Африкалық Аңшы Динозавры: Afrovenator Abakensis

Extinct genus of dinosaurs

Afrovenator (,/æ//f//r//oʊ//v//ᵻ/'/n//eɪ//t//ər/; "African hunter") is a genus of megalosaurid theropod dinosaur from the Middle or Late Jurassic Period on the Tiourarén Formation and maybe the Irhazer II Formation of the Niger Sahara region in northern Africa. Afrovenator represents the only properly identified Gondwanan megalosaur, with proposed material of the group present in the Late Jurassic on Tacuarembó Formation of Uruguay and the Tendaguru Formation of Tanzania.

The remains of Afrovenator were discovered in 1993 in the Tiourarén Formation of the department of Agadez in Niger. The Tiourarén was originally thought to represent the Hauterivian to Barremian stages of the early Cretaceous Period, or approximately 132 to 125 million years ago (Sereno et al. 1994). However, re interpretation of the sediments showed that they are probably Middle to Late Jurassic in age, dating Afrovenator to the Bathonian to Oxfordian stages, between 167 and 161 mya. The sauropod Jobaria, whose remains were first mentioned in the same paper which named Afrovenator, is also known from this formation. Afrovenator is known from a single relatively complete skeleton, holotype UC OBA 1, featuring most of the skull minus its top (likewise the mandible, or lower jaws, are lacking apart from the prearticular bone), parts of the spinal column, partial forelimbs, a partial pelvis, and most of the hind limbs. This skeleton is housed at the University of Chicago. The generic name comes from the Latin afer, "African", and venator, "hunter". There is one named species, Afrovenator abakensis. The generic name refers to its predatory nature, and its provenance from Africa. The specific name refers to Abaka, the Tuareg name for the region of Niger where the fossil was found. The original short description of both genus and species is found in a 1994 paper which appeared in the prestigious journal Science. The primary author was well known American paleontologist Paul Sereno, with Jeffrey Wilson, Hans Larsson, Didier Dutheil, and Hans Dieter Sues as coauthors. Recent discoveries in the region include referred teeth (MUPE HB 118, 125, 142) from the underliying Irhazer II Formation and TP4 12, a rostral part of left maxilla from the Tiourarén Formation at NE Tadibene.

Judging from the one skeleton known, this dinosaur was about long, from snout to tail tip, and had a weight of about 1 tonne according to Gregory S. Paul. Thomas R. Holtz Jr. estimated it at in length and in weight. In 2016 it was given a lower estimation of in length, tall at the hips and in weight. Sereno stressed that the general build was gracile and that the forelimbs and the lower leg were relatively long: the humerus has length of forty centimetres and the tibia and fourth metatarsal measure 687 and 321 millimetres respectively, as compared to a thighbone length of seventy six centimetres.