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.[1]
Description
Restorations of the skull and head
Europejara was a relatively small tapejarid, with an estimated wingspan of 2m (6.6ft). What is preserved of the holotype skull is incomplete and is flattened dorsoventrally (from top-to-bottom), whereas the mandible is preserved in a lateral (side) 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 (the bone behind the orbit, or eye socket) 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.[1]
Like other tapejarids, Europejara's dentaries (the bones at the front of the lower jaw) supported a large crest, four times deeper than the back of the lower jaw in its case. The crest pointed downward for at least 9cm (3.5in), making it the longest dentary crest relative to lower jaw length of any known pterosaur. While enough is preserved to determine that the posterior (rear) portion of the jaw was backswept, the tip and anterior (front) 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 13.5cm (5.3in) in length and 0.2cm (0.079in) in diameter.[1]
Phylogeny
Close-up of the lower jawComparison of azhdarchoid mandibles, notice Europejara (C)
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.[1] 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.[2]
Distribution through time and space of tapejarine pterosaurs and early angiosperms
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.[1] Direct evidence of frugivory in tapejarids has since been found in the form of a Sinopterus specimen with an abdominal cavity containing gastroliths (stones used to aid food processing in the gut) and phytoliths, minerals found in certain plants which persist after their decomposition.[3]
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