Machimosauridae is an extinct family of

teleosauroid Teleosauroidea is an extinct superfamily of thalattosuchian crocodyliforms living from the Early Jurassic to the Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostr ...

thalattosuchia Thalattosuchia is a clade of marine crocodylomorphs from the Early Jurassic to the Early Cretaceous that had a cosmopolitan distribution. They are colloquially referred to as marine crocodiles or sea crocodiles, though they are not members of Cro ...

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The family was first identified in 2016, when fossils of

ns, including an indeterminate close relative of ''

Lemmysuchus ''Lemmysuchus'' is a genus of machimosaurid thalattosuchian from the Middle Jurassic Callovian of England and France. Like many other teleosauroids from Europe, it has had a convoluted taxonomic history. History ''"Steneosaurus" obtusidens' ...

'' and '' Machimosaurus'', were described from the Middle Jurassic (

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. Str ...

) 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 t ...

. 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 ''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 in ...

'', but not '' Plagiophthalmosuchus gracilirostris'' and ''

Teleosaurus cadomensis ''Teleosaurus'' (from el, τέλειος , 'perfect' and el, σαῦρος , 'lizard') is an extinct genus of teleosaurid crocodyliform found in the Middle Jurassic Calcaire de Caen Formation of France. It was approximately in length and weig ...

''." 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 Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

* 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 ...

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. T ...

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

postorbital The ''postorbital'' is one of the bones in vertebrate skulls which forms a portion of the dermal skull roof and, sometimes, a ring about the orbit. Generally, it is located behind the postfrontal and posteriorly to the orbital fenestra. In some ...

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 Middle Jurassic 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