Megaporomya reymenti gen. et sp. nov. (Bivalvia, Pholadomyida) from the upper Turonian (Upper Cretaceous) of the Sergipe Basin, north-eastern Brazil

Abstract

Megaporomya, a new genus of the bivalve family Poromyidae (order Pholadomyida), is erected and the type species Megaporomya reymenti gen. et sp. nov. described from the upper Turonian of the Cotinguiba Formation, Sergipe Basin, north-eastern Brazil. The main morphological features of the new genus are the large to very large shell, wide umbonal area, large posterior gape, strongly inflated valves, and faint, irregular commarginal ribs crossed by radial tubercles. The hinge of the right valve consists of one large, inverted, U-shaped cardinal tooth, one straight and narrow cardinal tooth and two unequal sockets. M. reymenti gen. et sp. nov. differs from other related species from the Cretaceous of Sergipe by its large size, surface ornamentation, valve inflation, and hinge features. The life position of M. reymenti gen. et sp. nov. is reconstructed on the basis of a functional interpretation of its morphology and by comparison with closely related Recent forms. Megaporomya gen. nov. was a semi-infaunal selective predator which probably fed on crustaceans and burrowed in soft sediments, extending slightly above the sediment-water interface. It detected its prey with the help of specialized tentacles surrounding the large inhalant siphon. The palaeoenvironmental setting of the Sergipe Basin during the late Turonian is interpreted on the basis of the associated fauna and facies. © 2013 by the Sociedade Brasileira de Paleontologia.