Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . Fig. 88. A-C. Suture lines of Helicancyloceras {Helicancyloceras) vohimaranitraensis (Collignon, 1962) from unnumbered fragments, x 6. D. Suture line of Tonohamites aequicingulatus (von Koenen, 1902). SAS Z8/Tal. x 6. 354 ANNALS OF THE SOUTH AFRICAN MUSEUM. CRETACEOUS FAUNAS FROM SOUTH AFRICA 355 to be found in the region ranging east-west from Great Britain to east of theCaspian Sea, and current evidence suggests this as the source area of the group,genera migrating from there to other parts of the world during early
Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . Fig. 88. A-C. Suture lines of Helicancyloceras {Helicancyloceras) vohimaranitraensis (Collignon, 1962) from unnumbered fragments, x 6. D. Suture line of Tonohamites aequicingulatus (von Koenen, 1902). SAS Z8/Tal. x 6. 354 ANNALS OF THE SOUTH AFRICAN MUSEUM. CRETACEOUS FAUNAS FROM SOUTH AFRICA 355 to be found in the region ranging east-west from Great Britain to east of theCaspian Sea, and current evidence suggests this as the source area of the group,genera migrating from there to other parts of the world during early Cretaceoustime. There is great similarity between the faunas of Zululand and Mozambiqueand those of Madagascar, India, Australia and to a lesser extent south-easternSouth America and the Antarctic regions. There is little similarity, however,with the west coast faunas of the Americas. Part of the dispersal pattern shown in Figure 89 may be explained by takingocean currents prevailing during the Early Cretaceous into account. A study ofthis kind was recently undertaken by Gordon (1973), the results of which arehere briefly summarized and illustrated in the insert in Figure 89. Due to theabsence of the Panama Isthmus, a westward-flowing circumglobal tropicalcurrent existed. Apart from assisting in distributing heat around the
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Keywords: ., bookcentury1800, bookdecade1890, booki, booksubjectnaturalhistory
