Dimorphodontidae is a family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 of early "rhamphorhynchoid

Rhamphorhynchoidea

The Rhamphorhynchoidea forms one of the two suborders of pterosaurs and represent an evolutionary grade of primitive members of this group of flying reptiles. This suborder is paraphyletic in relation to the Pterodactyloidea, which arose from within the Rhamphorhynchoidea, not from a more distant...

" pterosaur

Pterosaur

Pterosaurs were flying reptiles of the clade or order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period . Pterosaurs are the earliest vertebrates known to have evolved powered flight...

s named after Dimorphodon

Dimorphodon

Dimorphodon was a genus of medium-sized pterosaur from the early Jurassic Period. It was named by paleontologist Richard Owen in 1859. Dimorphodon means "two-form tooth", derived from Greek δι/di meaning 'two', μορφη/morphe meaning 'shape' and οδων/odon meaning 'tooth', referring to the fact that...

, that lived in the Late Triassic

Late Triassic

The Late Triassic is in the geologic timescale the third and final of three epochs of the Triassic period. The corresponding series is known as the Upper Triassic. In the past it was sometimes called the Keuper, after a German lithostratigraphic group that has a roughly corresponding age...

 to Early Jurassic

Early Jurassic

The Early Jurassic epoch is the earliest of three epochs of the Jurassic period...

.

A family Dimorphodontidae was named in 1870 by Harry Govier Seeley (as "Dimorphodontae") with Dimorphodon as the only known member.

In 2003 David Unwin defined a clade

Clade

A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

 Dimorphodontidae, as the node clade consisting of the last common ancestor of Dimorphodon macronyx and Peteinosaurus zambellii

Peteinosaurus

Peteinosaurus was a prehistoric reptile genus belonging to the Pterosauria. It lived in the late Triassic period in the middle Norian .-Name:...

and all its descendants. The defining species were the only dimorphodontids known. This group would be the most basal clade within Pterosauria with the exception of Preondactylus

Preondactylus

Preondactylus is a genus of long-tailed pterosaur from the Late Triassic that inhabited what is now Italy. It was discovered by Nando Buffarini in 1982 near Udine in the Preone valley of the Italian Alps.-Anatomy:...

and the sister group of the Caelidracones within the Macronychoptera.

According to Alexander Kellner

Alexander Kellner

Alexander Wilhelm Armin Kellner is a Liechtensteinian/Brazilian paleontologist, a leading expert in the field of the study of pterosaurs....

, Dimorphodon is not closely related to Peteinosaurus and the concept would therefore be superfluous.