Azhdarchoidea (
, meaning "
azhdarchid
Azhdarchidae (from the Persian word , , a dragon-like creature in Persian mythology) is a family of pterosaurs known primarily from the Late Cretaceous Period, though an isolated vertebra apparently from an azhdarchid is known from the Early Cre ...
-like forms") is a group of
pterosaurs
Pterosaurs are an extinct clade of flying reptiles in the Order (biology), order Pterosauria. They existed during most of the Mesozoic: from the Late Triassic to the end of the Cretaceous (228 million to 66 million years ago). Pterosau ...
within the suborder
Pterodactyloidea. Pterosaurs belonging to this group lived throughout the
Early and
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...
periods, with one tentative member, ''
Tendaguripterus'', that lived in the
Late Jurassic
The Late Jurassic is the third Epoch (geology), epoch of the Jurassic Period, and it spans the geologic time scale, geologic time from 161.5 ± 1.0 to 143.1 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic stratum, strata.Owen ...
period. Remains of this group have been found in the Americas, Africa, and Eurasia, suggesting that they probably had a global distribution.
Azhdarchoids are generally distinguished from other pterodactyloids by their relatively low arm-to-leg-length ratio, suggesting that they were more proficient in moving on the ground than pterosaurs like ''
Pteranodon
''Pteranodon'' (; from and ) is a genus of pterosaur that included some of the largest known flying reptiles, with ''P. longiceps'' having a wingspan of over . They lived during the late Cretaceous geological period of North America in presen ...
'' or ''
Anhanguera'' (which had very long arms relative to the length of their legs). This has led some researchers to suggest that many azhdarchoids, such as the azhdarchids and dsungaripterids, may have been primarily terrestrial, while retaining the ability to fly when necessary.
Classification
Azhdarchoidea was named by paleontologist David Unwin in 1995. He later gave the clade a phylogenetic definition in 2003. He defined the group as the most recent common ancestor of ''
Quetzalcoatlus
''Quetzalcoatlus'' () is a genus of azhdarchid pterosaur that lived during the Maastrichtian age of the Late Cretaceous in North America. The Type (biology), type specimen, recovered in 1971 from the Javelina Formation of Texas, United States, ...
'' and ''
Tapejara'', and all its descendants.
Relationships
Azhdarchoidea is generally considered as one of three major clades of pterodactyloids. The other two major groups are
Archaeopterodactyloidea and
Pteranodontoidea. In some older classification schemes, azhdarchoids were considered to be closely-related to
ctenochasmatoids like ''
Pterodactylus
''Pterodactylus'' (from ) is a genus of extinct pterosaurs. It is thought to contain only a single species, ''Pterodactylus antiquus'', which was the first pterosaur to be named and identified as a flying reptile and one of the first prehis ...
'' and ''
Ctenochasma''. However, most researchers no longer consider this arrangement to be very likely. Instead, azhdarchoids are grouped as close relatives of pteranodontoids under the clade
Ornithocheiroidea, which would comprise the bulk of pterodactyloid diversity.
A simplified cladogram illustrating the relationships between azhdarchoids and other pterosaurs based on the analysis of Brian Andres,
James Clark, and
Xu Xing in 2014 is shown below.
Taxonomy
Azhdarchoidea is generally believed to be composed of several principle
families
Family (from ) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictability, structure, and safety as ...
:
Azhdarchidae
Azhdarchidae (from the Persian word , , a dragon-like creature in Persian mythology) is a family of pterosaurs known primarily from the Late Cretaceous Period, though an isolated vertebra apparently from an azhdarchid is known from the Early Cre ...
,
Chaoyangopteridae,
Tapejaridae
Tapejaridae (from a Tupi language, Tupi word meaning 'the lord of the ways') is a Family (biology), family of azhdarchoid pterosaurs from the Cretaceous Period (geology), period. Members are currently known from Brazil, England, Hungary, Morocco, ...
,
Thalassodromidae
Thalassodromidae (meaning "sea runners") is a group of azhdarchoid pterosaurs from the Early Cretaceous (Albian) of Brazil. All known definitive members come from the Romualdo Formation of Brazil, which include the type genus '' Thalassodromeus' ...
, and potentially
Dsungaripteridae
Dsungaripteridae is a group of pterosaurs within the suborder Pterodactyloidea. They were robust pterosaurs with good terrestrial abilities and flight honed for inland settings, and were commonly interpreted as durophagous and possibly piscivoro ...
, although Thalassodromidae of these is considered to be a lineage tapejarids by some researchers. However, the interrelationships of these groups is not confidently understood. The azhdarchids and chaoyangopterids are generally considered to be one another's closest relatives, but the affinities of tapejarids, thalassodromids, and dsungaripterids are controversial.
Some researchers also consider an additional grouping,
Alanqidae
Azhdarchoidea ( , meaning "azhdarchid-like forms") is a group of pterosaurs within the suborder Pterodactyloidea. Pterosaurs belonging to this group lived throughout the Early and Late Cretaceous periods, with one tentative member, '' Tendaguri ...
, composed of taxa formerly considered azhdarchids.
[
There are several competing views of azhdarchoid relationships. An early study presented by paleontologist Felipe Pinheiro and colleagues in 2011 considered the tapejarids to be a ]monophyletic
In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria:
# the grouping contains its own most recent co ...
clade including the thalassodromines and the chaoyangopterids (therein called "chaoyangopterines").[Pinheiro, F.L., Fortier, D.C., Schultz, C.L., De Andrade, J.A.F.G. and Bantim, R.A.M. (in press). "New information on ''Tupandactylus imperator'', with comments on the relationships of Tapejaridae (Pterosauria)." ''Acta Palaeontologica Polonica'', in press, available online 03 Jan 2011. ] Other earlier studies, such as that of paleontologists Darren Naish
Darren William Naish (born 26 September 1975) is a British vertebrate palaeontologist, author and science communicator.
As a researcher, he is best known for his work describing and reevaluating dinosaurs and other Mesozoic reptiles, including ...
&