Pronunciation: JEH-noo-SOR-us
Meaning: Knee lizard
Author/s: Accarie et al. (1995)
Synonyms: None known
First Discovery: Sisteron, France
Discovery Chart Position: #399
Genusaurus sisterornis
In 1984, near the town of Sisteron in southeastern France, palaeontologists uncovered a partial theropod skeleton in Albian-aged marine sediments. The remains—comprising vertebrae, pelvic fragments, and hind limb bones—were formally described in 1995 by Accarie et al., who named the new species Genusaurus sisteronis. The genus name references the placement of a prominent crest close to its knee ("genu" in Latin), with the species honouring its discovery site.
Initially declared as the first occurrence of Ceratosauria from the Cretaceous, Genusaurus was later reclassified in Abelisauridae, a group of stocky, puny-armed, short-snouted theropods more commonly associated with the continents that once formed Gondwana, which are largely situated south of the equator. Its anatomy—especially the hatchet-shaped shin crest, block of six fused hip vertebrae, and straight top edge of the hip blade—places it within the derived abelisaurid clade Furileusauria, making it the oldest known member of that lineage.
Despite its modest size (around 3.6 meters long and 35–60 kg in weight), Genusaurus carries significance. Its presence in what is now Europe during the Early Cretaceous suggests abelisaurids had already dispersed far beyond their traditional southern strongholds while the flamboyant Carnotaurus and Majungasaurus were still just flickers in Mother Nature's eye.
Initially declared as the first occurrence of Ceratosauria from the Cretaceous, Genusaurus was later reclassified in Abelisauridae, a group of stocky, puny-armed, short-snouted theropods more commonly associated with the continents that once formed Gondwana, which are largely situated south of the equator. Its anatomy—especially the hatchet-shaped shin crest, block of six fused hip vertebrae, and straight top edge of the hip blade—places it within the derived abelisaurid clade Furileusauria, making it the oldest known member of that lineage.
Despite its modest size (around 3.6 meters long and 35–60 kg in weight), Genusaurus carries significance. Its presence in what is now Europe during the Early Cretaceous suggests abelisaurids had already dispersed far beyond their traditional southern strongholds while the flamboyant Carnotaurus and Majungasaurus were still just flickers in Mother Nature's eye.
(Knee lizard of Sisteron)Etymology
Genusaurus is derived from the Latin "genu" (knee) and the Greek "sauros" (lizard), in reference to a bony crest (cnemial crest) at front and top of the shin (basically the knee area).The species epithet, sisterornis, refers to Sisteron, the town near which it was found.
Discovery
The first remains of Genusaurus were discovered in "greenish clays and glauconitic sands of Bevons", 4.25 km southwest of Sisteron Town in the Alps of Haute-Provence, France, by Hugues Accarie, Bernard Beaudoin and Gérard Friès in 1984. More fossils from the same individual were discovered during a short expedition by Friès, Jean-Guy Michard and Philippe Taquet in September 1986, and during two further visits by Michard. All efforts to
find the rest of the skeleton were in vain, and
it had likely been destroyed by erosion long before the initial discovery took place.
The holotype (MNHN Bev-1) consists of a partial pelvis, left thigh, partial left shin and calf, one toe, and eight partial vertebrae.
