Afrovenator (African-hunter)

Short Info

Afrovenator (African-hunter)

Phonetic : Af-ro-vee-nay-tor.

Named By : Paul Sereno, Jeffrey Wilson, Hans Larsson, Didier Dutheil, and Hans-Dieter Sues – 1994

Diet : Carnivore

Size : Estimated 7-8 meters long

Type of Dinosaur : Large Theropod

Type Species : A. abakensis (type)

Found in : Africa, Niger, Abaka, Tiouraren Formation.

When it Lived : Early Cretaceous, 132-121 million years ago

Afrovenator (/,aefroUvI’neIt@r”African hunter” or “African hunter”) is one of the megalosaurid theropod genus dinosaurs from The Middle Jurassic Period of northern Africa.

It is believed that the remains of Afrovenator were found in 1993 within the Tiouraren Formation of the department of Agadez in Niger. The Tiouraren Formation was initially believed to be an area of Hauterivian to Barremian stages of the Cretaceous Period, or approximately 130 to one million years old (Sereno and co. 1994). However, re-interpretation and interpretation of the sediments revealed that they are likely Mid-Jurassic in time, dating Afrovenator prior to Bathonian up to the Oxfordian stages, which occurred between 161 and 167 mya. The sauropod Jobaria which was first described in the same research paper that referred to Afrovenator is also believed to be from this particular formation.

 

Afrovenator mount
Kabacchi, CC BY 2.0, via Wikimedia Commons

Afrovenator is identified by one skeleton that is relatively complete of the holotype UC OBA 1, featuring much of the skull without its highest point (likewise Mandibles also known as lower jaws, are absent in addition to the bone that is prearticular) as well as components from the spine partial forelimbs, a part of the pelvis, as well as the majority of hindlimbs. The skeleton is located within the University of Chicago.

The name is derived from Latin Afer, “African”, and the word venator means “hunter”. There is a specific species Afrovenator abakensis. The generic name is a reference to the nature of its prey and it’s origins from Africa. The specific name is a reference to Abaka which is the Tuareg name of that region in Niger in which the fossil was discovered. The initial description of both the genus and species can be found in a paper from 1994 that was published in the highly regarded journal Science. The main author was famous American paleontologist Paul Sereno, with Jeffrey Wilson, Hans Larsson, Didier Dutheil and Hans-Dieter Sues coauthoring.

From the only skeleton identified from the fossil record, this dinosaur was eight metres (26 feet) in length, from the its snout to its tail tip and weighed around 1 tonne according Gregory S. Paul. Thomas R. Holtz Jr. estimated it to be 7.6 meters (25 feet) in length, and 453-907 kilograms (1.000-2.000 pounds) of weight. In 2016, it was given a lower estimate in the range of 6.8 meters (22.3 feet) in length, 1.9 meters (6.2 feet) taller at the hips, and 790 kilograms (1.742 pounds) of weight. Sereno said that the general physique was smooth and the forelimbs and lower leg were quite long. The humerus is the length of 40 centimetres, and the tibia as well as fourth metatarsal measure 687 millimetres and 321 millimetres, respectively, in comparison to a thighbone’s length of 76 centimetres.

There are a variety of autapomorphies that have been recognized characteristics that differentiate Afrovenator from the rest of its cousins. The depression where the antorbital fenestra can be found is frontal with the shape of the lobe. A third cervical vertebra features an elongated,, rectangular spine. The wrist bone with a crescent shape is extremely flat. The first metacarpal is an expansive contact area with that of the metacarpal 2. The pubic’s foot bone is cut from behind.

The skull, in general, is rather flat, with its height is just three-fifths of the length. This cannot be determined precisely because the praemaxillae do not have. The maxilla, with a large front branch has 14 teeth, which can be determined from the sockets of teeth and the teeth are missing. There is a tiny maxillary fenestra which does not extend to the edge of the anorbital depression. It is hidden behind a promaxillary. The lacrimal bone is characterized by distinct horns with a round shape on the top. The lower part of postorbital bones has a transversely wide. Jugal bone is small deep, and it is pneumatized.

 

Afrovenator mount (1)
Kabacchi, CC BY 2.0, via Wikimedia Commons

The majority of studies place Afrovenator in the Megalosauridae which was previously an “wastebasket family” which contained numerous theropods that were difficult to classify however, it has changed definition in an important and meaningful manner as it is a sister taxon of the family of Spinosauridae inside the Megalosauroidea.

An analysis from 2002, which focused mostly on noasaurids discovered Afrovenator to be an intermediate megalosaurid. It did not contain Dubreuillosaurus (formerly the Poekilopleuron Valesdunensis) and this could impact the results within that area within the cladogram (Carrano and co. 2002).

Some more recent and thorough cladistic analyses of Afrovenator show it within a Megalosauridae group which includes Eustreptospondylus as well as Dubreuillosaurus. The group can be referred to as Megalosaurinae (Allain 2002) or Eustreptospondylinae (Holtz and colleagues. 2004). The study that was published in 2004 also included Piatnitzkysaurus within this taxon. A study conducted by Matthew Carrano from 2012 placed Afrovenator within a megalosaurid Afrovenatorinae.

Some alternative hypotheses have been suggested regarding the Afrovenator’s relationship. In the original report by Sereno, Afrovenator was found to be an elongated spinosauroid (he then used the term “Torvosauroidea”), outside of Spinosauridae and Megalosauridae (which was referred to as “Torvosauridae”). A second study has placed Afrovenator outside of Megalosauroidea completely and discovers it is more closely related with Allosaurus (Rauhut 2003). This is the sole study to support this conclusion.

Source: Wikipedia