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 members of Crocodilia and records from Thailand and China suggest that some members lived in freshwater. The clade contains two major subgroupings, the Teleosauroidea and Metriorhynchoidea. Teleosauroids are not greatly specialised for oceanic life, with back osteoderms similar to other crocodyliformes. Within Metriorhynchoidea, the Metriorhynchidae displayed

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 England, France, Germany, Portugal, Switzerland and Tunisia. Machimosaurus rex is the largest named teleosauroid and thalattosuchian, with an estimated length of up to (skull length ). Machimosaurus is the largest known crocodyliform of the Jurassic.

Metriorhynchus is an extinct genus of marine crocodyliform that lived in the oceans during the Late Jurassic. The type species, M. brevirostris was named in 1829 as a species of Steneosaurus before being named as a separate genus by the German palaeontologist Christian von Meyer in 1832. The name Metriorhynchus means "moderate snout", and is derived from the Greek Metrio- ("moderate") and -rhynchos ("snout").

Teleosauridae is a family of extinct typically marine crocodylomorphs similar to the modern gharial that lived during the Jurassic period. Teleosaurids were thalattosuchians closely related to the fully aquatic metriorhynchoids, but were less adapted to an open-ocean, pelagic lifestyle. The family was originally coined to include all the semi-aquatic (i.e. non-metriorhynchoid) thalattosuchians and was equivalent to the modern superfamily Teleosauroidea. However, as teleosauroid relationships and diversity was better studied in the 21st century, the division of teleosauroids into two distinct e

thumb|Life restoration of members of the Metriorhynchinae compared to a human 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 was coined by the Austrian zoologist Leopold Fitzinger in 1843. The group contains two subfamilies, the Metriorhynchinae and the Geosaurinae. They represent the most marine adapted of all archosaurs.

Steneosaurus (from , 'narrow' and , 'lizard') is a dubious genus of teleosaurid crocodyliform from the Middle or Late Jurassic (Callovian or early Oxfordian) of France and possibly also India. The genus has been used as a wastebasket taxon for thalattosuchian fossils for over two centuries, and almost all known historical species of teleosauroid have been included within it at one point. The genus has remained a wastebasket, with numerous species still included under the label '''Steneosaurus''', many of which are unrelated to each other (either paraphyletic or polyphyletic with respect to eac

Pelagosaurus (meaning "lizard of the open sea") is an extinct genus of thalattosuchian crocodyliform that lived during the Toarcian stage of the Lower Jurassic, around 183 Ma to 176 Ma (million years ago), in shallow epicontinental seas that covered much of what is now Western Europe. The systematic taxonomy of Pelagosaurus has been fiercely disputed over the years, and was assigned to Thalattosuchia after its systematics within Teleosauridae were disputed. Pelagosaurus measured long.

thumb|Life reconstruction of C. albersdoerferi Cricosaurus is an extinct genus of marine crocodyliforms of the Late Jurassic. belonging to the family Metriorhynchidae. The genus was established by Johann Andreas Wagner in 1858 for three skulls from the Tithonian (Late Jurassic) of Germany. The name Cricosaurus means "Ring lizard", and is derived from the Greek '- ("ring") and -' ("lizard"). It was a relatively small reptile, with C. suevicus and C. araucanensis measuring and in total body length, respectively.

thumb|left|Holotype skull Mystriosaurus is an extinct genus of teleosaurid crocodyliform from the Early Jurassic (Toarcian). Fossil specimens have been found in the Whitby Mudstone of England and Posidonia Shale of Germany. The only known species, M. laurillardi, exceeded in length.

Macrospondylus is an extinct genus of thalattosuchian crocodylomorph from the Early Jurassic (Toarcian) of Europe. It was a large ocean-going reptile, being the largest known crocodylomorph from the Early Jurassic. Fossils have been found in the Posidonia Shale of Germany, the Whitby Mudstone of the United Kingdom, and the Schistes bitemineux of Luxembourg. The type and only species known is Macrospondylus bollensis and it is one of the best known early thalattosuchians, being known from hundreds of specimens, including complete skeletons.

Teleidosaurus is an extinct genus of carnivorous metriorhynchoid crocodyliform from Middle Jurassic (late Bajocian to early Bathonian stage) deposits of Normandy, France. The name Teleidosaurus means "Complete lizard", and is derived from the Greek ''- ("complete") and -sauros'' ("lizard").

thumb thumb|Historical reconstruction by Samuel Wendell Williston|Williston, 1914 thumb|Referred specimen Rhacheosaurus is an extinct genus of marine crocodyliform belonging to the family Metriorhynchidae. The genus was established by Christian Erich Hermann von Meyer in 1831 for skeletal remains from the Tithonian (Late Jurassic) of Germany. It was a relatively small reptile, measuring between long.

Proexochokefalos (meaning "big head with big tuberosities") is an extinct genus of machimosaurid teleosauroid from the Middle to Late Jurassic of France and Switzerland. In life, it was a large marine reptile that would have fed on other large animals.

thumb|left|250px|Alternative view of the holotype Seldsienean is an extinct genus of teleosauroid thalattosuchian from the Middle Jurassic of England and France. The only known species, S. megistorhynchus, is known from remains from the Calcaire de Caen and the Cornbrash Formation. In life, Seldsienean was a marine reptile that would have fed mostly on fish and other small animals.

Platysuchus ("flat crocodile") is an extinct genus of teleosaurid crocodyliform from the Early Jurassic (Toarcian) of southern Germany and Luxembourg.

Plagiophthalmosuchus is an extinct genus of thalattosuchian crocodylomorph from the Early Jurassic (Early Toarcian) Whitby Mudstone Formation of Whitby, Yorkshire, UK, and Dudelange, Luxembourg. It contains the single species Plagiophthalmosuchus gracilirostris. In life, it was a small marine predator that would have fed on fish.

Metriorhynchoidea is an extinct superfamily of thalattosuchian crocodyliforms from the Early Jurassic to the Early Cretaceous (Toarcian - Valanginian, possibly as late as early Aptian) of Europe, North America and South America. Metriorhynchids are fully aquatic crocodyliforms. Named by Fitzinger, in 1843, it contains the basal taxa like Teleidosaurus, Zoneait and Eoneustes and the family Metriorhynchidae. An unnamed taxon is known from Chile.

Charitomenosuchus (meaning "graceful crocodile") is an extinct genus of machimosaurid teleosauroid from the Callovian Oxford Clay Formation of England. upright|thumb|left|Illustration of the holotype

Aeolodon is an extinct genus of teleosaurid crocodyliform reptile from the Late Jurassic (Tithonian) of Germany and France that was initially named as a species of Crocodylus in 1814. Although previously synonymized with Steneosaurus, recent cladistic analysis considers it distantly related to the Steneosaurus type species and the type species is A. priscus, named in 1830 and described in 2020. thumb|left|Assigned specimen (MNHN.F.CNJ 78a) The holotype of Aeolodon priscus was found in the Mörnsheim Formation of Daiting, Bavaria, Germany, in the same quarry that produced the Geosaurus giganteu

left|thumb|Holotype of G. leedsi, NHMUK PV R3540 thumb Gracilineustes is an extinct genus of marine crocodyliform that lived in the oceans during the Middle to Late Jurassic. Gracilineustes was a carnivore that spent much, if not all, its life out at sea. It was a small reptile, with G. leedsi measuring long and G. acutus measuring long. thumb|Skull and limb of G. leedsi ==Discovery and species== Fossil specimens referrable to Gracilineustes are known from Middle-Late Jurassic deposits of England and France.

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 within Thalattosuchia containing Teleosaurus cadomensis, but not Metriorhynchus brevirostris". This group contains two main families, the more piscivorous and gracile Teleosauridae and the more macropredatory and robust Machimosauridae.

Magyarosuchus is an extinct monotypic genus of metriorhynchoid thalattosuchian described for the first time from fossils discovered in the Kisgerecse Marl Formation in Hungary. The type species Magyarosuchus fitosi lived during the Toarcian, about 180 million years ago. It is known from a fragmentary skeleton discovered in 1996.

Machimosauridae is an extinct family of teleosauroid thalattosuchian crocodyliforms. The family was first identified in 2016, when fossils of teleosauroid thalattosuchians, including an indeterminate close relative of Lemmysuchus and Machimosaurus, were described from the Middle Jurassic (Bathonian) of Morocco. 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.

Eoneustes (meaning "dawn swimmer") is an extinct genus of metriorhynchoid crocodyliform from Middle Jurassic (late Bajocian to early Bathonian stage) deposits of France. Eoneustes was a carnivore that lived in the oceans and spent much, if not all, its life out at sea.

Turnersuchus is an extinct genus of thalattosuchian, a group of marine crocodylomorphs, from the Pliensbachian of the United Kingdom. It is the oldest diagnostic member of Thalattosuchia and was also found to be the group's most basal member, being situated outside the two major groups Metriorhynchoidea and Teleosauroidea. Subsequently, this genus is considered to be of great importance to understanding the relationship between thalattosuchians and other crocodylomorphs as well as their rapid diversification during the early Jurassic. Turnersuchus is a monotypic genus, meaning it includes only

Thalattosuchus (from Ancient Greek θᾰ́λᾰττᾰ (thálatta), meaning "sea", and σούχος (soúkhos), meaning "crocodile") is an extinct genus of marine crocodyliform that lived in the oceans during the Middle to Late Jurassic. Though the genus Thalattosuchus itself was named in 2020, its fossils have historically been included under the well known name Metriorhynchus as the species M. superciliosus, from which much of the research on the latter genus has been based upon. M. superciliosus was named as its own genus after a team of palaeontologists led by Mark Young in 2020 argued that the name Metriorh

Clovesuurdameredeor (meaning "sea creature of Closworth"; from the Medieval Latin Clovesuurda and the Old English meredeor) is an extinct genus of machimosaurid teleosauroid from the Bathonian Cornbrash Formation of England. thumb|left|upright|Illustration of the holotype The type species, C. stephani, was originally named "Steneosaurus" stephani by Hulke in 1867. Vignaud (1995) considered S. stephani to be a minor synonym of Yvridiosuchus boutilieri (then still in the genus Steneosaurus), but Johnson (2019) and Johnson et al. (2020) discovered that S. stephani was a basal machimosaur that wa

thumb|left|Chinese teleosauroid previously referred to as Peipehsuchus Peipehsuchus is an extinct genus of metriorhynchoid crocodyliform from the Early Jurassic (Toarcian). The type species, P. teleorhinus, is known from China and fragmentary remains were found in the Callovian of Kyrgyzstan. The type specimen is known only by a fragmentary rostrum and teeth, and was originally believed to be a teleosaurid. A complete teleosaurid skull was referred to Peipehsuchus, however, the type specimen of Peipehsuchus has since been determined to be a metriorhynchoid and so the skull cannot belong to it

Neosteneosaurus is a genus of machimosaurid, known from the Middle Jurassic Oxford Clay of the UK, and Marnes de Dives, France.