), R. beaniana (King) and R. couchii (Hincks), in the family Phidoloporidae Gabb and Horn, 1862. In preparing updated accounts of the species of Reteporella for a revised edition of the Linnean Society Synopsis, specimens of all three species, from a number of localities in the British sea area, have been examined by scanning electron microscopy, in comparison with specimens from the Faroe Islands and from several Mediterranean localities. Of especial interest is R. septentrionalis (Harmer), which in Britain is known only from a few localities in the extreme north, is apparently common further north, yet has also been widely reported from shallow coastal habitats throughout the Mediterranean (e.g. Gautier, 1962; Hayward, 1974). Comparison of specimens from the northern and southern limits of its range confirm that only a single species may be recognized, although some Mediterranean specimens, resembling those described by Calvet (1927) as Retepora cellulosa var. aquilina, show slight morphological differences from north European specimens. Nordgaard (1907) noted a distinctive ‘variety’ of R. beaniana (King) from Iceland which he named var. watersi. The only subsequent author to recognise this taxon was Kluge (1962), who also figured it for the first time; Hayward (1994) redescribed it and raised it to full specific ranking, noting that previous authors (e.g. Ryland, 1963) did not distinguish it from R. beaniana. Reteporella watersi was found to be common around the Faroe Islands and the Faroe Bank (Hayward, 1994); it occurs along the western coasts of Norway, and northwards to Spitzbergen, Franz Josef Land and the Barents Sea. Its southern limit is presently unknown but it may prove to occur in deep waters to the west of the Shetland Isles, where the bryozoan fauna has many similarities with that of the Faroe Islands. Examination of specimens of R. couchii from several British localities revealed a further, previously undescribed species, almost certainly overlooked because of its superficial resemblance to R. couchii. It is here described as R. incognita sp. nov.. All five species of Reteporella present in the British sea area are here described and figured, using scanning electron microscopy. Specimens deposited in the collections of The Natural History Museum, London are denoted by the prefix NHM, and their respective registration numbers.
SYSTEMATIC ACCOUNTS
Reteporella beaniana (King) (Fig. 1A–C) Retepora beaniana King, 1846: 237 Retepora beaniana: Hincks, 1880; 391, pl. 53, figs. 1–5 Sertella beaniana: Hayward & Ryland, 1979: 262, figs 112A, 113
SOME BRITISH PHIDOLOPORIDAE (BRYOZOA: CHEILOSTOMATIDA)
Figure 1. A–C, Reteporella beaniana. A, group of autozooids, 3 70. B, detail of ovicelled autozooids, 3 140. C, primary orifice, 3 388. [A,B: 1911.10.1.795, Northumberland. C: 1911.10.1.792, Shetland] D,E, Reteporella couchii [1911.10.1.804, Guernsey]. D, autozooids at a branch edge, 3 70. E, ovicelled autozooids with characteristic development of the peristome, 3 100.
105
106
P. J. HAYWARD AND J. S. RYLAND
Material. NEOTYPE (selected here): NHM 1911.10.1.795, Northumberland. Other material: NHM reg.nos. 1994.3.8.16, Norway; 1911.10.1.798, Flor¨o, Norway; 1911.10.1.792, 1361, 1362, Shetland; 1888.6.9.22, Loch Lorn; 1898.8.25.4, Rockall Bank; 1899.7.1.2916, Beadnell, Northumberland. Description. Colony 40–50 mm high, with an equivalent horizontal spread; developing an open fan, or a shallow cup-shape, but with the edges of the colony usually folded or enrolled to a varying degree. Trabeculae consisting of three to five alternating, longitudinal series of autozooids, doubled at points of trabecular fusion; fenestrulae oval, longer than wide, commonly 1.5 3 0.5 mm. Autozooids about 0.5 3 0.2 mm, separated by distinct, raised sutures in early ontogeny, which become obscured by later ontogenetic thickening of the frontal shields; calcification smooth, each autozooid with few (3–5) large, distinct marginal pores. Frontal shield predominantly cryptocystidean, but with a reduced umbonuloid fold immediately proximal to the orifice, bounded on its inner face by a distinct ring scar. Primary orifice broadly bellshaped, about 0.09 3 0.11 mm, slightly wider than long; distal border distinctly toothed, condyles rounded. A single stout spine present on each side of the orifice, level with the condyles (occasionally a second, smaller spine above each); cylindrical, blunt, to 0.2 mm long, typically persisting in late ontogeny. Peristome developed laterally and proximally, partly obscuring orifice in frontal view; a single oval avicularium present on its rim, mid-proximally, 0.6 mm long, proximally or proximo-laterally directed, slightly acute to frontal plane and projecting conspicuously. Distal rim of avicularium finely toothed, proximal edge developed as a bifid mucro projecting above the orifice of the autozooid. Rim of peristome deeply notched adjacent to avicularium, forming an open pseudosinus, which does not close over in later ontogeny. Additional oval avicularia sporadically developed on frontal walls of autozooids and on abfrontal colony surface, often frequent on older parts of colony. Ovicell slightly wider than long, flattened frontally, with an elongate median fissure; aperture arched, without a labellum; partly obscured in later ontogeny by secondary calcification. Remarks. Reteporella beaniana was originally described from specimens collected off the Northumberland coast (King, 1846) but these could not be traced in the collections of The Natural History Museum, London, University College, Galway, or Trinity College, Dublin, and are considered to be no longer extant. A neotype is here selected, from the Northumberland coast, in order to stabilize the taxon. It is common off the east coasts of Britain, from Yorkshire northwards, and has recently been collected from a gas-drilling rig in the southern North Sea (R. Hamond, pers. comm.); it ranges northeastwards to the Faroe Islands and West Norway. Ryland’s (1963) material from the Bergen area, and material collected earlier from the Hardangerfjord (NHM 1963.3.30.246) included specimens of both this species and R. watersi (Nordgaard), and in mixed collections from the Faroe Islands (Hayward, 1994), R. watersi was more abundant than R. beaniana. It is distributed from Shetland southwards along the western coasts of Britain and Ireland, and occurs below 200 m in the Bay of Biscay, but does not appear to reach the Mediterranean. This species is readily distinguished from R. watersi by its more delicate, folded colony form, by the smooth frontal calcification of the autozooids, and by its open peristomial pseudosinus.
SOME BRITISH PHIDOLOPORIDAE (BRYOZOA: CHEILOSTOMATIDA)
107
Reteporella couchii (Hincks) (Fig.1D,E) Retepora couchii Hincks, 1878: 355, pl.18, figs 1–6; 1880; 395, pl.53, figs 6–11 Sertella couchii: Hayward & Ryland, 1979: 264, figs 112B, 114 Material. HOLOTYPE: NHM 1899.5.1.1242, Lands End, Hincks colln. (ex. Couch) Other material: NHM 1879.4.25.69, Naples; 1899.5.1.;1008, Naples; 1899.7.1.3014, 3020, Madeira; 1899.7.1.3015–3018, Mediterranean; 1911.10.1.806, Madeira; 1911. 10.1.793, Finmark; 1911.10.1.804, 1938.11.26.1, Guernsey; 1963.8.2.22,23, Alexandria; 1965.8.20.24, La Chapelle Bank. Description. Colony 20–30 mm high, with equivalent horizontal spread; growing edge lobed and loosely convolute, forming a three-dimensional structure. Trabeculae consisting of two to four alternating, longitudinal series of autozooids, doubled at points of trabecular fusion; fenestrulae elongate oval, 0.5–1.0 mm long, as wide as the trabeculae. Autozooids elongate, convex, smoothly calcified, separated by raised sutures; commonly 0.5 3 0.2 mm. Primary orifice broader than long, proximal border straight or slightly convex; condyles indistinct, distal denticulations minute. Two to four delicate, distal oral spines present in earliest ontogeny only, obliterated by the development of a deep peristome, formed from two elongate proximo-lateral flaps fused medially except at the extreme proximal end, where they part to define a round pseudospiramen. One side of the peristome incorporates a slender cylindrical avicularian cystid,up to 0.3 mm long, projecting conspicuously from the colony surface; rostrum terminal, oval, 0.05 mm long, with complete, slender crossbar. Frontal avicularia sporadic; normal to frontal plane, proximally directed, 0.2 mm long; rostrum parallel-sided, distally rounded, with a complete, slender crossbar; palate with a small triangular or trilobed foramen just distal to crossbar. Similar avicularia present, often numerous, on abfrontal surface of colony, 0.1–0.2 mm long; also small, oval avicularia, 0.05 mm long. Ovicell prominent and conspicuous, twice as long as wide, with a narrow median fissure extending the whole of its length. Remarks. Reteporella couchii occurs offshore, on coarse grounds, and is apparently widespread throughout the Mediterranean. It ranges south to the Gulf of Guinea (Cook, 1968), and northwards to the Channel Isles and South Cornwall. There is a single specimen from northern Norway (NHM 1911.10.1.793), and one specimen has been collected recently from the Faroe Islands, but it has yet to be reported from off the western coasts of Britain. Reteporella incognita sp. nov. (Fig. 2A–C) Material. HOLOTYPE: NHM 1994.3.11.10, Shetland, A.M. Norman colln. PARATYPE: NHM 1911.10.1.805, off SW Ireland. Other material: BIOFAR Stn. 090; 1897.5.1.1241, W of Great Skellig Ireland; 1897.5.1.1240, no locality; 1899.7.1.77, NNW of Rona, 55 fms; 1963.2.12.150, W of Ireland. Description. Colony architecture incompletely known, but broadly fan-shaped, with a lobed, folded edge; exceeding 40 mm high, with an equivalent spread. Fenestrulae irregularly oval, commonly 1.0 3 0.5 mm; trabeculae stout, consisting of three or
108
P. J. HAYWARD AND J. S. RYLAND
Figure 2. A–C, Reteporella incognita sp. nov. A, portion of holotype colony (1994.3.11.10), 3 35. B, detail, showing ovicells and characteristic peristome, 3 60. C, primary orifice (1911.10.1.805), 3 400. D–F, Reteporella septentrionalis. D, ovicelled autozooids in frontal view, 3 70. E, lateral view, to show cusps on avicularium rostrum [1911.10.1.807, Finmark], 3 50. F, a specimen from Rovinj (F.K. McKinney), 3 70.
SOME BRITISH PHIDOLOPORIDAE (BRYOZOA: CHEILOSTOMATIDA)
109
four alternating, longitudinal autozooid series,doubled at points of trabecular fusion. Autozooids elongate, irregularly polygonal, bounded by raised sutures; commonly 0.5 3 0.25 mm. Primary orifice longer than wide, proximal edge gently concave; condyles small, rounded, mid-distal border indistinctly toothed. Two widely spaced distal oral spines present in newly developed autozooids, neither of which persists in later ontogeny. Frontal shield smooth, with few ( < 10) irregularly spaced marginal pores. Avicularia polymorphic: consistently one lateral-suboral, with a columnar cystid, the rostrum 0.08 mm long, oval, terminal, normal to frontal plane, usually orientated along a disto-proximal axis; rostrum finely denticulate distally, crossbar complete, with a small columella. The length of the columnar cystid varies, most often 0.15–0.3 mm; basally it fuses with one lateral lobe of the peristome; on the other side of the orifice the peristome is produced as a narrow lobe which arches proximo-medially to fuse with the avicularian cystid, thus defining a large, round mid-proximal foramen. Frontal avicularia sporadic, sometimes identical to lateral suboral type, or larger (0.13 mm) with tapered rostrum supporting a triangular mandible. Both types of avicularia present abundantly around edges of fenestrulae, and more sparsely on the basal surfaces of the colony. Ovicell about as broad as long; its aperture highly arched, without a labellum, the longitudinal frontal fissure extending most of its length. Remarks. This species has a superficial resemblance to R. couchii (Hincks), for which reason it has probably been overlooked. The most striking similarity between the two species is the tall, columnar, lateral suboral avicularium, which in both varies in length in different parts of the colony. In R. couchii the rostrum of the avicularium is tapered proximally while that of R. incognita is regularly rounded. The peristome of R. couchii is very much deeper than that of this new species and bears a distinctive channelled line of fusion between the two lobes, and a relatively small mid-proximal foramen, distinct from the rim of the peristome. The fused peristomial lobes of R. incognita are each smaller than the large foramen. Other major points of difference lie in the ovicell, which is much longer than broad in R. couchii; and the frontal avicularia, which are short and triangular in R. incognita but elongate and lingulate in R. couchii.
Reteporella septentrionalis (Harmer) (Figs 2D–F, 3A) Retepora cellulosa forma cellulosa Smitt 1868: 35, pl.28, figs 222–225 Retepora cellulosa: Kluge 1962: 526, fig. 367; 1975: 639 Sertella septentrionalis Harmer 1933: 620; Hayward and Ryland 1979: 266, figs 112C, 115 Material. Arctic specimens: NHM reg. nos. 1899.7.1.2992, Norway; 1899.7.1.2995, 2999, Spitzbergen; 1899.7.1.2998, Godthaab; 1911.10.1.807, 808, Finmark; 1921.5.23.5, Whales Beach, Iceland. Mediterranean specimens: 1843.3.6.137, ‘Mediterranean’; 1878.5.10.270, Malta; 1899.7.1.2991, Mediterranean coast of Spain; 1899.7.1.2965,2974,2980, 2981,2989,2997, ‘Mediterranean’; 1899.7.1.2977, Tenerife; 1963.8.2.24, Alexandria; 1965.9.2.26, Mediterranean Stn.187 (Gautier,
110
P. J. HAYWARD AND J. S. RYLAND
1962); 1965.9.2.;34, Mediterranean Stn.182 (Gautier, 1962); 1965.9.2.35, Mediterranean Stn.279 (Gautier, 1962); 1975.1.12.410, Chios; Rovinj, Adriatic (F.K. McKinney colln.). Description. Colony up to 40 mm high, 80 mm horizontal spread; initially a shallow cup-shape, but its rim lobed or folded in larger colonies, often forming anastomoses defining narrow tubes or funnels, and developing a compact, convoluted, threedimensional form. Fenestrulae elongate oval, 1.0–1.6 mm long, wider than the rather slender trabeculae, giving a delicate, open fenestration. Autozooids in two to four longitudinal series, or up to eight at points of trabecular fusion; elongate, 0.4–0.6 3 about 0.2 mm; convex, separated by distinct sutures in early ontogeny. Primary orifice wider than long; distal edge with few, minute denticulations, proximal edge very slightly concave; condyles short, rounded, indistinct. A pair of delicate, lateral oral spines present in early ontogeny, obscured by development of the peristome. Peristome consisting of two unequal-sized proximo-lateral flaps, fusing distally to define a rounded pseudospiramen below a long, proximo-lateral suture. Frontal shield smooth or finely nodular, with three to five widely spaced and conspicuous marginal pores. Avicularia polymorphic, numerous: most frequently oval, normal to frontal plane, 0.09–0.11 mm long, with complete, slender crossbar; one or two present on the frontal shield of every autozooid, with variable orientation. Rarely, similarly-sized avicularia with acute rostra also present. Commonly and characteristically a massively enlarged avicularium occupies much of the frontal shield of the autozooid, the rostrum projecting at a right angle to the frontal plane, its proximal portion partly obscuring the primary orifice of the autozooid; rostrum up to 0.35 mm long, narrowly triangular, with a sharp, abruptly hooked tip, and a sharp cusp on each side halfway along its length. Ovicell slightly longer than wide, with a short, rounded labellum projecting over its aperture, and a wide frontal fissure running about two-thirds of its length. Remarks. Specimens from Arctic Norway display the large, strongly hooked avicularium, with prominent lateral cusps, figured by Smitt (1868). In Mediterranean specimens the enlarged avicularia tend to be more slender, without pronounced lateral cusps. In these specimens, also, the lateral oral spines tend to persist into late ontogeny, visible above the rim of the peristome even in ovicelled autozooids; the ovicell tends to be shorter than in Arctic specimens, with a straight-edged labellum. Reteporella septentrionalis has a curious geographical distribution. It is widespread, and apparently common, in Arctic seas; it is rare around the Faroes, but has occurred in deep water off St. Kilda (Ryland, 1965) and in the Bay of Biscay (Hayward, 1978). What appears to be the same species is widely distributed in shallow waters throughout the Mediterranean; it was accurately described and figured by Calvet (1927), as Retepora cellulosa var. aquilina. The Mediterranean specimens listed above all conform closely to Calvet’s account, with the single exception of the Malta specimen (1878.5.10.270), in which the enlarged avicularia bear lateral cusps similar to those seen in the Arctic specimens.
SOME BRITISH PHIDOLOPORIDAE (BRYOZOA: CHEILOSTOMATIDA)
111
Figure 3. A, Reteporella septentrionalis, a specimen from Malta (1878.5.10.270), 3 100. B, Reteporella watersi, a specimen from Hardangerfjorden collected by S.F. Harmer (1963.3.30.246), 3 190.
Reteporella watersi (Nordgaard) (Fig. 3B) Retepora beaniana var. watersi Nordgaard 1907: 16 Retepora beaniana var. watersi: Kluge 1962: 529, fig. 370 Reteporella watersi: Hayward 1994: 195, fig.8A,B Material. NHM 1896.8.3.1, Rockall, 90 fm; 1911.10.1.798, Flor¨o, Norway; 1911.10.1.799, Faroe Channel; 1963.3.30.246, Hardangerfjorden, Norway. Remarks. This species was recently redescribed from the Faroe Islands (Hayward, 1994), where it appears to be very common. Examination of material in The Natural History Museum, London, indicated that it had previously been confused with R. beaniana. The colony of R. watersi forms a broadly open fan-shape, and it is generally much more robust, with heavier calcification and proportionately smaller fenestrulae, than that of R. beaniana. The frontal calcification of the autozooids is regularly dimpled, or shagreened, and becomes especially coarse in late ontogeny. A final point of distinction between the two is the peristome: in R. watersi the suboral avicularium is proportionately larger than in R. beaniana and the peristomial notch adjacent to it closes distally in early ontogeny to define a distinct, round pseudospiramen. Reteporella watersi ranges north from the Faroe Islands to northern Norway and into the Arctic Sea. Its presently known southern limit is Rockall but it is probable that the species extends further south along the West European continental shelf.
ACKNOWLEDGEMENTS
We are grateful to the NERC for financial support, to Mary E. Spencer Jones (The
112
P. J. HAYWARD AND J. S. RYLAND
Natural History Museum, London) for the loan of specimens, and to Dr M.R. Fordy (SBS, University of Wales, Swansea) for scanning electron microscopy.
REFERENCES Busk G. 1884. Report on the Polyzoa. Part 1. The Cheilostomata. Report of the Scientific Results of the Voyage of HMS Challenger, Zoology 10: 1–126. Calvet L. 1927. Bryozoaires de Monaco et environs. Bulletin de l’Institute Oc´eanographique Monaco 503: 1–46. Cook PL. 1968. Bryozoa (Polyzoa) from the coast of tropical West Africa. Atlantide Report 10: 115–262. Gabb WM, Horn GH. 1862. The fossil Polyzoa of the Secondary and Tertiary Formations of North America. Journal of the Academy of Natural Sciences of Philadelphia 5(2): 111–179. Gautier YV. 1962. Recherches e´ cologiques sur les Bryozoaires chilostomes en Mediterran´ee occidentale. Recueil des Travaux de la Station Marine d’Endoume, Facult´e des Sciences de Marseille 38: 1–434. Gordon DP. 1989. The marine fauna of New Zealand: Bryozoa: Gymnolaemata (Cheilostomida Ascophorina) from the western South Island Continental Shelf and Slope. Memoirs of the New Zealand Oceanographic Institute 97: 1–158. Harmer SF. 1933. The genera of Reteporidae. Proceedings of the Zoological Society of London 1933: 615–627. Hayward PJ. 1974. Studies on the cheilostome bryozoan fauna of the Aegean Island of Chios. Journal of Natural History 8: 369–402. Hayward PJ. 1978. Bryozoa from the west European continental slope. Journal of Zoology, London 184: 207–224. Hayward PJ. 1994. New species and new records of cheilostomatous Bryozoa from the Faroe Islands, collected by BIOFAR. Sarsia 79: 181–206. Hayward PJ, Ryland JS. 1979. British Ascophoran Bryozoans. Linnean Society Synopses of the British Fauna (n.s.) 14: 1–312. Hincks T. 1878. Notes on the genus Retepora, with descriptions of new species. Annals and Magazine of Natural History (5)1: 353–365. Hincks T. 1880. A history of the British marine Polyzoa. Van Voorst; London. Vol. 1, 601 pp. Vol. 2, 83 pls. Jullien, J. 1903. In: Jullien J, Calvet L. Bryozoaires provenant des campagnes de l’Hirondelle. R´esultats des campagnes scientifiques accompli par le Prince Albert I 23: 1–188. King W. 1846. An account of some shells and other invertebrate forms found on the coasts of Northumberland and Durham. Annals and Magazine of Natural History 18: 233–251. Kluge GA. 1962. Mshanki severnykh morei SSSR. Opredeliteli po faune SSSR, Izdavaemye Zoologicheskim Muzeem Akademii Nauk 76: 1–584. Lamarck, JBP, de M. 1801. Systˆeme des Animaux sans vert`ebres…pr´ec´ed´e du discours d’ouverture du Cours de Zoologie, donn´e dans le Mus´eum National d’Histoire Naturelle, l’an 8. Paris. Nordgaard O. 1907 Bryozoen von dem norwegischen Fischereidampfer “Michael Sars” in den Jahren 1900-1904 gesammelt. Bergens Museums Aarbog 1907 (2): 1–20. Ryland JS. 1963. Systematic and biological studies on Polyzoa (Bryozoa) from western Norway. Sarsia 14: 1–59. Ryland JS. 1965. Two polyzoans new to the British Fauna. Nature 206: 957. ¨ Smitt FA 1868. Kritisk F¨orteckning o¨ fver Skandinaviens Hafs-Bryozoer. IV. Ofversigt af Kongliga Vetenskaps-Akademiens F¨orhandlingar 25: 3–230. Soldani A. 1789-98. Testaceographiae ac Zoophytographiae parvae et microscopicae tomus primus (– secundus), etc. Senis. 2 vols.