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ShortCommunication

NewinformationontheenigmaticDevonianvertebrate

Palaeospondylusgunni

MICHAELJ.NEWMAN1JANL.DENBLAAUWEN2

1LlanstadwellHouse,ChurchRoad,Llanstadwell,MilfordHaven,Pembrokeshire,SA731EB,UK

(e-mail:Newmanichthy@aol.com)

2UniversityofAmsterdam,Kruislaan406,1098SM,Amsterdam,TheNetherlands

Synopsis

TheenigmaticvertebratePalaeospondylusgunni,fromtheMiddleDevonianofScotland,

hasbeendescribedasalarvallungfish(dipnoan),mostprobablyofthegenusDipterus.

Metamorphosiswassaidtoaccountfortheextrememorphologicaldifferencesbetweenthe

twotaxa,withdistinctsizedifferencesbetweenthem.However,thisiscontradictedbyanewly

discoveredspecimenofDipterus,thesmallestknown.Thisspecimenfallswithinthesizerange

ofthelargestP.gunnispecimens,andpossesseswell-developedtoothplates,afeaturelacking

inallspecimensofP.gunni.Juveniledipnoansofotherspeciesareknown,whichalsoshow

thatthetoothplatesdevelopinthesmallestobservableindividuals.TheoccurrenceofP.gunni

intheSandwickfishbedinOrkneyisconfirmed,anditisconfirmedtoothatitdoesnotoccur

atBaligill,Sutherland.

IntroductionPalaeospondyluslocalities

ThefossilfishPalaeospondylusgunniTra