| Anabisetia | |
|---|---|
 | |
| Reconstructed skeleton cast | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | †Ornithischia |
| Clade: | †Ornithopoda |
| Clade: | †Elasmaria |
| Genus: | †Anabisetia Coria &Calvo,2002 |
| Species: | †A. saldiviai |
| Binomial name | |
| †Anabisetia saldiviai Coria & Calvo, 2002 | |
Anabisetia (/ˌɑːnəbiːˈsɛtiə/AH-nə-bee-SET-ee-ə) is agenus ofornithopoddinosaur from the LateCretaceous Period ofPatagonia,South America. It was a smallbipedalherbivore, around 2 metres (6 ft 7 in) long.
ArgentinepaleontologistsRodolfo Coria andJorge Orlando Calvo namedAnabisetia in 2002. The generic name honors the lateAna Maria Biset, an influentialarcheologist fromNeuquén Province in Argentina, where the remains of this animal were found. The one namedspecies is calledA. saldiviai, after Roberto Saldivia Blanco, a local farmer who had discovered thefossils in 1985 and brought them to the attention of science in 1993.[1] The finds had already been reported in the scientific literature in 1996.[2][3]
There are four specimens known, all listed in the original 2002 description. Theholotype,MCF-PVPH 74, is the most complete of the four. It consists of fragmentaryskull material, including a partial braincase and bothdentary (lower jaw) bones, as well as a complete forelimb from shoulder to hand, a complete hindlimb and foot, and representativevertebrae from all sections of thespinal column. The other three specimens are less complete, but include elements not seen in the holotype, including more vertebrae, a completepelvis and a nearly complete, articulated tail. Two specimens are theparatypes, MCF-PVPH-75 and MCF-PVPH-76. The fourth, MCF-PVPH-77, is referred to the species. When all four specimens are considered, the skeleton is more or less completely known except for the skull. These specimens are housed at theMuseo Carmen Funes inPlaza Huincul, Argentina.[1]
All four specimens were discovered at a locality called Cerro Bayo Mesa, thirty kilometers south of Plaza Huincul in the Neuquén province of Argentina. This locality is part of theCerro Lisandro Formation, which is ageologic formation within the Rio Limay subgroup of theNeuquén Group. The sediments in this formation preserve aswamp which existed from the lateCenomanian through earlyTuronian stages of theLate Cretaceous Period, or about 95 to 92 million years ago.[4]
Anabisetia was a small bipedal herbivore. In 2010Gregory S. Paul estimated its length at two meters, its weight at twenty kilograms.[5] The describers established several unique traits of the species. At the back of the head, the connection with the neck, theoccipital condyle, pointed rather downwards. The shoulder blade had an extension on its upper lower rim, the acromial process, that relatively was the largest ever found in theEuornithopoda. In the hand the fifthmetatarsal was flattened with straight edges, instead of rounded in cross-section. In the pelvis, theilium had a front blade that accounted for more than half of the total ilium length and extended in front of theprepubis. Theischium had a shaft that in the upper part was triangular in cross-section and in the lower part quadrangular. In the ankle thefibula touched theastragalus.[1]
This dinosaur is thought to be closely related to another Patagonian ornithopod,Gasparinisaura, although the lack of skull material makes it difficult to place with precision. When originally described,Gasparinisaura andAnabisetia were thought to bebasaliguanodontians, morederived thanTenontosaurus and members of thecladeEuiguanodontia, and seen as endemic remnants of an early dispersion of basal iguanodontians onPangea.[1] Relatively recentcladistic analyses performed by Coria and others indicated thatGasparinisaura lies just outside of Iguanodontia, closer toNorth American ornithopods likeThescelosaurus andParksosaurus.[6]Anabisetia may fall in a similar position. However, in 2015, both taxa were found to be part of the cladeElasmaria along with other Antarctic and Patagonian ornithopods.[7]
Cladogram based in thephylogenetic analysis of Rozadillaet al., 2015:
