Episode 282 is all about Arcovenator, a relative of Majungasaurus found in France.
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In this episode, we discuss:
News:
- The new dromaeosaurid Dineobellator was found in San Juan Basin, New Mexico source
- A UK family is creating dinosaur art from rocks on their daily walks at a local quarry source
- Colin Trevorrow, posted a behind the scenes photo of the Jurassic World: Dominion set source
The dinosaur of the day: Arcovenator
- Abelisaurid theropod that lived in the Late Cretaceous in what is now France
- Abelisaurids had short, tall skulls, very short arms, and stout legs
- Medium-sized. Originally estimated to be about 16-20 ft long, then later revised to be 16 ft (4.8 m) long
- Though some scientists (Molina-Pérez and Larramendi) estimate it to be 23.6 ft (7.2 m) long and weigh 2,094 lb (950 kg)
- Nearly complete braincase found
- Braincase similar in size to Majungasaurus and Carnotaurus
- Had some bone ornamentation on the skull, but not as flashy as Majungasaurus
- Had a bony brow ridge
- Skull may have had space for a pineal gland (produces some hormones, like melatonin)
- Arcovenator is a basal abelisaurid
- Carnivorous, and probably apex predator
- Type and only species: Arcovenator escotae
- Genus name means “arc hunter”
- Genus name refers to the river Arc, near where the fossils were found
- Species named in honor of the company Escota, which funded excavations since 2006
- Fossils found in France in 2007 when a construction company called Escota was working on extending the A8 motorway near the city Aix-en-Provence found fossils in fluvial sandstones. Found parts of the skull, caudal vertebra, parts of the lower right leg, as well as cranial material. Referred specimens consist of three teeth and two caudal vertebrae. Thierry Tortosa from the Museum of Natural History, Aix-en-Provence and Eric Buffetaut, named and described the dinosaur
- Named in 2013
- Holotype is at the Museum of Natural History, Aix-en-Provence
- Arcovenator shows that abelisaurids, instead of carcharodontosaurids, were the largest predators in Europe during the Campano-Maastrichtian (latest part of the Cretaceous)
- Lived on Ibero-Armorican island, which was made of parts of what is now France, Spain, and Portugal. Lived in a warm climate with seasons, and fossils found in fluvial sandstone which was probably the mouth of a river
- Other animals in the same time and place included turtles, crocodylopmorphs, pterosaurs, sharks
- Other dinosaurs in the same time and place included titanosaurs, the ornithopod Rhabdodon, and nodosaurids
- Phylogenetic analysis showed Arcovenator is more closely related to abelisaurs found in India and Madagascar than South American abelisaurids. (Genusaurus, Tarascosaurus, and other Late Cretaceous discoveries were identified as basal abelisaurids)
- Acrovenator discovery helps show that “Europe and Africa may have played a major role in abelisaurid dispersal, which apparently involved crossing marine barriers” (according to the paper), which means South America did not play as major a role
- According to Tortosa and others, there are three main dispersal models to explain the distribution in the Cretaceous of Gondwanan non-marine vertebrates, which includes abelisaurids. The first is the “Pan-Gondwana” model, where “a common fauna was distributed on all the Gondwanan landmasses during the Early Cretaceous, before the severing of Africa from all the other southern continents during a relatively brief interval at the beginning of the Late Cretaceous”
- Next is the “Africa first” model, where “Africa separated first from other Gondwanan landmasses, while terrestrial dispersal routes between South America, Antarctica, and Indo-Madagascar reminaed effective until a gradual break-up during the Late Cretaceous”
- The problem with the first two models is it doesn’t take into account animals from Europe, and abelisaurids, such as Genusaurus, were in Europe “before the total dislocation of Gondwana.” Also, there are lots of similarities between Arcovenator and relatives and abelisaurids in Africa, Madagascar, and India, and the origin of abelisauroids was thought to be, at the latest, in the early Middle Jurassic in Pangea
- The third model is the “Eurogondwana model” which includes “Atlantogea”, where Africa and Europe and Gondwana had biotic interchanges (fauna migrating), even after Gondwana broke up
- Discovery of Arcovenator helps show the Atlantogean idea, and the interchanges between Europe, Madagascar, and India
- Arcovenator is “the first direct link between European forms, the primitive African taxa and the derived Indo-Madagascan abelisaurids”
Fun Fact: Dinosaurs were (and are) susceptible to viruses.
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