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Carpocanistrum sp. A
(Nigrini, 1970)
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Description - Add description
Benson, 1966, p. 438-439; pl. 29, figs. 11-12:
Carpocanium sp.
Remarks. This species differs from Carpocanium petalospyris Haeckel in the presence of a cylindrical or nearly cylindrical thorax in all tests and larger pores that are equal, subcircular to hexagonal, arranged hexagonally but in fewer longitudinal rows (9-12 on half the circumference). The surface of the thorax varies from smooth to rough with hexagonal frames surrounding the pores. In a few specimens the portions of the hexagonal frames between longitudinal rows of pores are nearly straight although zig-zag, suggestive of longitudinal ridges. The mouth is slightly constricted in all tests. The peristomal teeth are present but much less evident than in C. petalospyris. When present they vary in number from 5-14 and are generally flat or blade-like and triangular to rectangular in outline. They either extend vertically downward or converge inward. In details of the cephalis and. thoracic ribs this species does not differ from C. petalospyris.
Because Haeckel described but did not illustrate several species of Carpocanium, the possiblity exists that one of these is identical to the species in question. Examination of his type material, however, is necessary. None of these species agrees in all details with the Gulf forms although C. cylindricum Haeckel (1887, p. 1281), C. enneaphyllum Haeckel (1887, p. 1281), C. trepanium Haeckel (1887, p. 1282), and C. dactylus Haeckel (1887, p. 1284) are described as being either cylindrical or subcylindrical or slenderly ovate. The last two species agree more closely with the Gulf species in the size of their pores, but without their illustrations their identity with the Gulf species cannot be determined.
Mesurements; based on 27 specimens from station 27: length of test (including peristomal teeth) 92-149 µm, of cephalis (when visible) 16-21 µm; maximum breadth of thorax 59-79 µm; length of peristomal teeth (when present) 4-27 µm.
Distribution. The distribution of this species in the Gulf is the same as that for Carpocanium petalospyris except that it occurs at station 99 but not at 133. It is likewise absent at station 151 and all those to the north. It is rare at all stations where it occurs, but it has a slightly greater frequency in the southern half of its range. It is an oceanic species with little affinity for Gulf waters, and it does not respond to upwelling in the southern Gulf.
The species listed in the remarks above were reported from tropical or low temperate latitudes of the Pacific, Atlantic, and Indian Oceans.
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