Family EMINOOECIIDAE Hayward & Thorpe, 1988

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Family EMINOOECIIDAE Hayward & Thorpe, 1988

Compiler and date details

July 2001 - Dr Philip Bock

Introduction

The small family Eminooeciidae was established for two endemic Antarctic genera, Eminooecia and Isoschizoporella by Hayward & Thorpe (1988). The former is presently monotypical, the latter comprises four living species. All are described and figured by Hayward (1995). A third genus, Macrocamera, was defined by Gordon & d'Hondt (1997), for a new species, M. erecta, from New Caledonia and for Schizomavella pansa Gordon 1989 from Fiordland, New Zealand.

Eminooecia and Isoschizoporella both develop erect colonies; E. carsonae (Rogick) and I. virgula Hayward & Thorpe are narrow branching forms, the other species of Isoschizoporella form foliaceous plates. The primary orifice is sinuate; adventitious avicularia occur; characteristically the ovicell is associated with a distal kenozooidal chamber.

Gordon & d'Hondt (1997) expressed doubts as to the close relationship between Eminooecia and Isoschizoporella. They associated Macrocamera with Eminooecia because both genera had large ovicells with a calcified ectooecium. Macrocamera is represented by several species from the Australian Tertiary, and one Recent species, found from the shelf off Western Australia (Bock & Cook, 2001).

Macrocamera erecta forms small colonies growing from a short encrusting portion to form erect narrow quadriserial branches. Ovicells are large, hyperstomial, and develop early in the astogeny of the colony. Avicularia are absent. Colonies are found growing on the frontal surface of the other bryozoans Canda and Caberea. This species is found from a small area south of Albany and Esperance in Western Australia, at depths from 140 to 180 metres.

Eminooecia carsonae forms slender rod-shaped colonies, attached by encrusting bases; they branch irregularly and form frequent anastomoses with adjoining rods; the height may exceed 50 mm, but maximum branch width is about 2 mm. Autozooids are disposed in spiralled whorls of about 12. They are elongate, rectilinear, with raised, crenulate, lateral walls and a flat, cryptocystidean frontal shield with very few, conspicuous, marginal septula. The primary orifice is large, more or less bell-shaped, with a broadly concave proximal edge below indistinct condyles. There is an inconstant median suboral avicularium. The globular ovicell incorporates a small chamber distally between its two layers, with a septulum linking its cavity with the autozooid on which it lies. In Isoschizoporella the ovicell is associated with an avicularium, which may be distally situated and rather squat, in I. secunda, or distal and/or lateral in other species, but columnar and pointed, with the avicularium rostrum on its side. The colonies of I. virgula are slender rods, exceeding 20 mm high but less than 2 mm wide, with zooids arranged in whorls of four. In other species of Isoschizoporella the colonies develop irregular, bilaminar, foliaceous plates.

Diagnosis

Colony moderately to well calcified, arising from a small encrusting base, erect, with narrow, sometimes anastomosing branches. Zooids in whorls, or in frontal, zooidal and abfrontal, non-zooidal series. Frontal shields lepralioid, elongated, with a few prominent marginal areolae only. Primary orifice often sinuate, with a suboral avicularium, other avicularia frontal. Ovicell large and globular, with two distinct and separated calcified layers, or with marginal septular pores.