Family PACHYZOIDAE d'Hondt, 1983

Museums

Regional Maps

• Pachyzoontidae D'Hondt, J.-L. 1983. Tabular keys for the identification of the Recent Ctenostomatous Bryozoa. Mémoires de l'Institut Océanographique, Monaco 14: 1-134 [amended by Gordon (2009)].

  Secondary source:

   Gordon, D.P. (ed.) 2009. The New Zealand Inventory of Biodiversity Volume 1: Kingdom Animalia: Radiata, Lophotrochozoa, Deuterostomia. Christchurch : Canterbury University Press 566 pp.

Introduction

The family Pachyzoontidae was introduced by d'Hondt (1983) for a new, monospecific genus of deep-water ctenostome, Pachyzoon.

The family is characterised by its small, bun-shaped colonies about 4-5 mm in diameter, composed of closely packed zooids. Long, tubular peristomes protrude from the main mass of the colony on one side, which is inferred to be uppermost in life, whereas long cuticular rhizoids anchor the colony on the opposite side (Cook 1988).

Pachyzoon atlanticum is confined to very deep waters, and has been reported from 457 to over 5000 m depth in the north Atlantic. Like many other deep-sea bryozoans, particularly ctenostomes, such as Pseudalcyonidium and Aethozoon, its distribution has been found to be much wider, and it has recently been recorded from 595-2103 m, off New Caledonia, by d'Hondt & Gordon (1996). It is certain to occur in the deeper slope waters off eastern Australia, and the family is therefore included here.

Diagnosis

Colony small, rounded, formed by contiguous autozooids with a thick cuticle and long, tubular peristomes on the upper face, and kenozooidal rhizoids on the lower face.

General References

Cook, P.L. 1988. Bryozoa. pp. 438-443 in Higgins, R.P. & Thiel, H. (eds). Introduction to the Study of Meiofauna. Washington, D.C. : Smithsonian Institution Press 448 pp.

D'Hondt, J.-L. 1983. Tabular keys for the identification of the Recent Ctenostomatous Bryozoa. Mémoires de l'Institut Océanographique, Monaco 14: 1-134

D'Hondt, Jean-Loup, & Gordon, Dennis P. 1996. Bryozoa: Cténostomes et Cheilostomes (Cellularines, Scrupariines et Malacostéges) des campagnes MUSORSTOM autour de la Nouvelle-Calédonie. (Résultats des campagnes MUSORSTOM, Vol. 15). Mémoires du Muséum national d'Histoire naturelle, Paris [1936-1950] 168: 55-123

History of changes