Machimosauridae is an extinct family of

teleosauroid Teleosauroidea is an extinct superfamily of thalattosuchian crocodyliforms living from the Early Jurassic to the Early Cretaceous. It is phylogenetically defined by Mark T. Young and colleagues in 2024 in the ''PhyloCode'' as "the largest clade w ...

thalattosuchia Thalattosuchia is a clade of mostly 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 member ...

n crocodyliforms. Text was copied from this source, which is available under
Creative Commons Attribution 4.0 International License
The family was first identified in 2016, when fossils of

ns, 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 in ...

'', were described from the

Middle Jurassic The Middle Jurassic is the second Epoch (geology), epoch of the Jurassic Period (geology), Period. It lasted from about 174.1 to 161.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relativel ...

(

Bathonian In the geologic timescale the Bathonian is an age (geology), age and stage (stratigraphy), stage of the Middle Jurassic. It lasted from approximately 168.2 ±1.2 annum, Ma to around 165.3 ±1.1 Ma (million years ago). The Bathonian Age succeeds ...

) of

Morocco Morocco, officially the Kingdom of Morocco, is a country in the Maghreb region of North Africa. It has coastlines on the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to Algeria–Morocc ...

. 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 in the ''

PhyloCode The ''International Code of Phylogenetic Nomenclature'', known as the ''PhyloCode'' for short, is a formal set of rules governing phylogenetic nomenclature. Its current version is specifically designed to regulate the naming of clades, leaving the ...

'' by Mark T. Young and colleagues as "the largest clade within Teleosauroidea containing '' Machimosaurus hugii'', but not ''

Teleosaurus cadomensis ''Teleosaurus'' (from , 'perfect' and , 'lizard') is an extinct genus of teleosaurid crocodyliform found in the Middle Jurassic Calcaire de Caen Formation of France. It was approximately in length. The holotype is MNHN AC 8746, a quarter of ...

''." The less inclusive subfamily Machimosaurinae is defined in the ''PhyloCode'' as "the largest clade within Teleosauroidea containing ''Machimosaurus hugii'', but not ''

Deslongchampsina larteti ''Deslongchampsina'' is an extinct genus of Machimosauridae, machimosaurid crocodyliform from the Middle Jurassic (Bathonian) Cornbrash Formation of England and France, possibly from the Calcaire de Caen. The type species, type and only known sp ...

'', ''

Macrospondylus bollensis ''Macrospondylus'' is an extinct genus of machimosaurid teleosauroid crocodyliform from the Early Jurassic (Toarcian) of Europe. Fossils are known from the Posidonia Shale of Germany, the Whitby Mudstone of the United Kingdom, and the "'' schi ...

'', and '' Charitomenosuchus leedsi''". The tribe Machimosaurini contains the largest, most robust, and latest living machimosaurids and is defined in the ''PhyloCode'' as "the largest clade within Teleosauroidea containing ''Machimosaurus hugii'', but not ''

Neosteneosaurus edwardsi ''Neosteneosaurus'' is a genus of machimosaurid, known from the Middle Jurassic Oxford Clay of the UK, and Marnes de Dives, France. The type species, ''N. edwardsi'', was originally named as a species of ''Steneosaurus'' in 1868, but was moved ...

''". 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 describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provi ...

* 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 mammals h ...

maxilla In vertebrates, the maxilla (: maxillae ) 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 two maxil ...

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

supratemporal fenestrae Temporal fenestrae are openings in the Temple (anatomy), temporal region of the skull of some Amniote, amniotes, behind the Orbit (anatomy), orbit (eye socket). These openings have historically been used to track the evolution and affinities of re ...

* 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 ve ...

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

{{Taxonbar, from=Q98901556 Thalattosuchia Pseudosuchian families