Төрт қабатты динозаврлар туысы Таленкауэн

Extinct genus of dinosaurs

Talenkauen is a genus of basal iguanodont dinosaur from the Campanian or Maastrichtian age of the Late Cretaceous Cerro Fortaleza Formation, formerly known as the Pari Aike Formation of Patagonian Lake Viedma, in the Austral Basin of Santa Cruz, Argentina.

One among a string of discoveries of ornithopods in South America, following taxa such as Gasparinisaura and Anabisetia, the specimen that would become Talenkauen was collected in February 2000 and would later be described and named in a short 2004 paper by Fernando E. Novas and colleagues. It was discovered on Los Hornos Hill on the coast of Viedma Lake, in the Santa Cruz Province region of Argentina. It has been recognized that, nestled amongst the rock matrix of the holotype specimen, are a collection of minuscule bone fragments and teeth. Identifiable as the teeth of some degree of ornithopod, and associated with the adult specimen, this is considered to be a neonatal, or recently hatched, baby specimen of Talenkauen. It was described in a 2013 paper, which separated the specimen number MPM–10001 into MPM–10001A, for the adult specimen, and MPM–10001B, for the neonate. The specimen is one of only very few embryonic or hatchling ornithopod specimen, and was the very first discovered from the southern hemisphere. Wear on the tiny, 1.7mm wide tooth crowns indicate the individual had fed, meaning it was not an embryo and had hatched, but only recently before death. It was noted as possible that the adult had been practicing parental care due to the individuals being found together, but that more concrete evidence would be needed to confidently make such an assertion.

Talenkauen was rather like Dryosaurus in shape and build, but with a proportionally longer neck. The full length of the body is estimated at no more than Unlike more derived iguanodontians, it still had teeth in the tip of the beak (premaxillary teeth), and a first toe. More derived iguanodonts lose this toe, retaining only the three middle toes. The humerus has reduced areas for muscle attachment, a featured shared with other South American ornithopods like Notohypsilophodon and Anabisetia. This and other similarities to South American ornithopods suggests that there may have been a distinct Southern Hemisphere ornithopod group, but at the time the authors cautioned that such an interpretation was not entirely justified. In 2015, the describers of Morrosaurus found that such a clade did indeed exist. and Macrogryphosaurus (also from Argentina, but from somewhat older rocks), which may have been related. In 2015, several other Patagonian and Antarctic ornithopods were also found to be related. The simplified cladogram below results from analysis by Rozadilla et al., 2019, showing all members of Elasmaria forming a polytomy.

Talenkauen, as a basal ornithopod, would have been a small, bipedal herbivore. Other dinosaurs from the Pari Aike Formation include the giant titanosaurid Puertasaurus and the large predatory theropod Orkoraptor.