N17

Phormospyris stabilis (Goll) antarctica (Haeckel)

Phormospyris antarctica Haecker, 1907, p. 124, fig. 9

Triceraspyris antarctica Haecker, Riedel, 1958, p. 230, text-figs. 3-5, pl. 2, figs. 6-7; Chen. 1975, p. 456, pl. 15, fig. 6; Petrushevskaya, 1975, p. 593, pl. 8, fig. 1

Triceraspyris (?) antarctica Petrushevskaya, 1967, p. 62, text-fig. 37.

Triospyris antarctica Goll and Bjorklund, 1974, text-fig. 8.

Desmospyris (?) haysi Petrushevskaya, 1975, p. 593, pl. 27, figs. 4-6 (in part).

DESCRIPTION "Shell of rather heavy construction, nut-shaped, with unequal rounded pores, generally smooth surface, and slight or pronounced sagittal constriction. Four large basal pores. Usually three basal feet, circular or three-bladed in section, of approximately the same length as the cephalis: of these, the unpaired one is usually simply latticed proximally, and in many specimens all three are forked distally. In a few specimens, secondary spines or a small amount of lattice-work are developed between the proximal parts of these basal feet. Sagittal ring approximately D-shaped, from which a short, free apical spine arises subapically, and a thorn-like vertical spine arises from the more curved part of the ring near the basal pores. In most specimens, two more thorn-like spines are present, one to either side of the apical part of the sagittal ring, and in some specimens several more thorns are scattered over the apical surface." (from Riedel, 1958).

DIMENSIONS "Height of sagittal ring 63-90 microns; maximum breadth of bilocular cephalis 80-125 microns." (from Riedel, 1958).

REMARKS

1. For further synonymy see Riedel, 1958 and Chen, 1975.

2. For further taxonomic discussion and illustrations see Goll, 1977.

Plate 20, figures 1a-d

N18

RECENT DISTRIBUTION

1. Riedel, 1958 (Triceraspyris antarctica); "This species occurs in both the American and Indian Ocean sectors of antarctic waters, and no form resembling it has been found at any other locality. Thus it appears to be an exclusively southern cold-water species."

2. Lozano, 1974 (Triceraspyris antarctica), Fig. IV-16; "It has the distribution which is characteristic for the Antarctic assemblage being generally present south of about 42 degrees S in the Atlantic sector, west of 35 degrees W and south of the average position of the Subtropical Convergence in the Indian Ocean Sector. It is found north of these latitudes only in deep cores, notably in samples from the Crozet and Argentine basins indicating that it is transported by bottom waters. T. antarctica reaches a maximum abundance of 3.5 percent in core RC15-92 at the average position of the APF. It is found in abundances over 1.5 percent under August sea surface temperatures lower than 10 degrees C in the Indian Ocean. The maximum August sea surface temperature under which it is found is over 20 degrees C but specimens not transported by bottom currents are probably found only under August sea surface temperatures of about 10 degrees C."

3. Morley, 1977 (Triceraspyris antarctica), Fig. I-24; "This species loads highest in factor 2 (polar). At present it is most abundant under polar waters south of 45 degrees S. At 18,000 YBP the 1% contour shifts slightly northward and the maximum abundance of this species increases in samples south of 50 degrees S."

4. Goll, 1977; "... common constituent of sediments south of the southern Subtropical Convergence. Moreover, it has low frequencies in Argentine Basin sediments as well as sporadic occurrences in sediments of the Brazil Basin..."