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Cycladophora humerus (Petrushevskaya, 1975)

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Clathrocyclas humerus
The number of pores (about 13 in the transverse row), the shell out- line with the small velum, and the dimensions are the same as in C. bicornis (Popofsky). The distinguishing characteristics are the pronounced "shoulders" and thickened part of the thorax (Plate 15, Figure 7). It is very similar to the "shoulders" of the Paleocene species (Plate 15, Figures 18-20), but C. humerus has more pores. It is difficult to say if the shoulders may originate in different branches of Clathrocyclas independently (in parallel way), or if the two species, the Paleocene and C. humerus are closely related. The description is based on 46 specimens from Site 278 (Cores 12-30). Holotype No 676767 in Marine Department. Species name means "shoulder."
Petrushevskaya 1975
Cephalis medium to small, subspherical, with scattered small subcircular pores and two long 3-bladed apical horns. The upper thorax is variably developed. In some specimens it is very compressed and moderately flared, while in other specimens it s more equant and less flared. The upper thorax is typically inflated on one side, flat on the other. The lower thorax is much wider than the upper thorax ans is joined to it by a very prominent shoulder. The lower thorax is slightly compressed to somewhat elongate, moderately flared, and flat-sided below the shoulder. Upper thorax pores are small, subcircular, arranged in regular rows. Lower thorax pores are of medium size, circular, uniform in size and shape, and are arranged in staggered horizontal rows. Lower thorax bars are narrow, of medium thickness; surface of shell smooth Internal ring marks base of thorax. Abdominal skirt is short, very strongly flared, and generally contains from 1 to 3 rows of small circular pores. A partial basal plate, thin walled and with medium sized circular pores is occasionally present.
Lombari and Lazarus 1988


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