Europejara

Europejara is a genus of tapejarid pterosaur from the Early Cretaceous of Spain. The type and only species known is Europejara olcadesorum.

Discovery and naming

In 2012, the type species Europejara olcadesorum was named and described by Romain Vullo, Jesús Marugán-Lobón, Alexander Kellner, Angela Buscalioni, Bernard Gomez, Montserrat de la Fuente and José Moratalla. The generic name combines the names of Europe and the related genus Tapejara, in reference to the fact that Europejara is the first tapejarid found in that continent. The specific name refers to the Olcades, the Celtiberic tribe inhabiting the region of Cuenca, the location of the find, in Antiquity.
The holotype, MCCM-LH 9413, was uncovered at the Las Hoyas site in a chalkstone layer of the Calizas de La Huergina Formation dating from the late Barremian. It consists of a partial skull with lower jaws, compressed on a slab and counterslab. Several scleral ring bones and two elements of the hyoid are present also. The skull has been vertically crushed, the lower jaws horizontally. The specimen was prepared by Mercedes Llandres Serrano, and is part of the Las Hoyas collection of the Museo de las Ciencias de Castilla–La Mancha.

Description

Europejara was a relatively small tapejarid, with an estimated wingspan of. What is preserved of the holotype skull is incomplete and is flattened dorsoventrally, whereas the mandible is preserved in a lateral view. Due to the crushing of the skull, its fragments, mainly representing elements from the area around the right eye socket, show little detail. Both maxillae are preserved, though are fragmentary. The part of the left jugal bone which connected to the postorbital and was found anterior to the quadrate bone, is known; the right jugal, if present, was too fragmentary to be identified with any level of confidence. The postorbital was roughly triangular. A lacrimal bone was tentatively identified by the authors, which, if that identification is correct, is typical in morphology among tapejarines.Like other tapejarids, Europejara's dentaries supported a large crest, four times deeper than the back of the lower jaw in its case. The crest pointed downward for at least, making it the longest dentary crest relative to lower jaw length of any known pterosaur. While enough is preserved to determine that the posterior portion of the jaw was backswept, the tip and anterior surface are not preserved, so its full shape cannot be established. The hyoid apparatus, a structure involved in supporting the tongue and larynx, is preserved in the form of the first pair of ceratobranchial bones. Each is about in length and in diameter.

Phylogeny

Europejara was assigned to the Tapejaridae. A cladistic analysis showed it to be more precisely a member of the Tapejarinae. Apart from being the first tapejarid known from Europe, it would also be the oldest pterosaur with certainty known to be edentulous; older fragments have been reported representing other generally toothless clades but these did not include the jaws themselves. The cladogram below follows a phylogenetic analysis by Kellner, one of the describers of Europejara, and colleagues in 2019. They recovered Europejara within the tribe Tapejarini, sister taxon to three other genera: Caiuajara, Tapejara, and Tupandactylus.

Paleobiology

Diet

Following earlier suggestions about the diet of tapejarids, the describers assumed a frugivorous lifestyle for Europejara. Because the species is so old it indicates a role for the tapejarids in the Cretaceous Terrestrial Revolution, a turn-over in the ecosystems of the Lower Cretaceous in which gymnosperms were replaced by angiosperms, flowering plants, and new groups of herbivores evolved, adapted to the changed food supply. In the case of tapejarids there could have been a reinforcing interactive cycle between the evolution of fruit and the pterosaurs dispersing the seed. Possibly the beaks of the tapejarids had ragged edges forming pseudo-teeth to better separate the fruit flesh from the seeds, as with some extant toucans. Direct evidence of frugivory in tapejarids has since been found in the form of a Sinopterus specimen with an abdominal cavity containing gastroliths and phytoliths, minerals found in certain plants which persist after their decomposition.

Paleoenvironment

The Las Hoyas Konservat-Lagerstätte, from which Europejara's holotype was recovered, has been dated to the late Barremian based on charophyte and ostracod assemblages, and was likely deposited in a subtropical wetland environment, between a lacustrine environment and a tree fern-dominated savannah. Preservation at the Las Hoyas site is so precise that certain taxa, such as Spinolestes, have been preserved with their internal organs intact, and even bacteria have been described. More than twenty thousand plant and animal fossils are known from Las Hoyas. The biota of Las Hoyas is intermediate between Jurassic and other Early Cretaceous biotas, and is thus representative of the early stages of the Cretaceous Terrestrial Revolution. Plants known from the site include the ferns Cladophlebis and Weichselia. Angiosperms, or flowering plants, were another component of the Las Hoyas flora: the oldest angiosperm macrofossil, the aquatic Montsechia, comes from this site.
Nonavian theropods are represented by the carcharodontosaurid Concavenator and the ornithomimosaur Pelecanimimus, as well as several taxa known from teeth; known avians are the enantiornitheans Concornis, Eoalulavis, and Iberomesornis. A single non-theropod dinosaur, the ornithischian Mantellisaurus, has been identified from Las Hoyas. Crocodyliforms are represented by the gobiosuchid Cassissuchus, and trackways presumably left by goniopholidids. Lepidosaurs from Las hoyas include the arboreal taxon Scandensia, and the characteristically small Jucaraseps. The exceptionally preserved eutriconodont mammal Spinolestes comes from Las Hoyas. An albanerpetontid amphibian, Celtedens, is known. Roughly twenty species of chondrichthyans, coelacanths, and actinopterygians, including species previously thought to be exclusively saltwater, constitute the known fish fauna of Las Hoyas. The invertebrate fauna of Las Hoyas is represented primarily by insects, and especially by aquatic beetles.