. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. REVISION OF LATE VALANGINIAN CEPHALOPODA 159 Material Numerous specimens, including BM-C25227-9, AM-844, 846, SAM- PCU1586-88, 5706, and 12784-88. Holotype By the lectotype designation of Spath (1930), the original of Tate's (1867) plate 7, figure 5a, BM-C25228, from Prince Alfred's Rest at the Sundays River mouth. Diagnosis A coarsely ribbed species of Bochianites with 4-7 prorsiradiate ribs in a distance equal to twice the whorl width and an elliptical to subtrigonal whorl Fig. 6. Bochian
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. REVISION OF LATE VALANGINIAN CEPHALOPODA 159 Material Numerous specimens, including BM-C25227-9, AM-844, 846, SAM- PCU1586-88, 5706, and 12784-88. Holotype By the lectotype designation of Spath (1930), the original of Tate's (1867) plate 7, figure 5a, BM-C25228, from Prince Alfred's Rest at the Sundays River mouth. Diagnosis A coarsely ribbed species of Bochianites with 4-7 prorsiradiate ribs in a distance equal to twice the whorl width and an elliptical to subtrigonal whorl Fig. 6. Bochianites africanus (Tate) The syntypes, of which the top right-hand specimen was selected as lectotype (after Tate 1867; composite suture after Spath 1930). x 1. Description A slowly expanding, coarsely ribbed Bochianites with an elliptical whorl section in immaturity, becoming subtrigonal at large sizes when the maximum width is near the dorsal shoulders. The dorsum is flattened in all but the youngest individuals. Ornament comprises coarse annular ribs, strongly projected on the flanks and sharply arched across the venter. Because of the oblique angle at which the ribbing crosses the distinctly tabulate venter of mature individuals, the ribs are broadest across the venter as well as being asymmetrical with a gentle adapical slope and a steep adoral slope. Rib density varies between 4 and 7 in a distance equal to twice the costal whorl width. Discussion Bochianites africanus (Tate) is closest to B. neocomiensis (d'Orbigny) (1842#, pi. 138 (figs 1-5)) which has, however, an almost perfectly circular whorl section. Spath (1930: 154) considered the present species to be very close to Baculites granatensis Karsten (1856: 105, pi. 2 (fig. 1)), to which illustration it certainly bears a considerable resemblance but, according to Thieuloy (in litt. 1980), the Columbian species (Fig. 8) is a late Cretaceous Please note that these images are extracted from scanned page im
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
