Marmoretta
| Marmoretta Temporal range: Middle-Late Jurassic
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| Skull ofMarmoretta | |
Scientific classification
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Lepidosauromorpha |
| Genus: | †Marmoretta Evans,1991 |
| Type species | |
| †Marmoretta oxoniensis Evans, 1991
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Marmorettais anextinctgenusof smalllepidosauromorphreptileknown from theMiddle Jurassic(Bathonian) of Britain, as well as the Late Jurassic of Portugal. It contains a single species,Marmoretta oxoniensis.[1][2]
Etymology
[edit]Marmorettawas first described and named bySusan E. Evansin1991and thetype speciesisMarmoretta oxoniensis.Thegeneric nameis derived fromLatinmarmoros,meaning "Marble"and refers to the Forest Marble Formation - the source of the initial specimens ofMarmoretta.Thespecific nameis derived fromOxonia,theLatinisedform of "Oxford", in reference toOxfordshire.[1]
Discovery
[edit]
Marmorettais known fromholotypeBMNHR.12020, the anterior region of a rightmaxilla.Many specimens are referred to the species from the type locality, and together represent a nearly completeskull.All specimens are housed in theNatural History Museum.They were collected from theMammal Bedof theForest Marble Formation,atKirtlington,Oxfordshire,which has yielded a rich assemblage of small vertebrates including mammals, frogs, salamanders and other small reptiles.Marmorettais very common in that locality but its remains are fragmentary.[1]In 1994, additional specimens ofMarmorettawere described from theKilmaluag Formation(previously known as the Ostracod Limestones) of theGreat Estuarine GroupinSkye.This material ofMarmorettaincludes the first associatedskullandpostcranialremains. They confirm the original description and reconstruction, and provide additional support for position ofMarmorettaas the sister taxon ofLepidosauria.[2]Both localities dates to the LateBathonianstage of theMiddle Jurassicperiod,about 166.2-164.7million years ago.[1][2]In 2021, the Skye material was redescribed with CT scanning, and was found to slightly differ from the specimens from Oxford, with a different arrangement of palatal teeth and a differently shapedparabasisphenoid.[3]Remains have also been reported from theAlcobaça Formationin Portugal, dating to the Late Jurassic.[1]
Description
[edit]Marmorettawas a small reptile, with a maximum skull length of about 4 centimetres (1.6 in).[1]The dentiton is subpleurodont.[3]
Phylogeny
[edit]Susan E. Evans and Magdalena Borsuk−Białynicka (2009) performed aphylogeneticanalysis that recoveredSophinetaas the sister group ofLepidosauria.The inclusion ofSophinetadisplaced the relictualMiddle JurassicMarmorettaand gave the origin of Lepidosauria much older age. Thecladogrambelow follows their results.[4]Some subsequent phylogenies have recoveredMarmorettaas a stem-squamate,closer to squamates than torhynchocephalians.[5][6]In the 2021 redescription, it was found to be a basal lepidosauromorph, most closely related toFraxinisaurafrom the Middle Triassic of Germany.[3]
Cladogram after Griffiths, 2021:
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References
[edit]- ^abcdefEvans, S. E. (1991). "A new lizard-like reptile (Diapsida: Lepidosauromorpha) from the Middle Jurassic of England".Zoological Journal of the Linnean Society.103(4): 391–412.doi:10.1111/j.1096-3642.1991.tb00910.x.
- ^abcWaldman, M.; Evans, S. E. (1994). "Lepidosauromorph reptiles from the Middle Jurassic of Skye".Zoological Journal of the Linnean Society.112(1–2): 135–150.doi:10.1111/j.1096-3642.1994.tb00315.x.
- ^abcGriffiths, Elizabeth F.; Ford, David P.; Benson, Roger B.J.; Evans, Susan E. (September 2021). Ruta, Marcello (ed.)."New information on the Jurassic lepidosauromorph Marmoretta oxoniensis".Papers in Palaeontology.7(4): 2255–2278.doi:10.1002/spp2.1400.ISSN2056-2799.S2CID239140732.
- ^Susan E. Evans and Magdalena Borsuk−Białynicka (2009)."A small lepidosauromorph reptile from the Early Triassic of Poland"(PDF).Paleontologica Polonica.65:179–202.
- ^Simões, Tiago R.; Caldwell, Michael W.; Tałanda, Mateusz; Bernardi, Massimo; Palci, Alessandro; Vernygora, Oksana; Bernardini, Federico; Mancini, Lucia; Nydam, Randall L. (May 2018)."The origin of squamates revealed by a Middle Triassic lizard from the Italian Alps".Nature.557(7707): 706–709.Bibcode:2018Natur.557..706S.doi:10.1038/s41586-018-0093-3.ISSN0028-0836.PMID29849156.S2CID44108416.
- ^Sobral, Gabriela; Simões, Tiago R.; Schoch, Rainer R. (2020-02-20)."A tiny new Middle Triassic stem-lepidosauromorph from Germany: implications for the early evolution of lepidosauromorphs and the Vellberg fauna".Scientific Reports.10(1): 2273.Bibcode:2020NatSR..10.2273S.doi:10.1038/s41598-020-58883-x.ISSN2045-2322.PMC7033234.PMID32080209.
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