Article: A Caribbean rudist bivalve in Oman: island-hopping across the Pacific in the Late Cretaceous
The hippuritid rudist bivalve Torreites is described from the Maastrichtian of Oman and the United Arab Emirates. Together with the single fragment from the region on which T. milovanovici Grubic, 1979 was based, the specimens are placed in a newly recognized geographical subspecies of T. sanchezi (Douville, 1927), a species previously considered endemic to the Caribbean Province. The Arabian T. s. milovanovici Grubic differs from its Caribbean parent, T. s. sanchezi (Douville) (incorporating all previously recognized T. sanchezi, as well as T. coxi Grubic, 1979) only in the angle (a) between the arete cardinale and the ventralmost pillar: a is 12°-75° in the former and 50°-126° in the latter.The loss of the normal hippuritid pore and canal system in Torreites is confirmed and shown to have been associated with exposure of the mantle margins, which may have contained symbiotic algae, as in the living Tridacna.Homeomorphy and plate tectonic drifting are rejected as explanations for the apparent disjunct endemism of Torreites. Rather, larval dispersal along a corridor of shallow staging posts is favoured. A Mediterranean Tethys/Atlantic route is considered unlikely, because of barriers. There is good evidence, in contrast, for such staging posts across the Pacific and eastern Tethys in Campanian-Maastrichtian times.