170-million-year-old fossilized remains discovered in Patagonia, Argentina, have been identified as a new genus and species of pterosaur.
An artist’s representation of the Jurassic pterosaur Allkauren koi. Image credit: Gabriel Lío.
Pterosaurs were highly successful flying reptiles that lived between 210 million and 65 million years ago.
These creatures were Earth’s first winged vertebrates, with birds and bats making their appearances much later. They first appeared in the Late Triassic and went on to achieve high levels of morphologic and taxonomic diversity during the Mesozoic era, with more than 150 species recognized so far.
Pterosaurs have traditionally been divided into two major groups: the primitive, primarily long-tailed rhamphorhynchoids (preferably currently recognized as non-pterodactyloids) and the derived short-tailed pterodactyloids.
They had an extraordinary adaptation to flight, including pneumatic bones to lighten its weight, and an elongated digit supporting a wing membrane. Some were the largest flying animals of all time, with wingspans exceeding 30 feet.
Pterosaurs are not rare in the fossil record, but their neuroanatomy is known from only a few three dimensionally preserved remains and, until now, there was no information on the intermediate forms.
Selected skeletal elements of Allkaruen koi: braincase, mandible and cervical vertebra. Abbreviations: ag – alveolar groove; alv – alveoli; atr – anterior tympanic recess; bo – basioccipital; btr – basipterygoid recess; bpt – basipterygoid process; bs – basisphenoid; bt – basal tuber; cmv – caudal middle cerebral vein foramen; co – condyle; ct – crista tuberalis; d – dentary; eo-op – exoccipital/opisthotic; f – frontal; fm – foramen magnum; lts – laterosphenoid; mf – metotic foramen; nc – nuchal crest; np – nasal process; ns, neural spine; oc – occipital condyle; p – parietal; pf – pneumatic foramen; poz – postzygapophysis; pro – prootic; prz – prezygapophysis; ptf – posttemporal fenestra; ptr – posterior tympanic recess; sc – sagittal crest. Roman numerals indicate cranial nerves. Scale bars – 10 mm. Image credit: Codorniú L et al.
Named Allkauren koi, the newly-discovered winged reptile is represented by several skeletal elements including an almost perfect, three-dimensionally preserved braincase that shows a unique combination of characters shared with both pterodactyloids and breviquartossans (non-pterodactyloids).
The fossilized material comes from a single locality within the Cañadón Asfalto Formation in northern central Chubut Province, Patagonia, Argentina.
“Allkauren koi, from the middle lower Jurassic limit, shows an intermediate state in the brain evolution of pterosaurs and their adaptations to the aerial environment,” said Dr. Diego Pol, a paleontologist at the Museum of Paleontology Egidio Feruglio in Trelew, Chubut, Argentina.
“As a result, this research makes an important contribution to the understanding of the evolution of all of pterosaurs.”
The research appears today (August 30, 2016) in the journal PeerJ.
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Codorniú L et al. 2016. A Jurassic pterosaur from Patagonia and the origin of the pterodactyloid neurocranium. PeerJ 4: e2311; doi: 10.7717/peerj.2311
