Machimosauridae Temporal range: Early Jurassic-Early Cretaceous,
Macrospondylus bollensis
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Archosauria
Clade:	Pseudosuchia
Clade:	Crocodylomorpha
Suborder:	†Thalattosuchia
Superfamily:	†Teleosauroidea
Family:	†Machimosauridae Jouve et al., 2016
Subgroups
†Charitomenosuchus †Clovesuurdameredeor †Deslongchampsina †Macrospondylus †Seldsienean †Machimosaurinae †Andrianavoay †Neosteneosaurus †Proexochokefalos †Machimosaurini †Lemmysuchus †Machimosaurus †Yvridiosuchus

Machimosauridae is an extinct family of teleosauroid thalattosuchian crocodyliforms.^[1] The family was first identified in 2016,^[2] when fossils of teleosauroid thalattosuchians, including an indeterminate close relative of Lemmysuchus and Machimosaurus, were described from the Middle Jurassic (Bathonian) of Morocco.^[2] The family was largely expanded in 2020 when the systematics of Teleosauroidea were re-reviewed.^[1] Members of this family generally were larger than the teleosaurids.^[1]

Classification

Machimosauridae is a diverse group of teleosauroids, phylogenetically defined as "the largest clade within Teleosauroidea containing Machimosaurus hugii, but not Plagiophthalmosuchus gracilirostris and Teleosaurus cadomensis."^[1] The members of the Machimosauridae share several unique characters among teleosauroids, which are:^[1]

• dorsally oriented external nares
• the premaxillary anterior and anterolateral margins are not sub-vertical and do not extend ventrally
• the premaxilla-maxilla suture is sub-rectangular and slightly interdigitating (most noticeably near the midline)
• no anterolateral expansion of the supratemporal fenestrae
• the postorbital is excluded from the orbit posteroventral margin
• a mostly horizontal pterygoid with a distinct posterolateral angle
• the cultriform process of the basisphenoid is exposed and bifurcates the pterygoids

The phylogenetic relationships of the Machimosauridae were analyzed in a comprehensive analysis of teleosauroid relationships. The results of the analysis are shown below:^[1]

Evolution

Machimosaurids grew in body size and diversified feeding strategies throughout their evolutionary history. Primitive machimosaurids, such as Macrospondylus and Charitomenosuchus, were longirostrine (long-snouted) generalists with body lengths less than 5 m (16 ft) long.^[1][3] Machimosaurines originated in the Bathonian stage of the Middle Jurassic and simultaneously underwent a decrease in snout length but an increase in body size with Neosteneosaurus reaching up to 6.6 m (22 ft) long.^[1][3] Machimosaurins were the largest teleosauroids, with body lengths up to 7.1 m (23 ft) (Machimosaurus rex), and were durophagous hunters, meaning they fed on hard prey.^[1][3]

References