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dc.contributor.authorFoffa, Davide
dc.contributor.authorYoung, Mark T
dc.contributor.authorBrusatte, Stephen L
dc.contributor.authorGraham, M
dc.contributor.authorSteel, Lorna
dc.date.accessioned2021-01-07T16:27:12Z
dc.date.available2021-01-07T16:27:12Z
dc.date.issued2017-10-02
dc.date.submitted2020-12-29
dc.identifier.citationDavide Foffa, Mark T. Young, Stephen L. Brusatte, Mark R. Graham & Lorna Steel (2018) A new metriorhynchid crocodylomorph from the Oxford Clay Formation (Middle Jurassic) of England, with implications for the origin and diversification of Geosaurini, Journal of Systematic Palaeontology, 16:13, 1123-1143en_US
dc.identifier.issn1477-2019
dc.identifier.doi10.1080/14772019.2017.1367730
dc.identifier.urihttp://hdl.handle.net/10141/622883
dc.description.abstractMetriorhynchids are an extinct group of Jurassic–Cretaceous crocodylomorphs secondarily adapted to a marine lifestyle. A new metriorhynchid crocodylomorph from the Oxford Clay Formation (Callovian, Middle Jurassic) of England is described. The specimen is a large, fragmentary skull and associated single ramus of a lower jaw uniquely preserved in a septarian concretion. The description of the specimen reveals a series of autapomorphies (apicobasal flutings on the middle labial surface of the tooth crowns, greatly enlarged basoccipital tuberosities) and a unique combination of characters that warrant the creation of a new genus and species: Ieldraan melkshamensis gen. et sp. nov. This taxon shares numerous characters with the Late Jurassic–Early Cretaceous genus Geosaurus: tooth crowns that have three apicobasal facets on their labial surface, subtly ornamented skull and lower jaws elements, and reception pits along the lateral margin of the dentary (maxillary overbite). Phylogenetic analysis places this new species as the sister taxon to Geosaurus. The new taxon adds valuable information on the time of origin of the macrophagous subclade Geosaurini, which was initially thought to have evolved and radiated during the Late Jurassic. The presence of Ieldraan melkshamensis, the phylogenetic re-evaluation of Suchodus durobrivensis as a Plesiosuchus sister taxon and recently identified Callovian Dakosaurus-like specimens in the Oxford Clay Formation, indicate that all major Geosaurini lineages originated earlier than previously supposed. This has major implications for the evolution of macropredation in the group. Specifically, we can now demonstrate that the four different forms of true ziphodonty observed in derived geosaurins independently evolved from a single non-functional microziphodont common ancestor.en_US
dc.language.isoenen_US
dc.publisherTaylor and Francisen_US
dc.rightsopenAccessen_US
dc.titleA new metriorhynchid crocodylomorph from the Oxford Clay Formation (Middle Jurassic) of England, with implications for the origin and diversification of Geosaurinien_US
dc.typeJournal Articleen_US
dc.identifier.eissn1478-0941
dc.identifier.journalJournal of Systematic Palaeontologyen_US
dc.date.updated2020-12-29T18:14:02Z
dc.identifier.volume16en_US
dc.identifier.issue13en_US
dc.identifier.startpage1123-1143en_US
dc.description.nhmThis is an Accepted Manuscript of an article published by Taylor & Francis in Journal of Systematic Palaeontology on 2 Oct 2017, available online: https://doi.org/10.1080/14772019.2017.1367730en_US
dc.subject.nhmIeldraanen_US
dc.subject.nhmMelksham monsteren_US
dc.subject.nhmGeosaurusen_US
dc.subject.nhmGeosaurinien_US
dc.subject.nhmJurassicen_US
dc.subject.nhmmacrophagyen_US
refterms.dateFOA2021-01-07T16:27:14Z


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