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Anthocyrtidium pliocenica Seguenza, 1880

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Shell smooth, with obliterated collar stricture. Length of the two joints= 3:10, breadth= 2:8. Cephalis subcylindrical, with an excentric, stout, pyramidal horn of the same length. Thorax bottle-shaped, with small, regular, circular pores of equal size. Mouth little constricted, with twenty to thirty small, triangular, convergent feet, about half as long as the cephalis.
Dimesions: Cephalis 0.03 long, 0.02 broad; thorax 0.1 long, 0.08 broad.
Haeckel 1887
Anthocyrtidium pliocenica (Seguenza), p. 357
Plate 2, figures 5, 6

Description: Cephalis trilobate, elongate, ovate-cylindrical with small, circular pores, arranged in longitudinal rows, and bearing a stout, three-bladed apical horn, approximately the same length or longer than the cephalis. In some specimens the end of the apical horn is somewhat thorny or rough. Collar stricture indistinct. Thorax generally heavy, elongate, ovate with longitudinal rows of circular to subcircular pores which may be hexagonally framed. Pores are uniform in size and arrangement, 15-15 on a half equator at the widest part the thorax. Mouth very slightly constricted, with a well-developed poreless peristome and 8-9 stout, flat, blunt or pointed terminal teeth which are directed inwards or downwards; rarely terminal teeth are bifurcated. Pointed subterminal teeth (up to 10) may also be present, but are never as well-developed as the terminal teeth.

Dimensions: Length of apical horn 25-50 µ; of cephalis 25-40 µ; of thorax 80-105 µ. Maximum breadth of thorax 65-90 µ.

Distinguishing characters: Apical horn as long as or longer than cephalis. Thorax elongated, ovate with large pores of uniform size. Well-developed peristome, subterminal and terminal teeth.

Stratigraphic range: The F.A.D. of this species in this study is in DSDP Site 573-14-6 (D. penultima Zone), but a similar form has been observed (A. Safilippo, personal communication) in other material as early as the L. elongata Zone. L.A.D. occurs nears the top of the S. pentas Zone.

Geographic range and abundance: Rare and poorly developed in the Indian Ocean and western pacific Ocean. Central Pacific forms are more robust with well-developed terminal teeth; few to common.

Phylogeny: Appears to arise from A. ehrenbergi at least as early as the D. petterssoni Zone (A. Sanfilippo, personal communication).

Nigrini and Caulet 1988











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