New Oligo-Miocene Pseudocheirids (Marsupialia) of the Genus Paljara

New Oligo-Miocene pseudocheirids(Marsupialia) of the genusPaljara from Riversleigh, northwestern Queensland

MINABASSAROVA, MICHAELARCHER & SUZANNE J. HAND

BASSAROVA, M., ARCHER, M. & HAND, S.J., 2001:12:20. New 0ligo-Miocene pseudocheirids (Marsupia1ia) of the genus Pa/jara from Rivers1eigh, northwestern Queens1and. Memoirs of the Association of Australasian Palaeontologists 25,61-75. ISSN 0810-8889

Two new species of the pseudocheirid genus Paljara Woodburne, Tedford & Archer, 1987 are described from Oligo-Miocene deposits of the Riversleigh World Heritage Property, northwestern " .'",..'"= Queensland, One of these, Paljara maxbourkei, is represented by an isolated Mi, The other new species, P. nancyhawardae, is represented by fifteen specimens and is distinguished from P. !(""-~ tirarensae, the type species, by the presence of an entostylid ridge on M2 and a cristid obliqua ! "'--~~ that ends before reaching the metaconid of M" P. maxbourkei is distinguished from both P. . -- ~ I~ " ;;.., . tirarensae and P. nancyhawardae by its distinctly larger size, the presence of a bladed posterior shelf and a prominent stylid (which may be equivalent to the protostylid) on the anterobuccal cingulum. A single Riversleigh specimen, QMF 40083 from Wayne's Wok Site (System B), has been referred to Paljara tirarensae on the basis of size and morphology. The latter significantly extends the geographical range for P. tirarensae, which was previously only known from the early Miocene Leaf Locality (Kutjamarpu Local Fauna) of the Tirari Desert, South Australia.

M. Bassarova, M. Archer* and S. J. Hand, School of Biological Science, University of New South Wales, New South Wales, 2052; * also Australian Museum, 6-8 College St, Sydney, New South Wales, 2000. Received 25 October 2000

Keywords:ringtail posswn,pseudocheirid, fossil, Paljara, Oligo-Miocene,Riversleigh

EXTANT pseudocheirids are referred to six studies (Archer et al. 1989, 1995, 1997b; Martin genera: Pseudochirops, Petropseudes, Hemibel- 1998; Woodburne et al. 1985), to have been ideus, Petauroides, Pseudocheirus and Pseudo- rainforest and/or wet sclerophyll forest cheirulus. All six are representedin Australia and environments. Pseudochirops and Pseudochirulus are also Species of eight pseudocheirid genera have found in New Guinea. In New Guinea, ringtail been described from the Australian Tertiary (Table possums inhabit montane rainforests (Flannery 1). Four of these, Pildra, Marlu, Pseudokoala 1994). In Australia, the majority of speciesinhabit and Paljara, are known only from extinct species. the tropical rainforests of Queensland. The only Speciesof Pildra and Marlu have been recovered members of the family not restricted to rainforest from late Oligocene to early Miocene deposits in environments are: the Australian Rock Ringtail the Tilari Desert, South Australia (Woodburne et (Petropseudes dahli), which inhabits open al. 1987,Pledge 1987).Marlu also occurs in Oligo- woodlands; the Greater Glider (Petauroides Miocene deposits of the Riversleigh World volans), which inhabits wet sclerophyll forests; Heritage Property, northwestern Queensland. and the Common Ringtail (Pseudocheirus Species of Pseudokoala are known only from peregrinus), which inhabits a range of drier forests, Pliocene deposits of South Australia and Victoria woodlands and heaths (Flannery 1994). and Pleistocene deposits ofVictoria (Tumbull & The wet forests of northeastern Queensland Lundelius 1970; Tumbull et al. 1987; Pledge 1992; appear to be remnants of the environment that Archer et al. 1997a). characterised much of central, northern and Prior to the discovery of Paljara material from easternAustralia until about 15 -10 million years Riversleigh fossil deposits, the genus was ago (Archer 1992;Archer et al. 1989,1995, 1997b; represented by a single species, Paljara Woodbume et al. 1985). All ringtails known from tirarensae Woodburne, Tedford & Archer, 1987, Oligo-Miocene deposits of South Australia and from the early Miocene Leaf Locality (Kutjamarpu northwestern Queensland inhabited what are Local Fauna)of Lake Ngapakaldi, South Australia. interpreted, on the basis of faunal and floral Woodburne et al. ( 1987) consider P. tirarensae to 62 AAP Memoir 25 (200 1)

Mya I lime period Queensland South Australia " Victoria I Northern Territory

2 I Pleistocene PseudochelfUSPseudoko~/a, I .,~

Petauroides, ; i '."\1~, 4.5 Pliocene Petropseudes t;:::::;: Pseudokoa/a

8 Late Miocere Pseudochirops 16.3-10.41 Middle Miocere Marlu. Pa/jars

23 3-16 3 E rt M' Pi/dra, Marlu. Pa/jars, Pi/drs. Marlu, ..ay locere P .. seudochlrops Pa/Jars 26-24 Late Oligocere -Marlu. Pa/jars Pi/drs, Marlu Table1. Occurrenceof pseudocheiridgenera in AustralianTertiary fossil deposits.Where precise ages are not known , intervalsare indicated. be the most plesiomorphic of ringtail possums are available from the authors. becauseit retains the greatestnumber of primitive Drawings were made with a camera lucida dental characters. Riversleigh deposits have now attachment to a Wild M5A stereomicroscope. produced specimensreferable to P. tirarensae and Scanning electron micrographs (SEMs) of two new species of Paljara. The new taxa are specimens were taken with a Jeol 840 scanning described here and inferences are drawn about electron microscope at the Electron Microscope the palaeoecology of species of Paljara. Unit of the University of New South Wales. Riversleigh specimens referable to Paljara MATERIAI.SAND MEmODS were found to vary in tooth morphology. To gauge Dental tenninology follows Luckett (1993) for whether or not these features represent species- molar, and Flower ( 1868) for premolar homology level distinctions, an examination of morphological (Fig. lA). Cusp nomenclature (Fig. IB) follows variation in the teeth of extant pseudocheirid Archer (1984). Higher level systematic species was carried out. Thirty-six specimens of nomenclature follows Aplin & Archer (1987). Pseudocheirusperegrinus , the Common Ringtail, Riversleigh 'System' nomenclature is based on and 17 specimens of Pseudochirops archeri, the Archer et al.(1989, 1995,1997b)and Creaser (1997). Green Ringtail, held in the collections of the Material described is in the fossil collections Australian Museum in Sydney were examined.The of the Queensland Museum, Brisbane (prefix modem species were used to provide a guide to QMF). Other specimensused in the study are from the extent of intraspecific variation in the South Australian Museum, Adelaide (prefix pseudocheirids. Pseudocheirus peregrinus was SAM P) and the University ofCalifornia, Berkeley expected to exhibit high levels of intraspecific (prefix UCMP). variation because of its wide geographic Measurements were made to the nearest 0.01 distribution and varied habitat (Flannery 1994). mm using a Wild MMS235 Digital Length- The localities of the P.peregrinus specimensused Measuring Set attached to a Wild M5A are given in Appendix 2. Pseudochirops archeri stereomicroscope. Length (L) was measured as was chosen to represent a possibly less variable the maximum length along the anteroposterioraxis speciesdue to its relatively small distribution and of the tooth. Anterior width (AW) of lower specific habitat requirements (Flannery 1994). premolars was measuredas the maximum width of the tooth at the point where the main cuspid SYSTEMAllCPALAEONTOLOGY occurs. All p Js of pseudocheirids become wider posteriorly, so the posterior width (PW) of SuperorderMARSUPIALIA Illiger, 1811 premolars was measuredas the maximum width of Order DIPROTODONTIA Owen, 1866 the tooth. TheAW of lower molars was measured SuborderPHALANGERIDAAplin &Archer, 1987 as the maximum width of the trigonid, Family PSEUDOCHEIRIDAE Winge, 1893 perpendicular to the anteroposterior axis. The PW of molars was measuredas the maximum width of Paljara Woodburne, Tedford &Archer, 1987 the talonid, perpendicular to the anteroposterior axis. Measurements of fossil specimensare given Type species. Pa/jara tirarensae Woodburne, in Appendix 1; measurements of Pseudocheirus Tedford&Archer,1987 peregrinus and Pseudochirops archeri specimens AAPMemoir25 (2001) 63

Imm

Fig. 1. A, PSeUdocheirusperegrinus dentary in buccal view illustrating dentary and tooth nomenclature used. B, Paljara nancyhawardae n. sp. (QMF 40084), occlusal view ofright MI and M2, illustrating cusp nomenclature. Abbreviations: abc, anterobuccal cingulum; alc, anterolingual cingulum; c. 0., cristid obliqua; end, entoconid; ensd, entostylid; ensdr, entostylid ridge; hyd, hypoconid; hyld, hypoconulid; med, metaconid; mesd, metastylid; pacd, paracristid; pad, paraconid; pcd, protocristid; poecd, postentocristid; pohcd, posthypocristid; pomcd, postmetacristid; popcd, postprotocristid; prd, protoconid; prmcd, premetacristid; prpcd, preprotocristid. Paljara maxbourkei sp. nov. (Fig. 2) World Heritage Property, northwestern Queensland. Holotype. QMF 36287, the only specimen, a right M,. Age. System B deposits; early Miocene (Archer etal. 1995, 1997b; Creaser 1997) Type locality. Camel Sputum Site, Riversleigh 64 AAPMemoir25 (2001)

Fig. 3. Paljara nancyhawardaen. sp.,holotype (QMF Fig. 2. Paljara maxbourkei n. sp., holotype (QMF 40084),right MI-2.A, SEMphoto of occlusalview; B, 36287), right MI. A, obliquely occlusal view; B, drawingofbuccal view. posterobuccalview. worn; the talonid basin has deep crenulations on Etymology. The species name honours one of the lingual side of the cristid obliqua; the cristid Australia's most significant and visionary obliqua is directed anterolingually towards the supportersof wildlife conservation and Australian metaconid, but due to damage of and around the palaeontology. metaconid, details of where it ends are not evident; the paraconid has two ridges forming an angle, Species diagnosis. Paljara maxbourkei is the the apex of which is directed anteriorly; the largest known species of Paljara, with MI being anterior buccal cingulum is not very pronounced approximately 20% larger than that of P. tirarensae and is restricted to the anterobuccal side of the and, on average, approximately 30% larger than trigonid; the prominent stylid on the anterobuccal that of P. nancyhawardae (see Table 2). P. cingulum that extends posterobuccally to the end maxboukei also differs from the other two species of the trigonid, is interpreted to be a protostylid; in having a large shelf with a bladed edge on the the protostylid is located buccally to the posterior end of MI and a prominent stylid protocristid; the tip of the protoconid has been structure on the anterobuccal cingulum. chipped off; the metastylid, seen from occlusal view, is small and appears to be a continuation of Description. The species is known so far from a the postmetacristid; the metastylid is separated single right lower molar. There is damage to the from the entoconid by a deep crevice; the central lingual region of this tooth, obscuring entoconid is not strongly ridged anteriorly; the details of metaconid and protoconid relative preentocristid is steeply inclined; the hypoconulid heights and the lingual end of the cristid obliqua. appears, in lingual view, as a continuation of the The tooth is double-rooted, with the enamel- postentocristid; the entostylid ridge connects the covered crown protruding anteriorly over the hypoconulid to the entostylid; the entostylid apex anterior root. The entoconid, hypoconid, is posterolingual, in occlusal view, to the deepest hypoconulid and entostylid ridge are not very point in the talonid basin; the posthypocristid AAP Memoir 25 (200 1) 65 ends posterobuccally to the hypoconulid with a structure on the anterobuccal cingulum of MI, crevice between them; the basin-like posterior and in the absence of a posterior shelf on M,. shelf begins at the lingual end of the posthypocristid and continues to the Referred material. From Creaser's Ramparts Site posterobuccal edge of tooth, just prior to the (System A): QMF 24628, right Mi; from Camel anterior curve of the crown; at its buccal end, the Sputum Site (SystemB): QMF 40077, right dentary shelf has an edge that appears bladed and has a fragment with II, p 3 and MI-3 present and QMF raised point which appears cuspid-like. 30439, right dentary fragment with M2-4present; from Upper Site (System B): QMF 40075, right Remarks. P. maxbourkei appears to be the most dentary, missing posterior margin, with II, p 3and derived of the Paljara species, due to the MI-4 present; QMF 40076, left MI; QMF 40078, presenceofaprotostylid. Woodburne etal. (1987) right dentary fragment with II' p 3and MI-3present; interpret a small or absent protostylid (as seen in QMF 40079, left dentary fragment with Ii, p 3and P. tirarensae and P. nancyhawardae) to be the MI-4 present; QMF 40080, left Mi; QMF 40081, plesiomorphic condition in pseudocheirids. left dentary missing anterior and posterior Thegotic facets are obvious on the entostylid margins, with alveoli for -2 and with p 3 and MI-3 ridge, posthypocristid and the blade of the present;QMF 40082, left dentary missing posterior posterior shelf ofQMF 36287. Thegosis sharpens margin, with II, p 1-3and Mi present; and QMF blades, thereby providing more efficient cutting/ 36436, right dentary with Ii and MI-2; from Wayne's shearing edgeson teeth. The palaeophysiological Wok Site (System B): QMF 40074, left Mi; from implications of this may be that perhaps P. Gag Site (System C): QMF 40073, left MI; from maxbourkei, with the extra blade on the posterior KCB Site (System C): QMF 31513, left MI. shel.f of Mi, was able to process tougher leaves than either P. tirarensae or P. nancyhawardae. Description. The holotype, QMF 40084, is a right dentary fragment with MI and M2 present and Paljara nancyhawardae sp. nov. (Figs 3,4, SB) unworn. Other specimens referred to P. nancyhawardae (for example, QMF 40075, QMF Holotype. QMF 40084, right dental)' fragment with 40077,QMF 40078 and QMF 40079) preservemore fIrst and second molars (MI-J. of the dentary and have more teeth remaining, but the teeth are worn and do not show the Type locality. Camel Sputum Site, Riversleigh distinguishing features of P. nancyhawardae as World Heritage Property, northwestern well as QMF 40084 does. The following Queensland. descriptions of MI and M2 are based on QMF 40084 and description of the remaining dentition Age. System B deposits; early Miocene (Archer is based on other specimens as noted. etal. 1995, 1997b; Creaser 1997) I1 is a slender, elongate tooth, much like that of P. tirarensae. There is a blade on the top of the Etymology. The species name honours Nancy tooth, running along the buccal edge. This blade Catherine Haward, long-time supporter of the life is best seenin specimen QMF 40082. The blade is sciences, and founder of a similarly significant sharper and extends further posteriorly than in lineage of clever Australian possums. the P. tirarensae holotype (SAM P 19960). From occlusal view the tooth gradually curves lingually; Species diagnosis. Striking features there is a wear surface on the lingual side ofl1 ; the distinguishing specimens of P. nancyhawardae tooth ends anteriorly in a sharp point. and P. tirarensae include the presence/absence P 1and P2' only seen in QMF 40082, are small, of the M2 entostylid ridge and the connection of single-rooted teeth. They are rounded and smooth the MI cristid obliqua to the metaconid. The MI on top, button mushroom-shaped. cristid obliqua of Paljara nancyhawardae does P3' as seen in QMF 40081, is double-rooted not connect to the metaconid and an entostylid with one main conical cuspid located above the and entostylid ridge are present and well- anterior root; the posterior root is thicker and developed in M2. The majority of specimens longer than the anterior root; the cuspid is almost referred to P. nancyhawardae are smaller than as tall as the protoconid ofMI ; a ridge runs along specimens of P. tirarensae (Table 2; Fig. 5). P. the anteroposterior axis, through the cuspid; the nancyhawardae differs from P. maxbourkei in its ridge running posteriorly from the cuspid appears smaller size, in the absenceof a prominent cuspid 'pinched' upwards; the buccal side of the tooth is 66 AAP Memoir 25 (200 1)

Fig. 4. Paljara nancyhawardae n. sp., paratype (QMF 40075), right 11,p 3- M4.A, stereopair of occlusal view; B, buccal view; C, lingual view. AAPMemoir25 (2001 67

like structure that emerges from the postmetacristid; a deep crevice separatesthe entoconid and metasylid; the hypoconulid is on the posterolingual corner of the talonid and is separated from the postentocristid by a dip; the entostylid ridge emerges slightly anterobuccally to the hypoconulid and connects to a distinct entostylid; the entostylid is located posterolingually to the deepestpoint of the talonid basin; there are no crenulations in the talonid basin; the posthypocristid is a straight ridge, directed posterolingually from the hypoconid to the hypoconulid; the cristid obliqua is directed anterolingually from the hypoconid towards the metaconid, but end posterobuccally to the metaconid, with a shallow crevice between them; at its most anterolingual point the cristid obliqua forks off into two small ridges that descend into the crevice between the cristid obliqua and the metaconid. M2 is a double-rooted tooth; there is a thin but distinct anterobuccal cingulum extending from the anteriormost point of the trigonid to the base of the protoconid, on the buccal side; a stylid is present on the anterolingual corner of the trigonid; the metaconid, protoconid, entoconid and hypoconid are approximately the sameheight; the premetacristid and postmetacristid are sharp and form a ridge through the metaconid that runs AB posterolingually from the anteriormost point of Fig. 5. A, Paljara tirarensae, holotype (SAMP 19960) the trigonid to the metastylid; the base of the in occlusal view, with right MI-3; B, Paljara metaconid spreads buccally well into trigonid nancyhawardae n. sp., paratype (QMF 40097) in basin; the metastylid is very distinct and protrudes occlusal view, with right P3- M4. Note the differences lingually from the tooth; the entoconid and in siZe; in the cristid obliqua ofM1 ; and in the entostylid metastylid are separated by a deep crevice; the ridge of M2 between the specimens. entoconid is not strongly ridged anteriorly; the hypoconulid is smaller than in MI and positioned less lingually; the entostylid ridge runs from the well rounded at the bottom; the tooth becomes hypoconulid, around the buccal side of the base wider posteriorly; in lingual view, the of the entoconid, and appears to merge into the posteriormost part of p 3 appears bulbous; p 3 is lingual wall of the cristid obliqua, just anterior to short and narrow compared to the molars. the preentocristid; the posthypocristid is as in MI is a double-rooted tooth; there is a strong MI; the cristid obliqua runs anterolingually from anterobuccal cingulum that extends posteriorly the hypoconid then turns sharply buccally to meet to the end of the trigonid (the distinctiveness of the postprotocristid and form a continuous ridge. this cingulum varies between specimens, with M3 is a double-rooted tooth; talonid and QMF 40081 having a rounded edge and QMF trigonid basins are not crenulated and are more 40082 and QMF 40084 having a sharp edge); the shallow than in MI-2; in QMF 30439, a relatively protoconid is the highest cuspid on MI and has a unworn specimen, the metaconid and entoconid very strongly ridged protocristid; the paracristid are of similar height, but the entoconid is more runs anteriorly from the protoconid then turns pointed; M3 hypoconid is the same size as that of slightly lingually to meet the paraconid; the M2; hypoconid is blunter than entoconid in M3; paraconid is distinct; the premetacristid is sharp; an entostylid ridge is present but not well the metaconid is a distinct cuspid, almost as tall developedin ~ ofQMF 30439, QMF 40075, QMF as the entoconid; the metastylid is a tiny spike- 40077 and QMF 40079; the cristid obliqua and 68 AAP Memoir 25 (2001)

3.5

0 2.5

I ~ 'i:

f 1.5 . ~x 0 Pseudochelrus peregl'lnus x\\ xx .Pseudochlrops orchel'l

.Poljora llrarensoe

x PoljOI'O nancyhawordae

+ Poljora maxbourkel

0.5 1.5 2.5 3.5 4.5 5.5 MI L (mm)

Fig. 6. Bivariate plot ofM1length (L) againstMI width (W) in millimetres, for specimensof Pseudocheirus peregrinusand Pseudochirops archeri and specimensreferable to Paljara. postprotocristid meet in the middle of the tooth to Neither specimen has an entostylid ridge on M2. fonn a continuous ridge; a weak ridge branches It is not known whether or not other specimens offthecristidobliqua,atthepointwhereitmeets referred to P. tirarensae by Woodbume et al. the postprotocristid, and runs lingually along the (1987) possessan M2 entostylid ridge. However, trigonid/talonid boundary towards the metastylid; basedon the comparisons made here, P. tirarensae the metastylid is not tall but it protrudes out and P. nancyhawardae evidently differ in this lingually; a crevice separatesthe entoconid from feature, with the latter having an obvious the metastylid; there is no hypoconulid; small entostylid ridge in M2. anterobuccal and anterolingual shelves are The presence of an entostylid ridge is present. considered to be a plesiomorphic condition by M4 is a double rooted tooth similar to MJ, but Woodbume et al. ( 1987) and therefore P. with a relatively smaller talonid and shorter cristid nancyhawardae is arguably more plesiomorphic obliqua; the metastylid is not positioned as far than P. tirarensae. The occurrence of P. lingually as in MJ for QMF 30439; the entostylid nancyhawardae in the older (System A) Creaser's ridge and hypoconulid are absent; the Ramparts Site may reflect this morphocline. posthypocristid is distinctly thicker than in M1-J; the entoconid ofQMF 30439 is the tallest cuspid Paljara tirarensae Woodburne,Tedford&Archer, on M4; the hypoconid is similar in size to that of 1987(Fig. SA) the MJ. Holotype, SAM P 19960, left dentary fragment Remark.\'.Woodburne et al. (1987), in describing with MI-3 and alveolus for M4' The anterior portion P. tirarensae, comment that there is an entostylid of the specimen has broken off since its ridge on the M2 of this species. We examined the description by Woodburne et al, (1987), leaving M2 of the holotype of P. tirarensae (SAM P 19960) the II detached from the dentary, The ascending and ofUCMP 99592 (the only specimens ofM2 ramus and articular condyle are not preserved, available for examination in the current study). AAPMemoir25 (2001) 69

Pa!iara nancyhawardaa Paljara tiraransaa .0. nancyhawardaa & P. tiraransae Lower .meanl OR I SD cv ~ R SD cv n mean OR teeth n I meanl ~-;;:; ~ 611.3311.29-1.411°.05 3.3811 I 1.24I 1.24- 1.24 7 1.32 1.24-1.411 0.051 4.091 ~ 610.841°.68-0.951°.1112.191 11°.79 0.79- 0.79 7 0.83 ~0.89-1.2.68_0.9 ~ ~ /3 MW 611.111°.99-1.251°.0918.36111°.891 0.89 -0.89 7 1.08 ~ M/1 L -::j 2.181.37 2.011.25-1.68 -2.38 01215.311312.3612.25-2.4310.110.11 8.12 3 1.49 1.44-1.58 o.oa 4.03 17 2.21 2.01-2.4 , - 0.13! 01118121311.4911.44-1.5810.081 5.231171 1.39 1.25-1.6 ~ M/1 AW - M/1 PW ._, 1.42 1.34 -1.50 0.08 5.48 441 1.551.551 1.45-1.45-1.6510.0815.281181 1.65 0.08 5.28 18 1.45 ; 0.09 1.34-1.6~

M/2 L 8 2.25 2.15- 2.42 0.08 3.69 2 2.71 2.71 -2.71 0 0 10 2.34 2.15-2.711 0.21 7 1.481.32-1.820.098.43 1 1.85 1.85-1.85 8 1.49 1.32-1.6S

M/2 PW 8 1.44 1.34-1.530.08 5.23 2 1.88 1.87-1.690.01 0.83 10 1.48 1.34-1.6S

M/3 L 5 2.19 2.12- 2.25 0.05 2.19 2 2.58 2.54 -2.61 O.OS 1.9 7 2.3 2.12-2.61

M/3 AW 5 1.38 1.33 -1.41 0.03 2.39 2 1.67 1.63 -1.71 0.06 3.41 1.461 1.33-1.71 M/3 PW -+ 1.361.32-1.430.043.23 21.65 1.65-1.710.042.55 1.45 1.32-1.711 M/4 L 2.17 2.11-2.260.08 3.59 1 2.54 2.54-2.54 2.27 2.11-2. 3 , ' .1.56 1.56 -1.56 1.31 1.15-1.5 M/4 AW 3' 0.181 1.19 1.12-1. M/4 PW 3l 1~21 1.85 I 1 I 1.34 I 1.34 -1.34 0:11

All Pa1jarsspecimens

I Lower cv n mean OR SD CV teeth 7 1.32 1.24-1.41 0.05 3.79 7 0.83 0.6 10.84

7 0.8 0.19 Table 2. Measurements (in 11.081 181 2.28 I 2.01-2.91 , 0.211 9-:2"9I mm) and statistics for species 857 ..ofPaljara and for selected com- 119 8 1~ 1.25-1.661°.121 .I binations of specimens refer- 1.461 1.31-1.671°.111 7.53 I able to Paljara. Abbreviations: 10 2.36 10.17! n, number of specimens; OR,

8 1.48 8.11 I observed range; SD, standard

10 1.49 I deviation; cY, coefficient of I variation. CY and SD not given 2.33 I 2.11-2.7510.241 ~ where n < 2. 1.48 I 1.34-1.7110.161 """"7l 7 ~I 1.32-1.72 1-0:-171 2.01-2.54 I 0.21 9.051

.21-1.56 12:41 r-r--r ~ir0:-09 ~

Additional material. QMF 40083, a right dentary Table 2 summarises statistics calculated for with MI preserved. fossil material referable to Paljara. Coeffecients of variation (CYs) for dental measurements of Revised species distribution. Kutjamarpu Local extant species are presented in Table 3. CYs for Fauna, Leaf Locality, Lake Ngapakaldi, South Paljara nancyhawardae are close to those for Australia; Wayne's Wok Site (System B deposits, Pseudocheirus peregrinus suggesting that P. early Miocene ), Riversleigh World Heritage nancyhawardae is likely to be a single species, Property, northwestern Queensland. with variation in size not greatly exceeding that of P. peregrinus. Pseudochirops archeri has lower MORPHOLOGICAL VARIAnON CY s, as would be expected for a speciesconfined The morphological differences observed to a small areawith uniform habitat. There are few between specimens referable to Pa/jara are specimens of Paljara tirarensae, thus CY values features found not to vary within Pseudocheirus for this group may not be reliable. CYs for P. peregrinus and Pseudochirops archeri. These nancyhawardae and P. tirarensae combined differences are therefore interpreted to represent (Table 2) show that, generally, variation exceeds interspecific morphological variation. that observed in modem species, but that CY

~ 70 AAP Memoir 25 (2001 )

3.5

.. ..i-

2.5

I ~ i . .5 * x -'* 0 PseudocheirllS peregrinus

.Pseudochirops archeri

.Paljara tirarensae

x Paljara nancyhawardae

0.5 1.5 2.5 3.5 4.5 5.5 M2L(mm)

Fig. 7. Bivariate plot of~ length (L) againstM2 width (W) in millirnetres, for specimensof Pseudocheirus peregrinusand Pseudochirops archeri and specimensreferable to Paljara. values do not tend to be much higher than 10. element of fossil mammals and is therefore the There does not appear to be much evidence to basis for most species distinctions (Gingerich separateP. nancyhawardae and P. tirarensae on 1974). Metric analyses and assessment of the grounds of size alone. The CY s for the mixed morphological differences in the dentition of fossil sample of Paljara specimens (including all mammals are two methods used to distinguish available specimens referable to Paljara) do not species. Obvious morphological differences are greatly exceed CY values for Pseudocheirus sufficient to separatetwo speciesbut very closely peregrinus. This suggeststhat species of Paljara related species may be indistinguishable on form cannot be distinguished only on the basis of size. alone. In such cases,differences in size offer the Bivariate plots ofMI and M2 measurementsare best potential for recognising separate species given in Figs 6 and 7. Most of the Paljara (Gingerich 1974). In this study, species were specimenspreserve MI-2. Further, size differences distinguished primarily on the basis of in theseteeth are likely to be more significant than morphological differences. size differences in other teeth becausethey usually Although tooth size alone does not separate exhibit lower size variability within species P. nancyhawardae and P. tirarensae, these (Gingerich 1979). Plots for Paljara specimensdo species cannot be regarded to be synonymous not provide convincing evidence to suggest that becauseof significant differences in morphology. P. tirarensae and P. nancyhawardae differ in size. Examination of morphological variation in living There is an overlap in MI size in thesetaxa, withP. pseudocheirids suggests that the features that tirarensae tending to be larger. Due to insufficient distinguish P. nancyhawardae from P. tirarensae numbers of specimens, no conclusions can be are invariable within Pseudocheirus peregrinus drawn from the observed size differences between and Pseudochirops archeri. On this basis P. fossil specimens. nancyhawardae and P. tirarensae are interpreted to represent distinct species. DISCUSSION South Australia's Kutjamarpu Local Fauna is The dentition is the most commonly recovered considered, on the basis ofbiocorrelative studies AAPMemoir25 (2001

Pseudocheirusperegrinus Pseudochiropsarcheri

I Lowerteeth n mean OR SO CV n mean OR SO cv ~ 37 3.43 2.89-4.12 0.25 7.29 17 4.7 4.43-4.94 0.17 ~~I P/3AW I 37 I 1.39 1.02-1.620.139.3517 1.97 1.78-2.150.115.58 'D/3MW I 37 I 1.8 1.61-2.110.137.22 172.44 2.20-2.620.114.51

IM/1- L 4.38 3.96- 4.83 0.23 5.25 17 5.28 5.07- 5.50 0.12 2.27 IM/1 AW 2.25 2.00- 2.50 0.13 5.78 17 2.96 2.68- 3.30 0.15 I 5.07 ~ I 37 2.32 1.98- 2.55 0.13 5.6 17 3.08 2.87- 3.27 0.09 I 2."92" ~ T37 4.16 3.69-4.48 0.19 4.57 17 4.75 4.52-4.99 0.1312.741

M/2AW 37 2.32 2.13-2.53 0.12 5.1717 3.1 2.97-3.22 0.082.58

iM/2PW 37 2.45 2.26-2.610.135.31 173.11 2.97-3.260.092.891

I 37 4.08 IM/3~ I 3.68-4.43 0.17 4.17 15 4.53 4.31-4.69 0.12 ~I

~~ 2.39 2.16- 2.69 0.13 5.44 15 3.05 2.87- 3.21 0.09 2.95

M/3PW 2.43 2.05-2.67 0.15 6.17 15 3.05 2.89-3.18 0.0812.62 I M/4L 344.32 4.04-4.64 0.184.17 164.53 4.26-4.79 0.143.09 IM/4AW 332.35 2.17-2.770.125.11 162.97 2.79-3.14 0.1 3.37 IM/4PW 322.27 2.07-2.50 0.114.85 162.82 2.65-3.04 0.11 3.9 Table 3. Measurements(in mrn) and statistics for Pseudocheirusperegrinus and Pseudochiropsarcheri. Abbreviations:n, numberof specimens;OR, observedrange; SD, standarddeviation; cY, coefficientof variation. (Archer et al. 1995, 1997b), to be approximately kutjamarpensis from Camel Sputum Site). In equivalent in age to Riversleigh's System B (early addition, Archer (1992) notes the presenceof nine Miocene) deposits. Taxa shared by these undescribed ringtail species in a single mid- assemblagesinclude the diprotodontid Neohelos Tertiary local fauna at Riversleigh. This high tirarensis, the potoroid Wakiewakie lawsoni, the diversity of arboreal herbivores in early Miocene marsupial lion Wakaleo oldfieldi (Archer et al. Riversleigh assemblages and the complete 1995), Marlu kutjamarpensis, and species of absenceof grazers (Archer et al. 1989, 1997b), in Pildra (Pildra sp. from Riversleigh and Pildra addition to other faunal and palaeobotanical tertius from Kutjamarpu Local Fauna). The evidence(Archeretal.1989, 1995, 1997b;Martin occurrence of Paljara tirarensae at Riversleigh's 1998), suggests that the vegetation of this time Wayne's Wok Site (System B) and at the Leaf was rainforest. Locality (Kutjamarpu Local Fauna) supports this A shift in palaeoclimate from greenhouse to biocorrelation. Mammal diversity of the icehouse conditions during the middle Miocene, Kutjamarpu Local Faunaassemblage more closely about 15 million years ago (Archer et al. 1995, approximates that of Riversleigh System B 1997b ), may explain why fewer arboreal assemblages -than does any other assemblage herbivorous species have been recovered from from central Australia (Archer et al. 1995). Riversleigh's upper System C assemblages,and In reconstructing extinct communities, the from other assemblages of equal age. Climatic proportion of arboreal to terrestrial speciesshould changes probably resulted in densely forested be compared (Eisenberg 1990). Tropical forests areas opening up, which would in turn result in a with a closed canopy tend to contain mainly decline in arboreal species diversity. This change arboreal species because of the reduced primary is reflected in pseudocheirid fossils spanning that productivity on the shadedforest floor (Eisenberg interval. Only three ringtail species have been 1990). Eight pseudocheirid species have been identified from Riversleigh's System C described from Riversleigh System B deposits assemblages (Marlu kutjamarpensis, Paljara (Pseudochirops sp. I, Pseudochirops sp. 2, nancyhawardae and an as yet unnamed taxon). Pseudochirops sp. 3, Pildra sp. and Paljara Species of Paljara, in all palaeocommunities nancyhawardae from Upper Site; Paljara from which they are known, coexisted with other, tirarensae, Paljara nancyhawardae and Marlu larger ringtails (based on tooth size differences). kutjamarpensis from Wayne's Wok site; Paljara For example, species of Pildra and Marlu have maxbourkei, Paljara nancyhawardae and Marlu been recovered from the Kutjamarpu Local Fauna. 72 AAPMemoir25 (2001)

In addition, speciesof Pseudochirops and a range identified from Riversleigh's Wayne's Wok Site of other larger but, as yet undescribed, (System B). Paljara tirarensae, P. pseudocheirids occur together in the Riversleigh nancyhawardae and 1': maxbourkei appear to be assemblages.To avoid competition, these species closely related, sympatric species. They all occur may have employed one or more of the strategies in early Miocene (System B) deposits of proposedby Giller (cited in Leite et at. 1996).They Riversleigh. 1': nancyhawardae also occurs in late may have, for example, eatendifferent foliage, had Oligocene and middle Miocene (Systems A and different activity times, or had different vertical C) deposits. The distribution of, at least, 1': distributions. Body size differences may also have tirarensae extended into South Australia been important in resource partitioning (Leite et (Woodburne et at. 1987). at. 1996). Maiorana ( 1990) points out that competitive displacement can often be detected ACKNOWLEDGEMENTS by body size differences among related animals, Vital financial support for the Riversleigh with body size having an influence on the species Project has come from the Australian Research of plants on which a herbivore can efficiently feed. Grant Scheme, National Estate Grant Scheme For the digestion of cellulose, the alimentary (Queensland), University of New South Wales, tracts of mammalian folivores need to be Commonwealth Department of Environment, sufficiently long, consequently the animals' size Sports and Territories, QueenslandNational Parks is limited at the lower end of the range (Kay & and Wildlife Service, Commonwealth World Hylander 1978; Cork 1994). The majority of small Heritage Unit, Earthwatch Pty Ltd, ICI Australia, arboreal folivores supplement their diet with fruit Australian Geographic Society, Queensland and, in many cases, with animal matter. Living Museum, Australian Museum, Royal Zoological species of ringtails that weigh less than 700 g, Society of New South Wales, Linnean Society of such as Pseudochirulus mayeri (149 g) and New South Wales, Pasminco Pty Ltd, Surrey Pseudochirulus canescens (226 g) are primarily Beatty and Sons Pty Ltd and the Riversleigh folivorous but their stomachs have been found to Society. Vital assistancein the field has come from contain mosses, ferns, lichens, fungi and pollen many hundreds of volunteers as well as staff and (Humeetal.1993). students of the University of New South Wales. Selenodonty is an adaptation used by many folivores (e.g. pseudocheirids, phasco1arctidsand REFERENCFB a range of placental herbivores) to efficiently APLIN , K. P. & ARCHER, M., 1987. Recent advances comminute leaves into tiny pieces. Living koalas in marsupial systematics with a new syncretic are obligate folivores (Cork 1994) and have a classification. xv-lxxii inArcher, M. (ed.), Possums selenodont molar morphology. The selenodont and opossums: studies in evolution. Surrey Beatty pseudocheirid dentition has many accessory & Sons, Chipping Norton. crests that increase the capacity to shear leaves ARCHER, M., 1984. The Australian marsupial (Kay & Hylander 1978).On the basisof correlation radiation. 633-808 in Archer, M. & Clayton, G. between dental and dietary features seenin living (eds), Vertebrate zoogeography and evolution in species, hypotheses about the diets of extinct Australia. Hesperian Press, Perth. speciescan be proposed. In this regard, the molars ARCHER, M., 1992. Ringtail possums of species of Paljara suggest that they would (Pseudocheiridae, Marsupialia) from the Tertiary have been best suited to a folivorous diet, like deposits ofRiversleigh. The Beagle 9, 257. other contemporary selenodont or buno- ARCHER, M., BLACK, K. & NETTLE, K., 1997a. selenodont possums of similar size, such as the Giant ringtail possums (Marsupialia, petauroid Djaludjangi yadjana from Riversleigh Pseudocheiridae) and giant koalas (Phascolarctidae) (Brammall1999). However, due to the small size of from the late Cainozoic of Australia. Proceedings these animals, it is likely they supplemented their of the Linnean Society of New South Wales 117, 3- diet with fungi, mosses, lichens and ferns, as is 16. the case for the similarly small Pseudochirulus ARCHER, M., GODTHELP, H., HAND, S.J. & mayeri and P. canescens. MEGIRIAN, D., 1989. Fossil mammals of In summary, two new species of Paljara have Riversleigh, northwestern Queensland: preliminary been identified from Oligo-Miocene deposits of overview of biostratigraphy, correlation and Riversleigh. A specimen (QMF 40083) referable environmental change. Australian Zoologist 25, 29- to P. tirarensae, a speciespreviously only known 65. from the Kutiamarou Local Fauna. has been ARCHER. M., HAND. S.J. & GODTHELP. H.. 1995. AAP Memoir 25 (200 1) 73

Tertiary environmental and biotic change in 1996. Diet and vertical spaceuse of three sympatric Australia. 77-90 in Vrba, E.S., Denton, G.H., opossums in a Brazilian Atlantic forest reserve. Partridge, T.C. & Burckle, L.H. ( eds), Paleoclimate Journal of Tropical Ecology 12, 435-40. and evolution, with emphasis on human origins. LUCKETT, W.P., 1993. An ontogenetic assessmentof Yale University Press, New Haven. dental homologies in therian mammals. 182-204 in ARCHER, M., HAND, S.l., GODTHELP, H. & Szalay, F.S., Novacek, M.J. & McKenna, M.C. CREASER, P., 1997b. Correlation of the Cainozoic ( eds), Mammal phylogeny: Mesozoic dzfferentiation, sediments of the Riversleigh World Heritage Fossil multituberculates, monotremes,early eutherians and Property, Queensland, Australia. 131-152 in marsupials. Springer- Verlag, New York. Aguilar, I.P., Legendre, S. & Michaux, I. ( eds), Actes MAIORANA, V.C., 1990. Evolutionary strategies and du Congres BiochroM'97, Memoires et Travaux, body size in a guild of mammals. 69-102 in Damuth, l'Ecole Pratique des Hautes Etudes, Institut de J. & MacFadden, B.J. (eds), Body size in mammalian Montpellier 21. paleobiology: estimation ofbiological implications. BRAMMAL, I.R., 1999. Anew petauroid possum Cambridge University Press, Cambridge. from the Oligo-Miocene ofRiversleigh, northwestern MARTIN, H.A., 1998. Tertiary climatic evolution and Queensland. Alcheringa 23, 31-50. the development of aridity in Australia. Proceedings CORK, S.l., 1995. Digestive constraints on dietary of the LinneanSociety of New South Wales119, 115- scopein small and moderately-small mammals: how 36. much do we really understand? 337-369 in Chilvers, PLEDGE, N.S., 1987. Pseudocheirids (Marsupialia: D.I. & Langer, P. (eds), The digestive system of Pseudocheiridae) from the Middle Miocene Ngama mammals: food, form and function. Cambridge Local Fauna of northern South Australia. 681-688 University Press, Cambridge. inArcher, M. (ed.), Possums and opossums: studies CREASER, P., 1997. Oligocene-Miocene sediments of in evolution. Surrey Beatty & Sons, Chipping Riversleigh: the potential significance of topography. Norton. Memoirs of the Queensland Museum 41, 303-14. PLEDGE, N .S., 1992. The Curramulka Local Fauna: a EISENBERG, I.F., 1990. The behavioural/ecological new late Tertiary fossil assemblage from Yorke significance ofbody size in the Mammalia. 25-37 in Peninsula, South Australia. The Beagle 9, 115-42. Damuth, I. & MacFadden, B.I. (eds), Body size in TURNBULL, W.D. & LUNDELIUS, E.L., 1970. The mammalian paleobiology : estimation of biological Hamilton Fauna, A Late Pliocene Mammalian Fauna implications. Cambridge University Press, from the Grange Burn, Victoria, Australia. Fieldiana: Cambridge. Geology 19,3-151. FLANNERY, T.F., 1994. Possums of the World. Geo TURNBULL, W.D., RICH, T.H. V. & LUNDELIUS, Productions Pty Ltd, NSW. E.L., 1987. Pseudocheirids (Marsupialia: FLOWER, W.H., 1868. Remarks on the homologies Pseudocheiridae) of the Early Pliocene Hamilton and notation of the teeth of the Mammalia. Journal Local Fauna, southwestern Victoria. 698-713 in of Anatomy and Physiology 3, 262-78. Archer, M. (ed.), Possums and opossums: studies GINGERICH, P.D., 1979. Paleontology, phylogeny, in evolution. Surrey Beatty & Sons, Chipping and classification: an example from the mammalian Norton. fossil record. Systematic Zoology 28, 451-64. WOODBURNE, M.O., TEDFORD, R.H. & HUME, I.D., IAZWINSKI, E. & FLANNERY, T.F., ARCHER, M., 1987. New Miocene ringtail 1993. Morphology and function of the digestive possums (Marsupialia: Pseudocheiridae) from tract in New Guinnean possums.Australian Journal South Australia. 639-679 in Archer, M. (ed.), ofZoology41,85-100. Possums and opossums: studies in evolution. Surrey KAY, R.F. & HYLANDER, W.L., 1978. The dental Beatty & Sons, Chipping Norton. structure of mammalian folivores with special WOODBURNE, M.O., TEDFORD, R.H., ARCHER, reference to primates and Phalangeroidea M., TURNBULL, W.D., PLANE, M.D. & (Marsupialia). 173-191 in Montgomery, G.G. (ed.), LUNDELIUS, E. L., 1985. Biochronology of the The ecology of arboreal folivores. Smithsonian continental mammal record of Australia and New Institution Press, Washington D.C. Guinea. Special Publications of the South Australian LEITE, Y.L.R., COSTA, L.P. & STALLINGS, I.R., Department of Mines and Energy 5, 347 -63. 74 AAP Memoir 25 (2001)

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APPENDIX 2

Specimen Locality Specimen Locality i M 2624 Railton, N. W. Tasmania M 8380 King Is., Bass Strait M 2625 Railton, N. W. Tasmania M 9679 Sydney, NSW

M 2632 Railton, No W. Tasmania M 9921 Sydney, NSW M 2633 Railton, N. W. Tasmania M 14154 Eungella, Queensland M 2634 Railton, No W. Tasmania M 14156 Eungella, Queensland M 2635 Railton, N. W. Tasmania M 18301 West coast, Tasmania

M 4625 Argalong via Tumut, NSW M 23631 Sydney, NSW M 4837 Fitzroy Valley, Queensland M 23827 Sydney, NSW M 5216 Sydney, NSW M 29532 Sydney, NSW

M 6358 Sydney, NSW M 29546 Sydney, NSW M 6883 Sydney, NSW M 29548 Mitta Mitta, Victoria

M 6884 Sydney, NSW M 29550 Mitta Mitta, Victoria M 6935 Sydney, NSW M 30182 Sydney, NSW M 6937 Sydney, NSW M 32685 Dorrigo National Park, NSW

M 7010 Sydney, NSW M 33364 Sydney, NSW M 7818 Sydney, NSW M 33365 Byron Bay, NSW M 8208 Sydney, NSW M 33366 Sydney, NSW M 8379 Sydney, NSW S 1834 Westernport, Victoria

List of Pseudocheirus peregrinus specimens used in this study and their localities.