Aristosuchus was a small coelurosaurian dinosaur

Dinosaur

Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

, whose name was derived from the Greek

Ancient Greek

Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...

 ἄριστος (bravest, best, noblest) and σουχος, the Ancient Greek corruption of the name of the Egyptian crocodile-headed god Sobek

Sobek

Sobek , and in Greek, Suchos was the deification of crocodiles, as crocodiles were deeply feared in the nation so dependent on the Nile River...

. It shared many characteristics with birds.

Aristosuchus was a biped

Biped

Bipedalism is a form of terrestrial locomotion where an organism moves by means of its two rear limbs, or legs. An animal or machine that usually moves in a bipedal manner is known as a biped , meaning "two feet"...

al, meat-eating (carnivorous

Carnivore

A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...

) theropod dinosaur. This predator is thought to have been about 2 meters in length (about 6.5 feet) and is estimated to have weighed about 30 kg (about 65 lbs).
It was found in deposits from the Early Cretaceous

Early Cretaceous

The Early Cretaceous or the Lower Cretaceous , is the earlier or lower of the two major divisions of the Cretaceous...

 of England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

, on the Isle of Wight

Isle of Wight

The Isle of Wight is a county and the largest island of England, located in the English Channel, on average about 2–4 miles off the south coast of the county of Hampshire, separated from the mainland by a strait called the Solent...

, i.e. from about 125 million years ago.

It was similar to its close relative Compsognathus

Compsognathus

Compsognathus was a small, bipedal, carnivorous theropod dinosaur. The animal was the size of a turkey and lived around 150 million years ago, the early Tithonian stage of the late Jurassic Period, in what is now Europe. Paleontologists have found two well-preserved fossils, one in Germany...

in appearance and size and some authors have argued that it belongs to that genus. It has also been confused with Calamospondylus

Calamospondylus

Calamospondylus was a theropod dinosaur genus. It lived during the Early Cretaceous, and its fossils were found in England. The type species, Calamospondylus oweni, was described by amateur paleontologist Reverend William D. Fox in 1866, but is based on fragmentary material...

e.g. by Richard Lydekker

Richard Lydekker

Richard Lydekker was an English naturalist, geologist and writer of numerous books on natural history.-Biography:...

 who assumed that Reverend William D. Fox

William Fox (palaeontologist)

William D. Fox was an English clergyman and palaeontologist who worked on the Isle of Wight and made some significant discoveries of dinosaur fossils....

 had named it Calamospondylus oweni in 1866. However, on the basis of the pubis

Pubis (bone)

In vertebrates, the pubic bone is the ventral and anterior of the three principal bones composing either half of the pelvis.It is covered by a layer of fat, which is covered by the mons pubis....

, it is considered by Darren Naish

Darren Naish

Darren Naish is a vertebrate palaeontologist and science writer. He obtained a geology degree at the University of Southampton and later studied vertebrate palaeontology under British palaeontologist David Martill at the University of Portsmouth, where he obtained both an M. Phil...

 to be a valid compsognathid

Compsognathidae

Compsognathidae is a family of small carnivorous dinosaurs, generally conservative in form, from the Jurassic and Cretaceous Periods. Compsognathids lie at or near the origin of feathers—skin impressions are known from four genera, Compsognathus, Sinosauropteryx, Sinocalliopteryx, and Juravenator...

. Since some species are only represented by a few skeletal fragments, this sort of discussion is not uncommon in dinosaur palaeontology. Aristosuchus is known from holotype

Holotype

A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...

 BMNH R178: a sacrum

Sacrum

In vertebrate anatomy the sacrum is a large, triangular bone at the base of the spine and at the upper and back part of the pelvic cavity, where it is inserted like a wedge between the two hip bones. Its upper part connects with the last lumbar vertebra, and bottom part with the coccyx...

, a pubis, a femur

Femur

The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...

 and a few vertebrae. The femur of Aristosuchus has a wing-like anterior trochanter

Trochanter

In human anatomy, the trochanter is a part of the thigh bone. It can refer to:* Greater trochanter* Lesser trochanter* Third trochanter-See also:* Intertrochanteric crest* Intertrochanteric line...

 and a markedly reduced fourth trochanter. Two ungual phalanges

Phalanx bones

In anatomy, phalanx bones are those that form the fingers and toes. In primates such as humans and monkeys, the thumb and big toe have two phalanges, while the other fingers and toes consist of three. Phalanges are classified as long bones.The phalanges do not have individual names...

 were found nearby, which may have been from the same animal and would suggest long claws.

The type species, Aristosuchus pusillus, was described in 1876, by Richard Owen

Richard Owen

Sir Richard Owen, FRS KCB was an English biologist, comparative anatomist and palaeontologist.Owen is probably best remembered today for coining the word Dinosauria and for his outspoken opposition to Charles Darwin's theory of evolution by natural selection...

 and named Poekilopleuron pusillus. The specific epithet means "small" in Latin

Latin

Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

. Harry Govier Seeley

Harry Seeley

Harry Govier Seeley was a British paleontologist.-Career:Seeley was born in London, the son of Richard Hovill Seeley, goldsmith, and his second wife Mary Govier. He attended classes at the Royal School of Mines, Kensington before becoming an assistant to Adam Sedgwick at the Woodwardian Museum,...

(1839–1909) gave it the name Aristosuchus, in 1887.