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Anthocyrtidium ophirense (Ehrenberg, 1872)

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Anthocyrtis ophirensis (p. 1270):
Shell smooth, with slight collar stricture. Length of the two joints = 2: 4, breadth = 1:5. Cephalis ovate, with irregular roundish pores, and a pyramidal, excentric, vertical horn of the same length. Thorax campanulate, with delicate network of large, regular, hexagonal pores. (In the specimen figured by Ehrenberg only seven feet are represented, two being broken off; two other specimens of this species, captured by Rabbe, exhibited nine regularly disposed feet.)

Dimensions: Cephalis 0.03 long, 0.02 broad; thorax 0.08 long, 0.1 broad.
Habitat: Indian Ocean, Zanzibar (Pullen); Madagascar (Rabbe), surface.
Haeckel 1887
Benson, 1966, p. 472-475; pl. 32, figs. 6-9:

Anthocyrtidium cineraria Haeckel

Anthocyrtidium cineraria Haeckel, 1887, Challenger Rept., Zool., vol. 18, p. 1278, Pl. 62, fig. 16; Popofsky, 1913, Deutsche Südpolar-Exped., vol. 14, pp. 370-371, Pl . 38, fig. 1, text fig. 87; Riedel, 1957, Swed. Deep-Sea Exped., Repts., vol. 6, fasc. 3, pp. 84-86, Pl. 2, figs. 6-9; fig. 4.
Not Sethocyrtis oxycephalis Haeckel; Riedel, 1957, Swed. Deep-Sea Exped., Repts., vol. 6, fasc. 3, p. 84.

Cephalis, dorso-lateral lobes, and apical horn similar to, if not the same as those of Anthocyrtium oxycephalis (Haeckel); four collar pores present; dorsal and primary lateral bars extend as thoracic ribs, raised in a few tests, for a distance of 3-5 pores and terminate in short thorns or spines as in A. oxycephalis. Thorax generally conical to campanulate, widely inflated at its base where it curves inward abruptly, terminating in a relatively wide but constricted mouth having a short hyaline peristome; proximally the thorax undergoes a definite change in contour below the cephalis, but it is not as abrupt nor as angular as in A. oxycephalis. Pores of thorax hexagonally arranged in vertical rows, subcircular to subhexagonal, increasing slightly in size distally, with intervening bars ranging from thin, surmounted by rudimentary hexagonal frames, to relatively wide (one-half the width of the pores) with a smooth flat surface. Six to twelve, generally three-bladed, sharply-pointed, divergent downward subterminal spines arise from the broadest part of the thorax at its base, just above the level of its basal inward curvature; in apical views these spines appear to be aligned with vertical but zig-zag intervening bars which separate the vertical rows of hexagonally arranged thoracic pores. Peristome of variable state of development but generally present as a thin hyaline ring surmounted by 4-16 flat, tooth-like, triangular thorns or spines which do not converge inward but project nearly vertically downwards; in about half the specimens studied the peristomal spines are lacking.

Measurements; based on 30 specimens from stations 27 and 34: length of test (including apical horn) 160-212 µm, of apical horn 22-59 µm, of cephalis (top of ventral face to median bar) 22-47 µm, of thorax 80-123 µm; breadth of cephalis (including dorsal, ventral or lateral views) 27-38 µm, of thorax 89-144 µm, (mean, 115.8 µm); length of subterminal spines 12-43 µm, of peristomal spines (when present) 2-18 µm.

Remarks. The differences between this species and Anthocyrtium oxycephalis (Haeckel) were discussed in the remarks of the latter. It differs from Lamprocyclas maritalis Haeckel in the absence of an abdomen separated from the thorax by an internal septal ring and in the presence of larger subterminal spines.
There is little doubt that this species is Anthocyrtidium cineraria. It differs from Riedel's (1957, pp. 84-85) description only in the lack of well-developed hexagonal frames surrounding the thoracic pores, but this feature is subject to intraspecific variation in most radiolarian species. A few Gulf specimens have rudimentary or poorly developed frames. It differs from Haeckel's description (1887, p. 1278) only in the general absence of double-contoured thoracic pores, although a few Gulf specimens have this feature. Popofsky's description (1913, pp. 370-371) agrees well with the Gulf species, and he reached a similar conclusion regarding the general absence of double-contoured pores. He also noted the presence of the dorsal and primary lateral spines which in the Gulf specimens extend as short spines from thoracic ribs. Riedel (1957, pp. 85-86) states that Eucyrtidium pleuracanthus Ehrenberg (1873b, Pl. 7, fig. 21) and Anthocyrtis ophirensis Ehrenberg (op. cit., Pl. 9, fig. 13) possibly should be grouped together with A. cineraria but that further work on assemblages from type localities of these forms is needed.

Distribution. This species is much rarer in the Gulf than Anthocyrtium oxycephalis (Haeckel). It occurs no farther north than station 151 and is absent at stations 95, 115, and 130. It is more abundant at the southern stations 27, 34, 46, 56, 60, and 64 and thus appears to be an oceanic species.
Haeckel (1887, p. 1278) reported A. cineraria from the central Pacific "Challenger" station 271. Popofsky (1913, p. 371) reported it at 5 stations--one from the tropical part of the Indian Ocean east of Madagascar (27-28 degrees S) and four extending northwestward off the west coast of South Africa (30 degrees S) to near the equator in the central Atlantic Ocean. Riedel (1957, p. 85) reported its occurrence in Swedish Deep-Sea Expedition cores from the tropical Indian Ocean. This species, therefore, appears to have world-wide distribution in the tropical parts of the oceans.
Benson 1966











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