Metriorhynchus

Extinct genus of reptiles
the genus of beetles
Speciesbox
|fossil range = Kimmeridgian,
|image = Metriorhynchus brevirostris. jpg
|image caption = Partial holotype rostrum (MHNG V 2232) of M. brevirostris as illustrated in 1824
|genus = Metriorhynchus
|parent authority = von Meyer, 1832
|species = brevirostris
|authority = (Holl, 1828) vide Young et al., 2020

Only one valid species is recognized today, the type species M. geoffroyii (now called M. brevirostris). Species in this genus were traditionally classed into two skull groups: longirostrine (long, narrow jaws) and brevirostrine (short, broad jaws). However, most of brevirostrine species have been transferred to the genera Purranisaurus and Suchodus. Metriorhynchus superciliosus was also shown to be generically distinct from the type species, M. brevirostris, and now has its own genus Thalattosuchus. Recent phylogenetic analyses however, do not support the monophyly of Metriorhynchus, as believed during the 1860s 2010. Later, Andrews (1913) considered there to be seven valid species: M. superciliosus, M. moreli, M. brachyrhynchus, M. durobrivensis, M. cultridens, M. leedsi and M. laeve. However, Adams Tresman (1987), using linear morphometrics, could only distinguish between the two skull groups, so she found there to be two species from the Oxford Clay, M. superciliosus and M. brachyrhynchus. Vignaud (1997) however, considered there to be three Callovian species: M. superciliosus, M. brachyrhynchus and M. leedsi, and a 2022 study describing a new metriorhynchid specimen advocated returning to this taxonomic system, considering Gracilineustes and Thalattosuchus junior synonyms of Metriorhynchus.

Fragmentary remains attributed to Metriorhynchus are known from South America during the Bajocian and Bathonian (both Middle Jurassic). However, phylogenetic analysis has shown that these species cannot be referred to Metriorhynchus.