Family CRIBRILINIDAE Hincks, 1879

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Family CRIBRILINIDAE Hincks, 1879

Compiler and date details

July 2001 - Dr Philip Bock

Introduction

The family was introduced by Hincks (1879) for Cribrilina, and many other genera have been assigned subsequently. The similarities among species variously assigned to Membraniporella and Crassimarginatella have been discussed by Gordon (1984, 1986), and are illustrated by the example of 'Figularia huttoni' figured by Wass & Yoo (1983) as a cribrimorph, but reassigned to the Calloporidae by Gordon, who placed it in Valdemunitella.

The Cribrilinidae includes all the Recent genera of cribrimorphs, and many of the Tertiary forms. The families of Cretaceous genera described by Lang and discussed by Larwood (1962) are not considered here. Taylor (1993) noted that the fossil record of the family was well established by the Late Cretaceous, but that its relationships were unclear.

Cribrimorphs are characterised by autozooids with a frontal shield formed by the fusion of a series of flattened, hollow, marginal spines arising from the gymnocyst and in contact internally with the visceral coelom. The spines curve above the frontal membrane, and the operculum is often coterminous with a secondary calcified orifice formed by the curved distal part of the mural rim, and the distal edge of the suboral spines. Condyles are often present, as are oral spines, which may be forked but not fused. The frontal spines may be intermittently fused laterally, forming series of lacunae. On the frontal surface, a series of cuticle covered windows may be present. These may expand and calcify, forming vertical spinous processes, which may branch and fuse with those of neighbouring zooids, forming a secondary frontal shield. Frontally budded kenozooids may occur between the autozooids, becoming extrazooidal, or producing rhizoids and other structures in some genera. Ovicells are hyperstomial and usually bear paired fenestrae in the frontal ectooecium. Avicularia may be adventitious, interzooidal or even vicarious. Three genera have been reported from Australia, and four from Antarctica; one further genus, Figularia, occurs in both regions.

The genus Puellina is characterised by its small zooids and elongated, acute, interzooidal avicularia. Recent revision has revealed that the 'cosmopolitan' species such as P. radiata and P. innominata include numerous distinct taxa. Wass & Yoo (1983) illustrated 'Cribrilaria radiata' from South Australia, but Hayward & Ryland (1995) recorded three new species from the Great Barrier Reef and noted that they had probably been reported before as one of the 'cosmopolitan' forms.

The genus Corbulipora is represented in Australia by Tertiary and Recent species, but apparently does not occur elsewhere. It is characterised by its capacity to occur in different growth phases, which seem to have different functions and often have totally different morphologies. As a result, the species Corbulipora tubulifera has been recorded under several different generic and specific names, including the 'flustrine' genus Watersia. Two Recent species are now known, one distributed from New South Wales to the Great Australian Bight, the other only in the western Bight region. Both have small encrusting primary phases, erect flustrine secondary phases and bilaminar phases anchored by rhizoids. Each phase is capable of an independent existence. The genus has been discussed by Bock & Cook (1994) and revised by Bock & Cook (1998 and 2001b).

The genus Anaskopora Wass was originally considered to be a subgenus of Corbulipora, but it has been revised and raised to generic rank by Bock & Cook (2001c). Like Corbulipora, it also occurs in the Victorian Tertiary, but also has two Recent species, which occur from Queensland to New South Wales. The genus is characterised by small, often globular colonies, which are known to be anchored by rhizoids. The autozooids have one or more distal interzooidal avicularia and are surrounded by frontally budded kenozooids. A. doliaris is remarkable in having colonies composed of alternating circlets of zooids produced by reversed frontal budding (Arnold & Cook, 1997).

The genus Figularia is widely distributed and has been reported from both Australia and Antarctica. Hincks (1881) recorded F. speciosa from Bass Strait, and the common F. figularis was reported for the first time in Australia by Ryland & Hayward (1992) from the Great Barrier Reef. F. tenuicosta, originally described from the Victorian Tertiary by MacGillivray (1895), was illustrated by Wass & Yoo (1983), who recorded it from numerous southern coast localities. In the Antarctic, F. discors occurs in the Ross Sea, and the closely similar genera Filaguria and Klugerella are found forming small patches on algae and other bryozoans from both Antarctic and subantarctic localities (Hayward, 1995).

The genus Dendriperistoma has a frontal shield formed by numerous costae and intercostal lacunae, appearing to be regularly perforated. D. projecta occurs on hard substrata, and is an endemic Antarctic form (Hayward 1995).

Diagnosis

Colony encrusting or erect. Frontal wall with extensive area of frontal membrane, almost entirely concealed by a shield of calcified hollow flattened spines, fusing medially to form a costal area, with openings between the spines for the passage of water from the epistegal space beneath the shield. Uncalcified windows may occur on the upper surface of the calcified spines. Gymnocyst extensive to absent. The primary orifice is uncalcified; the opening in the frontal shield is a secondary calcified orifice, its appearance variable, depending on the development of the distal pair of costal spines. Oral spines present in some forms. Avicularia adventitious, or interzooidal to vicarious, or absent. Ovicells hyperstomial, prominent; with smooth calcification or with varying types of windows in the ectooecium, or with pseudopores.