Siamosaurus

Siamosaurus (meaning 'Siamese lizard') is a carnivorous theropod dinosaur from the Early Cretaceous of Thailand. It is only known from fossil teeth, so paleontologists don't know much about its size, but it might have reached a length of 9.1 meters (30 ft). The teeth that were discovered looked a lot like those of Spinosaurus, so it probably ate fish.
A study made in 2010 by Roman Amiot and his colleagues compared the teeth of spinosaurids like ', ', "Siamosaurus", and "" to other meat-eating dinosaurs. They found that spinosaurids had very semiaquatic (living partly in water, and partly on land) lifestyles. This means they lived in habitats like those of hippopotamuses, crocodiles, and turtles. It also means they could exist at the same time and place as other large predators without competing for food.