|
|
|
Cyrtocapsella tetrapera
(Haeckel, 1887)
|
Description - Add description
Shell rough, pear-shaped, with three deep strictures. The three first joints are of equal lengths, and each half as long as the hemispherical fourth joint. Cephalis subspherical, with an oblique conical horn of the same length. The third joint is the broadest, three times as broad as long. Pores regular, circular.
Dimensions.-Length of the shell (with four joints) 0.15, breadth 0.09; length of each of the three first joints 0.03, of the last 0.06.
Habitat.-Western Tropical Pacific, Station 225, depth 4475 fathoms. | | Haeckel 1887 | Cyrtocapsella tetrapera
Description: Shell of four segments, with rounded termination. Cephalis spherical, poreless or with a few small pores, in some specimens with a short apical horn. Collar stricture moderately pronounced. Thorax conical to hemispherical: third segment annular or inflated; fourth segment hemispherical, with a strongly constricted mouth about twice as wide as a pore. Second to fourth segments rather thick-walled, with their pores subcircular to circular and rather regular in size and arrangement. Strictures in some specimens rather pronounced, in others not expressed externally. Some specimens have a variable, inverted caplike segment with a thinner wall and less regular pores than in the second to fourth segments.
Measurements: Based on 35 specimens from core AMPH 6P, 18-20 cm. and 52-54 cm., and from core DODO 39P, 1 84-186 cm. Total length (excluding horn and fifth segment) 100-140 µ (usually 115-130µ). Length of second segment 25-45 µ (usually about 35µ). of third segment 25-40µ. of fourth segment 30-55 µ. Maximum breadth 75-105µ.
Remarks: This species is distinguished from C. cornuta in lacking the pronounced change in contour between the second and third segments. It seems probable that the form described by Lucchese as Theocapsa piriformis actually has four segments, the cephalis not being noticed because the specimen was tilted. Vinassa appears also not to have observed the cephalis in Tricolocapsa elliptica. Stichocapsa laevigata Vinassa is only questionably synonymized because of its smooth surface. The fact that the range of Cyrtocapsella tetrapera is apparently interrupted in the late Lower and early Middle Miocene seems to indicate that we may here be dealing with two morphologically similar species that originated independently and therefore should be treated as separate taxa. This is not done here, however, pending confirmation of the interruption. | | Sanfilippo & Riedel 1970 |
|
|
 |
|
