Oxalaia

***Oxalaia*** was a large predatory dinosaur. It lived during the Upper Cretaceous of what is now Brazil, sometime between 100.5 to 93.9 million years ago. *Oxalaia* is known only from two bones of the skull, which were discovered in 1999. The animal was named in 2011 by a group of Brazilian palaeontologists.

It was a member of the Spinosauridae family, a group of crocodile-like theropod dinosaurs. Like other spinosaurids, *Oxalaia* had a long nose or  with jaws and teeth shaped to feed on fish. *Oxalaia*'s habitat was tropical, an area of large forests around which were dry deserts. *Oxalaia* shared this environment with many other animals, most of which are also known from other Cretaceous fossils discovered in Africa. It may also be synonomus with the African genus *Spinosaurus*.

## Discovery and naming 
 fossils in place]]

In 1999, two fossil bones of *Oxalaia* were found in rocks on an island in the Northeast Region of Brazil. This part of the island gets covered up by the sea at high tide. Because of the action of the waves which cause erosion, the fossils were almost lost.

The full name of the dinosaur is *Oxalaia quilombensis*. The animal was named by Brazilian palaeontologists Alexander Kellner, Elaine Machado, Sergio Azevedo, Deise Henriques, and Luciana Carvalho. 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. Machado said that people are interested in spinosaurids: because of how different they are from other carnivorous dinosaurs, and because they are known by the public through the *Jurassic Park* movies.

Only two pieces of bone are known from *Oxalaia.* The first is the tip of its snout, called the premaxilla bone. The second is a piece of its left maxilla, or main upper jaw bone. The two pieces were put on display in the National Museum of Brazil in 2011.

*Oxalaia* is the third spinosaurid named from Brazil so far. The other two are *Irritator* and *Angaturama* (which might be the same animal as *Irritator*). These two animals are known from another part of Brazil, and lived nine to six million years before *Oxalaia*.

## Description 
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To estimate its size, *Oxalaia*'s skull bones were compared with those of its close relative, *Spinosaurus*. *Oxalaia* was probably  long, and likely weighed . This makes it the largest known carnivorous dinosaur from Brazil.

The tip of *Oxalaia*'s snout, called the premaxilla, was  long. *Oxalaia*'s complete skull was probably  long.*

 of what *Oxalaia* might have looked like, based on its relatives]]

The front of *Oxalaia'''s upper jaw was spoon-shaped, or larger at its front end than at its rear end. The bottom of the snout tip was curved inwards. This shape would have joined with the lower jaw, or mandible, which was also spoon-shaped. The fossil snout preserves broad and deep holes. These probably contained blood vessels and nerves. *Oxalaia*'s teeth were also oval in cross section, instead of flattened somewhat sideways like in most theropods.

*Oxalaia* can be separated from *Spinosaurus* by differences between their jaw bones*.* For example: *Oxalaia* had a rounder snout, and more closely spaced teeth than *Spinosaurus*. *Oxalaia*'s two replacement teeth per socket, and less smooth secondary palate, also make it unique among the other known spinosaurs. 

The cone-shaped teeth of *Oxalaia* were built for  prey, instead of cutting flesh like those of most theropod dinosaurs. *Oxalaia*'s nostrils were placed far back on the head. This was probably to avoid water getting inside its nostrils when fishing. Both of these features were unique to spinosaurid dinosaurs, and were useful for catching and feeding on fish. The spoon-shaped front jaws and piercing teeth of spinosaurs worked as an efficient fish trap. This trait is also seen in the Indian gharial—the most fish-eating of modern crocodilians.

*Oxalaia* shared this habitat with many different kinds of animals. Other dinosaurs found in the formation included giant carnivores like *Carcharodontosaurus*, and perhaps *Spinosaurus*. Smaller predators lived there too, such as dromaeosaurids, and an animal very similar to *Masiakasaurus*. There were also large sauropods, a group of herbivorous (plant-eating) dinosaurs. Fish found in the formation included bony fish, ray-finned fish, and lungfish. There were also giant coelacanths and sawfishes. Besides dinosaurs, there were other reptiles, like pterosaurs and crocodilians. Fossils of snakes and molluscs have also been found.

## References 
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