New Silurian nautiloids Phragmoceras Broderip, 1839, and Tubiferoceras Hedström, 1917, from the Prague Basin (Bohemia)

Bulletin of geosciences

Manda Å ¹ 

关键词: Nautiloidea;    Discosorida;    new taxa;    palaeobiogeography;    Silurian;    Prague Basin;   

DOI  :  

来源: Czech Geological Survey

【 摘 要 】

ThemorphologicallydistinctnautiloidgeneraPhragmocerasandTubiferoceras(Discosorida,Phragmoceratidae)withanendogastricbreviconeshellandacontractedaperturearecharacteristiccomponentsoftheSiluriantropicalfaunasofBalticaandLaurentia.SevenpreviouslyknownspeciesofPhragmocerasfromthePragueBasin(Perunica)aremainlyfromcephalopodlimestonesoftheLudlowage.Amongstthese,twospeciesarerecordedfrombeyondthePragueBasin.PhragmocerasimbricatumisrecognisedinAvaloniaandBalticaanditsgeographicdistributionsuggestsapalaeobiogeographicalconnectionacrosstheRheicOceanduringtheearlierLudlowtime.PhragmoceraslabiosumwasrecordedintheBohemian-typeLudfordianfaunaofSardinia(peri-Gondwana).ThispaperdealswithseveralphragmoceridsfromthePragueBasinwhichhavenotbeenrecordedbefore.TheyincludePhragmocerasmuntheifromthelatestLlandoveryandearlierWenlock,TubiferocerasproboscoideumfromtheearlyWenlock,Phragmocerasacuminatum,Phragmocerassigmoideum,Phragmocerascf.undulatum,andPhragmocerascf.ventricosumfromthelateWenlock.AnewspeciesPhragmoceraskoneprusensissp.nov.fromtheearlyLudfordian(Ludlow)isestablished.ThesespeciesarecloselyrelatedorconspecifictothosedescribedfromGotland(Baltica),Ireland(Laurentia)orWales(Avalonia)andindicateanopenseawaybetweenthePragueBasin(Perunica)andBaltica,LaurentiaandAvalonia,respectively,sincethelatestLlandovery.Inaddition,occurrencesofphragmoceridsinthePragueBasinsuggestthatincontrasttotherestofperi-GondwananareasarelativetemperatewaterenvironmentwastypicalforPerunicasincelatestLlandovery.

【 授权许可】

Unknown