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Anthocyrtidium angulare Nigrini, 1971

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Cephalis trilobate, elongate, with subcircular pores, bearing a stout three-bladed apical spine of approximately the same length as the cephalis. Thorax shaped like a biretta. Three stout thoracic ribs, which may become external to form short, thorn-like wings, control the shape of the upper thorax. There is a sharp break in shell contour where the ribs terminate, and the lower thorax is approximately cylindrical. Pores circular to subcricular, usually arranged longitudinally. Eight to eleven, three-bladed subterminal teeth, directed outwards, ae usually present, but may be absent or much reduced. Distally from the subterminal teeth, the thoracic wall curves sharply inwards and terminates at a narrow, poreless peristome which often bears numerous short, delicate, lamellar, terminal teeth, directed downwards and inwards. Figured specimens from SDSE 62, 1028-30cm, USMN No. 650932 (holotype fig. 3a), USMN No. 650933 (paratype fig. 3b).
Dimensions (based on 20 specimens): Length of apical horn 18-27µ; of cephalis 18-36µ; of thorax 36-81µ; of subterminal teeth 9-18µ. Maximum breadth of cephalis 18-27µ; of thorax 72-100µ.
Nigrini 1971











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