| Genusaurus | |
|---|---|
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Superfamily: | †Abelisauroidea |
| Family: | †Abelisauridae |
| Genus: | †Genusaurus Accarieet al., 1995 |
| Species: | †G. sisteronis |
| Binomial name | |
| †Genusaurus sisteronis Accarieet al., 1995 | |
Genusaurus (/ˌdʒɛnjʊˈsɔːrəs/JEN-yuu-SOR-əs;[1] meaning "knee lizard") is agenus ofabelisauridtheropod from theEarly Cretaceous. Itsfossils were found inFrance.Genusaurus is believed to have lived during theAlbianstage, around 112-100 million years ago.[2][3]
Genusaurus possesses several distinguishing traits. The dorsal vertebrae are elongated. The elements of the pelvis are strongly fused. The thighbone shows a low bone plateau below the major trochanter; to the front an accessory trochanter is present. Theepicondyle of the inner femoral condyle is well-developed. The cnemial crest strongly extends to the front and is curved upwards. The fibula has a distinctive boss serving as an attachment for theMusculus iliofibularis. The upper inner side of the fibula is strongly hollowed out.[4]
Genusaurus was originally estimated to have been 3.16 metres (10.4 ft) long. From the 38 centimetres (15 in) thighbone, a weight of 129.6 kilograms (286 lb) was extrapolated.[4] Later estimates, while confirming the length of 3 metres (9.8 ft),[2] have reduced the weight to 50 kilograms (110 lb),[5] or even 35 kilograms (77 lb).[6] In 2016, its length was estimated at 3.6 metres (12 ft), making it the smallest abelisaurid.[7]
Thetype species,Genusaurus sisteronis, is the only named species. It is based on a partialskeleton found in 1984-1986 in the AlbianBevons Beds,holotypeMNHN Bev.1. The holotype contains seven partial dorsal vertebrae, a piece of a sacral, a piece of an ilium, the top of apubic bone, a thighbone, the top of a shinbone, the top of a fibula and ametatarsal. It was named and described byHugues Accarie,Bernard Beaudoin,Jean Dejax,Gérard Friès,Jean-Guy Michard andPhilippe Taquet in 1995.[4] The genus name is derived from the Latin wordgenu (knee) and refers to thecnemial crest in front of the proximal end of thetibia.[4] Thespecific name refers toSisteron, the town near which the specimen was found.[4]
Accarieet al. assignedGenusaurus to theceratosaur group oftheropods, more precisely to theCoelophysoidea.[4] A 2008cladistic analysis by Carrano andSampson placedGenusaurus in theNoasauridae along withLaevisuchus,Masiakasaurus,Noasaurus, andVelocisaurus; in turn, noasaurids are part of theAbelisauroidea group, which is part of the ceratosaur group.[3] Subsequent phylogenetic analyses foundGenusaurus to be either a member of theNoasauridae orAbelisauridae.[8][9][10]
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