FIRSTTERTIARY MOLOSSID (MICROCHIROPTERA: MOLOSSIDAE) FROMAUSTRALIA: ITS PHYLOGENETICAND BIOGEOGRAPHICIMPLICATIONS SuzeNNs J. Halrp Hand, S'J. 19903 3l: First Tertiary Molossid (Microchiroptera : Molossidae) from Australia: its Phylogeneticand BiogeographicImplications . Mem. ed Mus.2E(l):175-192. Brisbane.ISSN 0079-8835. Petramops creaseri n.gen., n.sp. is described from Middle Miocene freshwater limestones on Riversleigh Station in northwestern Queensland. One of 25 new bat speciesidentified among fossil remains recovered from the Riversleighdeposits, it is Australia's first Tertiary molossid. Its affinities appear to lie outsidethe modern Australian molossid radiation. It seemslikely that bats of the Petramops lineage were proficient long-distance fliers which colonized Australia before the Miocene. Subsequentor coincident colonizations of Australia by molossids would have involved speciesof Nyclinomus, Chaerephon and Mormopterus. A Chiroptera, Molossidae, Riversleigh, Miocene, Petramops creasei, biogeography. Suzanne J. Hand, School of Biological Science, University of New South Woles, pO Box I, Kensington, NSW 2033; 14 December, 1988. Fossil material referableto a new genusanc In this study, dentalmorphology is usedin an speciesof molossidhas recentlybeen recovered attemptto interpretthe phylogeneticposition of the from Tertiary freshwaterlimestones on Riversleigh Riversleighfossil with respectto otherAustralian Station, northwesternQueensland (Fig. l). The and non-Australianmolossids. A biogeographic Riversleighfossil deposits cover an areaof at least hypothesisinvolving the new molossid is proposed. 40 sq. km and appearto comprisea sequenceof sedimentsranging in agefrom approximately25 to Specimensor castsexamined in this studyinclude 4 My ago (Archer et al., 19861'Archer et al., 1989). representativesoi all species of Australian From the remarkablymammal-rich Riversleigh molossidsand subgenericleveltaxa of living Tertiarydeposits, some 25 newspecies of fossilbats non-Australian species. Also examined were havebeen identified. These include Hipposideros specimens or casts of the fossil species: (Hydromops) (Brachipposideros)nooroleebas Sig€, Hand and Mormopterus helveticus,M. (H.) Archer (Sig€e/ a1..,1982), Macroderma godthelpi stehlini, Nyctinomus (Nyctinomus)engesseri (see below for discussionof the nameNyctinomus), Hand (Hand, 1985),M. sp.and a numberof other N. (N.) leptognathus and 'Meganycteris hipposiderids, megadermatids, rhinolophids, monslapidensrs'(Table 2). Fossil specimensnot emballonurids and vespertilionids, as yet examinedbut well-enoughdescribed or illustrated undescribed(Hand, 1987). in the literatureto be includedin this studywere The bat describedhere is Australia's first Cuvierimopsparisiensis (Legendre & Sig€, 1984) Tertiarymolossid, the first representative of bats and.Mormopterus (Neomops) (Legendre, outside the superfamilyRhinolophoidea faustoi to be 1984a,1985). Other fossil molossids, too poorly describedfrom the Riversleigh sediments.The representedto includeinthe phylogeneticanalysis, pancontinental family Molossidaeis otherwise arediscussed more briefly. representedin Australiaby five living specieswhose Repositoriesof specimensare indicated by taxonomyis currentlyconfused (e.g. Hill, l96l; prefixes as follows: AM, Australian Museum; Felten,1964; Allison, 1978, 1983; Freeman, l98l; SAM, SouthAustralian Museum; BMNH, British Honacki et ol., 1982;Legendre, 1984b; Mahoney Museum (Natural History); AMNH, American & Walton,1988). Museum of Natural History; QM, Queensland t76 MEMOIRS OF THE QUEENSLAND MUSEUM Frc. l. Map of Riversleigh area showing location of Gotham City Site (after a map prepared by K. Gri mes and modified by H. Godthelp and M. Archer). Museum; CG, Museum National d'Histoire Ervvor-ocv Naturelle, Paris; SG, Museum d'Histoire The generic name is from the Greek petra (rock) Naturelle, Basle; 1970 XVIII, Bayerische and mops (bats), and refers to the fossil nature of Staatssammlungftir Paldontologieund historische this new Australian molossid; the gender is Geologie,Mtinchen. masculine. Dentalterminology follows Legendre(1985) or is modified as in Fig. 2. Phylogeneticsystematic DIAGNOSIS in Wiley termsused in this paperare summarized This molossid genus differs from all others in the (198r). following combination of features:loss of I3; lower molar morphology nyctalodont (as defined by Menu & Sig€, 1971; see DEscrtpttoN below); Po SYSTEMATICS with rudimentary but distinct metaconid; M' with Order CHIROPTERA Blumenbach,1779 distinct and well developed paraloph and SuborderMICROCHIROPTERA Dobson, 1875 metaloph; Ml with tall conical hypocone isolated SuperfamilyVESPERTILIONOIDEA Gray, l82l from the protocone and postp.rotocrista by an Family MOLOSSIDAE Gill, 1872 obliquely oriented depression;M' only moderately reduced, such that the premetacristais longer than creaserin.gen, n.sP. Petramops the pre- and postparacristae; lower premolars oriented longitudinally (or only slightly obliquely) TvpESpnctes in the tooth row; lower molar trigonids with Petromopscreaseri sP. nov. marked anteroposterior compression; Mt with 178 MEMOIRS OF THE QUEENSLAND MUSEUM Frc.3. petramops geaserifromthe Gotham City Local Fauna,Riversleigh Station, northwestern Queensland. QMF 13080,holotype, left dentarycontaiping C r, Pr, M1, M2, Ml andalveoli for I t, Iz andPz. A, buccalview; B, oblique buccaiview; b, lingual view; D- D', stereopairsocclusal view; E, antero-occlusalview showingalveoli for Pz; F' anteriorview showing alveoli for It,z;G, obliqueJingualview. Scale indicates I mm. FIRST TERTIARY AUSTRALIAN MOLOSSID(MICROCHIROPTERA) 177 fostparac.rsla llesostYl€ \ DIAGNoSIS The speciesdiagnosis is the same as that for the genus heparacrist€ until additional speciesare known. hracom Meiacone TYPE LocAt-rry, AcE, Lrrnor_ocy AND TapnoNor,ry The type locality, Gotham City Site, l,4etacjngutum occurs within the Tertiary sequenceof limestone Prolotossa atopn sediments on Riversleigh Station, northwestern (Fig. l). It occurs hfa(oph 'Drclocfista Queensland in Ray's Amphitheatre at a level interpreted to be - *':":,,':":.'r' llet*onule stratigraphically above the Gag Site (Hand, 1985) nel and Ringtail Site but below Henk's Hollow Site (Flannery & Archer, 1987)and Jaw Junction Site J (Archer et al., 1989). "nt"r,oa On the basis of its mammal fauna (at least 24 speciesof marsupials and bats), the Gotham City deposit is interpreted to be of Middle Miocene age and to be younger than the Riversleigh anieror Dwornamor I and Upper Site Local Faunas and the South l{eta l'lelacfrstrd b!ccat Pre-enlocfrs I d Australian Ditjimanka and Kutjamarpu Local Paracon Faunas (Woodburne et al., 1985; Archer et al., Pafacfrstid 1989)but older than the Riversleigh Henk's Hollow Local Fauna. The detailed ftotocon 1d Hypocfrstid stratigraphy of the Riversleighsites and their relationships to those of Pos+enf crngulh South Australia are now under study. l-lypocon rd The sediment is fine-grained, argillaceous freshwater limestone. Taphonomically, the Gotham fossil material Bucaal crnq!l!m Lcnshd obLrqua is thought to representthe o remains of prey collected by the megadermatid, Macroderma sp. The remains are consistent in FIc. 2. Toothterminology for molossids:A, uppertooth; size and fragmentation prey and,B, lowertooth. (After Legendre,1983; fig. l). with remains recovered from roosts of the Australian megadermatid, Macroderma gigas, the latter's closest living relative. well-developedparaconid; C1 much taller than P+: dentary depth tapering posteriorly. DnscntprroN The dentary is represented by the holotype eMF Petramops creaserin.sp. 13080(Fig. 3). It decreasesmarkedly in depth from Figs 3-4 Cr to below the posterior root of M:. The large mental foramen occurs below the alveoli for Pz, the MarrntRr- ExalrrNlo steepsymphysis extending posteriorly to this same HoLorypE: QMF 13080, a left dentary point. The mandibular foramen is not preserved. containing Cr, P+, Mr, Mz, M: and alveoli for pz. Two small foramina occur immediately adjacent to PenArypns:pMF 13081,a right M', and eMF the symphysis midway between the alveolar border 13082.a left M'. and the base of the dentary. The larger dorsal foramen is closer to the symphysis than the smaller, Erynaolocy more ventral foramen. The posterior margin of the The speciesis named for Mr Phil Creaserof the ascendingramus inclines at an angle of about 300 National Estate and World Heritage Sectionof the to the horizontal. Department of the Arts, Sport, the Environment, The lower dental formula is Ir,z Ct Pz,+Mr,z,:. Tourism and Territories. His untiring efforts to The incisors are unknown. find support for the Riversleigh fossil bat research The Cr is surrounded by a basal cingulum on and his indispensablehelp in collecting fossil-rich which are developed minute swellings at the limestone on Riversleigh Station are gratefully anteroJingual high point and postero-buccal low acknowledged. point of the cingulum. Postero-lingually, a very 180 MEMOIRS OF THE QUEENSLAND MUSEUM large cingular cusp contributes to the formation of The Mr has two roots and six distinct cusps, the a pronounced posterior heel, making the lingual hypoconulid being a small cingular cusp. In height face of the tooth markedly longer than the buccal the protoconid exceeds the hypoconid, which face. This postero-lingual cusp is separatedfrom exceedsthe subequal paraconid, metaconid and the protoconid by a wide, shallow facet that passes entoconid. The trigonid is much narrower than the is transverselyacross the tooth. The lingual