Manidens

Manidens Temporal range: Middle Jurassic, 171–167 Ma PreЄ Є O S D C P T J K Pg N ↓
Skull reconstruction
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	†Ornithischia
Family:	†Heterodontosauridae
Subfamily:	†Heterodontosaurinae
Genus:	†Manidens Pol et al., 2011
Type species
†Manidens condorensis Pol et al., 2011

Manidens is a genus of heterodontosaurid dinosaur from the Middle Jurassic of Patagonia. Fossils have been found from the Cañadon Asfalto Formation in Chubut Province, Argentina, dating to the Bajocian.^[1]

Etymology

The type species of Manidens, Manidens condorensis, was described in the journal Naturwissenschaften in 2011. Manidens was named in by Diego Pol, Oliver Rauhut and Marcos Becerra. 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.^[1]

Description

The holotype specimen of Manidens, 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. The specimens MPEF-PV 1719, 1786, 1718, 3810, 3811, isolated posterior teeth, from the same locality and horizon as the holotype are also referred to this genus. The specimens were found in the Queso Rallado locality of the Cañadón Asfalto Formation, dating to the Aalenian–Early Bathonian stages, 171 ± 5 to 167 ± 4 Ma.^[1]

Manidens was a relatively basal heterodontosaurid that grew to about 60 to 75 centimetres (24 to 30 in) in length, smaller than later heterodontosaurids. It has high-crowned teeth indicative of an increased adaptation to a herbivorous diet but lacks the wear facets seen in more advanced forms like Heterodontosaurus. Manidens is the sister taxon of a clade consisting of the African species Heterodontosaurus, Abrictosaurus and Lycorhinus, indicating an early radiation of the heterodontosaurids.^[1]

Life restoration

Phylogeny

Cladogram after Pol et al., 2011:^[1]

*Note: Pol et al. regard Echinodon as a genus of Heterodontosauridae.

Possible Arboreal lifestyle

Fossils attributed to Manidens from Argentina indicate that this dinosaur may have been at least partially arboreal. The specimens, a series of bones from both hind feet and a few tail vertebrae, indicate the dinosaur might have been able to climb trees. The long toe bones and distinct anchor attachments for the muscles and tendons of the hallux indicate that while its hallux was smaller than the rest of the toes, it was still capable of grasping, like the other toes were. When compared with a broad range of birds and other non-avian dinosaurs, it was discovered that Manidens' feet were most similar to those of tree-perching birds. If true, Manidens might represent the first known case of an arboreal or partially arboreal ornithischian.^[2]

References