Europejara is a genus of tapejarid pterosaur that lived during the Barremian age of the Early Cretaceous epoch in what is now Spain. The only known specimen was found at the Las Hoyas site of Cuenca, a location noted for its exceptional Konservat-Lagerstätte preservation. In 2012, the new genus and species Europejara olcadesorum was named based on it. The generic name refers to Europe, where it was found, and to the related genus Tapejara from what is now Brazil, while the specific name refers to the Olcades, an ancient people that lived in the region. The holotype specimen consists of an incomplete, crushed skull; the bones of the postorbital region are displaced while the mandible is almost complete.
The first tapejarid known from Europe, Europejara was also the oldest known member of that group and the oldest known toothless pterosaur at the time of its naming. A relatively small pterosaur, Europejara is estimated to have had a wingspan of around . As a tapejarid, it had a short skull with downturned jaws and would have had two crests on the upper part of its skull connected by a keratinous structure. The genus is mainly distinguished from other tapejarids in that the dentary crest, which projected down from the front of the lower jaws, was recurved backwards, and was more developed from top to bottom than from front to back. A combination of other skull features is also used to distinguish it.
Researchers have found Europejara to be related to Brazilian tapejarids and, given its age, have used this relationship as evidence for the group's origin on the northern palaeocontinent of Laurasia. The function of tapejarid dentary crests is uncertain, but a role in aerodynamics, thermoregulation, or social behavior has been suggested. Due to the shape of their skulls and jaws, they have been considered frugivorous (fruit-eaters) and/or granivorous (seed-eaters), and the age of Europejara led its describers to suggest that tapejarids had a role in seed dispersal when angiosperms (flowering plants) first appeared. Europejara is known from the La Huérguina Formation, which represents a subtropical wetland environment.
Discovery and naming
The Castilla-La Mancha region of eastern Spain contains many rich fossil localities spanning from the Precambrian to the Pleistocene; the Las Hoyas site in Cuenca in the southwestern Iberian Ranges has been particularly noted for its Konservat-Lagerstätte preservation (with exceptionally preserved fossils). The locality belongs to the La Huérguina Formation and dates to the late Barremian of the Early Cretaceous. The site was discovered in 1985, and as of 2023, nearly 30 excavation campaigns have yielded over 20,000 fossils; these are housed at the in Cuenca. The preservation and extent of the site's fossil flora and fauna have given it worldwide scientific renown, and it was declared a Site of Cultural Interest by the regional government in 2016.
In 2012, the palaeontologist Romain Vullo and colleagues reported an incomplete skull of a pterosaur (an extinct order of flying reptiles) from Las Hoyas, new to science. This pterosaur is the first member of the family Tapejaridae known from Europe, adding to the poorly known pterosaur fauna of the locality. Previously, tapejarids were only certainly known from Brazil and China, where pterosaur fossils of similar age are more abundant and more complete than in Europe. At the time, the specimen was also the oldest known tapejarid and the oldest known toothless pterosaur. The specimen (designated as MCCM-LH 9413 in the Sciences Museum) was made the holotype of the new genus and species Europejara olcadesorum. The generic name combines the names of Europe (itself derived from Europa of Greek mythology) where it was found, and the related genus Tapejara, the Brazilian genus that defines the clade Tapejarinae. The name Tapejara itself is composed of the Tupí-Guaraní words tapi or tape, which means , and yara or jara, which means . The specific name refers to the Olcades, an ancient Celtiberian people from Hispania that first inhabited the region of Cuenca.
The holotype consists of the hind part of a skull with lower jaws, compressed on a slab and counterslab of limestone. Several scattered plates that formed the scleral ring (a bony ring inside the eye) and two elements of the hyoid (tongue bone) are also present. The skull is crushed and flattened from top to bottom, with bones of the left postorbital region (the area behind the orbit or eye socket) being displaced, but the mandible is almost complete and is preserved in side view. No integument, such as soft tissue and keratinous parts, is preserved. The preparation of the specimen included removing elements from the fossil matrix with acid, and it was photographed under ultraviolet light for its description. The fossil was presented at an outreach event in 2012, which included the best Las Hoyas fossils from the Sciences Museum, where the audience interacted with the researchers, who demonstrated study techniques.
Description
Based on the proportions of other tapejarids, the describers of Europejara considered it a relatively small pterosaur in 2012, with an estimated wingspan of around . In 2023, some of the same authors gave a wingspan of , considering Europejara a mid-sized pterosaur.
Tapejarids are characterised by their short faces and downturned jaw tips. Most mature skulls had two crests on their upper surface—one at the front (on the premaxilla, the frontmost bone of the upper jaw) and one at the back, with keratinous soft-tissue structures occupying the space between the two. The lower jaws of adults had a rounded crest projecting down from the dentary bone at the mandibular symphysis (where the two halves of the mandible connected at the front). Although Europejara is only known from skull bones, relatives show tapejarids had comparatively robust and complex limb girdles, elongated limbs for their body size, but rather short wing fingers and feet, and very short tails. As a pterosaur, Europejara was covered with hair-like pycnofibres and had extensive wing membranes (which were extended by the wing finger).
Both maxillae (the bones that form most of the upper jaw) of Europejara are preserved, though incompletely, with their upper margins exposed, and form an angle of around 12 degrees. The postorbital bone (the bone behind the orbit) is roughly triangular, with no visible suture (joint) between it and the jugal bone (or cheek bone) underneath. The plates of the scleral ring are trapezoidal in shape and thin. A lacrimal bone (the bone that separates the orbit from the bony nostril) was tentatively identified and is typical for tapejarids, being thin and fenestrated (having openings).
The lower temporal fenestra (the opening behind the orbit) at the back of the skull of Europejara was narrow, as indicated by the position of the quadrate bone (which forms part of the jaw joint). The palate is preserved in top view and has two narrow, elongated choanae (internal nostrils), separated by a thin vomer (part of the middle of the palate). 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, and their hind halves are slightly curved.
The preserved part of the almost-complete mandible is , with an estimated total length of , and each mandibular ramus (halves that constituted the mandible) is in height. Most of their length is made up of the dentary bones. Each ramus is robust, and its upper and lower borders are parallel. The outer surface of each ramus is smooth, while the inner surface has shallow, well-marked depressions, and there is a bulge on the upper, inner surface of each dentary, a distinguishing combination for this genus. In side view, the cutting edge of the dentaries is slightly sigmoid curved in the area of the mandibular symphysis. The upper surface of the symphysis is concave in cross-section.
Europejara had a deep, bony crest that projected downward from the dentaries and was distinct from those of its relatives in being recurved backwards and more developed from top to bottom than from front to back. The crest was at least deep, four times deeper than the back of the lower jaw and therefore proportionally deeper than in other tapejarids. The dentary crest of Europejara was larger, better developed and deeper than those of the Chinese tapejarids Sinopterus and Huaxiadraco, while those of the Brazilian Tapejara and Tupandactylus were longer from front to back.
Both the premaxillary and dentary crests are low in Sinopterus and Huaxiadraco, while they are well-developed in Tapejara and Tupandactylus, indicating that their dimensions can be roughly correlated in tapejarids. Vullo and colleagues therefore inferred that the deep dentary crest of Europejara suggested that its premaxillary crest was relatively high, and may have been backwards recurved, reflecting the shape of the dentary crest.
Classification
Europejara was classified as a member of the pterosaur family Tapejaridae by Vullo and colleagues in the phylogenetic analysis accompanying their 2012 description. At the time, this group was divided into two subfamilies; the long-faced and large-sized Thalassodrominae, and the short-faced and smaller-sized Tapejarinae, both with well-developed cranial crests. Europejara was assigned to the latter due to the presence of a dentary crest and a step-like upper edge at the symphyseal area of the dentary, a unique feature of tapejarines. The position of Europejara within Tapejarinae was poorly determined due to its incompleteness. The describers stated that the presence of a tapejarid in Spain during the Barremian age shows that the group was distributed earlier and more broadly throughout the palaeocontinents of Gondwana (the southern continent) and Laurasia (the northern continent) than previously known, living from Brazil to China.
Despite Europejaras phylogenetic position within Tapejarinae being unresolved, the describers suggested that it might be the sister group to a clade consisting of taxa from Brazil and China; this would be the most stratigraphically sound conclusion, as grouping Europejara with Chinese tapejarines would be inconsistent unless older Gondwanan taxa were found. As the oldest tapejarids were from the late Barremian of Spain and China, these authors suggested that the group originated in Eurasia near the beginning of the Early Cretaceous rather than in Gondwana, and could have spread to Brazil during the later Aptian. The occurrence of a tapejarid in the Cenomanian of Morocco suggests that the group diversified in Gondwana during the mid-Cretaceous, but these authors cautioned that knowledge about tapejarid evolution and palaeobiogeography was affected by uneven fossil sampling. They added that the absence of the group in North American, European, and African deposits from the Aptian–Albian could be due to the lack of pterosaur-bearing sites in those regions at that time.