Metriacanthosauridae

Metriacanthosauridae (Greek for "moderately-spined lizards") is an extinct family of allosauroid theropod dinosaurs that lived in Europe and Asia from the Middle Jurassic to the Early Cretaceous. The family is split into two subgroups: Metriacanthosaurinae, which includes dinosaurs closely related to Metriacanthosaurus, and another group composed of the close relatives of Yangchuanosaurus. Metriacanthosaurids are considered carnosaurs, belonging to the Allosauroidea superfamily. The group includes species of large range in body size. Of their physical traits, most notable are their neural spines. The records of the group are mostly confined to Asia, though Metriacanthosaurus is known from Europe. Metriacanthosauridae is used as a senior synonym of Sinraptoridae.

== Diagnostic traits == thumb|Life restoration of Yangchuanosaurus shangyouensis Metriacanthosaurids share the following unambiguous synapomorphies among allosauroids: A short or absent anterior ramus of the maxilla (also found in carcharodontosaurids and piatnitzkysaurids). The laterosphenoid articulated on the frontal and postorbital. A squamosal without constriction of the lower temporal fenestra. (also found in megalosauroids) A flange on the squamosal covering the quadrate head laterally. A well-defined longitudinal groove on the lateral side of the dentary housing a row of neurovascular foramina. Broad, well developed spinopost-zygapophyseal lamina on the axis. A manus shorter than the forearm. Subrectangular and sheet-like neural spines of middle caudal vertebrae. A manus without digit V or the phalanges of digit IV (also found in neovenatorids). A heart-shaped cross section of the ilium's paired midshafts (also found in coelophysids). Fused distal end of the ischium (also found in neovenatorids and basal tetanurans). Metriacanthosaurids share the following dental synapomorphies among theropods: surface centrally positioned on the labial surface of the crown roughly flattened in lateral teeth irregular and non-oriented enamel surface texture