Family CHORIZOPORIDAE Vigneaux, 1949

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Introduction

The family Chorizoporidae was introduced by Vigneaux (1949) and is monogeneric for Chorizopora Hincks (1879). Zooids generally have an imperforate, gymnocystal frontal shield. This is either smooth, or bears few to numerous papillae, spikes or conical processes (Gordon 1984). Like Haplopoma, Chorizopora has zooids with a semicircular orifice, but is distinguished by the absence of any ascopore, the presence of tubular processes which link the discrete zooids to one another, and by the interpolated avicularia (Hayward & Ryland 1979). Three species are known from Australian waters. Harmer (1957) described the smooth-shielded, almost cosmopolitan C. brongniartii, and C. spinosa from Torres Strait and the East Indies. C. spinosa has an unusually small ovicell, trifurcate processes by the orifice, and often some papillae on the frontal shield. C. vittata was described (as Lepralia) from Victoria by MacGillivray (1869, 1879). It has a median shallow depression in its frontal shield, in which there are apparent spine elements. This arrangement is such a distinctive feature that a new genus might be appropriate for this species, which is also distinguished by the presence of an ascopore in the ancestrula. C. spinosa resembles one of the species described from New Zealand by Gordon (1984).

The family is not known before the Upper Miocene (Taylor 1993), but, like Haplopoma, probably derives from Cretaceous hippothoids with a porous gymnocyst. Evidence for an early origin of the family is the occurrence of true avicularia with cross-bars. These are unknown elsewhere in the superfamily Hippothooidea, although avicularia with mandibular pivots do occur in Cretaceous hippothoids with porous gymnocysts, and in the putative cribrilinid ancestors of hippothoids. Although chorizoporids lack abundant gymnocystal pores in the frontal shield, such pores can occur between papillae and they also occur in the frontal walls of the tubular connections between zooids in loci that can be occupied by small avicularia. Species of Chorizoporidae encrust stones, shells, and crustose coralline algae.

Diagnosis

Colony encrusting, thinly calcified, forming a sheet or network of disjunct zooids connected by tubular processes which are extensions of pore-chambers. Zooids with a gymnocystal frontal and semicircular orifice. Avicularia interzooidal. Ovicells hyperstomial and prominent.

General References

Gordon, D.P. 1984. The marine fauna of New Zealand: Bryozoa: Gymnolaemata from the Kermadec Ridge. New Zealand Oceanographic Institute Memoir 91: 1-198

Harmer, S.F. 1957. The Polyzoa of the Siboga Expedition. Part 4. Cheilostomata Ascophora II. Siboga-Expéditie Report 28D: 641-1147

Hayward, P.J. & Ryland, J.S. 1979. British Ascophoran Bryozoans. pp. 1-312 in Kermack, D.M. & Barnes, R.S.K. (eds). Synopses of the British Fauna. n.s London : Academic Press for the Linnean Society Vol. 14 pp.

Hincks, T. 1879. On the classification of the British Polyzoa. Annals and Magazine of Natural History 5 3: 153-164

Macgillivray, P.H. 1869. Descriptions of some new genera and species of Australian Polyzoa; to which is added a list of species found in Victoria. Transactions and Proceedings of the Royal Society of Victoria 9: 126-148

Macgillivray, P.H. 1879. Polyzoa. 21-40, pls 35-39 in McCoy, F. (ed.). Prodromus of the Zoology of Victoria Decade 4. Melbourne : George Robertson.

Taylor, P.D. 1993. Bryozoa. pp. 465-489 in Benton, M.J. (ed.). The Fossil Record 2. London & New York : Chapman & Hall 845 pp.

Vigneaux, M. 1949. Révision des Bryozoaires néogènes du Bassin d'Aquitaine et essai de classification. Mémoires de la Société Géologique de France, n.s 28: 1-153

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