Scientific name Metriacanthosauridae Rank Family | Phylum Chordata | |
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Lower classifications | ||
Metriacanthosauridae is an extinct family of carnivorous allosauroid theropod dinosaurs. They tended to be large predators, some growing to sizes of 10 metres (33 ft). Metriacanthosaurids are carnosaurs, and many were initially classified within Megalosauridae or Allosauridae. A gigantic tooth belonging to what most likely is a giant sinraptorid has been described by Xu and Clarke in 2008.
Classification
Cladistically, Sinraptoridae was latest defined in 2005 by Paul Sereno as the most inclusive monophyletic group that contains Sinraptor dongi and all species closer related to Sinraptor than to either Allosaurus fragilis, Carcharodontosaurus saharicus, or the house sparrow (Passer domesticus).
Carrano, Benson & Sampson (2012) noted that the name Metriacanthosauridae should be used as it has priority over Sinraptoridae. Furthermore, they named a new subfamily Metriacanthosaurinae to include all metriacanthosaurids more closely related to Metriacanthosaurus than to Yangchuanosaurus. A much larger phylogenetic analysis found the basal megalosauroid Xuanhanosaurus (according to Benson et al., 2010) as the basalmost metriacanthosaurid. Both Poekilopleuron and Lourinhanosaurus were recovered outside the family, and many taxa within the Metriacanthosauridae were in polytomy. However, the position of Xuanhanosaurus and Poekilopleuron is very unstable, and their exclusion from the analysis gave more resolved and stable cladogram. The cladogram presented here follows that study.