First evidence of denticulated dentition in teleosaurid crocodylomorphs

Abstract

Teleosauridae was a group of largely marine Mesozoic crocodylomorphs, typically considered as akin to “marine gavials” due to their elongate, tubular, polydont rostra that are indicative of a piscivorous diet. Here we show that these extinct crocodylomorphs were more anatomically, and perhaps ecologically, varied than previously thought. We report the first evidence of denticles in a teleosaurid tooth, revealed by scanning electron microscopic (SEM) analysis of a tooth from the holotype of “Steneosaurus” obtusidens. These denticles are cryptic, because they are microscopic, not contiguous along the carinae (instead forming short series), and are detectable only using SEM. This incipient denticle morphology is similar to that recently discovered in a closely related group of marine crocodylomorphs, the Metriorhynchidae. In particular, the denticulation morphology of “Steneosaurus” is similar to that of the geosaurin metriorhynchid Torvoneustes, indicating that these two taxa may have employed similar feedi...