A new genus and species of furileusaurian abelisaurid that lived during the Cretaceous period has been identified from fossilized skeletal remains found in Patagonia, Argentina.
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Koleken inakayali. Image credit: Gabriel Díaz Yantén.
Koleken inakayali lived in what is now Argentina about 69 million years ago (Maastrichtian age of the Late Cretaceous epoch).
This species belonged to Furileusauria, a group of derived abelisaurid dinosaurs known from South America.
“Abelisaurids (family Abelisauridae) were the most abundant theropods during the latest Cretaceous, occurring in all Gondwanan regions, except Antarctica and Australia where they remain unknown,” said Dr. Diego Pol, a paleontologist at the Museo Argentino de Ciencias Naturales Bernardino Rivadavia and CONICET, and his colleagues.
“They are known principally from South America, which has the best fossil record for this group, as well as from India, northern Africa, and Madagascar.”
“Incomplete abelisaurid specimens were also discovered in Europe, adding evidence to the biogeographical link between southern Europe and Gondwana.”
“Furileusaurian abelisaurids are a diverse clade that encompasses most South American abelisaurids known from the latest Cretaceous.”
Koleken inakayali is known from several skull bones, almost complete hind limbs, and other skeletal elements.
The fossils were found in the La Colonia Formation at the Cerro Bayo Norte area, east of the Sierra de La Colonia, center north of Chubut Province, Patagonia, Argentina.
“The holotype is composed of a partial skeleton, including cranial, axial and appendicular elements, with a unique set of characters that distinguish it from all known theropods,” the paleontologists said.
“In particular, Koleken inakayali shows several anatomical traits, especially in the skull bones, that differentiate it from Carnotaurus sastrei, the only other abelisaurid known from the La Colonia Formation.”
The discovery indicates that abelisaurid dinosaurs were more diverse than previously thought.
“We analyzed the evolutionary relationships between abelisaurids and and their closest relatives, noasaurids (family Noasauridae),” said Dr. Fernando Novas, a paleontologist at the Museo Argentino de Ciencias Naturales Bernardino Rivadavia and CONICET.
“We found periods of time in which these groups changed rapidly, and other periods in which their evolution remained almost on pause.”
The team’s paper was published in the journal Cladistics.
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Diego Pol et al. A new abelisaurid dinosaur from the end Cretaceous of Patagonia and evolutionary rates among the Ceratosauria. Cladistics, published online May 21, 2024; doi: 10.1111/cla.12583
