Family UMBONULIDAE Canu, 1904

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Introduction

The Family Umbonulidae was introduced by Canu and discussed by Cheetham (1968) and Gordon (1984). Colonies are typically encrusting, but may have erect portions. The frontal shield is umbonuloid, with marginal septula which are seen at the surface as deep areolar depressions. The orifice is subquadrate. Frontal avicularia are present. Ovicells are hyperstomial, with pores in the frontal surface. The majority of species have a Northern Hemisphere distribution.

One genus with an Antarctic distribution, Astochoporella, (Hayward, 1995) has been included in this family, although the genus has also been assigned to the Bryocryptellidae. A. cassidula forms large, unilaminar, convoluted and anastomosing sheets, and is common in the Ross Sea and Prydz Bay.

The earliest known fossil umbonulid is from the Late Eocene of France (Taylor 1993).

Diagnosis

Colony encrusting, forming sheets, or semi-erect, unilaminar, anastomosing and convoluted. Frontal shield umbonuloid. Ovicells immersed.

General References

Cheetham, A.H. 1968. Morphology and systematics of the bryozoan genus Metrarabdotos. Smithsonian Miscellaneous Collections 153: 1-121

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

Hayward, P.J. 1995. Antarctic cheilostomatous Bryozoa. Oxford, New York, Tokyo : Oxford University Press 355 pp. [197]

Hayward, P.J. 1995. Antarctic cheilostomatous Bryozoa. Oxford, New York, Tokyo : Oxford University Press 355 pp.

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

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