''Genusaurus'' ( ; meaning "knee lizard") is a genus of

abelisauroid Abelisauroidea is typically regarded as a Cretaceous group, though the earliest abelisauridae remains are known from the Middle Jurassic of Argentina (classified as the species Eoabelisaurus mefi) and possibly Madagascar (fragmentary remains o ...

dinosaur from the

Early Cretaceous The Early Cretaceous ( geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma. Geology Pro ...

. Its

fossils A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ...

were found in France. ''Genusaurus'' is believed to have lived during the Albian stage, around 112-100 million years ago.

Description

''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. The

epicondyle An epicondyle () is a rounded eminence on a bone that lies upon a condyle ('' epi-'', "upon" + ''condyle'', from a root meaning "knuckle" or "rounded articular area"). There are various epicondyles in the human skeleton, each named by its anatomic ...

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 the '' Musculus iliofibularis''. The upper inner side of the fibula is strongly hollowed out.

Size

''Genusaurus'' was originally estimated to have been long. From the thighbone, a weight of was extrapolated. Later estimates, while confirming the length of , have reduced the weight to , or even . In 2016, its length was estimated at , making it the smallest abelisaurid.

Discovery and naming

The type species, ''Genusaurus sisteronis'', is the only named species. It is based on a partial

skeleton A skeleton is the structural frame that supports the body of an animal. There are several types of skeletons, including the exoskeleton, which is the stable outer shell of an organism, the endoskeleton, which forms the support structure inside ...

found in 1984-1986 in the Albian Bevons Beds, holotype MNHN Bev.1. The holotype contains seven partial dorsal vertebrae, a piece of a sacral, a piece of an ilium, the top of a pubic bone, a thighbone, the top of a shinbone, the top of a fibula and a metatarsal. It was named and described by

Hugues Accarie Hugues may refer to People: * Hugues de Payens (c. 1070–1136), French soldier * Hugues I de Lusignan (1194/95 –1218), French-descended ruler a.k.a. Hugh I of Cyprus * Hugues IV de Berzé (1150s–1220), French soldier * Hugues II de Lusign ...

Bernard Beaudoin Bernard ('' Bernhard'') is a French and West Germanic masculine given name. It is also a surname. The name is attested from at least the 9th century. West Germanic ''Bernhard'' is composed from the two elements ''bern'' "bear" and ''hard'' "bra ...

, Jean Dejax, Gérard Friès, Jean-Guy Michard and Philippe Taquet in 1995.Accarie, H., B. Beaudoin, J. Dejax, G. Fries, J.C. Michard, and P. Taquet (1995). "Découverte d'un Dinosaure théropode nouveau (''Genusaurus sisteronis n. g., n. sp''.) dans l'Albien marin de Sisteron (Alpes de Haute-Provence, France) et extension au Crétacé inférieur de la lignée cératosaurienne". ''Compte rendu hebdomadaire des scéances de l'Académie des Sciences à Paris''. 320 (2): 327-334
Translation into English.
/ref> The genus name is derived from the Latin word ''genu'' (knee) and refers to the cnemial crest in front of the proximal end of the tibia. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

refers to Sisteron, the town near which the specimen was found.

Classification

Accarie ''et al.'' assigned ''Genusaurus'' to the ceratosaur group of theropods, more precisely to the Coelophysoidea. A 2008 cladistic analysis by Carrano and Sampson placed ''Genusaurus'' in the Noasauridae along with '' Laevisuchus'', '' Masiakasaurus'', ''

Noasaurus ''Noasaurus'' ("Northwestern Argentina lizard") is a genus of ceratosaurian theropod dinosaur genus from the late Campanian-Maastrichtian (Late Cretaceous) of Argentina. The type and only species is ''N. leali''. Discovery and naming In the m ...

'', and '' Velocisaurus''; in turn, noasaurids are part of the Abelisauroidea group, which is part of the ceratosaur group. Subsequent phylogenetic analyses found ''Genusaurus'' to be a member of the Abelisauridae, specifically the Majungasaurinae.

References

External links