Family EUTHYROIDIDAE Levinsen, 1909

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Introduction

The family Euthyroididae was introduced by Levinsen (1909) for Euthyroides Harmer (1902), and was revised and redefined by Gordon (1989). It includes only one genus and two species, the type species, Carbasea episcopalis, first described by Busk from Bass Strait (1852a; 1852b); and E. jellyae Levinsen, from New Zealand.

Colonies are large, up to 100 mm high, flustrine, flexible and unilaminar. They are anchored by proximal rhizoids, and have tubular kenozooids running down the margins of each branch. Zooids are thinly calcified, the frontal shield is principally a smooth, imperforate gymnocyst. At the distal end of the shield, just proximal to the orifice, there are two to three small, spinous processes forming a minute 'cribrimorph' costal shield in autozooids. Brooding zooids have a distinct costal shield of two to six costae with frontal pelmatidia. Ovicells are very large and prominent, with paired, cuticle-covered windows in the ectooecium, exposing the underlying entooecium. E. episcopalis does not have any avicularia, which are large and vicarious in E. jellyae.

E. episcopalis occurs at shelf depths from southern Australia and from numerous localities in New Zealand, documented by Gordon (1989), who noted the association of the family with the Cribriomorpha.

Diagnosis

Colony erect, branching, attached by rhizoids. Branches flexible, weakly calcified, unilaminar; calcification gymnocystal, imperforate. Long narrow kenozooids on margins of branches. A small costal field proximal to orifice, in some forms vestigial, visible only as a sutural line in the calcification. Orifice rounded to semicircular with concave proximal margin. No spines or avicularia. Ovicells often in groups, hyperstomial, prominent, with a pair of windows in the ectooecium.

General References

Busk, G. 1852. An account of the Polyzoa and Sertularian Zoophytes, collected in the voyage of the "Rattlesnake" on the coast of Australia and the Louisade Archipelago, etc. Appendix no. IV. pp. 343-402 in MacGillivray, J. (ed.). Narrative of the Voyage of H.M.S. Rattlesnake. London : T. & W. Boone Vol. 1.

Busk, G. 1852. Catalogue of marine Polyzoa in the collection of the British Museum, Part 1. London : Trustees of the British Museum pp. 1-54.

Gordon, D.P. 1989. The marine fauna of New Zealand: Bryozoa: Gymnolaemata (Cheilostomida Ascophorina) from the western south Island continental shelf and slope. New Zealand Oceanographic Institute Memoir 97: 1-158

Harmer, S.F. 1902. On the morphology of the Cheilostomata. Quarterly Journal of Microscopical Science 46: 263-350

Levinsen, G.M.R. 1909. Morphological and systematic studies on the cheilostomatous Bryozoa. Copenhagen : Nationale Forfatteres Forlag 431 pp.

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