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

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of targaryendraconian

pterosaur Pterosaurs are an extinct clade of flying reptiles in the 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). Pterosaurs are the earli ...

. It is known from a lower jaw discovered in

Upper 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 ''cret ...

rocks of northeastern

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

Description

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

Southern Methodist University Southern Methodist University (SMU) is a Private university, private research university in Dallas, Texas, United States, with a satellite campus in Taos County, New Mexico. SMU was founded on April 17, 1911, by the Methodist Episcopal Church, ...

), 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 external surface of the mandible is marked in the median line by a faint ridge, indicating the mandibular symphysis (Latin: ''symphysis menti'') or line of junction where the two lateral ha ...

(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 the Mansfield District in Nottinghamshire, England. It is the largest town in the wider Mansfield Urban Area and the second largest settlement in Nottinghamshire (following the city ...

, 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, North Texas. The lake encompasses parts of Tarrant County, Texas, Tarrant, Dallas County, Texas, Dallas and E ...

(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 (mineral), lime or being chalky. The term is used in a wide variety of Science, scientific disciplines. In zoology ''Calcare ...

marine

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

rich in mud–sized particles, from the middle

Cenomanian The Cenomanian is, in the International Commission on Stratigraphy's (ICS) geological timescale, the oldest or earliest age (geology), age of the Late Cretaceous epoch (geology), Epoch or the lowest stage (stratigraphy), stage of the Upper Cretace ...

-age (approximately 97 million years old) Tarrant Formation. Also found were fish teeth and

vertebra Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spina ...

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

Turonian The Turonian is, in the International Commission on Stratigraphy, ICS' geologic timescale, the second age (geology), age in the Late Cretaceous epoch (geology), Epoch, or a stage (stratigraphy), stage in the Upper Cretaceous series (stratigraphy), ...

–age

Eagle Ford Group The Eagle Ford Group (also called the Eagle Ford Shale) is a Sedimentary rock, 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 pr ...

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

2010 The year saw a multitude of natural and environmental disasters such as the 2010 Haiti earthquake, the Deepwater Horizon oil spill, and the 2010 Chile earthquake. The 2009 swine flu pandemic, swine flu pandemic which began the previous year ...

. The

type species In International_Code_of_Zoological_Nomenclature, 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 spe ...

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 sp ...

''. ''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 Anhanguera may refer to: People * Bartolomeu Bueno da Silva (1672–1740), a bandeirante also known as Anhanguera * Anhangüera I, father of Bartolomeu Bueno da Silva Places in Brazil * Anhanguera, Goiás, a municipality in the state of Goiás ...

'', ''

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 Engla ...

'', 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 United Kingdom and possibly Morocco. Several species ha ...

'', 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 ''Cimoliopterus'' is a genus of pterosaur that lived during the Late Cretaceous in what is now England and the United States. The first known specimen, consisting of the front part of a snout including part of a crest, was discovered in the Gr ...

'' instead.

Classification

Below is a

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

by Pêgas ''et al.'' (2019), reassigning ''Aetodactylus'' to the clade

Targaryendraconia Targaryendraconia is an extinct clade of lanceodontian pterosaurs that lived from the Early to Late Cretaceous period in Europe, North America, South America, and Australia. Classification Below is a cladogram following a topology by Pêgas an ...

within the more inclusive group

Ornithocheirae Ornithocheiromorpha (from Ancient Greek, meaning "bird hand form") is a group of pterosaurs within the suborder Pterodactyloidea. Fossil remains of this group date back from the Early Cretaceous, Early to Late Cretaceous Period (geology), period ...

, and more specifically to the family

Cimoliopteridae Targaryendraconia is an extinct clade of lanceodontian pterosaurs that lived from the Early to Late Cretaceous period in Europe, North America, South America, and Australia. Classification Below is a cladogram following a topology by Pêgas and ...

: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 Pteranodontoidea Late Cretaceous pterosaurs of North America Fossil taxa described in 2010

Description

Classification

See also

References