. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. 200 ANNALS OF THE SOUTH AFRICAN MUSEUM. Fig. 41. Olcostephanus {Olcostephanus) cf. atherstoni (Sharpe) (?). The holotype, by monotypy, of Astieria sudandina Windhausen, a nomen nudem since it was not described, whilst the scale and locality are also unknown (after Windhausen 1931). x 1. terminate in prominent rounded tubercles on the umbilical shoulder and give rise to bundles of 3-4 coarse, prorsiradiate secondaries characterized by fre- quent bifurcation at midflank. Parabolae are lacking. This spe
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. 200 ANNALS OF THE SOUTH AFRICAN MUSEUM. Fig. 41. Olcostephanus {Olcostephanus) cf. atherstoni (Sharpe) (?). The holotype, by monotypy, of Astieria sudandina Windhausen, a nomen nudem since it was not described, whilst the scale and locality are also unknown (after Windhausen 1931). x 1. terminate in prominent rounded tubercles on the umbilical shoulder and give rise to bundles of 3-4 coarse, prorsiradiate secondaries characterized by fre- quent bifurcation at midflank. Parabolae are lacking. This species differs from O. atherstoni in its coarser, more distant ribbing with frequent bifurcation and in possessing swollen, rounded umbilical tubercles. Olcostephanus bossingaulti (d'Orbigny) (Fig. 46), of which O. laticosta (Gerth) (Fig. 47) is merely based upon a juvenile, is an Hauterivian species which is very close to O. andartae, but seems to lack bifurcating secondaries. 'Simbirskites' araucanus Leanza (1957) is a moderately large, fairly evolute species of Olcostephanus, with inclined umbilical walls ornamented with about 20-23 prorsiradiate primaries per whorl. These terminate in prominent umbilical bullae which generally give rise to three radial, to slightly prorsiradiate secondaries, frequently with an intercalated rib between bundles. There are about seventy secondary ribs per whorl, a short distance of which are exposed in the umbilicus, beneath the umbilical seam. Parabolae lacking. This species differs from the microconch of O. atherstoni in its more evolute form, with sloping umbilical walls and prorsiradiate primaries, and should be assigned to the subgenus Subastieria. It seems likely that the Sardinian O. (Subastieria) nicklesi Wiedmann & Dieni (Fig. 48) is merely based upon juveniles of this Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of th
Size: 1504px × 1661px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
