PRlSClLEO ROSKEUY AE SP. NOV. (THYLACOLEONillAE, MARSUPIALIA) FROM THE OLIGOCENE-MIOCENE OF RIVERSLEIGH, NORTHWESTERN QUEENSLAND

ANNA GILLESPIE

Gillespie, A., 19970630. Priscileo roskellyae sp. nov. (Thylacoleonidae, Marsupialia) from the 0ligocene-Miocene of Riversleigh, northwestern Queensland Memoirs of the Queens- land Museum 41(2): 321-327. Brisbane. ISSN 0079-8835.

Upper dentition of the marsupial lion Priscileo roskellyae sp. nov. from the Upper Site Local Fauna of Riversleigh provides the first detailed infonnation about upper dentition of the genus. The upper adult dental fonnula is 11-3. C I, PI-3, M 1-4. This species is smaller than P. pitikantensis and is the most plesiomorphic thylacoleonid. Relative to Wakaleo, P3 is less bowed and molars are square and have a metaconule at their posterior margin. OThylacoleonidae. Wakaleoninae, Priscileo. Riversleigh. Oligocene. Miocene.

Anna Gillespie, School of Biological Science, University of New South Wales, New South Wales 2052, Australia; received 15 February 1997.

The marsupial lion genus Priscileo Rauscher, outline, with a posterolingual metaconule; ante- 1987 contains only P. pitikantensis Rauscher, rior root of the zygomatic arch projecting an- 1987, from the late Oligocene Ngapakaldi Local terolaterally dorsal to M2-3. Fauna, S. Aust which is known only from a max- illary fragment, a few teeth, and a number of post Priscileo roskellyae sp. nov. cranial elements. Additional Priscileo material (Figs 1-3) has been recovered from the Oligocene-Miocene of Riversleigh, northwestern Queensland. This MATERIAL. Holotype QMF23453, a skull with left material includes a near complete skull from the and right P3, Ml-2, alveoli for left and right 12-3, CI, Upper Site Local Fauna representing Priscileo Pl-2, M3-4, and partial alveoli for the left and right II roskellyae sp. nov. from early Miocene Upper Site, Godthelp Hill, Dental terminology for molars and the last pre- Riversleigh. molar follows Luckett (1993) who has shown that ETYMOLOGY. For the former Australian Minister of a molariform dP3 (MI of Archer, 1978) in mar- Arts, Sport, the Environment, Tourism and Territories, supials is replaced by P3. Accordingly, the re- the Hon. Ros Kelly, who provided significant support maining molars represent MI-4. However, for the Riversleigh Project. homology of the other premolars follows Flower ( 1867). Material is housed in the Commonwealth DIAGNOSIS (by comparison with the type and Palaeontological Collection, Bureau of Mineral only other species). Smaller; P3 approximately Resources, Canberra (CPC), Northern Territory 2/3 as long; metaconule on MI and M2; alveolus Museum (NTM), Queensland Museum (QMF), of PI closer to the P2 alveolus than to the canine South Australian Museum (SAMP), Museum of alveolus; lingual root on MI smaller, not intrud- Palaeontology, University of California, Berke- ing as far medially into the palate. ley (UCMPB). DESCRIPTION. Upper dentition. Formula 11-3, SYSTEMATICS CI, PI-3, MI-4. Alveoli for II large and incom- plete. Alveolus for 12 smallest of incisor alveoli. Superorder MARSUPIALIA IIliger, 1811 Alveolus for C 1 ovoid, larger than alveolus for Order DIPROTODONTIA Owen, 1866 13, smaller than that for I I. Canine alveolus closer Family THYLACOLEONIDAE Gill, 1872 to 13 alveolus than to PI alveolus. Two small alveoli for two single-rooted premolars between Priscileo Rauscher, 1987 thecanineandP3.CI and PI alveoli separated by

TYPE SPECIES. Priscileo pitikantensis Rauscher, an approximately 3 mm. P2 alveolus close behind 1987. that for PI, abutting the anterior base of P3.

DIAGNOSIS. Small; P3 length usually less than P3. As in Wakaleo but 25-66% smaller. Posterior 12mm; MI and M2 relatively square in basal portion only slightly broader than the anterior 322 MEMOIRS OF THE QUEENSLAND MUSEUM

FIG. I. Priscileo roske//yae sp. nov., holotype, QMF23453, partial skull, from Upper Site, Godthelp Hill, Riversleigh. Ventral view stereopair, showing upper dentition. portion (unlike Wakaleo where the posterior is curving slightly anteriorly as it ascends and much broader). Longitudinal blade slightly in- merges with the base of the crown. Many T. wardly-curved in contrast to the distinctive in- carnif ex and T. crassidentatus also with lingual wardly-curved blade of most Wakaleo. blade in contrast to W. alcootaensis and W. Relatively uniform width with gently curved lon- vanderleueri in which it is absent. Posterior to the gitudinal blade giving P3 rectangular shape.Lon- lingual blade the lingual flank of P3 formiing a gitudinal blade running between 2 major cusps. sharp depression extending from the base to the In buccal view, the shearing blade of P3 w- crown. Lingual flank following the curve of the shaped,the longitudinal blade forming the rise in posterior root, curving convexly to the posterior the middle, and the anterior and posterior blades border. Buccal blade of the anterior cusp ascend- ascending from the major cusps at each end. The ing in a slight posterior direction, merging with anterior cusp is slightly higher than the posterior the crown midway up the tooth. Short buccal (as in W. alcootaensis). In,W. vanderleueri the blade also ascending from the posterior cusp, cusps are approximately equal in height. Three merging with the crown midway up the tooth, not vertical blades, one anterior, one lingual, and one as prominent as the anterior buccal blade. Similar buccal, ascending from the anterior cusp to the anterior and posterior buccal blades in Wakaleo. base of the crown. Anterior blade curving lin- Posterior blade running posterolaterally from the gually as it ascends,bending slightly posteriorly posterior cusp to the posterior margin of the tooth, before merging with the base of the crown. Lin- an extension of the longitudinal blade, contiguous gual curvature of blade producing a small vertical with the preparacrista of MI, in P3 of Wakaleo lip towards the base of the blade. Similar lip in but absent in Thylacoleo. Short oblique blade at some Riversleigh Wakaleo. Posterior to this blade termination of posterior blade at the posterior lingual face of the crown curving concavely margin of P3, ascending anterolaterally on the forming an anterolingual basin. Lingual blade buccal flank, merging midway with the base of PRJSCJLEO ROSKELLYAE SP. NOV. FROM RIVERSLEIGH 323

TABLE I. Dimensions of upper cheek teeth of species trigon basin. W. vanderleueri and Riversleigh of Priscileo and Wakaleo. Data from Clemens & Wakaleo with much straighter and longer blade Plane (1974), Archer& Rich (1982), Rauscher(1987) ascending lingually from the paracone. Pre- and Murray & Megirian ( 1990). Measurements for P. protocrista arising from the anterior edge of the pitikantensis (except P3) were taken from from a caste of UCMP88448. a=alveolus measurement. trigon basin medial to the paraconule, running posteromedially to the protocone. From the pro- tocone a postprotocrista running posteriorly to a metaconule. Postmetaconulecrista curving posterolaterally from the metaconule, ascending to merge with the posterior margin of the postmetacrista. Short crescent-shaped ridge as- cending lingual face of metacone, terminating midway between metacone and metaconule. MI of W. vanderleueri and Riversleigh Wakaleo with similar ridge. Blades joining the 4 major cusps forming margins of a deep, square trigon basin. Within the basin, fine enamel crenulations radiate outwards. Similar crenulated trigon basins occur in Wakaleo and T. crassidentatus. Buccal flank ofMI, especially anteriorly, swollen resulting in a broad base for the stylar shelf. A stylar basin running from the posterobuccal face of the paracone to the posterobuccal margin of the the crown, lacking in Thylacoleo and W. al- metacone, becoming shallower posteriorly. Lat- eral wall of the basin lined with small vertical cootaensis. W. vanderleueri with a small blade in a similar position, differing by commencing a ridges. short distance before the end of the posterior M2. M2 smaller than MI, lacking the distinctive blade, more vertically oriented. On the buccal broad stylar shelf and basin. Paracone highest flank of P3, a broad valley running between the cusp, more lateral than in MI. Short, semicircular anterior and posterior buccal blades, much preparacrista running anteromedially from the broader, in Wakaleo. paracone. Small ridge buttressing lingual base of the paracone. Medial to this ridge a preprotocrista Molars. Left and right MI and M2 relatively arising, running posteromedially to the pro- unworn. Alveoli for M3 and M4 indicating 3 tocone. Protocone prominent, more anteriorly roots for each; 2 equal anterior roots, with slightly placed than in MI. Protocone lingually bulbous larger posterior one. In Wakaleo vanderleueri as in P. pitikantensis and Wakaleo. A narrow anterior roots of M3 larger. Molar gradient steep, anterior shelf running from the base of the pre- similar to P. pitikantensis and Wakaleo. MI and paracrista to the protocone. Postprotocrista run- M2 square, unlike the triangular molars in ning posterobuccally to a gently-rounded, Wakaleo. Molar morphology similar to Wakaleo. posterior metaconule, producing squaring of the MI wider anteriorly than posteriorly. Paracone lingual outline. No metaconule on M2 of P. highest cusp. Small blade ascending anteriorly pitikantensis but could be lost by damage to rear from the paracone to the anterior edge, joining portion of the tooth. Short postmetaconulecrista stylar cusp B, contiguous with brade ascending running posterolaterally, merging with the poste- from the posterior cusp ofP3. Postparacrista run- rior margin of the tooth. Metacone rounded and ning- posteriorly, meeting the ascending pre- more posteriorly situated than in M I, with lingual metacrista, forming a notch midway along the blade running medially, connecting with a small straight centrocrista. Metacone well-developed. blade running laterally from the metaconule, Postmetacrista ascending posteriorly from the forming anterior border of a small, oval, basin at metacone to the posterior margin ofMI. Buttress- the posterior. Postparacrista running ing the steep lingual face of the paracone a short posterolaterally to the buccal margin of the stylar crescent-shaped preparaconulecrista straighten- shelf, converging with anterolaterally orientated ing medially, terminating at a paraconule. Short premetacrista. Deep, square, trigon basin be- postparaconulecrista running posteriorly into the tween the major cusps with fine enamel crenula- 324 MEMOIRS OF THE QUEENSLAND MUSEUM

FIG. 2. Priscileo roskellyae sp. nov., holotype, QMF23453, measurements (mm) of left tooth row.p3 on left, Mi and M2. tions concentrated on the lateral and posterior crenulate, anteroposteriorly broad trigon basin. walls. Crenulated basins in M2 of P. pitikantensis Some of the new Riversleigh Wakaleo specimens and Wakaleo. On the buccal margin of M2 a have these features. Two Wakaleo specimens small, elongate, stylar basin parallel to the have an M4 (Table I ), and most have a relatively postparacrista, terminating midway between the broad crenulated basin on M2. All species of paracone and metacone. Similar basin in WakaleohaveaP3/M1 ratio of less than 1.70. The Riversleigh Wakaleo, difficult to discern in the value for P. roskellyae ( 1.41) falls midway within heavily worn M2 of W. vanderleueri. this range. Rauscher (1987) distinguished Priscileo from COMPARISON. P. roskellyae differs from all Wakaleo by the loss of PI or 2 and M4 in the speciesof Wakaleo in: being smaller; the P3 of P. latter. Although some new Riversleigh Wakaleo roskellyae is approximately 1/3 length of P3 of specimens have these teeth, the plesiomorphic W alcootaensis, 1/2 the length of P3 of W features of P. roskellyae exhibits (significantly vanderleueri, and 2/3 the length of P3s of smaller size, square molar shape,metaconule and Riversleigh Wakaleo; having a lingual crest as- relatively straight cutting blade on P3) require cend from the anterior cusp of P3; having the generic distinction. P. pitikantensis and P. shearing blade of P3 straighter; having the poste- roskellyae sharegeneric features of dental dimen- rior root of P3 only slightly enlarged; having the sions, shape of M2 and position of the anterior posterior half of P3 relatively square in basal base of the zygomatic arch. Specific distinction outline; having MI and M2 relatively square in of P. roskellyae is based on the size difference basal outline. P. roskellyae differs from Thy- between these two species,P.pitikantensis being lacoleo in: being smaller; P3 being approxi- 33% larger. mately 1/31ength ofP3 ofT. hilli and l/61ength ofP3 ofT. carnifex; having M3+4; having Ml+2 INTRAF AMILIAL RELATIONSHIPS relatively square in basal outline. Rauscher (1987) found no synapomorphies unit- DISCUSSION ing Priscileo and Wakaleo, or uniting Priscileo and Thylacoleo. Analysis of Priscileo and Thy- The diagnosis of Priscileo is amended to include lacoleo included comparison of postcrania1 ma- P. roskellyae. Rauscher ( 1987) distinguished terial and for a number of character-states, Priscileo from other thylacoleonids by M4, a Thylacoleo exhibited the plesiomorphic condi- P3/M 1 length ratio less than 1.70, and M2 with a tion while Priscileo was derived. Rauscher con- PRISClLEO ROSKELLYAE SP. NOV. FROM RIVERSLEIGH 325

prpac

me

I Smm

FIG: 3. Priscileo roskellyae sp. nov., holotype, QMF23453, left cheek dentition. Ib=longitudinal blade; ab=an- tenor blade; pb=posterior blade; ac=anterior cusp; pc=posterior cusp; abb=anterior buccal blade; linb=lingual blade; pbb=posterior buccal blade; alb=anterior lingual basin; pa=paracone; pacl=paraconule; prpac=pre- paracrista; popac=postparacrista; prpaclc=preparaconulecrista; popaclc=postparaconulecrista; pr=protocone; mcl=metaconule; pomclc=postmetaconulecrista; me=metacone; pomc=postmetacrista; prmc=premetacrista; stB=stylar cusp B; trb=trigone basin. cluded that Thylacoleo's primitive features were Thylacoleoninae which includes Thylacoleo and secondarily deri ved and not a retained possibly Priscileo. Wakaleonines were regarded plesiomorphic condition. Because Wakaleo and to differ from thylacoleonines in absence of PI Thylacoleo share the synapomorphy of loss of and formation of a tympanic wing composed of M4, Rauscher (1987) considered them to be sister alisphenoid and squamosal contributions. Fea- groups. Priscileo was regarded as the sister group lures distinguishing thylacoleonines from of a Wakaleonhylacoleo clade. wakaleonines include PI, squamosal contribu- Rauscher (1987) suggested that loss of the lion to the tympanic wing and frontal-squamosal metaconule could be a diagnostic feature for the contact on the lateral cranial wall. The new thy- Thylacoleonidae based on the tritubercular upper lacoleonid specimens from Riversleigh indicate molars of Wakaleo and Priscileo and the second- that, in terms of dental morphology, Priscileo arily quadritubercular MI of Thylacoleo. How- exhibits no features that prevent it from being ever, M 1 and M2 of P. roskellyae have a ancestral to Wakaleo and Thylacoleo. The dental metaconule and are basicalIy square in outline. features of Priscileo, including small P3 and The metaconule on these molars, especially on molar size, square (nearly bunodont) molar M2, is posteriorly positioned and its seeming shape, metaconule, and full premolar and molar absence from M2 of P. pitikantensis may be a complement are almost certainly plesiomorphic result of damage which is evident at the rear features within the family. margin of this tooth. Consequently, loss of the However, these same features clarify some metaconule can no longer be considered a syn- questions about relationships of the family with apomorphy for the family. the Order Diprotodontia. 11 was once commonly Murray et al. (1987) placed Wakaleo and Thy- believed that thylacoleonids evolved from a lacoleo in separate subfamilies: the Waka- phalangerid-like diprotodontian which had leoninae includes Wakaleo; and the quadritubercularuppermolarsincludingahyper- 326 MEMOIRS OF THE QUEENSLAND MUSEUM

trophied metaconule (Krefft, 1872; Broom, 1898; Beavis, Martin Dickson, Sue & Jim Lavarack and Bensley, 1903; Ride, 1964; Archer, 1976). Sue & Don Scott-Orr. Invaluable assistancein the Archer & Rich ( 1982) hypothesi sed that the field has come from numerous volunteers, staff tritubercular shapeof the molars of W. alcootaen- and postgraduate students of the University of sis were secondarily derived from an ancestral New South Wales. quadritubercular shape through suppression of the metaconule. It has been suggested that the LITERATURE CITED triangular molars of Wakaleo are plesiomorphic for the family (Murray et al., 1987). The primitive ARCHER, M. 1976. Phascolarctid origins and the po- dental features of P. roske//yae. especially the tential of the selenodont molar in the evolution of metaconule and square molar shape,provide sup- diprotodont marsupials. Memoirs of the Queens- land Museum 17: 367-371. port for Archer & Rich ( 1982). 1978. The nature of the molar-premolar boundary in Priscileo and Wakaleo have been collected marsupials and a reinterpretation of the homol- from Riversleigh's System B sites indicating ogy of marsupial cheekteeth. Memoirs of the overlapping of early Miocene thylacoleonid lin- Queensland Museum 18: 157-164. eages. Temporal overlapping of species of Thy- ARCHER. M. & DAWSON, L. 1982. Revision of lacoleo (T. crassidentatus and T. hi//i) also marsupial lions of the genus Thylacoleo Gervais occurred in the early Pliocene (Archer & Daw- (Thylacoleonidae: Marsupialia) and thy- son, 1982). In each case there was a distinct size lacoleonid evolution in the late Cainowic. pp. difference in the lineages involved. In termsofP3 477-494. In Archer, M. (ed.), Carnivorous marsu- length, System B specimens of Wakaleo are ap- pials. (Royal Zoological Society of New South proximately 1.5 times larger than P. roske//yae. Wales: Sydney). Similarly, P3 of T. crassidentatus is twice the ARCHER, M., HAND,J.H. &GODTHELP, H. 1991. length of that tooth in T. hi//i (Pledge, 1977). It is Riversleigh. (Reed Books: Sydney). 1994. Patterns in the history of Australia's mammals possible that size differences of this magnitude and inferences about palaeohabitats. Pp. 80-103. among sympatric thylacoleonids were an import- In Hill, R. (ed.), History of Australian vegetation. ant factor in reducing competition. Morphologi- (Cambridge University Press: Cambridge). cal studies of the limbs of P. pitikantensis suggest 1995. Tertiary environmental and biotic change in it was arboreal (Rauscher, 1987). Wakaleo, being Australia. Pp 77-90. In Vrba, E.S., Denton, G.H., larger and no doubt heavier, may have been more Partridge, T.C. & Burckle, L.H. (eds), Paleocli- terrestrial. Murray & Megirian ( 1990) also inti- mate and evolution, with emphasis on human mated a terrestrial existence for Wakaleo based origins. (Yale University Press: New Haven). on the wrist joint and heavily-wom dentition ARCHER, M. & RICH, T.H. 1982. Results of the Ray which they consider may indicate a scavenging E. Lernley Expeditions. Wakaleo alcootaensis n. sp. (Thylacoleonidae: Marsupialia), anew marsu- mode of life. pial lion from the Miocene of the Northern Terri- tory, with a consideration of the early radiation of ACKNOWLEDGEMENTS the family. Pp. 495-502. In Archer, M. (ed.), Car- nivorous marsupials. (Royal Zoological Society I thank Michael Archer and Henk Godthelp for of New South Wales: Sydney). constructive comments and Stephan Williams, BENSLEY, B.A. 1903. On the evolution of the Austra- Karen Black and Jenni Brammall for assistance lian Marsupialia; with remarks on relationships of with photography. Support for research at the marsupials in general. Transactions of the Riversleigh has come from the Australian Re- Linnaean Society of London (Zool.) Ser. 29: 83- search Grant Scheme; the National Estate Grants 217. Scheme (Queensland); the University of New BROOM, R. 1898. On the affinities and habits of Thy- South Wales; the Commonwealth Department of lacoleo .Proceedings of the Linnean Society of Environment, Sports, and Territories; the New South Wales 22: 57-74. CLEMENS, W.A. & PLANE, M. 1974. Mid-Tertiary Queensland National Parks and Wildlife Service; Thylacoleonidae (Marsupialia, Mammalia). Jour- the Commonwealth Heritage Unit; ICI Australia; nal of Paleontology 48: 652-60. the Australian Geographic Society; the Queens- R-OWER, W .H. 1867. On the development and suc- land Museum; the Australian Museum; the Royal cession of teeth in the Marsupialia. Philosophical Zoological Society ofNSW; the Linnean Society Transactions of the Royal Society of London 157: ofNSW; Century Zinc; Mount Isa Mines; Surrey 631-641. Beatty & Sons; the Riversleigh Society; and pri- GIlTLEMAN, J.L. 1989. Carnivore group living: vate supporters including Elaine Clark, Margaret comparative trends. pp. 183-207. In Gittleman, PRISClLEO ROSKEUYAE SPoNOVo FROM RIVERSLEIGH 327

j.L. (ed.), Carnivore behaviour, ecology and evo- MURRA Y, P. & MEGIRIAN, D. 1990. Further obser- lution. (Cornell University Press: Ithaca). vations on the morphology of Wakaleo GUGGISBERG, C.A. W. 1975. Wild cats of the world. vanderleueri (Marsupialia: Thylacoleonidae) (David & Charles: London). from the mid-Miocene Camfield Beds, Northern KREFFT, G. 1872. A Cuverian principle in palaeonto- Territory. The Beagle 7: 91-102. logy, tested by evidences of an extinct leonine PLEDGE, N. 1977. A new species of 77Iylacoleo marsupial (Thylacoleo carnifex) by Professor Owen etc. Reviewed by Krefft. Annals and Mag- (Marsupialia, Thylacoleonidae) with notes on the occurrence and the distribution of Thy- azine of Natural History 4: 169-182. lacoleonidae in South Australia. Records of the LUCKETr, W.P. 1993. An ontogenetic assessmentof South Australian Museum 17: 277-283. dental homologies in therian mammals. pp. 182- RAUSCHER, B. 1987. Priscileo pitikantensis, a new 204. In Szalay, F., Novacek, M.j. & McKenna, genus and species of thylacoleonid marsupial M.C. (eds), Mammalian phylogeny. Mesowic (Marsupialia: Thylacoleonidae ) from the Miocene differentiation, multituberculates, monotremes, Etadunna Formation, South Australia. Pp. 423- early therians, and marsupials. (Springer-Verlag: 432. In Archer, M. (ed.), Possums and opossums: New York). studies in evolution. (Surrey Beatty & Sons and MURRAY, P., WELLS, R. & PLANE, M. 1987. The the Royal Zoological Society of New South cranium of the Miocene thylacoleonid, Wakaleo Wales: Sydney). vanderleueri : click go the shears-a fresh bite at RIDE, W.D.L. 1964. A review of Australian fossil thylacoleonid systematics. Pp. 433-466. In marsupials. Journal and Proceedings of the Royal Archer, M. (ed.), Possumsand opossums: studies Society of Western Australia 47:97-131. in evolution. (Surrey Beatty & Sons and the Royal Zoological Society of New South Wales: Sydney).