About 66 million years ago, in the Late Cretaceous era (Maastrichtian stage), pterodactyloid pterosaurs of the genus Tethydraco existed in what is now Morocco. Tethydraco was first placed in the Pteranodontidae family. Although this has been contested, some academics claimed that later evidence indicated that it could have been an azhdarchid and potentially synonymous with Phosphatodraco. T. regalis is the only species and the type.
Discovery and Naming
The Khouribga plateau, part of the Ouled Abdoun Basin, is home to the phosphate mines where workers gather the pterosaur fossils that a group of paleontologists has been purchasing from commercial Moroccan fossil dealers since 2015. Determining pterosaur diversity during the most recent Cretaceous is the aim of this endeavor. At now, there are no known Konservat-Lagerstätten, which are locations that offer remarkable preservation with a wide range of species. The great bulk of pterosaur fossils and taxa have been found in these kinds of locations. Azhdarchidae only possessed a few partially complete skeletons from the most recent Cretaceous. This fact has typically led researchers to believe that other pterosaur groups had already become extinct. An other theory, however, would be that undersampling brought about by the inadequate fossil record resulted in a skewed picture of the actual situation. All the pterosaur bones discovered as a result of the extensive and organized commercial mining of the Khourigba phosphate levels were gathered in an attempt to verify this theory. It became out that several findings probably belonged to different groups and could not be identified as azhdarchids. In 2018, Tethydraco was one of the four finds that were described as new species. The Tethydraco regalis type species was named and described by Brian Andres, David M. Martill, and Nicholas R. Longrich in 2018. In the generic name, "dragon" is derived from the Latin draco and alludes to the Tethys, the ocean that divided Africa from Europe and Asia during the Late Cretaceous period. The Latin meaning of the particular name is "royal". The late Maastrichtian holotype, FSAC-OB 1, was discovered in the middle Couche III, the lowest phosphate layer complex at Sidi Daoui. It is made up of the left humerus. In comparison, the bone is crushed. The species has been applied to more specimens. An ulna is FSAC-OB 199. A second ulna is FSAC-OB 200. This is a thighbone, FSAC-OB 201. A thighbone and shinbone make up FSAC-OB 202. Given the paucity of overlapping material, the describing authors acknowledged that it is difficult to establish a relationship between the holotype and the other specimens. Still, the remarkable distal breadth of the humerus was fitted by the large ulnae. The thighbones appeared to be pteranodontid, therefore they were more hesitantly referred.
Description
With a body mass of 15 kilograms (33 lb), Tethydraco measured 5 meters (16 ft) in length. The authors of the description listed a few characteristics that set Tethydraco apart from other recognized pteranodontids. The nearest border of the deltopectoral crest in the humerus is situated very close to the start of the opposing crest, the crista ulnaris, and it is positioned very proximally, closer to the animal's torso. The humerus has a wide triangle expansion that extends away from the body at a distance. When the wing is extended, there is a noticeable process pointing upward along the bone ridge that leads to the outer joint condyle. The ridge that leads to the inner condyle is expanded and stretches far in the direction of the torso. The ulna is rather broad and short, with a large expansion at its proximal end where it meets the humerus.
Phylogeny
Tethydraco belonged to the Pteranodontidae family, and because its fossil remains were discovered 66 million years ago, it would have been the newest member of that family known to science. The discovery was seen as evidence that the diversity of pterosaurs in the Maastrichtian was greater than previously thought. Due to the Signor–Lipps effect, which makes groups appear to vanish before a mass extinction because their earliest fossils have accidentally been discovered in strata that are considerably older than the extinction event, the apparent pterosaur decrease would have been an illusion. The phylogenetic study findings are displayed in the cladogram below, which was updated with new data by Longrich and colleagues in 2018 after it was initially reported by Andres and colleagues in 2014. Tethydraco was determined to be the sister taxon of the two Pteranodon species (P. longiceps and P. sternbergi) in this research. The three of them together make up the Pteranodontidae family, which is the sister taxon of the Nyctosauridae family.
| Ornithocheiroidea |
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The morphology revealed that Tethydraco was an azhdarchid, not a pteranodontid as first thought, and may have represented the wing-elements of Phosphatodraco. In 2020, a wing from the same deposit was ascribed to the genus. The humerus of Epapatelo and other non-Nyctosaurus pteranodontoids are comparable, according to researchers who characterized Epapatelo in 2022. Tethydraco was identified as a pteranodontian that was closely linked to Pteranodon.
Paleoecology
In Morocco's Ouled Abdoun Basin, Tethydraco was found. Tethydraco was found in Couche III, one of the "Couches" that make up this basin. It shared a home with the abelisaurid dinosaur Chenanisaurus as well as the pterosaurs Alcione, Barbaridactylus, Simurghia, and Phosphatodraco.
Realistic reconstruction of Tethydraco, on a beach.
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