A new species of Azendohsaurus (Diapsida: Archosauromorpha) from the Triassic Isalo Group of southwestern Madagascar: cranium and mandible

摘要: Abstract:  Here, we describe a new species of Azendohsaurus from the Middle–Late Triassic Madagascar, extending geographical range taxon known otherwise only by single Morocco. Although has consistently been regarded as an early dinosaur (based on various advanced dental and gnathic features resembling those characterizing certain subgroups), relatively complete skeletal material, now available argues strongly against its dinosaurian affinities. Rather, retention numerous primitive cranial postcranial indicates surprisingly divergence within Archosauromorpha unusual mosaic characters in this taxon. Features considered diagnostic Sauropodomorpha thus are inferred to occur homoplastically at least one clade nondinosaurian archosauromorphs, indicating complex evolution distribution traditionally thought be derived archosaurs. teeth both sauropodomorph ornithischian dinosaurs, yet also possesses inarguable basal archosauromorph attributes. This highlights risk uncritically referring isolated, (or even later), ‘leaf-shaped’ with denticles Dinosauria. Similarly, occurrence such diverging that specializations for herbivory originated more frequently than conventionally assumed. For example, taxa share array convergently acquired associated herbivory, including tooth denticles, expanded crowns, downturned dentary articular located ventral margin mandible. Some these (denticles, crowns ventrally deflected articular) widespread among aetosaurs, silesaurs dinosaurs. A occurs Trilophosaurus, further marked unique transversely lophate, tricuspid teeth. An rhynchosaurs crocodilians (e.g. Simosuchus). suggests craniodental were much pervasive across previously recognized, possibly evolving six eight times independently.