| Monofenestratans | |
|---|---|
 | |
| Several pterosaur skulls prominently displaying the eponymous single fenestra | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Order: | †Pterosauria |
| Clade: | †Pterodactylomorpha |
| Clade: | †Monofenestrata Lüet al., 2010 |
| Subgroups | |
Monofenestrata is aclade ofpterosaurs. It includes the pterosaurs in which the nasal andantorbitalfenestra (openings/holes) in the skull are merged into a single fenestra. The clade includes thepterodactyloids and their close relatives.[1]
Theclade Monofenestrata was in 2010 defined as the group consisting ofPterodactylus and all species sharing withPterodactylus thesynapomorphy of an external nostril confluent with theantorbital fenestra, the major skull opening on the side of the snout. The name is derived fromGreekmonos, "single", andLatinfenestra, "window". The concept was inspired by the discovery ofDarwinopterus, a species combining a pterodactyloid-type skull with a more basal build of the remainder of the body.[1] TheDarwinoptera, a primitive subgroup of monofenestratans showing this transitional anatomy, was also named forDarwinopterus and defined as all descendants of its common ancestor withPterorhynchus.[2]
.jpg)
The earliest known monofenestratan fossils have been found in theStonesfield Slate formation of theUnited Kingdom, which dates to theBathonian stage of theMiddle Jurassic, dated to about 166 million years ago. Identified elements include cervical vertebrae, fourth metacarpals and a possible pterodactyloid synsacrum.[3] An earlier undescribed taxon along with the coeval and corregionalAllkaruen may also belong to the group, both reported from MiddleToarcian layers of theCañadón Asfalto Formation of Argentina.[4][5]
Below is acladogram showing the results of aphylogenetic analysis presented by Andres, Clark & Xu, 2014. This study found the two traditional groupings of ctenochasmatoids and kin as an early branching group (represented as the groupArchaeopterodactyloidea), with all other pterodactyloids grouped into theEupterodactyloidea.[2]
| Pterodactylomorpha |
| ||||||
Contrastingly, a 2024 paper by David Hone and colleagues describing the transitional taxonSkiphosoura found primitive monofenestratans to represent anevolutionary grade leading towards Pterodactyloidea, rather than a distinct darwinopteran or wukongopterid grouping. A cladogram of their results is shown below.[6]
| Monofenestrata/Darwinoptera | |||||||||||||
