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Cornutella profunda
Ehrenberg, 1854
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Description - Add description
Cornutella clathrata profunda:
Siliceous tests, the shells straight with pores in alternating longitudinal rows, swollen at the narrow end, armed with a short spine. Length 90µ. Pores circular, 13 in a longitudinal row 150µ long, 3-5 in a transverse row, larger in the broad part; margin of the aperture irregular. I never saw these Cornutellas curved, though they occur frequently. Some forms, lacking the horn at the apex, may be assigned to another variety or species. (Translated from Latin by E.M. Riedel and W.R. Riedel.)
| | Ehrenberg 1854 | Cornutella profunda:
Shell slender, conical, with smooth surface. Cephalis small, hyaline, poreless, with conical, acute apical horn. Pores of thorax regularly arranged, subcircular, increasing in size distally, 4-7 on the half-circumference. Proximal part of the thorax usually poreless. Some specimens have a heavier shell-wall, with wider intervening bars between the pores which are fewer in number, and tend to be subcylindrical or slightly contracted in the distal one-third or one-quarter. Length of apical horn 2-30µ, of cephalis 7-20µ , of thorax 110-200µ . Maximum shell breadth 45-65µ . ...Besides its occurrence in the Indian Ocean sector of antarctic waters, this species has been found at widespread localities in the tropical parts of the Pacific and Indian Ocean, and in the northern Pacific. Ehrenberg (1856) described it from the North Atlantic. It thus appears to be cosmopolitan.
| | Riedel 1958 | Benson, 1966, p. 430-432; pl. 29, figs. 7-8:
Cornutella profunda Ehrenberg
Cornutella clathrata B profunda Ehrenberg, 1856, Mikcrogeologie, Pl. 35B, fig. 21; Bailey, 1856, Amer. Jour. Sci., vol. 22, p. 2, Pl. 1, fig. 23.
Cornutella profunda Ehrenberg, 1859, Akad. Berlin, Monatsb. (1858), p. 31; Riedel, 1958, B.A.N.Z.A.R.E. Repts., ser. B, vol. 6, pt. 10, p. 232, Pl. 3, figs. 1, 2.
Sethoconus profundus (Ehrenberg) Haeckel, 1887, Challenger Rept., Zool., vol. 18, p. 1294.
Cornutella hexagona Haeckel, 1887, Challenger Rept., Zool., vol. 18, p.1180, Pl. 54, fig. 9.
Test consisting of a small, smooth, hyaline cephalis with a slender, conico-cylindrical thorax. Cephalis with a short, conical apical spine arising eccentrically from its upper face. Thorax smooth, separated by a slight constriction from the cephalis; long, slender, and conical for about one-half to one-third of its length from stricture, cylindrical for the remainder of its length; in more fully developed forms its basal portion tapers slightly inward. Pores of thorax just below cephalis with infillings of silica, increase in size and are open toward lower part of conical portion; pores of cylindrical portion of thorax large, of nearly equal size although increasing slightly in size distally, generally hexagonal in shape, becoming circular to elliptical in specimens with heavier deposits of silica (wider intervening bars); pores arranged hexagonally in longitudinal rows, about 5-7 rows on half the circumference of the cylindrical thorax. Collar pores, vertical spine, and primary lateral and dorsal spines or thoracic ribs not observed.
Measurements; based on 30 specimen.a from stations 27 and 34: maximum length of test exclusive of apical spine 114-191 µm; length of cephalis 6-9 µm, of apical spine 1-12 µm; breadth of cephalis 5-9 µm; maximum breadth of thorax 43-71 µm.
Remarks. Riedel (1958, p. 232) has investigated the synonymy of this species, but due to the unavailability of topotypic material, he was unable to do a thorough analysis. I observed specimens of this species from the Gulf which are nearly identical with Sethoconus orthoceras Haeckel (1887, p. 1294, Pl. 54, fig. 11)--having circular to elliptical pores separated by wide intervening bars due to heavier desposits of silica; a second stricture below the collar stricture was not observed, but the lower stricture of Haeckel’s species may represent the lower termination of infilled thoracic pores. Sethoconus bimarginatus Haeckel (1887, p.1295, Pl. 54, fig. 12) is characterized by doubly-contoured thoracic pores separated by wide intervening bars. A few thoracic pores of a few tests from the Gulf have double rims; therefore, this feature is subject to intraspecific variation.
Distribution. This species is rare but nearly cosmopolitan in the Gulf, occurring as far north as stations 191 and 192. It is absent north of this region as well as at stations 194, 130, 99, 95, 90, and 64. Its absence from marginal and northern shelf localities indicates its preference for an offshore, more nearly oceanic habitat. Its frequency undergoes no significant fluctuations throughout the Gulf; therefore, it apparently does not respond to upwelling. Its frequency and distribution in both the northern and southern halves of the Gulf are similar.
Riedel (1958, p. 232)) states that this species appears to be cosmopolitan. It is present in the Indian Ocean sector of Antarctic waters, the tropical parts of the Pacific and Indian Oceans, and in the northern Pacific and northern Atlantic.
| | Benson 1966 |
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