Family DENSIPORIDAE Borg, 1944

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Family DENSIPORIDAE Borg, 1944

Compiler and date details

July 2001 - Dr Philip Bock

Introduction

Borg (1944) introduced the family Densiporidae for Densipora corrugata MacGillivray (1881). The family was for a time included in the Cerioporidae (Taylor 1993), but its separation has been reconfirmed (Taylor & Weedon 2000). Gordon & Taylor (2001) have proposed that the genera Favosipora and Flosculipora be included in the Densiporidae. A characteristic of the members of the family is that the autozooids and heterozooids are generally free-walled, lacking calcified frontal walls, while the brood chambers are roofed by an exterior wall. Some autozooids with extended peristomes have a fixed wall.

Densipora corrugata is common in shallow water off southern Australian coasts, forming large, fusiform colonies, up to 25 mm long and 12 mm in diameter, encircling stems of the seagrass Amphibolis antarctica (Bock 1982). The colony surface is raised into regular, screw-like ridges, an appearance also seen in several species of the cheilostome genus Celleporaria, particularly C. cristata. Autozooids have a short peristome sourrounded by about 6 to 9 short rounded spinous processes; the orifice is often closed by a calcified plate. Brood chambers cover extensive areas of the depressions between the ridges, surrounding many autozooid tubes. The brood chamber is covered with a porous wall; the ooeciostome is large and oval. Waters (1879) described a similar species with raised corrugations, growing on algal stems off Adelaide, South Australia, which he called Heteropora cervicornis d'Orbigny. D. cervicornis (Waters not d'Orbigny) is probably a synonym of D. corrugata. Another synonym may be Heteropora maeandrina Kirkpatrick (1888) from Victoria, according to Borg (1933). Undescribed material from southwestern Australia at depths of 40-50 m grows as flat colonies, and may be a different species.

Flosculipora pygmaea is also common in southern Australia.

Diagnosis

Colony encrusting, sometimes thickly, or small and pedunculate; radially symmetrical or, if extensive, with macular centres. Autozooids and kenozooids free-walled (lacking exterior frontal walls), although some autozooid peristomes fixed-walled. Autozooids arranged radially or quincuncially, flanked or surrounded by kenozooids lacking diaphragms. Brood-chamber roof exterior-walled, entire or pierced by autozooidal peristomes, densely pseudoporous and typically bordered by raised rim; ooeciostome relatively simple tube, ooeciopore generally simple, sometimes flared. (Gordon & Taylor 2001)