Annals of the South African MuseumAnnale van die Suid-Afrikaanse Museum . la. It is withfinal loss of coarse tuberculation that the change to the posterior set occurs inwhich the wavy, crowded, subvertical costellae are finely crenulated are about 10-12 costae in the anterior set and 8-12 in the posterior set. Discussion Kitchin (1903: 104, pi. 10 (fig. 4)) identified material from the Tithonian ofCutch with T. ventricosa (Krauss). Van Hoepen (1929: 38), however, consideredthe anterior ribs of the Cutch species to be too coarse, with larger and moreprominent nodes, and the pos
Annals of the South African MuseumAnnale van die Suid-Afrikaanse Museum . la. It is withfinal loss of coarse tuberculation that the change to the posterior set occurs inwhich the wavy, crowded, subvertical costellae are finely crenulated are about 10-12 costae in the anterior set and 8-12 in the posterior set. Discussion Kitchin (1903: 104, pi. 10 (fig. 4)) identified material from the Tithonian ofCutch with T. ventricosa (Krauss). Van Hoepen (1929: 38), however, consideredthe anterior ribs of the Cutch species to be too coarse, with larger and moreprominent nodes, and the posterior ribs too uneven for assignment to T. ventri-cosa. Consequently, he renamed the Cutch species Pisotrigonia parva (Fig. 22).Although Rennie (1936) was highly critical of Van Hoepens (1929) taxonomy,the writer has—through the courtesy of Drs N. J. Morris and R. J. Cleevely,studied topotype material of P. parva van Hoepen and concurs that it is a dis-tinctive Tithonian species. Also closely allied is Pisotrigonia tuberculifera 40 ANNALS OF THE SOUTH AFRICAN MUSEUM. Fig. 21. Pisotrigonia ventricosa (Krauss), x 1. A-D. Lateral, posterior, anterior and dorsalviews of the provisional neotype. E-F. Dorsal and lateral views of a topotype. G-H. Lateraland dorsal views of a topotype. I-J. Internal and external views of a left valve. All the speci-mens are in the South African Museum. LOWER CRETACEOUS TRIGONIOIDA FROM THE ALGOA BASIN 41
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