Geosaurinae is a

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...

metriorhynchid Metriorhynchidae is an extinct family of specialized, aquatic metriorhynchoid crocodyliforms from the Middle Jurassic to the Early Cretaceous period (Bajocian to early Aptian) of Europe, North America and South America. The name Metriorhynchidae ...

crocodyliform Crocodyliformes is a clade of crurotarsan archosaurs, the group often traditionally referred to as "crocodilians". They are the first members of Crocodylomorpha to possess many of the features that define later relatives. They are the only pseudo ...

s 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 ...

to the

Early Cretaceous The Early Cretaceous ( geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma. Geology Pro ...

(

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 ...

Aptian The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous Epoch or Series and encompasses the time from 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ago), a ...

) of

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

. Named by

Richard Lydekker Richard Lydekker (; 25 July 1849 – 16 April 1915) was an English naturalist, geologist and writer of numerous books on natural history. Biography Richard Lydekker was born at Tavistock Square in London. His father was Gerard Wolfe Lydekker, ...

, in 1889, it contains the metriorhynchids ''

Suchodus ''Suchodus'' is an extinct genus of marine crocodyliform from the Middle to Late Jurassic period of England and France. It measured between in total body length. Taxonomy and phylogeny In the 2000s, phylogenetic analysis has shown that ''Su ...

'', '' Purranisaurus'', '' Neptunidraco'', '' Tyrannoneustes'', '' Torvoneustes'', '' Dakosaurus'', ''

Geosaurus ''Geosaurus'' is an extinct genus of marine crocodyliform within the family Metriorhynchidae, that lived during the Late Jurassic and the Early Cretaceous. ''Geosaurus'' was a carnivore that spent much, if not all, its life out at sea. No ''Geosa ...

'' and '' Plesiosuchus''. The last four taxa form a tribe within Geosaurinae, the Geosaurini. Geosaurinae is one of two subfamilies of Metriorhynchidae, the other being

Metriorhynchinae Metriorhynchinae is a subfamily of metriorhynchid crocodyliforms from the late Middle Jurassic to the Early Cretaceous (Callovian - Valanginian) of Europe, North America and South America. Named by Fitzinger, in 1843, it contains the metrior ...

. These marine reptiles were widespread during the Late Jurassic and Early Cretaceous, their fossilized remains are being frequently found on various places around the world.Daniel Madzia, Sven Sachs, Mark T. Young, Alexander Lukeneder and Petr Skupien (2021)
Evidence of two lineages of metriorhynchid crocodylomorphs in the Lower Cretaceous of the Czech Republic
''Acta Palaeontologica Polonica''. doi: https://doi.org/10.4202/app.00801.2020

Phylogeny

Geosaurinae is a stem-based taxon defined in 2009 as the most inclusive clade consisting of ''

Geosaurus giganteus ''Geosaurus'' is an extinct genus of marine crocodyliform within the family Metriorhynchidae, that lived during the Late Jurassic and the Early Cretaceous. ''Geosaurus'' was a carnivore that spent much, if not all, its life out at sea. No ''Geo ...

'', but not '' Metriorhynchus geoffroyii''. Geosaurini was named by Lydekker in 1889, and it is a

node-based taxon Phylogenetic nomenclature is a method of nomenclature for taxa in biology that uses phylogenetic definitions for taxon names as explained below. This contrasts with the traditional approach, in which taxon names are defined by a '' type'', which ...

defined by Andrea Cau and Federico Fanti in 2011 as the least inclusive clade consisting of ''

'', ''

Dakosaurus maximus ''Dakosaurus'' is an extinct genus of crocodylomorph within the family Metriorhynchidae that lived during the Late Jurassic and Early Cretaceous. It was large, with teeth that were serrated and compressed lateromedially (flattened from side t ...

'' and '' Torvoneustes carpenteri''. The cladogram below follows the topology from a 2020 analysis by Young ''et al.''

References

Early Cretaceous crocodylomorphs Middle Jurassic crocodylomorphs Middle Jurassic first appearances Early Cretaceous extinctions Late Jurassic crocodylomorphs Thalattosuchians {{paleo-archosaur-stub