Torvosaurus

Type Species: Torvosaurus tanneri

Classification: Dinosauria - Saurischia - Theropoda - Carnosauria - Megalosauroidea - Megalosauria - Megalosauridae - Megalosaurinae

Time Period: Late Jurassic 

Location: North America and Europe

Diet: Carnivore   

The massive-bodied Torvosaurus was the largest predator in its environment. Its remains have been found in both North America and Spain. The specimen from the Morrison Formation lived in an environment that had rivers flowing westward into a giant, saline alkaline basin lake surrounded by wetlands. Other dinosaurs of this environment included plentiful sauropods such as Apatosaurus, Diplodocus, and Camarasaurus; ornithopods such as Dryosaurus and Camptosaurus; the stegosaur Stegosaurus; and the early ankylosaur Gorgoyleosaurus. Other large theropods, namely Allosaurus and Ceratosaurus, also lived in the area. 

Researchers believe that Torvosaurus and Ceratosaurus preferred to prowl waterways; their lower, more sinuous bodies would give them an advantage in forest and underbrush terrains; meanwhile, Allosaurus – with its longer legs – was faster but less maneuverable, and may have preferred to hunt in dry floodplains. Torvosaurus may have hunted large land animals whereas Ceratosaurus, in the same watery environment, preferred to hunt marine organisms such as fish, amphibians, and crocodylomorphs. Some scientists believe that because of its huge size, it would’ve been a clumsy hunter and instead scavenged the large dinosaur carcasses of the Morrison Formation. The idea is that it could use its ‘bulk and brawn’ to scare other theropods away from their kills and then steal the meat. However, other scientists point out that Torvosaurus’ size would be a boom in preying on larger dinosaurs; the Morrison Formation had plenty of prey – stegosaurs and ornithopods were numerous, and large sauropod herds were common – so Torvosaurus could ‘pick and choose’ what it hunted. It may have preferred to hunt juvenile or sick sauropods; one kill could fill its stomach for days. 

Torvosaurus grew up to thirty-three feet long and weighed as much as a hippo. It was the same size as Allosaurus but more massive. Its short, powerful arms were capped by large claws. Its skull – which may have been five feet long, at least according to some Portuguese remains – was elongated with a narrow snout. It had a kink in its profile just above its nostrils, and the lacrimal bone had a distinctive lacrimal horn. In 2005 Torvosaurus eggs were discovered in Portugal and dated to the Tithonian stage of the Late Jurassic. This find was remarkable for a number of reasons: first, these eggs contained the most primitive dinosaur embryos yet known; second, they were the only basal theropod embryos known; third, fossilized eggs and embryos are rarely found together; and fourth, it represents the first evidence of a one-layered eggshell for theropod dinosaurs. Because the eggs were abandoned due to unknown reasons, it’s unknown whether Torvosaurus provided parental care to its eggs and young or abandoned them shortly after laying. 

Wiehenvenator

Type Species: Wiehenvenator albati

Classification: Dinosauria – Saurischia – Theropoda – Carnosauria - Megalosauroidea - Megalosauria - Megalosauridae - Megalosaurinae

Time Period: Middle Jurassic

Location: Europe (Germany)

Diet: Carnivore 

Wiehenvenator was a two-ton, thirty-foot-long megalosaurid from Germany. It was larger than its English cousin Megalosaurus and was one of the largest Middle Jurassic theropods (and one of the largest European theropods in general). It’s known from a single specimen that was nine to ten years old when it met a watery grave in the warm, shallow North Sea. Its remains were discovered in the Ornatenton Formation, a marine deposit which stretches from the Eastern Alps to the Rhine Valley. Numerous marine fossils have been uncovered in the formation, including bones belonging to the pliosaur Liopleurodon and the oceangoing crocodylomorph Metriorhynchus. At this point in the Jurassic, Germany was riddled with bays and inlets from the shallow and sub-tropical North Sea; western France and Germany were a series of archipelagos bordering the flurry of wooded islands of England. Wiehenvenator was the apex predator among these German archipelagos; its teeth were recurved with the root making up more than two-thirds of the tooth length. The largest teeth measured slightly more than five inches in length. Research Dr. Rauhut notes, ‘Apparently there was in these islands [of Germany] a wide range of sometimes very large predators mainly from the group of Megalosauroidea as finds from France and England, as well as the new predators from Germany show. The Megalosauroidea were the first giant predatory dinosaurs of Earth’s history’ – and Wiehenvenator was the tyrant of them all. Sadly, Wiehenvenator’s legacy wouldn’t last, as the Late Jurassic saw the demise of the megalosaurids and the rise of the coelurosaurs and allosaurs. 

Dubreuillosaurus

Type Species: Dubreuillosaurus valesdunensis

Classification: Dinosauria – Saurischia – Theropoda – Carnosauria - Megalosauroidea -  Megalosauria - Megalosauridae - Megalosaurinae

Time Period: Middle Jurassic

Location: Europe (France) 

Diet: Carnivore 

Dubreuillosaurus was a large theropod that prowled the beaches of prehistoric France. The remains of a juvenile have been discovered, and in life this theropod would’ve reached about sixteen feet in length and weighed a quarter ton; however, a full grown adult may have grown up to thirty feet in length. Its remains were found in sedimentary rocks that had been laid down in coastal, mangrove swamps in what is now France. This has led scientists to speculate that it may have been piscivorous (a fish-eater). It may have caught fish in tidal pools or combed the beaches looking for tidally-stranded fish or dead marine reptiles washed ashore. It may have used its oddly long head to stand still in bays, lagoons, or inlets, waiting for fish to come near before darting its jaws under the water. This theory is supported by the fact that it had an unusually low and long skull with a length three times its height; the head shape would give Dubreuillosaurus the ability to plunge its long head into the water to catch swimming fish. Though the arms and hands of this theropod haven’t been discovered, scientists assume it had short, powerful arms with three-fingered hands like its closest relatives. 

Afrovenator

an Afrovenator goes for a swim in the Middle Jurassic Sahara

Type Species: Afrovenator abakensis

Classification: Dinosauria – Saurischia – Theropoda – Carnosauria - Megalosauroidea -  Megalosauria - Megalosauridae - Megalosaurinae

Time Period: Middle Jurassic

Location: Africa (Niger) 

Diet: Carnivore 

In the Middle Jurassic, Saharan Africa was a lush mosaic of woodlands, rivers, and lakes – and the African hunter Afrovenator was at the top of the food chain. Our knowledge of the theropod Afrovenator comes from a single specimen discovered in 1990. It was a remarkable find, for the skeleton was almost complete; all that was missing was the lower jaw, some ribs and vertebrae, and the toe bones. It prowled the woods and rivers of the prehistoric Sahara, and its bite marks have been found on the fossilized ribs of a juvenile sauropod Jobaria. Its similarities to the later North American Allosaurus indicate the close proximity of northern Africa and southern North America during the Bathonian. Afrovenator was more lightweight and fleet-footed than its North American cousin, and its arm bones were longer and more slender. Afrovenator grew up to thirty feet in length, and its strong hind legs were built for active hunting. Its tail was stiffened by overlapping bony struts, and its skull was low and lacking ornamentation. Its jaws were filled with long, blade-shaped teeth it used to slice into prey, and its long arms were capped with vicious, curved claws designed for catching and holding prey. 

Megalosaurus

Type Species: Megalosaurus bucklandii
Classification: Dinosauria - Saurischia - Theropoda - Carnosauria - Megalosauroidea - Megalosauria - Megalosauridae - Megalosaurinae
Time Period: Middle Jurassic
Location: Europe (England)
Diet: Carnivore

The remains of Megalosaurus were first documented in the 17th century, and the bone discovered was described by Robert Plot as the thighbone of a Roman war elephant; it was later attributed to one of the giants of biblical lore. In the 18th century, the first name given to it was Scrotum humanum; in the next century, scientists began realizing they'd stumbled upon something extraordinary. In 1824, realizing that the bones probably belonged to a giant reptile, its name was changed to Megalosaurus, and in 1827 it became Megalosaurus bucklandii. Its name literally means 'Great Lizard.' Sir Richard Owen, who coined the name Dinosauria, included reproductions of Megalosaurus in the Crystal Palace. His depiction of Megalosaurus looks nothing like what modern paleontologists believe it to have looked like. Owen's recreations were founded on the assumption that dinosaurs were nothing more than big lizards, and the recreations muddled discoveries from different dinosaurs into a somewhat-coherent picture:

As dinosaur discoveries have intensified, more remains of Megalosaurus have been discovered, offering a more complete picture of this theropod. Megalosaurus reached up to twenty feet long snout-to-tail, and it weighed around 1500 pounds. It was bipedal, walking on stout hind legs and balanced by a tail held horizontal from the body. Its arms were robust but short. It had a large head filled with curved teeth. While many of the early theropods were lithe and agile, or at least stream-lined, Megalosaurus was robust and heavily-muscled.

This Jurassic theropod was smaller than its Cretaceous descendants, but that didn't make it any less ferocious. For many years, any theropod fossils discovered were deemed as Megalosaurus. Famous dinosaurs such as Tyrannosaurus, Allosaurus, and Dilophosaurus were thrown into the Megalosauridae family, making it the "waste-basket" of theropod dinosaurs. Nowadays, however, paleontologists have distinguished Megalosaurus from its ancestors and descendants, and Megalosaurus stands in a category all its own.