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RPerboni — #dinocember2019 - Part 6

#paleoart #paleoillustration #gnathovorax #brazil #brontosaurus #dinosaur #hadrosaur #herrerasaurus #paleontology #parasaurolophus #sauropod
Published: 2020-04-16 15:11:12 +0000 UTC; Views: 1461; Favourites: 22; Downloads: 0
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Description From that point on, I started posting my drawings on a new IG profile, more focused on my work as an illustrator and that I suggest you follow too  www.instagram.com/renatodesenh…

Dinosaurs has always been a passion of mine. But this thread is very important to me not only for that reason. At the end of last year my head asked for rest and care. Everything was starting to weigh and I finally started a treatment with a psychiatrist and psychologist, which I continue to this day.

My idea, as with the drawings of Brazilian folklore, was also to take the opportunity to educate lay people. I am not a scientist and at most amateur paleoartist , but I think that combining art and knowledge is the best thing that an illustrator can do. So I will post the descriptions that I did on IG here too. Any mistake I made please point here, both in the text and in the drawings.

* Gnathovorax cabreirai - Described in 2019 in the Santa Maria Formation, in southern Brazil, the Gnathovorax was a herrerasaurid dinosaur that lived during the Late Triassic (233-229 million years BC), whose fossil presents itself as one of the most complete of its kind , with almost complete skull and a lot of post-cranial material, allowing a thorough analysis of its anatomy, with only bones of the left shoulder and upper limb missing. The fossil had been found together with skeletons of a cynodont - a proto-mammal - and a rhyncosaur - compact-bodied archosaurs with sharp beaks - showing the abundance of species in the Santa Maria Formation, which housed a river system indicated by the rocks from where the Gnathovorax was excavated, in the midst of a possible semi-arid ecosystem, similar to what covered good part of Pangea at that time.
Being a medium-sized predator, the Gnathovorax measured about 3 meters in length, being among the largest of the herrerasaurids. These carnivorous dinosaurs are among the oldest known, whose fossils are found most commonly in Brazil and Argentina, but also in parts of India and the USA. Due to their differentiated anatomy, herrerassaurids are not considered ancestors of any later group, with an evolutionary relationship still not clear, being classically placed as primitive Saurischians, older than the split between the two main dinosaur groups - Saurischians and Ornithischians. In the study published by Norman et al (2017), Herrerasauridae would be closer to Sauropodomorphs in the clade Saurischia, with the Theropods and Ornistischians together in the new clade Onithoscelida. Cau (2018) also suggests that herrerasaurs should be classified separately from other dinosaurs, with Sauropodomorphs closer to other dinosaur families.
Herrerasaurids came to extinction at the end of the Triassic, probably due to the separation of the supercontinent Pangea in landmasses of Gondwana - to the south - and Laurasia - to the north - which also caused the extinction of other groups of dominant archosaurs in the period, opening space for the dinosaurs diversify as the dominant group of animals on Earth until the end of the Cretaceous.

* Parasaurolophus - One of the most recognizable non-avian dinosaurs, the genus Parasaurolophus consists of three confirmed species - P. walkeri, P. tubicen and P. cyrtocristatus - and a dubious one - P. jiayensis, currently of the genus Charonosaurus - that lived during the Late Cretaceous (76-75 million years a.EC) in North America and China - considering the fourth species. First described in 1922 from a skull found in the Dinosaur Park Formation in Alberta, the Parasaurolophus is easily recognized by its bony crest, which measures up to 2 meters from nose to tip in P. tubicen, which was probably used to channel sounds that the animals used to communicate, since the skull of these animals was full of hollow tubes connected to the nostrils. In addition, recent studies and findings seem to have revealed that the ridge was covered with skin, with possible flaps on the sides that would move with the thunderous sounds and calls of these animals.
For a long time, it was thought that the Parasaurolophus would be a semi-aquatic herbivore, similar to a moose, using its crest as a kind of snorkel when diving for aquatic plants, a behavior that has now been discarded, since the claws of these dinosaurs, as well as of other lambeosaurids, a group to which the genus belongs together with other crested hadrosaurs, are like hooves, adapted for movement on land possibly in large herds, with males with large and attractive crests together with juvenile individuals and females with smaller and discreet crests, perhaps with a structure similar to a herd of wildebeests or zebras.
Lambeosaurids, in addition to striking crests, had batteries of teeth firmly attached to their "cheeks", occupying the niche of "medium browsers" in their habitats, with flattened beaks thinner than that of hadrosaurids, being less generalistic as to plant varieties they consumed.

* Brontosaurus excelsus - The name that always pops on people's heads when thinking of dinosaurs, the Brontosaurus was a diplodocid sauropod whose fossils were excavated in the Morrison Formation in the USA, dating from the Late Jurassic (156-146 million years BCE) that for a long time had its findings classified together with the genus Apatosaurus, which date from the same geological extract. In 2015, enough differences were found between species for Brontosaurus to become a valid genus again, something that has not occurred since the end of the 19th century.
Occupying a "near-high browser" niche, the Brontosaurus inhabited a savannah region cut by a system of rivers that sometimes flooded, using its long necks to reach the high branches, but not as much as the Brachiosaurus and Diplodocus with which it shared the habitat of the Morrison Formation, sharing space with a paleofauna rich in other dinosaurs, such as stegosaurs, ornithopods, allosaurs and other sauropods like him.
As a diplodocid, the Brontosaurus has a relatively short barrel-shaped body and long tail and neck - not as extreme as its relatives of the genus Barosaurus and Diplodocus - with adults reaching 22 meters in length and weighing around 15 tons, in addition to the whip-like tail, which could be both a defense weapon and a form of communication.
As in Apatosaurus, its closest relative, the Brontosaurus has thick and reinforced neck vertebrae, with studies indicating that strong muscles adapted for impact would anchor there, leading to the belief that these animals would use their neck as a weapon in intraspecific disputes, as well as today's giraffes do. Ventral processes in the vertebrae seem to indicate the presence of structures such as dermal spines or ossified bumps, which would be used in these battles as an extra advantage against an opponent.
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