Family BUSKIIDAE Hincks, 1880

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Introduction

The family Buskiidae was introduced by Hincks (1880) for the genus Buskia, which includes a wide range of species, some with inconspicuous colonies, others with erect, branching stolons. Autozooids are budded singly or in groups but without the organization apparent in Amathia. They are adnate and attached to the stolon kenozooid for much of their length, and often have their lateral margins produced into projections. The orifice region is raised and 8-10 tentacles have been reported. There is a gizzard, and embryos are brooded in the tentacle sheath.

Australian records include two species. The first, B. socialis, has an almost world-wide temperate to warm-water distribution, and was described as a fouling species by Gordon & Mawatari (1992). B. socialis has wide stolons and numerous, closely apposed autozooids budded throughout the length of each branch stolon. There are 8 tentacles. B. socialis was reported erroneously as Bowerbankia gracilis from Adelaide by Brock (1985), who illustrated the wide stolons and adnate autozooids. The second species was recorded from Torres Strait by Harmer (1915). Buskia pilosa has inconspicuous creeping stolons which bud isolated autozooids. These have long, branched lateral projections and the entire zooidal surface is covered with long setose expansions of body wall, particularly around the orifice, where they may equal the autozooid in length.

The genus Cryptopolyzoon was originally described from two species occurring from Port Phillip by Dendy (1888), who emended the original generic name (Cryptozoon) in 1900. It is characterised by its nodular groups of autozooids, each separated by robust stolons. It is, however, virtually impossible to see the autozooids because they are completely covered by adherent sand grains or minute pieces of shell attached to the zooidal cuticle. The tentacles are protruded between the sand grains for feeding, Colonies are quite large, reaching 5 cms across and straggling over algae and other bryozoans from water depths of about 20 m. Bock (1982) has pointed out that species of Cryptopolyzoon may not be recognised as bryozoans at all. The two species differ in the extent of the autozooidal groups, which are regular and rounded in C. wilsoni and almost continuous in C. concretum.

Tentacle numbers range from 10-12 in C. wilsoni and 14 in C. concretum. Dendy (1888) described the morphology in great detail, including the gizzard, which has large paired conical teeth rather like those of Aeverrillia.

C. wilsoni has also been reported from South Africa (O'Donoghue & de Watteville 1944). Marcus (1941) described another form from Brazil, but the colonies have no stolons and may be generically distinct. Buskia has been reported as a fossil from bioimmurated Jurassic specimens by Todd (1994).

Diagnosis

Colony creeping, inconspicuous, or erect and branching, composed of kenozooidal stolons and groups of autozooids. Some autozooids covered by adherent shell fragments. Gizzard present; embryos brooded in the tentacle sheath.

General References

Bock, P.E. 1982. Bryozoans (Phylum Bryozoa). pp. 319-394 in Shepherd, S.A. & Thomas, I.M. (eds). Marine Invertebrates of Southern Australia. Handbook of the Flora and Fauna of South Australia Adelaide : Government Printer Part 1 491 pp.

Brock, B.J. 1985. South Australian fouling Bryozoans. pp. 45-49 in Nielsen, C. & Larwood, G.P. (eds). Bryozoa: Ordovician to Recent. Fredensborg : Olsen & Olsen.

Dendy, A. 1888. On the anatomy of an arenaceous Polyzoon. Proceedings of the Royal Society of Victoria 1: 1-11

Dendy, A. 1900. Cryptopolyzoon, an emendation in nomenclature. Zoologischer Anzeiger 23: 391-392

Gordon, D.P., & Mawatari, S.F. 1992. Atlas of marine-fouling Bryozoa of New Zealand ports and harbours. Miscellaneous publications of the New Zealand Oceanographic Institute 107: 1-52

Harmer, S.F. 1915. The Polyzoa of the Siboga Expedition. Part 1. Entoprocta, Ctenostomata and Cyclostomata. Siboga-Expéditie Report 28A: 1-180

Hincks, T.H. 1880. A history of the British Marine Polyzoa. London : John van Voorst 601 pp.

Marcus, E. 1941. Sôbre Bryozoa do Brasil. Boletim da Faculdade de Filosofia, Ciências e Letras da Universidade de São Paulo, Zoologia 5 (22, Zoologia): 3-208

O'Donoghue, C.H., & de Watteville, D. 1944. Additional notes on Bryozoa from South Africa. Annals of the Natal Museum 10: 407-432

Todd, J.A. 1994. The role of bioimmuration in the exceptional preservation of fossil ctenostomates, including a Jurassic species of Buskia. pp. 187-192 in Hayward, P.J., Ryland, J.S. & Taylor, P.D. (eds). Biology and Palaeobiology of Bryozoans. Fredensborg : Olsen & Olsen.

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