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Oxalaia

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Oxalaia
Temporal range: Upper Cretaceous
100.5–93.9 mya
Holotype snout fossil of Oxalaia in right lateral view, left lateral view, ventral view, and slightly oblique ventral view
Holotype snout in multiple views
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Saurischia
Suborder: Theropoda
Family: Spinosauridae
Subfamily: Spinosaurinae
Genus: Oxalaia
Type species
Oxalaia quilombensis
Kellner et al., 2011

Oxalaia was a large meat-eating dinosaur. It lived in what is now Brazil. It lived during the Upper Cretaceous, about 98 million years ago.[1] Like Spinosaurus, It was a spinosaurid, a family of crocodile-like dinosaurs. Oxalaia had teeth and jaws made to grab and hold slippery fish.[2]

Discovery and naming[change | change source]

Diagram showing fossil snout in place

Fossils of Oxalaia were found at the northeastern part of Brazil in 2004. The region they were found in always gets covered up by the sea and eroded, so they were almost lost.[1] Multiple fossil teeth were also found at the same site.[3]

The full name of the dinosaur is "Oxalaia quilombensis". It was named by Alexander Kellner and the other paleontologists who discovered it. The first part of the dinosaur's name (the genus), comes from an African god. The second part of the name (the species), comes from the quilombos, a group of Brazilian towns.[1]

Description[change | change source]

What Oxalaia quilombensis could have looked like, based on its close relative Spinosaurus

Oxalaia might have been 12 to 14 metres (39 to 46 feet) long. It weighed 5 to 7 tonnes. This makes it the biggest known meat-eating dinosaur from Brazil.[1]

Skeleton[change | change source]

Paleontologists have found only two bones from the animal so far. The first bone is the tip of its snout, which is 201 millimetres (7.9 inches) long. The second bone is a piece of its left upper jaw (or maxilla).

Scientists used the two known bones, and the bones from Oxalaia's relatives, to estimate the size of Oxalaia's skull. The skull was probably 1.35 metres (4 feet 5 inches) long. The snout of Oxalaia had seven tooth sockets on each side. It had one tooth in each socket, and there were two teeth underneath to replace it if it fell out.[1]

Classification[change | change source]

Size compared to a human

Oxalaia is more closely related to the African than Brazilian members of its family. Oxalaia, Irritator, and Spinosaurus are the only three dinosaurs from their clade that don't have knife-like (or serrated) teeth. That means they get their own group called spinosaurinae.[1][4]

The diagram below is called a cladogram. It shows the relationships of Oxalaia with other theropods in the Megalosauroidea superfamily:[4]

Megalosauroidea


Condorraptor Condorraptor (Flipped).jpg



Marshosaurus Marshosaurus restoration.jpg



Piatnitzkysaurus Piatnitzkysaurus floresi by Paleocolour.jpg





Afrovenator Afrovenator Abakensis by PaleoGeek.jpg



Dubreuillosaurus Dubreuillosaurus NT Flipped.png



Duriavenator Duriavenator NT (Flipped).jpg



Eustreptospondylus Eustrept1DB1 (Flipped).jpg



Leshansaurus



Magnosaurus Magnosaurus (Flipped).jpg



Megalosaurus Megalosaurus silhouette by Paleogeek.svg



Piveteausaurus



Torvosaurus Torvosaurus tanneri Reconstruction (Flipped).png




BaryonyxBaryonyx walkeri restoration.jpg



Cristatusaurus



SuchomimusSuchomimustenerensis (Flipped).png




Angaturama




Oxalaia



MSNM V4047 (referred to Spinosaurus) Spinosaurus by Joschua Knüppe.png








References[change | change source]

  1. 1.0 1.1 1.2 1.3 1.4 1.5 Kellner, Alexander W.A. et al (2011). "A new dinosaur (Theropoda, Spinosauridae) from the Cretaceous (Cenomanian) Alcântara Formation, Cajual Island, Brazil". Anais da Academia Brasileira de Ciências 83 (1): 99–108. doi:10.1590/S0001-37652011000100006. ISSN 0001-3765. http://www.scielo.br/pdf/aabc/v83n1/v83n1a06.pdf. 
  2. Rayfield, Emily J. 2011. “Structural Performance of Tetanuran Theropod Skulls, with Emphasis on the Megalosauridae, Spinosauridae and Carcharodontosauridae.” Special Papers in Palaeontology 86 (November). https://www.researchgate.net/publication/250916680_Structural_performance_of_tetanuran_theropod_skulls_with_emphasis_on_the_Megalosauridae_Spinosauridae_and_Carcharodontosauridae.
  3. Medeiros, M.A. (2006). "Large theropod teeth from the Eocenomanian of northeastern Brazil and the occurrence of Spinosauridae". Revista Brasileira de Paleontologia 9: 333–338. doi:10.4072/rbp.2006.3.08. 
  4. 4.0 4.1 Sales, M.A.F.; Schultz, C.L. (2017). "Spinosaur taxonomy and evolution of craniodental features: Evidence from Brazil". PLoS ONE 12 (11): e0187070. doi:10.1371/journal.pone.0187070. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0187070.