| Home> Cenozoic> Holocene (Recent)> Gulf of California>
 

List species

Carpocanistrum spp. (Nigrini, 1970)

Description - Add description

Benson, 1966, p. 434-437; pl. 29, figs. 9-10; text-fig. 25:

Carpocanium petalospyris Haeckel

Carpocanium petalospyris Haeckel, 1887, Challenger Rept., Zool., vol. 18, p. 1283, Pl. 52, fig. 19.
Carpocanium peristomium Haeckel, 1887, Challenger Rept., Zool., vol. 18, pp. 1283-1284, Pl. 52, figs. 16, 17.
Carpocanium irregulare Haeckel, 1887, Challenger Rept., Zool., vol. 18, p. 1284, Pl. 52, fig. 14.
Carpocanium verecundum Haeckel, l887, Challenger Rept., Zool., vol. 18, pp. 1284-1285, Pl. 52, figs. 12, 13.
Carpocanium virgineum Haeckel, 1887, Challenger Rept., Zool., vol. 18, p. 1285, Pl. 52, fig. 20.
Asecta prunoides Popofsky, 1913, Deutsche SŘdpolar-Exped., vol. 14, p. 373, text fig. 89.

Test consisting of a cap-shaped cephalis and a thorax; cephalis hidden at top of thorax, in a few specimens separated from thorax by slight constriction but generally indistinguishable; with an internal collar ring consisting of four collar pores (cardinals and cervicals) at its base; collar ring joined to inner wall of thorax by the primary lateral and dorsal bars, which extend as ribs coincident with furrows in the thoracic wall and by a few accessory bars that arise from the collar ring and join the inner thoracic wall but do extend as ribs (text-fig. 25). Thorax variable in shape from nearly cylindrical with constricted mouth to greatly inflated, nearly subspherical, with constricted mouth. Pores of thorax equal, small, the same size as those of cephalis, arranged hexagonally in longitudinal rows (15-22 rows on the half circumference), subcircular to hexagonal; surface of intervening bars variable from smooth to one with hexagonal frames surrounding pores. Mouth constricted, in most specimens surrounded by a hyaline peristome (4-16 Ám in length); peristome absent in a few tests. Peristome surmounted by tooth-like, lamellar to pyramidal, triangular to rectangular, terminal spines or teeth, variable in number from 0-16 or more. Teeth of some specimens triangular, converging inward, of others lamellar or rectangular, extending vertically downward. A few specimens with a few adjacent teeth fused together. One specimen observed with all teeth fused together to form a vertical, lamellar, hyaline extension of the peristome. Another specimen observed with similar peristomal extension but not hyaline, instead with pores similar to those of the thorax giving the appearance of a rudimentary abdomen separated from the thorax by a hyaline septal ring.

Measurernents; based on 30 specimens from station 27: length of test (not including terminal teeth) 80-107 Ám, of cephalis (when visible) 15-20 Ám; breadth of thorax 59-98 Ám; length of peristomal teeth 5-33 Ám.

Remarks. Most of Haeckel's illustrated species of Carpocanium (Haeckel, 1887, Pl. 52, figs. 12-20) represent one or two species only because the shape of the thorax and the nature of the peristomal teeth are subject to intraspecific variation and are poor characters for defining species. The constant characters of the Gulf specimens of this species include 15-22 longitudinal rows of small, equal, hexagonally arranged thoracic pores and a constricted mouth, generally with a hyaline peristome with or without teeth. By page preference the first species conforming to the above becomes the nominal species. With the exception of having terminal teeth nearly as long as the shell, C. petalospyris Haeckel (1887, p. 1283, Pl. 52, fig. 19) fits the description of the Gulf specimens. The other species listed in the synonymy were separated by Haeckel on the basis of characters of the peristomal teeth or shape of thorax, but the nature of their pores conforms to the Gulf species. Three species of Carpocanistrum Haeckel (op. cit., Pl. 52, figs. 9-11) all conform in outward appearance to the Gulf species but differ apparently in their lack of a hidden cephalis, although further study of Haeckel' s type material may reveal its presence. Asecta prunoides Popofsky (1913, p. 373) has pores similar to those of the Gulf species but differs from the majority of the Gulf specimens in the lack of terminal teeth. Because this is a variable character, Popofsky's species is placed in synonymy with Carpocanium petalospyris.

Distrtbution. This species is confined to the southern two-thirds of the Gulf. It is rare at all stations where present but has a slightly greater frequency in the southern half of its range. It is absent at stations 91, 99, 115, 130, 151, and all those to the north. 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 synonymy are reported from all seas but are confined to tropical or temperate regions. The Gulf species, therefore, is widely distributed in Recent tropical to temperate seas.
Benson 1966


Description

 

Images

 

Synonyms

 

References

 

Distribution

 

Discussion / Comments

 

Web links