''Macrospondylus'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

machimosaurid Machimosauridae is an extinct family of teleosauroid thalattosuchian 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, ...

teleosauroid crocodyliform from the

Early Jurassic The Early Jurassic Epoch (in chronostratigraphy corresponding to the Lower Jurassic Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic-Jurassic extinction event, 201.3 Ma ...

(

Toarcian The Toarcian is, in the ICS' geologic timescale, an age and stage in the Early or Lower Jurassic. It spans the time between 182.7 Ma (million years ago) and 174.1 Ma. It follows the Pliensbachian and is followed by the Aalenian. The Toarc ...

) of Europe. Fossils are known from the

Posidonia Shale The Posidonia Shale (german: Posidonienschiefer, also called Schistes Bitumineux in Luxembourg) geologically known as the Sachrang Formation, is an Early Jurassic (Toarcian) geological formation of southwestern and northeast Germany, northern Swi ...

of Germany, the

Whitby Mudstone The Whitby Mudstone is a Toarcian (Early Jurassic; ''Falciferum''-''Bifrons'' in regional chronostratigraphy) geological formation in Yorkshire and Worcestershire, England.schistes bitumineux"'' of Luxembourg.

Evolutionary relationships

''Macrospondylus'' has historically been synonymized with ''

Steneosaurus ''Steneosaurus'' (from el, στενός , 'narrow' and el, σαῦρος , 'lizard') is a dubious genus of teleosaurid crocodyliform from the Middle or Late Jurassic (Callovian or early Oxfordian) of France. The genus has been used as a wa ...

''. A 2005

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

analysis of

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 C ...

, however, did not support the

monophyly In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gr ...

of ''Steneosaurus'', as the genera ''

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 i ...

'' and ''

Teleosaurus ''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 we ...

'' both fell within ''Steneosaurus''. Reinforcing the paraphyly of ''Steneosaurus'', Young et al. (2012), Ősi et al. (2018), and Wilberg et al. (2019) recovered ''Steneosaurus bollensis'' and other ''Steneosaurus'' species in disparate positions within Teleosauridae. In 2016, its length was estimated at , making it the largest known Early Jurassic crocodylomorph. In 2020, the genus was formally revived.

References

Prehistoric pseudosuchian genera Prehistoric marine crocodylomorphs Early Jurassic crocodylomorphs Fossil taxa described in 1830 Early Jurassic reptiles of Europe Thalattosuchians {{jurassic-reptile-stub

Evolutionary relationships

See also

References