Metriorhynchidae is an extinct family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 of metriorhynchoid crocodyliforms from the Middle Jurassic

Middle Jurassic

The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from 176-161 million years ago. In European lithostratigraphy, rocks of this Middle Jurassic age are called the Dogger....

 to the Early Cretaceous

Early Cretaceous

The Early Cretaceous or the Lower Cretaceous , is the earlier or lower of the two major divisions of the Cretaceous...

 period (Bajocian

Bajocian

In the geologic timescale, the Bajocian is an age or stage in the Middle Jurassic. It lasted from approximately 171.6 Ma to around 167.7 Ma . The Bajocian age succeeds the Aalenian age and precedes the Bathonian age....

 - Valanginian

Valanginian

In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 140.2 ± 3.0 Ma and 136.4 ± 2.0 Ma...

 stages) of Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

, North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

 and South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

. Metriorhynchids are fully aquatic crocodyliforms. Their forelimbs were small and paddle-like, and unlike living crocodilians, they lost their osteoderms ("armour scutes"). Their body shape maximised hydrodynamy (swimming efficiency), as did having a shark-like tail fin.

Metriorhynchids were the only group of archosaur

Archosaur

Archosaurs are a group of diapsid amniotes whose living representatives consist of modern birds and crocodilians. This group also includes all extinct non-avian dinosaurs, many extinct crocodilian relatives, and pterosaurs. Archosauria, the archosaur clade, is a crown group that includes the most...

s to become fully adapted to the marine realm, becoming pelagic in lifestyle.

The name Metriorhynchidae was coined by the Austrian

Austrians

Austrians are a nation and ethnic group, consisting of the population of the Republic of Austria and its historical predecessor states who share a common Austrian culture and Austrian descent....

 zoologist Leopold Fitzinger

Leopold Fitzinger

Leopold Joseph Franz Johann Fitzinger was an Austrian zoologist.Fitzinger was born in Vienna and studied botany at the university of Vienna under Nikolaus Joseph von Jacquin...

 in 1843. It contains two subfamilies, the Metriorhynchinae

Metriorhynchinae

Metriorhynchinae is a subfamily of metriorhynchid crocodyliforms from the late Middle Jurassic to the Early Cretaceous of Europe, North America and South America. Named by Fitzinger, in 1843, it contains the metriorhynchids Metriorhynchus, Gracilineustes, Cricosaurus and Rhacheosaurus...

 and the Geosaurinae

Geosaurinae

Geosaurinae is a subfamily of metriorhynchid crocodyliforms from the Middle Jurassic to the Early Cretaceous of Europe, North America and South America. Named by Richard Lydekker, in 1889, it contains the metriorhynchids Suchodus, Purranisaurus, Neptunidraco, Torvoneustes, Dakosaurus and Geosaurus...

.

Geographical distribution

The family has a wide geographic distribution, with material found in Argentina

Argentina

Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

, Chile

Chile

Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...

, Cuba

Cuba

The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...

, England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

, France

France

The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

, Germany

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

, Italy

Italy

Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...

, Mexico

Mexico

The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

, Poland

Poland

Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...

, Russia

Russia

Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

 and Switzerland

Switzerland

Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....

.

Classification

Phylogenetic analyses published during the 2000s cast doubt on the idea that many traditional metriorhynchid genera formed natural groups (i.e., include all descendants of a common ancestor). The traditional species of Geosaurus

Geosaurus

Geosaurus is an extinct genus of marine crocodyliform within the family Metriorhynchidae that lived during the Late Jurassic to the Early Cretaceous. Geosaurus was a carnivore that spent much, if not all, its life out at sea...

, Dakosaurus

Dakosaurus

Dakosaurus is an extinct genus within the family Metriorhynchidae that lived during the Late Jurassic and Early Cretaceous. It was large, with teeth that were serrated and compressed lateromedially . The genus was established by Friedrich August von Quenstedt in 1856 for an isolated tooth named...

and Cricosaurus

Cricosaurus

Cricosaurus is an extinct genus of marine crocodyliform belonging to the family Metriorhynchidae. The genus was established by Johann Andreas Wagner in 1858 for three skulls from the Tithonian of Germany...

were found to represent unnatural groups, and the species traditionally classified in these genera were reshuffled in a study published in November 2009 by Mark T. Young and Marco Brandalise de Andrade. The monophyly

Monophyly

In common cladistic usage, a monophyletic group is a taxon which forms a clade, meaning that it contains all the descendants of the possibly hypothetical closest common ancestor of the members of the group. The term is synonymous with the uncommon term holophyly...

 of Metriorhynchus

Metriorhynchus

Metriorhynchus is an extinct genus of marine crocodyliform that lived in the oceans during the Middle to Late Jurassic. Metriorhynchus was named by the German palaeontologist Christian von Meyer in 1830. Metriorhynchus was a carnivore that spent much, if not all, its life out at sea...

and Teleidosaurus

Teleidosaurus

Teleidosaurus is an extinct genus of carnivorous metriorhynchoid crocodyliform from Middle Jurassic deposits of Normandy, France...

is also unsupported, and the species of these genera are pending reclassification.

The classification presented by Young and Andrade in 2009 was approved in later studies of the Metriorhynchidae. Metriorhynchidae is a node-based taxon defined in 2009 as the least inclusive clade consisting of Metriorhynchus geoffroyii and Geosaurus giganteus. The cladogram

Cladogram

A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...

 below follows the topology from a 2011 analysis by Andrea Cau and Federico Fanti with clade names from Young et al. 2011 and reduced to genera only.

List of genera

The type genus

Type genus

In biological classification, a type genus is a representative genus, as with regard to a biological family. The term and concept is used much more often and much more formally in zoology than it is in botany, and the definition is dependent on the nomenclatural Code that applies:* In zoological...

 of the family Metriorhynchidae is Metriorhynchus

Metriorhynchus

Metriorhynchus is an extinct genus of marine crocodyliform that lived in the oceans during the Middle to Late Jurassic. Metriorhynchus was named by the German palaeontologist Christian von Meyer in 1830. Metriorhynchus was a carnivore that spent much, if not all, its life out at sea...

from the Middle to Late Jurassic. Other genera included within this family are Cricosaurus

Cricosaurus

Cricosaurus is an extinct genus of marine crocodyliform belonging to the family Metriorhynchidae. The genus was established by Johann Andreas Wagner in 1858 for three skulls from the Tithonian of Germany...

, Geosaurus

Geosaurus

Geosaurus is an extinct genus of marine crocodyliform within the family Metriorhynchidae that lived during the Late Jurassic to the Early Cretaceous. Geosaurus was a carnivore that spent much, if not all, its life out at sea...

, and Dakosaurus

Dakosaurus

Dakosaurus is an extinct genus within the family Metriorhynchidae that lived during the Late Jurassic and Early Cretaceous. It was large, with teeth that were serrated and compressed lateromedially . The genus was established by Friedrich August von Quenstedt in 1856 for an isolated tooth named...

. Though once considered a metriorhynchid, Teleidosaurus

Teleidosaurus

Teleidosaurus is an extinct genus of carnivorous metriorhynchoid crocodyliform from Middle Jurassic deposits of Normandy, France...

has since been found to be slightly more distantly related to these animals within the superfamily Metriorhynchoidea

Metriorhynchoidea

Metriorhynchoidea is an extinct superfamily of thalattosuchian crocodyliforms from the early Middle Jurassic to the Early Cretaceous of Europe, North America and South America. Metriorhynchids are fully aquatic crocodyliforms. Named by Fitzinger, in 1843, it contains the basal taxa like...

.

Within this family, the genus Neustosaurus

Neustosaurus

Neustosaurus is a genus of marine crocodyliform from the Early Cretaceous. Neustosaurus was a carnivore that spent much, if not all, its life out at sea...

is considered nomen dubium

Nomen dubium

In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...

("doubtful name").

The genus Capelliniosuchus was once thought to be a metriorhynchid similar to Dakosaurus. However, Sirotti demonstrated that it is a junior synonym of Mosasaurus

Mosasaurus

Mosasaurus is a genus of mosasaur, carnivorous, aquatic lizards, somewhat resembling flippered crocodiles, with elongated heavy jaws. The genus existed during the Maastrichtian age of the Cretaceous period , around 70-65 millions years ago in the area of modern Western Europe and North America...

.

Genus	Status	Author	Age	Location	Description	Synonyms	Images
Cricosaurus Cricosaurus Cricosaurus is an extinct genus of marine crocodyliform belonging to the family Metriorhynchidae. The genus was established by Johann Andreas Wagner in 1858 for three skulls from the Tithonian of Germany...	Valid	Wagner Johann Andreas Wagner Johann Andreas Wagner was a German palaeontologist, zoologist and archaeologist.Wagner was a professor at the University of Munich, and curator of the Zoologische Staatssammlung .... , 1858	middle Oxfordian to upper Valanginian Valanginian In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 140.2 ± 3.0 Ma and 136.4 ± 2.0 Ma...	Argentina, Chile, Cuba, England, France, Germany, Mexico, Russia and Switzerland.		Enaliosuchus
Dakosaurus Dakosaurus Dakosaurus is an extinct genus within the family Metriorhynchidae that lived during the Late Jurassic and Early Cretaceous. It was large, with teeth that were serrated and compressed lateromedially . The genus was established by Friedrich August von Quenstedt in 1856 for an isolated tooth named...	Valid	von Quenstedt Friedrich August von Quenstedt Friedrich August von Quenstedt , was a German geologist and palaeontologist.-Life:Von Quenstedt was born at Eisleben in Saxony, and educated at the Humboldt University of Berlin... , 1856	lower Oxfordian to lower Berriasian Berriasian In the geological timescale, the Berriasian is an age or stage of the Early or Lower Creteceous. It is the oldest or lowest subdivision in the entire Cretaceous. It spanned between 145.5 ± 4.0 Ma and 140.2 ± 3.0 Ma...	Argentina, England, France, Germany, Mexico, Poland, Switzerland and possibly Russia.		Aggiosaurus Dacosaurus (lapsus calami)
Geosaurus Geosaurus Geosaurus is an extinct genus of marine crocodyliform within the family Metriorhynchidae that lived during the Late Jurassic to the Early Cretaceous. Geosaurus was a carnivore that spent much, if not all, its life out at sea...	Valid	Cuvier Georges Cuvier Georges Chrétien Léopold Dagobert Cuvier or Jean Léopold Nicolas Frédéric Cuvier , known as Georges Cuvier, was a French naturalist and zoologist... , 1824	upper Kimmeridgian Kimmeridgian In the geologic timescale, the Kimmeridgian is an age or stage in the Late or Upper Jurassic epoch or series. It spans the time between 155.7 ± 4 Ma and 150.8 ± 4 Ma . The Kimmeridgian follows the Oxfordian and precedes the Tithonian....  to upper Valanginian	France, Germany, Italy and Switzerland.		Brachytaenius Halilimnosaurus
Gracilineustes Gracilineustes 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.-Discovery and species:...	Valid	Young et al., 2010 2010 in paleontology -Anomalocaridids:-Newly named crustaceans:-Newly named insects:* A new family, Cascopleciidae, is published by Poinar Jr.* A new family of ceraphronoid Hymenopters, Radiophronidae, is published by Ortega-Blanco, Rasnitsyn, and Delclòs....	lower Kimmeridgian	France (Normandy)
Metriorhynchus Metriorhynchus Metriorhynchus is an extinct genus of marine crocodyliform that lived in the oceans during the Middle to Late Jurassic. Metriorhynchus was named by the German palaeontologist Christian von Meyer in 1830. Metriorhynchus was a carnivore that spent much, if not all, its life out at sea...	Valid	von Meyer Christian Erich Hermann von Meyer Christian Erich Hermann von Meyer was a German palaeontologist.He was born at Frankfurt am Main.In 1832 von Meyer issued a work entitled Palaeologica, and in course of time he published a series of memoirs on various fossil organic remains: molluscs, crustaceans, fishes and higher vertebrata,... , 1830	lower Callovian Callovian In the geologic timescale, the Callovian is an age or stage in the Middle Jurassic, lasting between 164.7 ± 4.0 Ma and 161.2 ± 4.0 Ma. It is the last stage of the Middle Jurassic, following the Bathonian and preceding the Oxfordian....  to upper Kimmeridgian.	England, France, Germany and Switzerland.		Metiorychus (lapsus calami)
Neptunidraco Neptunidraco Neptunidraco is an extinct genus of carnivorous marine crocodyliform which lived during the middle Jurassic period in what is now northeastern Italy. It is known from a partial skeleton recovered from the nodular limestone of the Rosso Ammonitico Veronese Formation...	Valid	Cau & Fanti, 2011 2011 in paleontology -Lobopods:-Arachnids:-Insects:-Newly named jawless vertebrates:-Newly named acanthodian:-Newly named cartilaginous fishes:-Newly named bony fishes:-Newly named lepospondyls:-Newly named temnospondyls:-Newly named lissamphibians:...	late Bajocian Bajocian In the geologic timescale, the Bajocian is an age or stage in the Middle Jurassic. It lasted from approximately 171.6 Ma to around 167.7 Ma . The Bajocian age succeeds the Aalenian age and precedes the Bathonian age....  to earliest Bathonian Bathonian In the geologic timescale the Bathonian is an age or stage of the Middle Jurassic. It lasted from approximately 167.7 Ma to around 164.7 Ma...	Italy
Neustosaurus Neustosaurus Neustosaurus is a genus of marine crocodyliform from the Early Cretaceous. Neustosaurus was a carnivore that spent much, if not all, its life out at sea...	nomen dubium Nomen dubium In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...				— potential senior synonym of Cricosaurus Cricosaurus Cricosaurus is an extinct genus of marine crocodyliform belonging to the family Metriorhynchidae. The genus was established by Johann Andreas Wagner in 1858 for three skulls from the Tithonian of Germany...
Purranisaurus Purranisaurus Purranisaurus is an extinct genus of marine crocodyliform from the Middle to Late Jurassic period of Chile and Argentina. Rusconi originally regarded Purranisaurus potens to be a plesiosaur; however, Gasparini demonstrated that it was in fact a metriorhynchid crocodyliform, and that may be a...	Valid	Rusconi, 1948 1948 in paleontology -Newly named dinosaurs:Data courtesy of George Olshevsky's dinosaur genera list and Dr. Jeremy Montague's dinosaur genus database.-New taxa:-Non-mammalian:...	lower Callovian to lower Tithonian Tithonian In the geologic timescale the Tithonian is the latest age of the Late Jurassic epoch or the uppermost stage of the Upper Jurassic series. It spans the time between 150.8 ± 4 Ma and 145.5 ± 4 Ma...	Argentina and Chile.
Rhacheosaurus Rhacheosaurus Rhacheosaurus is an extinct genus of marine crocodyliform belonging to the family Metriorhynchidae. The genus was established by von Meyer in 1831 for skeletal remains from the Tithonian of Germany.-History and classification:...	Valid	von Meyer, 1831	lower Tithonian	Germany
Suchodus Suchodus Suchodus is an extinct genus of marine crocodyliform from the Middle to Late Jurassic period of England and France.-Taxonomy and phylogeny:Recent phylogenetic analysis has shown that Suchodus is a distinct metriorhynchid genus.-Valid species:...	Valid	Lydekker Richard Lydekker Richard Lydekker was an English naturalist, geologist and writer of numerous books on natural history.-Biography:... , 1890	lower Callovian to lower Oxfordian	England and France.
Torvoneustes Torvoneustes Torvoneustes is a genus of extinct metriorhynchid mesoeucrocodylian. It is known from a partial skull and some postcranial remains that have been found from the Kimmeridge Clay of Wiltshire, England. The skull was first to be found, and was first assigned to the species Metriorhynchus superciliosus...	Valid	Andrade et al., 2010 2010 in paleontology -Anomalocaridids:-Newly named crustaceans:-Newly named insects:* A new family, Cascopleciidae, is published by Poinar Jr.* A new family of ceraphronoid Hymenopters, Radiophronidae, is published by Ortega-Blanco, Rasnitsyn, and Delclòs....	upper Kimmeridgian	England