Prehistoric marine crocodylomorphs

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 to side). The genus was established by Friedrich August von Quenstedt in 1856 for an isolated tooth named Geosaurus maximus by Theodor Plieninger in 1846. Dakosaurus was a carnivore that spent much, if not all, of its life out at sea. The extent of its adaptation to a marine lifestyle means that it is most likely that it mated at sea, but since no eggs or nests

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.

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 Geosaurus eggs or nests have been discovered, so little is known of the reptile's lifecycle, unlike other large marine reptiles of the Mesozoic, such as plesiosaurs or ichthyosaurs which are known to give birth to live young out at sea. Where Geosaurus mated, whether on land or at sea, is currently unknown. The name Geosaurus means "Mother of Giants lizard", and is d

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").

Stomatosuchus (meaning "mouth crocodile") is an extinct stomatosuchid neosuchian from the Late Cretaceous (Cenomanian) Bahariya Formation of Egypt. The type and only species is S. inermis. Much of what is known about Stomatosuchus has been inferred from the related genus Laganosuchus.

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

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 a skull and other associated postcranial remains, while other fragmentary specimens are known. The type species is T. cadomensis, but a second species, T. geoffroyi may also exist. It was previously considered a wastebasket taxon, with many other remains assigned to the genus.

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.

Dyrosauridae is a family of extinct neosuchian crocodyliforms that lived from the Campanian to the Eocene. Dyrosaurid fossils are globally distributed, having been found in Africa, Asia, Europe, North America and South America. Over a dozen species are currently known, varying greatly in overall size and cranial shape. A majority were aquatic, some terrestrial and others fully marine (see locomotion below), with species inhabiting both freshwater and marine environments. Ocean-dwelling dyrosaurids were among the few marine reptiles to survive the Cretaceous–Paleogene extinction event.

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

Dyrosaurus is a genus of extinct crocodylomorph that lived during the Early Eocene. The name Dyrosaurus comes from () the Greek for lizard or reptile, and Dyr for Djebel Dyr (mountain) close to where the type species was discovered. It was a large reptile with an estimated body length of .

thumb|left|Size (2), compared to other Brazilian Cretaceous Crocodylomorphs

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.

Gavialosuchus is an extinct genus of gavialoid crocodylian from the early Miocene of Europe. Currently only one species is recognized, as a few other species of Gavialosuchus have since been reclassified to other genera.

Aggiosaurus is an extinct genus of geosaurine metriorhynchid crocodyliform known from the Late Jurassic (late Oxfordian stage) of Nice, southeastern France. It contains a single species, Aggiosaurus nicaeensis, which was named by H. Ambayrac in 1913.

Elosuchus is an extinct genus of neosuchian crocodyliform that lived during the Middle Cretaceous of what is now Africa (Niger, Morocco, and Algeria).

Plesiosuchus is an extinct genus of geosaurine metriorhynchid crocodyliform known from the Late Jurassic (late Kimmeridgian to early Tithonian stage) of Dorset, England and possibly also Spain. It contains a single species, Plesiosuchus manselii.

Torvoneustes is an extinct genus of metriorhynchid thalattosuchian. It is known from skull and postcranial remains found in the Kimmeridge Clay Formation of Dorset and Wiltshire, England, the Virgula Marls of Switzerland and also from Oaxaca, Mexico . The holotype skull of the type species was initially assigned to the species Metriorhynchus superciliosus. Postcranial remains were later discovered from the same quarry as the skull, and then these specimens were recognised as belonging to a new species of Dakosaurus, as D. carpenteri. The species was named to honour Simon Carpenter, an amateur

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.

Chenanisuchus ("Chenane crocodile") is a genus of dyrosaurid crocodyliform from the Late Cretaceous of Mali and the Late Palaeocene of Sidi Chenane in Morocco. It was described in 2005, after expeditions uncovered it in 2000.

Suchodus is an extinct genus of metriorhynchid thalattosuchian from the Middle to Late Jurassic period of England and France It measured between in total body length.'''' It was a fully marine reptile that would have fed on other large marine fauna.

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").

Tyrannoneustes is an extinct genus of geosaurine metriorhynchid crocodyliform from the Callovian stage Oxford Clay Formation of England and the Marnes de Dives of France. It contains a single species, Tyrannoneustes lythrodectikos, meaning "blood-biting tyrant swimmer".

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.

Neptunidraco (meaning "Neptune's dragon") is an extinct genus of metriorhynchid thalattosuchian that lived during the middle Jurassic period (late Bajocian to earliest Bathonian stage) in what is now northeastern Italy. It is currently the oldest known metriorhynchid, an extinct group of fully marine reptiles related to modern crocodylians.

Purranisaurus is an extinct genus of marine crocodyliform from the Late Jurassic aged Vaca Muerta of Argentina. Rusconi originally regarded Purranisaurus potens (the type species) to be a plesiosaur; however, Gasparini demonstrated that it was in fact a metriorhynchid crocodyliform, and that may be a junior synonym of Metriorhynchus. It was about long.

Hyposaurus is a genus of extinct marine dyrosaurid crocodyliform. Fossils have been found in Paleocene aged rocks of the Iullemmeden Basin in West Africa, Campanian–Maastrichtian (Late Cretaceous) Shendi Formation of Sudan and Maastrichtian (Late Cretaceous) through Danian (Early Paleocene) strata in New Jersey, Alabama and South Carolina. With an Indeterminate species from the Mid to Late Palaeocene Teberemt Formation of Mali. Isolated teeth comparable to Hyposaurus have also been found in Thanetian (Late Paleocene) strata of Virginia. It was related to Dyrosaurus. The priority of the species

Terminonaris is a genus of extinct pholidosaurid crocodyliforms that lived during the Late Cretaceous (Cenomanian and Turonian) epoch. The name means: “enlarged snout or nose” at the front of the skull. Terminonaris is an early crocodile, within a subgroup called Mesoeucrocodylia. Its remains have only been found in North America and Europe. Originally known under the generic name Teleorhinus, it was once believed to be a teleosaurid (a family of marine gavial-like thalattosuchians). Both prehistoric crocodiles such as Terminonaris, as well as modern crocodiles, belong to the same group called

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.

Rhabdognathus is an extinct genus of dyrosaurid crocodylomorph. It is known from rocks dating to the Paleocene epoch from western Africa, and specimens dating back to the Maastrichtian era were identified in 2008. It was named by Swinton in 1930 for a lower jaw fragment from Nigeria. The type species is Rhabdognathus rarus. Stéphane Jouve subsequently assessed R. rarus as indeterminate at the species level, but not at the genus level, and thus dubious. Two skulls which were assigned to the genus Rhabdognathus but which could not be shown to be identical to R. rarus were given new species: R. a

Sokotosuchus is an extinct genus of dyrosaurid crocodyliform which existed during the Maastrichtian in western Africa. Fossils of the genus were found in the Dukamaje Formation of Nigeria, and some cranial material has possibly been found in Mali.

Phosphatosaurus is an extinct genus of dyrosaurid crocodylomorph. It existed during the early Eocene, with fossils having been found from North Africa in Tunisia and Mali. Named in 1955, Phosphatosaurus is a monotypic genus; the type species is P. gavialoides. A specimen has been discovered from Niger, but it cannot be classified at the species level.

Cerrejonisuchus is an extinct genus of dyrosaurid crocodylomorph. It is known from a complete skull and mandible from the Cerrejón Formation in northeastern Colombia, which is Paleocene in age. Specimens belonging to Cerrejonisuchus and to several other dyrosaurids have been found from the Cerrejón open-pit coal mine in La Guajira. The length of the rostrum is only 54-59% of the total length of the skull, making the snout of Cerrejonisuchus the shortest of all dyrosaurids.

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.

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.

Argochampsa (meaning "Argo crocodile", in reference to the mythological Argo of Jason) is an extinct genus of eusuchian crocodylomorph, usually regarded as a gavialoid crocodilian, related to modern gharials. It lived in the Paleocene of Morocco. Described by Hua and Jouve in 2004, the type species is A. krebsi, with the species named for . Argochampsa had a long narrow snout, and appears to have been marine in habits.

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

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

Congosaurus is an extinct genus of dyrosaurid mesoeucrocodylian. Fossils have been found from Lândana, in Angola and date back to the Paleocene epoch. In 1952 and 1964 Congosaurus was proposed to be synonymous with Dyrosaurus. The genus was later thought synonymous with Hyposaurus in 1976 and 1980. It has since been proven a distinct genus of dyrosaurid separate from both Dyrosaurus and Hyposaurus.

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

Arambourgisuchus ("Prof. Camille Arambourg's crocodile") is an extinct genus of dyrosaurid crocodylomorph from the late Palaeocene of Morocco, found in the region of Sidi Chenane in 2000, following collaboration by French and Moroccan institutions, and described in 2005 by a team led by palaeontologist Stéphane Jouve. Arambourgisuchus was a large animal with an elongated skull 1 meter in length.

thumb Maledictosuchus is an extinct genus of marine crocodyliform belonging to the family Metriorhynchidae. It is the most basal member of the Rhacheosaurini Tribe with a relatively short body length, measuring based on the type specimen. thumb|left|Holotype skull

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

Neustosaurus is a dubious genus of marine crocodyliform from the Early Cretaceous. Neustosaurus was a carnivore that spent much, if not all, its life out at sea. No Neustosaurus eggs or nest have been discovered, so little is known of the reptile's lifecycle, unlike other large marine reptiles of the Mesozoic, such as plesiosaurs or ichthyosaurs which are known to have given birth to live young out at sea. Where Neustosaurus mated, whether on land or at sea, is currently unknown. The name Neustosaurus means "Swimming lizard", and is derived from the Greek Neustos- ("swimming") and -sauros ("li

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.

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.

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

Thecachampsa is an extinct genus of gavialoid crocodylian, traditionally regarded as a member of the subfamily Tomistominae. Fossils have been found from the eastern United States in deposits of Miocene age. Those named in the 19th century were distinguished primarily by the shape of their teeth, and have since been combined with T. antiquus. More recently erected species were reassigned from other genera, although their assignment to Thecachampsa has since been questioned.