The origin(s) of extant amphibians: a review with emphasis on the “lepospondyl hypothesis”

Geodiversitas

David Marjanović¹  Michel Laurin¹ 

关键词: Amphibia;    Lissamphibia;    Albanerpetontidae;    Temnospondyli;    Lepospondyli;    phylogenetics;    Tetrapoda;    divergence dating;    evo-devo;    Carroll's Gap;    Amphibia;    Lissamphibia;    Albanerpetontidae;    Temnospondyli;    Lepospondyli;    phylogénétique;    Tetrapoda;    datation de divergences;    evo-devo;    lacune de Carroll;   

DOI  :  10.5252/g2013n1a8

学科分类：生物科学（综合）

来源: Museum National d Histoire Naturelle

【 摘 要 】

Theoriginsoftheextantamphibians(frogs,salamanders,caecilians)remaincontroversialafteroveracenturyofdebate.Threegroupsofhypothesespersistinthecurrentliterature:the“temnospondylhypothesis”(TH)whichrootsLissamphibiaHaeckel,1866(thesmallestcladecomposedoftheextantamphibians)withinthePaleozoictemnospondyls,the“lepospondylhypothesis”(LH)whichpostulatesamonophyleticLissamphibianestedwithinthePaleozoiclepospondyls,andthe“polyphylyhypothesis”(PH),accordingtowhichthefrogsandthesalamandersaretemnospondylswhilethecaeciliansarelepospondyls.ThediscoveryoftheMiddleJurassictoPliocenealbanerpetontids,whichareverysimilartotheextantamphibians,hascomplicatedratherthanresolvedthissituation.Wepresentareviewofrecentpublicationsandthesesinthisfield,severalofwhichshowmoresupportfortheLHthanfortheTHandconsiderablymorethanforthePH.Inaddition,weshowthatthereisnoparticularattractionbetweenlong-bodiedlissamphibians(caecilians)andlong-bodiedlepospondyls(suchasthelysorophians):whentheyareremovedfromtwopublishedmatrices,reanalysesnonethelessfindtheLH.InonecasetheLHisfoundevenwhenallsalamandersareremovedaswell.Wefurthermoreproposethatthecomplexofcharacterscalledthesalamandermodeofautopodiumdevelopmentis(initslessextremeforms)plesiomorphicforlimbedvertebrates,sotheapparentpresenceofthismodeofdevelopmentintemnospondylscannotsupporttheTHorthePH.Still,aconsensuswillnotbereachedsoon,despitetheincreasingrangeofdataandtypesofanalysisthatareused(morphological,molecularandcombinedphylogenetics,developmentbiology,moleculardivergencedating,paleontologicalsupertreedating,combineddating,andcalculationofconfidenceintervalsonfirstappearancesinthefossilrecord).Wepresentexamplesofpertinentcharacterstatedistributionsandexplorealargegapinthefossilrecordofsmallstegocephalians.

【 授权许可】

Unknown