Machimosauridae is an extinct family of teleosauroid thalattosuchian crocodyliforms. CC-BY icon

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The family was first identified in 2016, when fossils of teleosauroid thalattosuchians, including an indeterminate close relative of '' Lemmysuchus'' and ''

Machimosaurus ''Machimosaurus'' is an extinct genus of machimosaurid crocodyliform from the Late Jurassic (Kimmeridgian and Tithonian) and Early Cretaceous. The type species, ''Machimosaurus hugii'', was found in Switzerland. Other fossils have been found ...

'', were described from the

Middle Jurassic The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations co ...

(

Bathonian In the geologic timescale the Bathonian is an age and stage of the Middle Jurassic. It lasted from approximately 168.3 Ma to around 166.1 Ma (million years ago). The Bathonian Age succeeds the Bajocian Age and precedes the Callovian Age. Strat ...

) of

Morocco Morocco (),, ) officially the Kingdom of Morocco, is the westernmost country in the Maghreb region of North Africa. It overlooks the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to ...

. The family was largely expanded in 2020 when the systematics of Teleosauroidea were re-reviewed. Members of this family generally were larger than the teleosaurids.

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''." The members of the Machimosauridae share several unique characters among teleosauroids, which are: * dorsally oriented external nares * the premaxillary anterior and anterolateral margins are not sub-vertical and do not extend ventrally * the

premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has b ...

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...

suture is sub-rectangular and slightly interdigitating (most noticeably near the midline) * no anterolateral expansion of the

supratemporal fenestrae The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, the ...

* 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:

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 long. Machimosaurines originated in the

stage of the

and simultaneously underwent a decrease in snout length but an increase in body size with ''Neosteneosaurus'' reaching up to long. Machimosaurins were the largest teleosauroids, with body lengths up to (''Machimosaurus rex''), and were durophagous hunters, meaning they fed on hard prey.

References

Thalattosuchians Prehistoric reptile families {{Paleo-archosaur-stub