Metriorhynchidae is an extinct family of specialized, aquatic metriorhynchoid crocodyliforms from the Middle Jurassic to the Early Cretaceous period (Bajocian to Valanginian stages, potentially as late as early Aptian[2]) of Europe, North America and South America. The name Metriorhynchidae was coined by the Austrian zoologist Leopold Fitzinger in 1843.[3] The group contains two subfamilies, the Metriorhynchinae and the Geosaurinae.[4][5]

Temporal range: Middle Jurassic-Early Cretaceous, 170–135 Ma
Dakosaurus maximus.JPG
Dakosaurus maximus skull, Staatliches Museum für Naturkunde Stuttgart
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Suborder: Thalattosuchia
Superfamily: Metriorhynchoidea
Family: Metriorhynchidae
Fitzinger, 1843


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 they did have a shark-like tail fluke.[6]

Metriorhynchids were the only group of archosaurs to become fully adapted to the marine realm, becoming pelagic in lifestyle.[7] With tail flukes, reduced limb musculature, and long bones histologically comparable to other obligately aquatic animals, they were almost certainly incapable of terrestrial locomotion; combined with an unusually tall hip opening, as also seen in other obligately aquatic reptiles including the viviparous Keichousaurus, this has lent credence to the suggestion that metriorhynchids gave live birth.[8]

The family has a wide geographic distribution, with material found in Argentina, Chile, Cuba, England, France, Germany, Italy, Mexico, Poland, Russia and Switzerland.[7][5]


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,[9][10][11] Dakosaurus[9] and Cricosaurus[9] 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.[4] The monophyly of Metriorhynchus [9][10][12] and Teleidosaurus[9][11] is also unsupported, and the species of these genera are pending reclassification.[4]

The classification presented by Young and Andrade in 2009 was approved in later studies of the Metriorhynchidae.[5][13][14] Metriorhynchidae is a node-based taxon defined in 2009 as the least inclusive clade consisting of Metriorhynchus geoffroyii and Geosaurus giganteus.[4] The cladogram 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.[5][13]




Metriorhynchinae indet. (USNM 19640)





Geosaurinae indet. (="Metriorhynchus" aff. "M." brachyrhynchus)







List of generaEdit

The type genus of the family Metriorhynchidae is Metriorhynchus from the Middle to Late Jurassic.[7] Other genera included within this family are Cricosaurus, Geosaurus, and Dakosaurus. Though once considered a metriorhynchid, Teleidosaurus has since been found to be slightly more distantly related to these animals within the superfamily Metriorhynchoidea.

Within this family, the genus Neustosaurus is considered nomen dubium ("doubtful name").[15]

The genus Capelliniosuchus was once thought to be a metriorhynchid similar to Dakosaurus.[16] However, Sirotti demonstrated that it is a junior synonym of Mosasaurus.[17]

Genus Status Author Age Location Description Synonyms Images
Ambayrac, 1913 late Oxfordian


Sometimes considered to be a nomen dubium.
Valid Wagner, 1858 middle Oxfordian to upper Valanginian

Argentina, Chile, Cuba, England, France, Germany, Mexico, Russia and Switzerland.

Valid von Quenstedt, 1856 lower Oxfordian to lower Berriasian

Argentina, England, France, Germany, Mexico, Poland, Switzerland and possibly Russia.

Valid Cuvier, 1824 upper Kimmeridgian to upper Valanginian

France, Germany, Italy and Switzerland.

  • Brachytaenius
  • Halilimnosaurus
Valid Young et al., 2010 lower Kimmeridgian

England and France.

Valid Parrilla-Bel et al., 2013


Valid von Meyer, 1830 lower Callovian to upper Kimmeridgian.

England, France, Germany and Switzerland.

Valid Cau & Fanti, 2011 late Bajocian to earliest Bathonian


nomen dubium — potential senior synonym of Cricosaurus
Valid Owen, 1884 late Kimmeridgian to early Tithonian

England and possibly Spain.

Valid Rusconi, 1948 lower Callovian to lower Tithonian

Argentina and Chile.

Valid von Meyer, 1831 lower Tithonian


Valid Lydekker, 1890 lower Callovian to lower Oxfordian

England and France.

Valid Andrade et al., 2010 upper Kimmeridgian


Valid Young et al., 2013


See alsoEdit


  1. ^ Andrews CW. 1913. A descriptive catalogue of the marine reptiles of the Oxford Clay, Part Two. London: British Museum (Natural History), 206 pp.
  2. ^ Alfio A. Chiarenza, Davide Foffa, Mark T. Young, Gianni Insacco, Andrea Cau, Giorgio Carnevale, Rita Catanzariti (2015). "The youngest record of metriorhynchid crocodylomorphs, with implications for the extinction of Thalattosuchia". Cretaceous Research. 56: 608–616. doi:10.1016/j.cretres.2015.07.001.CS1 maint: uses authors parameter (link)
  3. ^ Fitzinger LJFJ. 1843. Systema Reptilium. Wien: Braumüller et Seidel, 106 pp.
  4. ^ a b c d Mark T. Young and Marco Brandalise de Andrade (2009). "What is Geosaurus? Redescription of Geosaurus giganteus (Thalattosuchia: Metriorhynchidae) from the Upper Jurassic of Bayern, Germany". Zoological Journal of the Linnean Society. 157 (3): 551–585. doi:10.1111/j.1096-3642.2009.00536.x.CS1 maint: uses authors parameter (link)
  5. ^ a b c d Mark T. Young, Stephen L. Brusatte, Marcello Ruta and Marco Brandalise de Andrade (2010). "The evolution of Metriorhynchoidea (Mesoeucrocodylia, Thalattosuchia): an integrated approach using geometrics morphometrics, analysis of disparity and biomechanics". Zoological Journal of the Linnean Society. 158 (4): 801–859. doi:10.1111/j.1096-3642.2009.00571.x.CS1 maint: uses authors parameter (link)
  6. ^ Fraas E (1902). "Die Meer-Krocodilier (Thalattosuchia) des oberen Jura unter specieller Berücksichtigung von Dacosaurus und Geosaurus". Palaeontographica. 49: 1–72.
  7. ^ a b c Steel R. 1973. Crocodylia. Handbuch der Paläoherpetologie, Teil 16. Stuttgart: Gustav Fischer Verlag,116 pp.
  8. ^ Herrera, Y.; Fernandez, M.S.; Lamas, S.G.; Campos, L.; Talevi, M.; Gasparini, Z. (2017). "Morphology of the sacral region and reproductive strategies of Metriorhynchidae: a counter-inductive approach". Earth and Environmental Science Transactions of the Royal Society of Edinburgh. 106 (4): 247–255. doi:10.1017/S1755691016000165.
  9. ^ a b c d e Young MT (2007). "The evolution and interrelationships of Metriorhynchidae (Crocodyliformes, Thalattosuchia)". Journal of Vertebrate Paleontology. 27 (3): 170A. doi:10.1080/02724634.2007.10010458.
  10. ^ a b Wilkinson LE, Young MT, Benton MJ (2008). "A new metriorhynchid crocodilian (Mesoeucrocodylia: Thalattosuchia) from the Kimmeridgian (Upper Jurassic) of Wiltshire, UK". Palaeontology. 51 (6): 1307–1333. doi:10.1111/j.1475-4983.2008.00818.x.
  11. ^ a b Mueller-Töwe IJ (2005). "Phylogenetic relationships of the Thalattosuchia". Zitteliana. A45: 211–213.
  12. ^ Gasparini Z, Pol D, Spalletti LA (2006). "An unusual marine crocodyliform from the Jurassic-Cretaceous boundary of Patagonia". Science. 311 (5757): 70–73. doi:10.1126/science.1120803. PMID 16282526.
  13. ^ a b c Andrea Cau; Federico Fanti (2011). "The oldest known metriorhynchid crocodylian from the Middle Jurassic of North-eastern Italy: Neptunidraco ammoniticus gen. et sp. nov". Gondwana Research. 19 (2): 550–565. doi:10.1016/
  14. ^ Mark T. Young, Mark A. Bell and Stephen L. Brusatte (2011). "Craniofacial form and function in Metriorhynchidae (Crocodylomorpha: Thalattosuchia): modelling phenotypic evolution with maximum-likelihood methods". Biology Letters. 7 (6): 913–916. doi:10.1098/rsbl.2011.0357. PMC 3210659. PMID 21543396.CS1 maint: uses authors parameter (link)
  15. ^ Buffetaut E (1982). "Radiation évolutive, paléoécologie et biogéographie des Crocodiliens mésosuchienes". Mémoires Societé Geologique de France. 142: 1–88.
  16. ^ Simonelli V (1896). "Intoro agli avanzi di coccodrilliano scoperti a San Valentino (provincial di Reggio Emilia) nel 1886". Atli della Reale Accademia dei Lincei, Series Qunita Rendiconti. 5 (2): 11–18.
  17. ^ Sirotti A. 1989. Mosasaurus hoffmanni Mantell, 1828 (Reptilia) nelle <<argille scagliose>> di S. Valentino (Reggio E.). Atti della società dei naturalisti e matematici di Modena 120: 135-146.
  18. ^ Koken E (1883). "Die reptilian der norddeutschen unteren Kreide". Zeitschrift Deutschen Geologischen Gesellschaft. 35: 735–827.
  19. ^ Quenstedt FA. 1856. Sonst und Jetzt: Populäre Vortäge über Geologie. Tübingen: Laupp, 131.
  20. ^ Cuvier G. 1824. Sur les ossements fossiles de crocodiles, 5. In: Dufour & D'Occagne, eds. Recherches sur les ossements fossiles, 2nd édition. Paris: 143-160
  21. ^ Young Mark T., Brusatte Stephen L., Ruta M., Andrade Marco B. (2009). "The evolution of Metriorhynchoidea (Mesoeucrocodylia, Thalattosuchia): an integrated approach using geometrics morphometrics, analysis of disparity and biomechanics". Zoological Journal of the Linnean Society. 158 (4): 801–859. doi:10.1111/j.1096-3642.2009.00571.x.CS1 maint: multiple names: authors list (link)
  22. ^ Von Meyer H (1830). "Achte Versammlung der Naturforscher und Aerzte zu Heidelberg im September 1829". Isis von Oken. 1830: 517–519.
  23. ^ Andrade, M.B.D.; Young, M.T.; Desojo, J.B.; Brusatte, S.L. (2010). "The evolution of extreme hypercarnivory in Metriorhynchidae (Mesoeucrocodylia: Thalattosuchia) based on evidence from microscopic denticle morphology". Journal of Vertebrate Paleontology. 30 (5): 1451–1465. doi:10.1080/02724634.2010.501442.