[4][5][6] The family Megalosauridae was first defined by Thomas Huxley in 1869, yet it has been contested throughout history due to its role as a "waste-basket" for many partially described dinosaurs or unidentified remains.

However, recent research by Carrano, Benson, and Sampson has systematically analyzed all basal tetanurans and determined that Megalosauridae should exist as its own family.

Afrovenatorinae (all megalosaurids more closely related to Afrovenator than Megalosaurus) are characterized by a squared anterior margin of the antorbital fossa and the puboischiadic plate being broadly open along the midline.

One dental condition present in Megalosauridae is multiple enamel wrinkles near the carinae, the sharp edge or serration row of the tooth.

Megalosaurus was the first paleontological finding of its kind when William Buckland discovered a giant femur and named it in 1824, predating even the term Dinosauria.

[1] When initially defined, the species M. bucklandii was anatomically based on various dissociated bones found in quarries around the village of Stonesfield, UK.

[2] As more information was uncovered about basal theropods and phylogenetic characteristics, modern paleontologists began to question the proper naming for this group.

In 2005 paleontologist Paul Sereno rejected the use of the clade Megalosauridae due to its ambiguous early history in favor of the name Torvosauridae.

Using the characters described in this study, Allain defined Megalosauridae as dinosaurs including Poekilopleuron valesdunesis, now known as Dubreuillosaurus, Torvosaurus, Afrovenator, and all descendants of their common ancestor.

Carrano, Benson, and Sampson also included various megalosaurids that had previously been excluded from cladograms in their 2012 study, such as Duriavenator and Wiehenvenator in Megalosaurinae and Magnosaurus, Leshansaurus, and Piveteausaurus in Afrovenatorinae.

[2] Piatnitzkysauridae Streptospondylus Spinosauridae Eustreptospondylus Duriavenator Megalosaurus Torvosaurus Afrovenator Dubreuillosaurus Magnosaurus Leshansaurus Piveteausaurus Scuirumimus albersodoerferi, a small theropod described in 2012 which preserved protofeathers, was initially believed to be a juvenile megalosauroid.

[17] Eustreptospondylus Dubreuillosaurus Magnosaurus Afrovenator Piveteausaurus Duriavenator Megalosaurus Wiehenvenator Torvosaurus In 2019, Rauhut and Pol described Asfaltovenator vialidadi, a basal allosauroid displaying a mosaic of primitive and derived features seen within Tetanurae.

[18] Monolophosaurus Spinosauridae Megalosauridae Xuanhanosaurus Piatnitzkysauridae Asfaltovenator Metriacanthosauridae Allosaurus Carcharodontosauria Megalosaurids have been suggested to be predators or scavengers inhabiting coastal environments.

Spinosaurids, which were close relatives of megalosaurids, had numerous adaptations for piscivory and semiaquatic life, so such a lifestyle is supported by phylogenetic data.

[20] Species included in Megalosauridae have been found on every modern continent, split relatively equally between sites on the Gondwana and Laurasia supercontinents.

Paleogeography findings show that Megalosauridae was mainly restricted to the Middle to Late Jurassic, suggesting they went extinct at the Jurassic-Cretaceous boundary 145 million years ago.

[10] Teeth from the Berriasian-Valanginian aged Bajada Colorada Formation in Argentina suggest that the group may have persisted into the Early Cretaceous in South America.

[10] Most recently, megalosaurids have been found in the Tiourarén Formation in Niger, proving again that these basal tetanurans have experienced global radiation.