| Alamodactylus | |
|---|---|
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Order: | †Pterosauria |
| Suborder: | †Pterodactyloidea |
| Clade: | †Nyctosauromorpha |
| Genus: | †Alamodactylus Andres & Myers,2013 |
| Type species | |
| †Alamodactylus byrdi Andres & Myers, 2013 | |
Alamodactylus is anextinctgenus ofpteranodontianpterosaur known from theLate Cretaceous ofTexas, southern United States. It contains a single species,Alamodactylus byrdi.[1]
Alamodactylus is known solely from itsholotype,SMU 76476, a partial leftwing first described by Myers (2010).[2] This specimen is crushed and consists of a lefthumerus, the distal end of the fourth wingmetacarpal and the proximal end of the first wingphalanx of fourth digit. Other elements of the holotype first reported by Andres and Myers (2013) include a left proximal syncarpal, manual phalanx, and some fragments including four tapering processes that may representskull bones, an articular surface that appears to be themandible articulation of the right quadrate as well as thin bones that do not taper and may be ossifiedtendons.Alamodactylus was first named by Brian Andres and Timothy S. Myers in2013 and thetype species isAlamodactylus byrdi. Thegeneric name is derived fromAlamo – symbol of Texas independence anddactylos, meaning "finger" inAncient Greek which is a traditional suffix forpterosaur genera in reference to their elongate wing digits. Thespecific name,byrdi, honors Gary Byrd for discovering the holotype. The holotype was collected from theAtco Formation of Austin Group, north ofDallas inCollin County, dating to the lowerConiacian stage of the middleLate Cretaceousperiod, about 89.8–88 million years ago.[1]
The holotype ofAlamodactylus was originally referred toPteranodontidae by Myers (2010) and tentatively identified as cf.Pteranodon. Myers (2010) noted that the humerus was superficially similar to that ofPteranodon while other similarities were noted withNyctosaurus, but the holotype being crushed rendered comparison difficult. Andres and Myers (2013) diagnosedAlamodactylus on the basis of unique combination of constricted humerus mid-shaft and D-shaped distal humerus cross-section. This medium-sized pterosaur also hasautapomorphic small pneumaticforamen on ventral surface of humerus proximal end, and dorsal nutrient foramen positioned on midline of humerus shaft level with the middle of deltopectoral crest. Additionally, its warped humerus deltopectoral crest thickens proximally.[1]
As suggested in the original description by Myers (2010), thephylogenetic analysis performed by Andres & Myers (2013) recoveredA. byrdi as closely related toPteranodon and the Nyctosauridae.A. byrdi andnyctosaurids were recovered as successive sister groups to thePteranodontoidea, of whichPteranodon is defined to be the mostbasal taxon. Although the clade namePteranodontia usually applies to the clade exclusively formed by pteranodontids and nyctosaurids, it was originally converted by Unwin (2003) to includePteranodon andNyctosaurus so under their phylogeny it contains also theOrnithocheirae and other taxa. Therefore,A. byrdi was classified as a non-pteranodontoid pteranodontian, and itssister taxon relationship withPteranodontoidea warranted the erection of a new genus and species for this material. Below is acladogram based on the study upheld by Andres and Myers in 2013, showing the phylogenetic placement ofA. byrdi within the clade Pteranodontia.[1]
| Pteranodontia |
| ||||||||||||||||||
In 2018, a phylogenetic analysis published by Nicholas Longrich and colleagues recoveredAlamodactylus within the familyNyctosauridae, in thebasalmost position, contrary to the analysis by Andres and Myers above.[3][4]
However, subsequent phylogenetic analyses placedAlamodactylus as a pteranodontian outsideNyctosauridae.[5][6]
