"Dimorphodon" weintraubi

"Dimorphodon" weintraubi is a species of pterosaur originally thought to be a species of Dimorphodon from the Early Jurassic of Mexico. It was named by James Clark and others in 1998, in honour of Dr. Robert L. Weintraub.^[1] However, in the descriptions of the basal pterosaur Seazzadactylus and the anurognathid Sinomacrops, Vecchia and Wei et al. separately found "Dimorphodon" weintraubi as the most primitive of anurognathids, and extends their origins to the Early Jurassic.^[2][3]

"Dimorphodon" weintraubi Temporal range: Early Jurassic, 189–185 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	†Pterosauria
Family:	†Dimorphodontidae
Genus:	†Dimorphodon
Species:	†D. weintraubi
Binomial name
†Dimorphodon weintraubi Clark et al., 1998

Description

The type specimen, IGM 3494, includes a uncrushed partial skeleton, composed of the posterior part of the skull, four cervical vertebrae, scapulocoracoids from both sides, the left humerus, the right leg, and most of the right arm of the animal. According to the authors of its description, the specimen came from an animal bigger than the largest Dimorphodon specimens.^[1]

Locomotion

The completeness of the right foot, as well as the fact the specimen was uncrushed, helped Clark and others to deduce that the animal was a plantigrade, instead of the bird-like digitigrade feet, because for the animal to walk in a digitigrade position, it would have to separate the joints in it feet. This helped to "revive" the idea that pterosaurs were quadrupedal when on the ground, at least in primitive pterosaurs.^[1]

Classification

"Dimorphodon" weintraubi was originally described as a species of Dimorphodon, until the 2019 description of Seazzadactylus by Vecchia that placed the animal as the most basal anurognathid, and the 2021 description of Sinomacrops by Wei and others also supported this idea.^[2][3] Below is the simplified cladogram made from the phylogenetic analyses performed by Wei et al.

Anurognathidae	"Dimorphodon" weintraubi Batrachognathinae Sinomacrops bondei Batrachognathus volans Anurognathinae Dendrorhynchoides curvidentatus Luopterus mutoudengensis Jeholopterus ningchengensis Anurognathus ammoni Vesperopterylus lamadongensis