''Aetodactylus'' (meaning "eagle finger") is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

of targaryendraconian

pterosaur Pterosaurs (; from Greek ''pteron'' and ''sauros'', meaning "wing lizard") is 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 Cre ...

. It is known from a lower jaw discovered in

Upper Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger 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 ''creta'', ...

rocks of northeastern

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...

Description

''Aetodactylus'' is based on SMU 76383 (Shuler Museum of Paleontology,

Southern Methodist University , mottoeng = " The truth will make you free" , established = , type = Private research university , accreditation = SACS , academic_affiliations = , religious_affiliation = United Methodist Church , president = R. Gerald Turner , pr ...

), a nearly complete lower jaw lacking the right retroarticular process (the bony prong posterior to the jaw joint), part of the posterior end of the

mandibular symphysis In human anatomy, the facial skeleton of the skull The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more p ...

(where the two halves of the lower jaw meet), and all but two teeth. This specimen was found in 2006 by Lance Hall near a construction site in

Mansfield Mansfield is a market town and the administrative centre of Mansfield District in Nottinghamshire, England. It is the largest town in the wider Mansfield Urban Area (followed by Sutton-in-Ashfield). It gained the Royal Charter of a market t ...

, near

Joe Pool Lake Joe Pool Lake is a fresh water impoundment (reservoir) located in the southern part of the Dallas/Fort Worth Metroplex in North Texas. The lake encompasses parts of Tarrant, Dallas and Ellis counties. The lake measures with a conservation sto ...

(recorded as SMU Loc. 424). The rock it was found in is a

calcareous Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines. In zoology ''Calcareous'' is used as an a ...

marine

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...

rich in mud–sized particles, from the middle Cenomanian-age (approximately 97 million years old) Tarrant Formation. Also found were fish teeth and

vertebra The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characterist ...

e, and indeterminate bones. The Tarrant Formation is the lowest rock unit of the Cenomanian–

Turonian The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous Epoch, or a stage in the Upper Cretaceous Series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded ...

–age

Eagle Ford Group The Eagle Ford Group (also called the Eagle Ford Shale) is a sedimentary rock formation deposited during the Cenomanian and Turonian ages of the Late Cretaceous over much of the modern-day state of Texas. The Eagle Ford is predominantly compos ...

. ''Aetodactylus'' was named by Timothy S. Myers of SMU in

2010 File:2010 Events Collage New.png, From top left, clockwise: The 2010 Chile earthquake was one of the strongest recorded in history; The Eruption of Eyjafjallajökull in Iceland disrupts air travel in Europe; A scene from the opening ceremony of ...

. The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen( ...

is ''A. halli'', named in honor of the discoverer. ''Aetodactylus'' is differentiated from other ornithocheirids by several anatomical details of the lower jaw, including the slight expansion of the anterior end of the lower jaw, the strong vertical compression of the symphysis, the relatively constant spacing of the teeth, and the slight upward curve of the lower jaw. Myers found that ''Aetodactylus'' compared best with the Chinese genus ''

Boreopterus ''Boreopterus'' is a genus of boreopterid pterodactyloid pterosaur from the Barremian-Aptian-age Lower Cretaceous Yixian Formation of Dalian, Liaoning, China. Etymology ''Boreopterus'' was named in 2005 by Lü Junchang and Ji Qiang. The type ...

''. ''Aetodactylus'' represents one of the youngest definitive records of ornithocheirids. The jaw SMU 76383 is long, (~41%) of which is joined left and right jaws. 27 pairs of teeth were present; the two remaining teeth are pointed, curved slightly backward, flattened from side to side, and slender. The tip of the jaw is slightly expanded (to from a minimum of just posterior) and contains the first four pairs of teeth, with the first pair projecting forward. Based on the size of the tooth sockets, the teeth of the second and third pairs were largest, with tooth size decreasing posteriorly. There are small pits between the posterior teeth, interpreted as points where the teeth of the upper jaw rested against the lower jaw. These pits disappear partway along the tooth row, suggesting that the anterior teeth of the upper jaws were longer and projected outwards to a degree. Unlike some other ornithocheirids, such as '' Anhanguera'', ''

Coloborhynchus ''Coloborhynchus'' is a genus of pterodactyloid pterosaur belonging to the family Anhangueridae, though it has also been recovered as a member of the Ornithocheiridae in some studies. ''Coloborhynchus'' is known from the Lower Cretaceous of E ...

'', and ''

Ornithocheirus ''Ornithocheirus'' (from Ancient Greek "ὄρνις", meaning ''bird'', and "χεῖρ", meaning ''hand'') is a pterosaur genus known from fragmentary fossil remains uncovered from sediments in the UK and possibly Morocco. Several species have ...

'', there is no bony crest on the lower jaw. ''Aetodactylus'' was considered a possible relative of ''

'' in the original description, but subsequent cladistic analysis found it to be closely related to '' Cimoliopterus'' instead.

Classification

Below is a

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ...

by Pêgas ''et al.'' (2019), reassigning ''Aetodactylus'' to the clade Targaryendraconia within the more inclusive group

Ornithocheirae Ornithocheirae is an extinct clade of pteranodontoid pterosaurs from the Early Cretaceous to the Late Cretaceous (Valanginian to Turonian stages) of Asia, Europe, North America and South America. It was named by Harry Seeley in 1870 as a family ...

, and more specifically to the family Cimoliopteridae:Rodrigo V. Pêgas, Borja Holgado & Maria Eduarda C. Leal (2019) On ''Targaryendraco wiedenrothi'' gen. nov. (Pterodactyloidea, Pteranodontoidea, Lanceodontia) and recognition of a new cosmopolitan lineage of Cretaceous toothed pterodactyloids, Historical Biology,

References

{{Taxonbar, from1=Q20672247, from2=Q2072505 Pteranodontoids Late Cretaceous pterosaurs of North America Fossil taxa described in 2010

Description

Classification

See also

References