Back
Hystrichosphaera tertiaria var. obliqua

Hystrichosphaera tertiaria var. obliqua Wall, 1967

Now Spiniferites pseudofurcatus ssp. obliquus. Originally Hystrichosphaera tertiaria var. obliqua, subsequently (and now) Spiniferites pseudofurcatus ssp. obliqua.
Holotype: Wall, 1967, pl.14, fig.16
Locus typicus: Core A254/327, depth 400 cm., 20¦ 45" N., 83¦ 00" W.
Stratum typicum: Late Pleistocene-Recent

Original description: Wall, 1967, p. 103
The test is ovoid sometimes with a rudimentary apical boss has a smooth to weakly microgranular wall and is divided by an equatorial narrow descending girdle. Its tabulation is 4", 0a, 6"", 6g, 6""", 1p, 1"""" and the arrangement of plate-areas is identical with that seen in H. furcota and H. bentori. The longitudinal furrow is narrow anteriorly but widens posteriorly and is oblique while the girdle is quite strongly displaced about it. The spines are characteristic: the most complex closely resemble those of H. tertiaria as figured by Eisenack (1954 pl.9 figs.1-4; text-fig.3) under the synonym H. cf. furcata. They are trifurcate with secondary branchlets which tend to remain parallel and often are connected by delicate membranes as they flare. Such spines are restricted to plate-area corners but bifurcate spines occasionally ornament longitudinal septa. The two dorsal antapical spines are particularly prominent as an aid to identification.
Dimensions. Test only 40-50 Ám, spines 10-12 Ám. 6 specimens measured.

Affinities:
Wall, 1967, p. 103: This variety differs from the typical form of H. tertiaria Eisenack and Gocht in being smaller (less than 50 Ám) but has the characteristic spines and general appearance of the former. (The plate-pattern of H. tertiaria is considered to be gonyaulacid (text-fig.2A) and not as origtnally stated by Eisenack and Gocht (1960, p.515): this reinterpretation is based upon the original illustrations and examples from cores A254/330 and A254/327.) Hystrichosphaera bentori is closely related but can be distinguished by its stronger apical boss and more numerous processes.
Feedback/Report bug