Javelina azhdarchid

Size chart of TMM 42489-2 reconstructed as a thalassodromine

Size chart of TMM 42489-2 reconstructed as an azhdarchid, including the jaws and neck vertebrae

In March 1986, jaws and neck vertebrae of a large pterosaur were discovered in Brewster County by preparator Robert Rainey. In 1991, Peter Wellnhofer illustrated the find by a picture in his The Illustrated Encyclopedia of Pterosaurs and in the photo caption assigned it to Quetzalcoatlus sp.[3] Accordingly, his illustrator John Sibbick reconstructed Quetzalcoatlus with a too blunt snout, a mistake repeated in many popular science works. In 1996, Alexander Kellner and Wann Langston jr. pointed out that the remains dated from older layers than those which had produced Quetzalcoatlus sp. and represented a form with a shorter snout and neck.[4] In 2004, Kellner, limiting himself to the skull material which he reconstructed, stated that it was a member of the Tapejaridae.[5] In 2006, David Michael Martill and Darren Naish concluded that the snout resembled that of Tupuxuara more than that of Quetzalcoatlus and referred to the taxon as the "Javelina Tupuxuara".[6] In 2012, the fossils were studied by Brian Andres whose cladistic analysis recovered the taxon as a member of the Azhdarchidae, both when the neck vertebrae were included and when only the skull material was entered.[7] In 2013, Mark Witton similarly favoured an azhdarchid interpretation over a thalassodromid one, comparing it to other "blunt-jawed" azhdarchids.[8]

In August 2021, the type species Javelinadactylus sagebieli was named and described by Hebert Bruno Nascimento Campos. The generic name combines a reference to the Javelina Formation with a Latinised Greek daktylos ("finger"), a usual suffix in the names of pterosaurs. The specific name honours James Christopher Sagebiel, head vertebrate fossils collection of the University of Texas. It is the second pterosaur species named from the latest Cretaceous of Texas, after Quetzalcoatlus.[1] The holotype, TMM 42489-2, was found in a layer of the Javelina Formation dating from the middle Maastrichtian. It consists of the front of the paired premaxillae, the paired maxillae and jugals, the front of the mandibular symphysis of the lower jaws and the dentary rami. The remains had been partially articulated. The neck vertebrae, specimens TMM 42489-2.3 to 2.7, were in early 2021 not considered to be part of the holotype.[1]

Later, in December, the complete specimen, including the jaws and the cervical vertebrae, were independently named by Brian Andres and posthumously Wann Langston Jr. as the type species of a short-snouted azhdarchid, Wellnhopterus brevirostris. The generic name, Wellnhopterus is Wellnhofer’s name combined with the Greek pteron, meaning "Wellnhofer's wing", and the specific name, brevirostris (IPA: [brɛvɪˈrɒstrɪs]) meaning "short-beaked" is a combination of the Latin words brevis, meaning short, and rostrum, meaning beak, in reference to its description in the literature as a “short-faced animal”.[2]

Size (middle bottom) compared to contemporary pterosaurs and a human, reconstructed as an azhdarchid

A cladistic analysis in the Javelinadactylus study found the taxon to be a thalassodromine (which the describer assigns to the family Tapejaridae). It was unique in that it in 2021 was the only tapejarid and thalassodromine known from the Maastrichtian, and the only one known from North America. Other members of Thalassodrominae were only known from the much older Romualdo Formation of Brazil.[1] The Wellnhopterus study instead recovered the taxon as an azhdarchid.[2]

Phylogeny after Campos, 2021:[1]

Phylogeny after Andres, 2021:[9]

Regardless of its specific phylogenetic placement, the "Javelina azhdarchid" was likely raptorial, as both "blunt-jawed" azhdarchids and thalassodromids are thought to have been specialised to hunt proportionally large prey.[10][11][12]

Its co-existence with Quetzalcoatlus and a possible additional pterosaur taxon have been used as examples of pterosaur diversity being higher in the Maastrichtian than traditionally thought.[13]