Aetodactylus
Aetodactylus is a genus of targaryendraconian pterosaur. It is known from a lower jaw discovered in Upper Cretaceous rocks of northeastern Texas, United States.
Description
Aetodactylus is based on SMU 76383, a nearly complete lower jaw lacking the right retroarticular process, part of the posterior end of the mandibular symphysis, and all but two teeth. This specimen was found in 2006 by Lance Hall near a construction site in Mansfield, near Joe Pool Lake. The rock it was found in is a calcareous marine sandstone rich in mud–sized particles, from the middle Cenomanian-age Tarrant Formation. Also found were fish teeth and vertebrae, and indeterminate bones. The Tarrant Formation is the lowest rock unit of the Cenomanian–Turonian–age Eagle [Ford Group].Aetodactylus was named by Timothy S. Myers of SMU in 2010. The type species 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. Aetodactylus represents one of the youngest definitive records of ornithocheirids.
The jaw SMU 76383 is long, 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 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, and Ornithocheirus, there is no bony crest on the lower jaw.
Aetodactylus was considered a possible relative of Boreopterus in the original description, but subsequent cladistic analysis found it to be closely related to Cimoliopterus instead.