Microchiroptera: Hipposideridae) from the Australian Miocene
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Journal of Vertebrate Paleontology l8(2)::130 '139. June l99lt O 1998 by the Society of Vertebrate Paleontology XENORHINO.S, A NEW GENUS OF OLD WORLD LEAF-NOSED BATS (MICROCHIROPTERA: HIPPOSIDERIDAE) FROM THE AUSTRALIAN MIOCENE SUZANNE HAND School of Biological Scicnce. University of New South Wales, Sydney, New South Wales 2052, Australia ABSTRACT-A new genus and spcciesol'hipposidcrid is describcd fl-om thc Bitesantenn.rrvSitc. Riversleigh,north w,esternQueensland, Austr:rlia. Xenorhino.s hulli. gen. ct sp. nov.. diff'erstionr all othcr hipposideridsin. alrtlttg tlther 1'eatures.its broad rostrum and interorbital rcgion. exceptionallv short palate.constrictccl sphenoidll bridge. and pro- nOuncedrotation of thc rostrunr.lts precisc phylogeneticrclatronships remain obscurc. but it lippearslo hc part ot an early hipposidcridradiation that includesspecics ol' (-oelt4ts.Clocoti.s.'l-riuenttp.s, ltcl Rhitrortt'ttt'ri.r.attd that is u'iclely distributedthroughout the Old World tropics. Fror-nanalogy with liring hipposidcrids.Lhe peculiar rcstral and palatal n.rorphologyol'X. lrulli is probably correlatedwith ultrasounclproduction anclentission. ancl. lt-ss certainly. with size and structureol thc noseleirt. INTRODUCTION Museum, Brisbane. Stratigraphic nomenclature tor the River- sleigh region lbllows Archer et al. (1994). Acetic acid-processing of Tertiary freshwater limestones from the Riversleigh World Heritage property, Lawn Hill Na- SYSTEMATIC PALEONTOLOGY tional Park, northwestern Queensland, Australia, has produced a number of new late Oligocene of early Pliocene microchirop- Suborder MlcnocHrtt<.rp'nr.RADobson. 1875 teran species(Archer et al., 1994). These bats include hippos- Superfamily RHr^-or.opsotoEnBell, 1836 (Weber, 1928) iderids, megadermatids,molossids, vespertilionids, and embal- Family HtppostoentorEMiller, 1907 lonurids (Sig6 et al., 1982; Hand. 1985, 1990. 1995, 1996. XtNonutt'os,gen. nov. 1997a,b, in press).Hipposiderids are by far the most abundant and diverse chiropteran group represented. Type and Only Species-Xenorhinos hulli, gen. et sp. nov. Living hipposiderids.commonly known as Old World leaf- (Figs. l-2). nosed bats, are mostly cave-dwelling. They are referred to 65 Age and Distribution-Early Miocene of northern Austra- extant species(Koopman, 1994);the most speciosegenus, 11zp- lia. po.sideros, contains 53 species, with eight other genera (Rfti- Diagnosis-The genus diagnosis is the same as that fbr the nonycteri.s, Coelops, Paracoelops, Triaenops, Cloeotis, An' type speciesuntil additional spccics are known. thops, Asellia, and Aselliscas) containing one to two species Etymology-The namc ref'ers t. the strange and unique each. The family has an Old World tropical to subtropical mod- stmcture of the rostrum and palate. ern distribution, and apparently similar fossil distribution. Ter- tiary hipposiderids are known fiom rnainly karstic sediments, XtxonutNosHAI-1-1. sD. nov. with the oldest representatives being fiom the middle Eocene Figures 1 2 of Europe, early Oligocene of Arabia. late Oligocene of Aus- Holotype-QM F229 18, skull with left C I. P4-M3 and right tralia, early Miocene of Africa, and Pleistoceneof Asia. Riv- P4-M3. ersleigh's fossil hipposiderids are ref-erable to the genera and Paratypes-QM F22919, right dentary with ml-m3; subgenera Rhinonyt'teris, Riversleigha, Hipposideros, and Bra' QM F2Z92O. left maxillary fragment with Cl-M3; F22921. chipposidero.r(Sig6 et al., l9t12: Hand, 1997a,b). QM right maxillary fiagment with Cl-M3; F22922, left den- The new hipposiderid described here is represented by many QM tary with cl, p4-m3; QM F22923. left dentary with cl-m-l: hundredsof well-preserved skulls, dozens of which have been QM F22924. skull with left and right periotics in situ. prepared.It is so lar known only fiom BitesantennarySite, a Diagnosis-Differing tiom all other hipposiderids in its to be of early Miocene age (Archer et al., deposit interpreted broad rostrum and interorbital region, exceptionally short pal- Riversleigh 1994).This site was the first of the many depositsat ate. constricted sphenoidal bridge, and pronounced rostral ro- (Hand to be interpreted as represcnting an ancient cave-fill et tation. al., 1989). It contains at least eight other hipposiderid species, Locality, Stratigraphic Position, and Age-The Bitesan- a megadermatid bat, many snails, and rarer marsupials,birds. tennary Site occurs on the northeasternedge of the D Site Pla- reptiles, and frogs. teau. in the Riversleigh World Heritage property, Lawn Hill The new species differs strikingly from all other hipposider- National Park. northwestern Queensland (Hand et al.. 1989; ids in, among other features, its broad rostrum and interorbital Archer et al.. 1994). The 150 square metre deposit is cut into region, its exceptionally shorl palate, pronounced rostral rota- an older, relatively non-fossilil'erouslimestone that may be con- tion, and narrow sphenoidal bridge that completely exposes the tiguous with lirnestonesunderlying or containing three adjacent optic foramen and sphenoidal {issure. Its many autapomorphies Oligo-Miocene fbssil deposits: VIP, Burnt Ofl'ering, and Ne- and probable phylogenetic relationships suppon its ref-erralto a ville's Garden sites.On the basis of stratigraphyand contained new genus. local faunas, the latter have been interpreted to be part of Riv- Skull terminology follows Hand (1993. and Fig. l); dental ersleigh'sSystem B depositsand. as such, early Miocene in age terminology follows Sigd et al. (1982). The prefix QM F ref'ers (Archer et al. 1994; Hand, 1997a, b). to specimensheld in the fossil collections ol- the Queensland Etymology-The species is named for Dr. Leslie S. Hall of 430 HAN D-MIOC ENE HI P P OS ID ERID 431 the University of Qucensland,Brisbane, in recognition of his (?lacrimal foramen; Pedersen (1995) has fbund that the lacrimal pioneering work on all aspects of Australian chiropteran biol- bone does not develop in at least some living hipposiderids).A ogy. smaller, circular foramen opens posteroventrally to this. Medi- Associated Fauna and Taphonomy-The Bitesantennary ally, at the most anteroventralpoint of the orbit, is the post- deposit contains thousandsof bat skulls, limb bones,and snails. palatal foramen. Almost all arc complete, suggesting fossilisation occurred at or Palate-The tooth rows are convergent anteriorly. The deep, very near the point of accumulation. The boundary or contact V- to U-shaped indentation that marks the junction of the palate between the fossiliferous fil| and remnants of the older, non- with the premaxillae extends posteriorly to the level of the mc- fbssiliferous cave wall has been identified at several points tacone of M1. The midline of the palate extends posteriorly around the perimeter of the deposit. For these reasons, the de- level with the posterior tace of M2, resulting in a strikingly posit is interpreted to be a cave-fill (Hand et al., 1989). The short palate, equal in length to 1-1.5 molar lengths. Two pos- many snails of the deposit and what seem to be extensive algal- terolateral indentations extend anteriorly to at least the level of like mats suggest that, for some period during its history, the the paracone of M3. Maximum width of the palate occurs at depositional area was open to light and under water. M3, and palatal foramina are well devcloped adjacent to the Xenorhinos halli is preserved in the deposit with at least cight paracone of M3. Paired, anteroposteriorly elongated foramina other hipposiderids (Hand, 199'7b) and a megadermatid. Less occur adjacent to the anterior face of Ml, close to the border well represented in the Bitesantennary deposit are frogs, Iizards, between the premaxillae and palate. a boid, a stort, a swift, peramelids, a dasyurid, and a bulun- Nasals-The inflated nasal cavities arc incomplctcly divided gamayine macropodid. by a median septum. The septum is fused with the anterior one- third of the dorsal palate, such that the left and right nasal DESCRIPTION passagesare incompletely separated. Further, there is little lat- eral development of the mesethmoid plates so that the choanae Xenorhinos halli is known from many well-preserved skulls or ventral respiratory passagesare not separated by bone from and dentaries. The description of the skull is based primarily the dorsal, olfactory chambers. Limitcd lateral development of on the holotype (QM F22918), but other refered specimens the plates occurs well posterior to the posterior limit of the hard (list available through the author and/or Museum) Queensland palate. These plates extend anteroventrally only fbr a short dis- provide additional matcrial. As in the skull of Brachipposidero,s tance (to a point that is still posterior to the level of the hard nooraleebu"^ (Hand, 1993) from Riversleigh, it has not been palate), but extend dorsally to reach the roof of the nasal cavity possible to determine the precise limits of each bone of Xeno- and anterodorsally branch to almost fill the nasal cavity. In an- rhinos halli due to fusion of elements during development (a terior view, an ethmoidal lattice partially divides each nasal cornmon feature of microchiropteran bats). However, as a guide cavity into an anterolateral rnaxillary chamber and a narrower for interpreting the approximate boundaries between bones, median passage.In this view, a large, paired hook-like swelling, severaljuvenile rhinolophoids were examined (i.e., specimens developed in the ethmoid lattice and protruding into the median of Hipposidero,s diadema, Rhinoktphus megaphyllus,