. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. Fig. 102. Olcostephanus {Jeannoticeras) frequens (Zwierzycki) (<?). Two of the syntypes of Astieria auriculatus Zwierzycki from Tanzania, of which the right-hand specimen is herein selected as the lectotype (after Zwierzycki 1914). x 1. Olcostephanus frequens (Zwierzycki) (Fig. 101), O. auriculatus (Zwierzycki) (Fig. 102), O. pecki Imlay (Fig. 103), and O. popenoei Imlay (Fig. 104) are all characterized by abundant primary ribs from which the secondaries commonly bifurcate and should, therefore, b
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. Fig. 102. Olcostephanus {Jeannoticeras) frequens (Zwierzycki) (<?). Two of the syntypes of Astieria auriculatus Zwierzycki from Tanzania, of which the right-hand specimen is herein selected as the lectotype (after Zwierzycki 1914). x 1. Olcostephanus frequens (Zwierzycki) (Fig. 101), O. auriculatus (Zwierzycki) (Fig. 102), O. pecki Imlay (Fig. 103), and O. popenoei Imlay (Fig. 104) are all characterized by abundant primary ribs from which the secondaries commonly bifurcate and should, therefore, be included in the subgenus Jeannoticeras, as should O. colorinensis Imlay (Fig. 105). It is doubtful whether more than one species is involved in the above list. Bose (1923) created Hoplites aquilerae for a juvenile form with a rather narrow umbilicus and a depressed, almost semicircular whorl section. On the outer whorl, between 27 and 28 primary ribs terminate in weak bullae on the umbilical shoulder and generally give rise to 2 prorsiradiate secondaries, with occasional intercalatories between bundles. Parabolae are apparently lacking. This species clearly belongs to the subgenus Jeannoticeras and diners from the present material in its much finer ribbing, more numerous umbilical bullae and the absence of parabolae. Whiteaves (1893) introduced the species Olcostephanus (Astieria) deansii (Fig. 106) for a compressed form lacking parabolae and with flexuous secondary ribs which bifurcate just above the umbilical shoulder. This form is perhaps better assigned to the genus Homolsomites. Olcostephanus huizachensis (Cantu Chapa) (Fig. 107) is a small, somewhat compressed species with an oval whorl section. Fifteen primaries terminate in bullae from the umbilical shoulder from which secondary ribs arise in pairs, so that there are thirty distant secondaries across the venter of the outer whorl. This species is close to the present material from which it differs in lacking parabolae
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
