Describer

Pol, Rauhut & Becerra 2011

Time

Jurassic Middle Aalenian Bajocian Bathonian

Classification

Ornithischia Ornithopoda Heterodontosauridae

Diet

Herbivore

Fossilsite

Canodon Asfalto Formation, Queso Rallado locality, Chubut Province, Patagonia, Argentina

Info

Abstract

Heterodontosauridae is a morphologically divergent group of dinosaurs that has recently been interpreted as one of the most basal clades of Ornithischia. Heterodontosaurid remains were previously known from the Early Jurassic of southern Africa, but recent discoveries and studies have significantly increased the geographical and temporal range for this clade. Here, we report a new ornithischian dinosaur from the Middle Jurassic Canodon Asfalto Formation in central Patagonia, Argentina.

This new taxon, Manidens condorensis gen. et sp. nov., includes well-preserved craniomandibular and postcranial remains and represents the only diagnostic ornithischian specimen yet discovered in the Jurassic of South America so far. Derived features of its anatomy indicate that Manidens belongs to Heterodontosauridae, as the sister taxon of Heterodontosaurus and other South African heterodontosaurids. The presence of posterior dentary teeth with high crowns but lacking extensive wear facets in Manidens suggests that this form represents an intermediate stage in the development of the remarkable adaptations to herbivory described for Heterodontosaurus.

The dentition of Manidens condorensis also has autapomorphies, such as asymmetrically arranged denticles in posterior teeth and a mesially projected denticle in the posteriormost teeth. At an estimated total length of 60–75 cm, Manidens furthermore confirms the small size of basal heterodontosaurids.

Holotype

MPEF-PV 3211, consists of a partial skeleton with skull and lower jaws, including the axial column except most of the tail; a left shoulder girdle; and the pelvis.

Refered specimens

MPEF-PV 1719, 1786, 1718, 3810, 3811, isolated posterior teeth, from the same locality and horizon

Etymology

The generic name is derived from Latin manus, \\\"hand\\\", and dens, \\\"tooth\\\", a reference to the hand-shaped form of the posterior lower teeth. The specific name refers to the village of Cerro Cóndor, located near to the Queso Rallado site where the specimen was found by zoologist Guillermo Rougier

Length

60 to 75 centimetres (24 to 30 in)