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

List species

Phormospyris sp. cf. P. ophirensis Ehrenberg, 1872

Description - Add description

Benson. 1966, p. 318-321; pl. 22, figs. 11-14:

Petalospyris cf. ophirensis Ehrenberg

?Petalospyris ophirensis Ehrenberg, 1872a, Akad. Berlin, Monatsb. (1872), p. 318; 1872b, Akad. Berlin, Abhandl. (1872), Pl. 9, fig. 24.

Cephalis bilocular, relatively smooth, in most specimens elongated in the lateral axis resembling a peanut; with relatively large, circular to subcircular but unequal pores, larger than those of Tristylospiris scaphipes; pores on either side of the sagittal ring, which occupies the sagittal constriction, are larger than the other cephalic pores, circular to elliptical, the lower pair on the dorsal and ventral sides being larger than those above them, 2-3 pairs each on the dorsal, upper, and ventral faces of the cephalis. Sagittal ring, asymmetrical, three-bladed, as in Tristylospiris scaphipes with two blades extending laterally inward, the third lying in the sagittal plane and extending outward and from which originate the bars of the latticed cephalis; a short, horizontal, cylindrical median bar; vertical bar ascends ventrally and extends as a short, thin, conical vertical spine; thin, conical apical spine extends from and is collinear with the straight apical bar of the ring, of variable but generally short length. Four collar pores present, similar to those of Tristylospiris scaphipes. A variable number of spines (not true feet) arise from the collar ring, with a maximum of seven corresponding to the secondary and primary lateral bars, the dorsal spine, and a pair of spines each arising from the lateral extremity of the collar ring, herein termed the cardinal spines (or feet). The dorsal and primary lateral spines are generally present. All spines are circular in section and are branched distally in many specimens. In some specimens (Pl. 22, fig. 14) the primary and secondary lateral bars extend as short, thin, barely visible spines which are collinear with them; arising from the collar ring at the distal ends of these bars are downward divergent spines which join at an angle to the bars. In most specimens (Pl. 22, fig. 11) the primary and secondary lateral bars extend nearly horizontally but with a slight downward curvature as spines that are forked distally. The cardinal spines follow the same pattern as the primary and secondary lateral spines. The dorsal spine is either straight or with convex outward curvature. In many specimens a pair of spines each arising from the latero-ventral corners of the collar ring extend ventrally in a near horizontal plane (Pl. 22, fig. 13) but are not to be confused with the downward-divergent foot-like spines described above; these are likewise branched distally.

Measurements; based on 30 specimens from stations 92 and 93: sagittal height of cephalis 47-75 µm, maximum breadth (lateral axis) 85-157 µm; length of spines (feet) arising from collar ring 13-55 µm, of apical spine 0-10 µm, of vertical spine 2-7 µm.

Remarks. The distinguishing characters of this species are the elongate, peanut-shaped cephalis and the presence of as many as seven, cylindrical, foot-like spines that are often nearly horizontal and forked distally. It differs from Ceratospyris polygona in the lack of spines and bars that are three-bladed and in the lack of spines arising from the cephalis.
This species is similar to Ehrenberg’s poor illustration of Petalospyris ophirensis in having a smooth cephalis, a single apical spine, and in the number of foot-like spines. Ehrenberg's illustration, however, shows three-bladed instead of conical or cylindrical feet, and the pores of the cephalis are more like Tricolospyris scaphipes Haeckel. It shows a certain resemblance to specimens of Ceratospyris polygona that have three-bladed feet and a sma1l-pored lattice instead of polygonal pores developed laterally from the large polygonal pores on either side of the sagittal ring. For these reasons the Gulf species is only tentatively identified with Ehrenberg's species.

Distribution. This species is cosmopolitan but rare in the Gulf, occurring as far north as station 192. It is absent at stations 130, 194, and all those to the north. Its frequency in the southern half of the Gulf is slightly greater than in the northern half. It does not appear to be controlled by upwelling although at station 99 it has a greater frequency. This may reflect the smaller total number of species present at this station; however, its occurrence in the northern Gulf may be associated with upwelling responsible for high diatom production, but the numerical data do not suggest this. This species, therefore, has greater affinity for oceanic than for Gulf waters.
Ehrenberg (1873a, p. 318) reported Petalospyris ophirensis from the tropical Indian Ocean near Zanzibar. Due to the uncertain identification of the Gulf species nothing can be stated about its world-wide distribution except that it is present in the eastern tropical Pacific.
Benson 1966











Discussion / Comments


Web links