On the Last Occurrence of Marginella Lamarck, 1799 (Gastropoda, Marginellidae) in the Mediterranean: Description of a New Species from the Early Pleistocene and Paleoceanographic Implications

[摘要] AnewspeciesofMarginellaLamarck,1799isdescribedfromtheEarlyPleistoceneoftheMessinaStraitarea,M.seguenzain.sp.Theremarkablevariabilityinshellsizeandshaperequiredapreliminarymorphometricanalysis,whichprovidedevidenceofasinglespecies.ThisisthelastknownrepresentativeofthegenusMarginellaintheMediterranean,todayhighlydiverseinthetropicalandsubtropicalshallowwatersofWestAfrica,uptoabout28°N.ThegenusMarginellawasthoughttohavedisappearedfromtheMediterraneanandtheadjacentAtlanticaftertheEarlyPliocene,duetoearlycoolingphases.Anyway,Marginellaseguenzain.sp.wasadeepwaterspecies,anditsextinctionwasmostprobablyduetothelossofpsychrosphere,intheEarlyPleistocene,ratherthantoclimaticdeterioration.Theremarkableclosenessbetweenthenewspeciesandadeepwaterlivingspecies,endemictothreeseamountsintheNEAtlantic,suggestsacommonoriginforbothspecies.HighproductivityseemstohavebeenakeyfactorintheMediterraneandistributionofMarginella,eitherinshallowanddeepwaters.

[学科分类] 生物科学（综合）

[关键词] Marginella;shape analysis;Early Pleistocene;Messina Strait;Mediterranean;paleoceanography;new species;Marginella;analyse de contours;Pléistocène inférieur;Détroit de Messine;Méditerranée;paléoceanographie;espèce nouvelle