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: 232 MEMOIRS OFTHEQUEENSLAND MUSEUM POSSIBLE AFFINITIES BETWEEN VARANUS ESTES, R., DE QUEIROZ, K. & GAUTHIER, J. 1988. GIGANTEUSANDMEGALANIAPRISCA,Memoirsofthe Phylogenetic relationships within Squamata. Pp. 119- Queensland Museum 39(2):232. 1996:- Molnar (1990) 281 In Estes, R. & Pregill, G. K. (eds). 'Phylogenetic describedtwo frontals, and aparietal, ofagiant Pleistocene relationshipsofthelizardfamilies'.(StanfordUniver- varanidatKingCreek,eastern DarlingDowns.Thematerial sityPress: Stanford). wasassignedtoMegalaniaprisca,theonly varanidofcom- MOLNAR, R.E. 1990. New cranial elements of a giant parable size. This identification is probably correct since varanidfromQueensland. MemoirsoftheQueensland undoubtedremainsofMegalaniaoccurinthesamedeposits. Museum29:437-444. Molnar(1990) noted that the frontals and parietal ofthe PIANKA,E.R. 1995. Evolutionofbodysize: varanidlizards KingCreekvaranidexhibitedmany unusual features, which asamodelsystem. AmericanNaturalist 146: 398-414. couldnotbefoundinanyvaranidskullsexamined,andwere PREGILL,G.,GAUTHER,J.&GREENE, H.W. 1986.The thus presumably derived within varanids. Among these fea- evolutionofhelodermatidsquamates,withdescription turesweretheprominentsagittalcrestalongthemediansuture ofanewtaxonandanoverviewofVaranoidea.Trans- betweenthefrontals,andtheparalleltransverseridgesextend- actionsoftheSanDiegoSocietyofNaturalHistory21 ing at right angles to this crest. Both these features are also 167-202. found in Varanusgiganteus(Fig. 1) and are absent in other RIEPPEL,O. 1980.Thephylogenyofanguinomorphlizards. speciesofVaranus(Molnar, 1990)andinthenearestoutgroup Denkschrifte Schweizerbartsche Naturf. Gesellshaft taxa, Latuhanotttsand Heloderma(Rieppel, 1980; Pregill et 94: 1-86. al., 1986; Estes et al., 1988). They are thus derived within M.S.Y. Lee, SchoolofBiologicalSciences, UniversityofSyd- V«ra/?M^suggestingaffinitiesbetweentheKingCreekvaranid ney,NSW2006,Australia; 10December1995. andV.giganteus.Molnar(1990)notedthat,intheKingCreek varanid as in V. giganteus (Fig.l), the sagittal crest and parallel transverse ridges were confined to the frontals, and didnotextendontotheparietals.Thisphylogeny isbasedon veryincompletematerialandonlytwocharacters. Megalaniaprisca, Varanusgiganteus, V. salvadoriand V. komodoensisarethe4largestknown varanids(Pianka, 1995). DespitethelattertwonotbeingAustraliannatives,all4belong to a discrete radiation of Australian monitors, the 'gouldii speciesgroup' (Baverstocketal.,1993). If Megalaniaprisca has affinities with V. giganteus and thus belongs within the gouldiispeciesgroupMegalaniawillhavetobesynonymised with Varanus. Relationships within thegouldii species group arenotyetwellestablished(Baverstocketal. 1993).:thereisa distinctpossibilitythat,whenrelationshipswithinthisradiation are resolved, V. giganteus, V. salvadori, V, komodoensis, and Megalaniapriscawillformaclade.Ifso,thiswouldmeanthat the four largest varanid species represent a single discrete radiationofgiantpredatory lizards. IthanktheAustralianResearchCouncilforfunding,Jenny ClackandRaySymondsforloanofthefiguredspecimen,and MalcomRickettsforphotography. LiteratureCited BAVERSTOCK, P.R., KING, D., KING, M., BIRRELL,J. &KRIEG,M. 1993.Theevolutionofthespeciesofthe Varanidae: Microcomplement fixation analysis of serum albumins. Australian Journal of Zoology 41: 621-638. A B FIG. I.SkullofVaranusgiganteus(UniversityMuseumofZoology,CambridgeR9586)in(A)dorsal,and(B)rightlaterodorsal view,showingthesagittalcrestanddermal sculptureonthefrontalsbetweentheorbits. Scalebar=3cm.