Mimodactylus is a genus of istiodactyliform pterosaur that lived in what is now Lebanon during the Late Cretaceous, 95 million years ago. The only known specimen was discovered in a limestone quarry near the town of Hjoula, belonging to the Sannine Formation. The owner of the quarry allowed the specimen to be prepared and scientifically described by an international team of researchers. When it was eventually sold, the buyer donated it to the MIM Museum in Beirut. In 2019, the researchers named the new genus and species Mimodactylus libanensis; the generic name refers to the MIM Museum, combined with the Greek word daktylos for "digit", and the specific name refers to Lebanon. The well-preserved holotype specimen is the first complete pterosaur from the Afro-Arabian continent (which consisted of the then joined Arabian Peninsula and Africa), and the third pterosaur fossil known from Lebanon. The holotype specimen is comparatively small, with a wingspan of 1.32 metres (4.3 ft), and was probably a young individual. Its snout is broad and the cone-shaped teeth are confined to the front half of the jaws. The tooth crowns are compressed sideways and have a cingulum (a thickened ridge at the base), and lack sharp carinae (cutting edges). The skeleton is distinctive in that the deltopectoral crest of the humerus (ridge for attachment of the deltoid and pectoral muscles) is rectangular and that the humerus is less than half the length of the wing-finger's second phalanx bone. The describers of Mimodactylus classified it in the new clade Mimodactylidae along with Haopterus, this group being part of Istiodactyliformes. The teeth of Mimodactylus suggest its feeding habits differed from other pterosaurs. Possibly it foraged for decapod crustaceans from water surfaces. The marine deposits of Hjoula are late Cenomanian in age and are well known for fish fossils. Lebanon was submerged in the Neotethys ocean at the time, but some small islands were exposed.
History of discovery The only known specimen of this pterosaur was collected from a private limestone quarry near the town of Hjoula, Lebanon, more than fifteen years before its 2019 scientific description. Hjoula is located 35 km (22 mi) northeast of the capital Beirut and 10 km (6.2 mi) inland from the city of Byblos. The locality is considered a Lagerstätte, a place with fossils of exceptional preservation, and belongs to the Sannine Formation, which dates to the late Cenomanian age of the Cretaceous period. Lebanese Cretaceous deposits have been known for well-preserved fish and invertebrates since the Middle Ages, but fossils of tetrapod (ancestrally four-limbed) animals are very rare. Information about Mesozoic fossils of the Afro-Arabian continent (which consisted of the then joined Arabian Peninsula and Africa, also known as the Arabo-African palaeocontinent) is generally very limited, with only South Africa having been systematically studied.
The very fragile but well-preserved pterosaur specimen was split in two pieces when discovered on the limestone slab, and apart from a fracture caused by the pickaxe of a quarry worker, its skull was intact, as were the wings, legs, and body. The owner of the quarry allowed a team of researchers from the University of Alberta in Canada to prepare and describe the specimen, while intending for the fossil to be eventually sold, which is legal in Lebanon. The palaeontological community in Lebanon lacked the technology needed to prepare the fossil material in a way that would most effectively reveal information from the specimen. The specimen spent about eight years at the University of Alberta, where it was prepared, assembled, and studied. Subsequently, the owner of the quarry sold the specimen, but around 2016, after years of negotiations, the anonymous buyer donated it to the MIM Museum, hosted at the Saint Joseph University of Beirut, so that it could be kept in Lebanon. The Canadian palaeontologists Michael W. Caldwell and Philip J. Currie teamed up with an international group of researchers to scientifically describe the specimen, including the Brazilians Alexander W. A. Kellner, Borja Holgado, and Juliana M. Sayão, Italian Fabio M. Dalla Vecchia, and Lebanese Roy Nohra (Kellner and Dalla Vecchia had previously done fieldwork in Lebanon together). In interviews, the researchers expressed pleasure in the specimen being returned to Lebanon, where it can be used for education and research, and in having the opportunity to collaborate internationally. The majority of fossil type specimens (on which scientific names are based) from Lebanon are stored in collections outside the country, and Lebanese researchers are typically not included in publications about Lebanese fossils; a 2024 study therefore concluded Lebanon is impacted by scientific colonialism.
In 2019, Kellner and colleagues named the new genus and species Mimodactylus libanensis; the generic name refers to the MIM Museum, in recognition of where the specimen is housed and according to the wishes of the philanthropist who acquired the specimen, combined with the Greek word daktylos (δάκτυλος) for "digit". The specific name refers to Lebanon. The holotype specimen is catalogued as MIM F1, and casts are present at the University of Alberta and the National Museum of Brazil. The holotype skeleton is well-preserved and mostly articulated, with some bones slightly displaced from their anatomical position; the skull and lower jaw are exposed from below, and the occipital region at the back of the skull and the jaw joint flattened. The holotype is the first complete and articulated pterosaur specimen known from the Afro-Arabian continent, which had otherwise only yielded a few fragmentary specimens. The previous most completely known pterosaur specimens from the continent were also from Lebanon: a partial forelimb of an unnamed ornithocheiroid (catalogued as MSNM V 3881) from the Hakel Lagerstätte of the same age, and Microtuban, an azhdarchoid consisting mainly of the wings and shoulder girdle, also from Hjoula. Although these specimens are less complete, their anatomical features can be clearly distinguished from Mimodactylus. The specimen has become the centrepiece of the fossil vertebrate collection at the MIM Museum, where it is nicknamed "Mimo" and is exhibited alongside a hologram, a movie, a life-sized reconstruction, and a game.
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