An unusual marine crocodyliform from the jurassic-cretaceous boundary of Patagonia

Abstract

Remains of the marine crocodyliform Dakosaurus andiniensis from western South America reveal a lineage that drastically deviated from the skull morphology that characterizes marine crocodyliforms. The snout and lower jaw are extremely robust, short, and high and only bear a few large teeth with serrated edges (resembling those of some terrestrial carnivorous archosaurs). This unusual morphology contrasts with the long and gracile snout and lower jaws bearing numerous teeth, which are present in the closest relatives of D. andiniensis (and interpreted as indicating feeding on small fish or mollusks). Thus, the morphological diversity of pelagic marine crocodyliforms was wider than had been thought.