SUAS tytn BTN or iy i

ate Por wie ght , Spa ‘ hp etree 5 y : wee Uf read hay e ie Bye the naire rans ; $ eed r SuENaNaNf a8 dM

uw

it Peter regs soe

fey Laatste

Sai Fathi

sh tute an he ENS

Jrathte twk Rice ial SLES 2 , ; ayo) oni

“ay Fake dere i ni Sala ; rod eh Jejnets fe By ae ; RAN Tar ycitytte bet . eth ot ae ye ‘ thorn de ae

nthe ge Pater d

eer

Laie,

PROCEEDINGS of the

LINNEAN SOCIETY

NEW SOUTH WALES

This volume contains a selection of papers dealing with vertebrates or vertebrate fossil sites, arising from a Symposium held by the Linnean Society of New South Wales at Wellington Caves, New South Wales, in December 1995. Papers concerning Holocene vegetation will appear in volume 118.

The opening session of that symposium was held in Cathedral Cave. The cover of this volume is based on a colour photograph, supplied by the Museum of Natural History, London, of an aquatint of nearby Breccia Cave, also known as Mitchell’s Cave, by Thomas Mitchell. It was first published in 1831 in Part XIV of the Edinburgh New Philosophical Journal. A version of this drawing was also published by Mitchell in 1838 in his book “Three expeditions into the Interior of Eastern Australia”.

The legend to the original states, “The cave in which the fossil bones are found at Wellington Valley is in compact secondary limestone, as described more fully in a memo- randum which accompanied a very large bone sent by Mr Rankin to Prof. Jameson. It is near a larger cave* where no breccia has been found, and which is very different in character from that of which this drawing is intended to convey an idea, the appearance of disruption and with unshapely masses overhanging being characteristic of all the situations where the fossil bones have hitherto been discovered in N.S. Wales. 12 Oct 1830. The bone above mentioned is that of an elephant**”’.

*Cathedral Cave **Tt was Diprotodon

VOLUME 117 March 1997

Dedication

PROFESSOR RICHARD DEHM July 1907— March 1996

The contents of this volume would have been noticeably different and the course of research into Australian Quaternary mammals substantially altered had fate not inter- vened to prevent research begun by Dr Richard Dehm from being concluded. Inspired by lectures and contacts with cave researchers from his teenage years, Dr Dehm jumped at the chance to travel to Australia in 1939 with his colleague Dr Joachim Schréder, sup- ported and encouraged by the director of the Bavarian Collection of Palaeontology and Historical Geology in Munich. The timing was however most unfortunate, and the two scientists found themselves in Australia when war broke out between Germany and Great Britain. The story of their internment and difficult return to Germany has been partly told (Augee at al., 1986, The Australian Zoologist 22, 3-6), and further details and documentation provided by Prof Dehm shortly before his death will, when fully translat- ed, be incorporated into a future publication. The tragic outcome for palaeontology was that fossils collected from Australia, especially from Wellington Caves and Jenolan, were largely destroyed or lost. The few that survived the misfortunes of war remain in the museum at Munich, excellently preserved and stored, but are of little research value. A list which I compiled while on study leave in Munich in 1986 is held in the archives at the Wellington Caves Fossil Studies Center.

Richard Dehm had the view that the remains of small animals, particularly mam- mals, held the secret to understanding climatic and faunal changes. He studied fossils found in fissure fillings, and therefore Wellington Caves were of particular interest. Prof Dehm had a life-long desire to return to Australia and sites such as Wellington and Jenolan, however a successful career and the added duties from 1958 as Director of the “Universitatsinstitut and Staatssammlung fiir Palaontologie und Historische Geologie Miinchen” intervened and he was never to make the journey. In a way the research he would have carried out was finally begun in the early 80s when the University of NSW began the stratigraphically controlled excavation in Cathedral Cave. A brass plaque at Wellington Caves marks one of the spots from which the remaining Munich collection was obtained, and this is readily viewed by visitors to the Phosphate Mine section.

Prof Dehm remained very active following his retirement as Director of the Munich collection and museum. During my three month study of the Australian mammal fossil in Munich, he was a delightful host, with a keen interest in current Australian palaeontological studies on which he was well informed. His death marked the end of a remarkable career and a sad loss to colleagues around the world.

M.L. Augee

Richard Dehm (left) and Michael Augee on the steps of the Munich museum which houses the Bavarian State fossil collection, winter 1985.

Proc. LINN. Soc. N.S.w., 117. 1997

z a es 9 oer Huis stati

y Say Ciel tbo) bs reqate oh Wey Wogan 1S mbyorciee piel A sy wives Ws ental, or gaseeiaillaraett

Giant Ringtail Possums (Marsupialia, Pseudocheiridae) and Giant Koalas (Phascolarctidae) from the Late Cainozoic of Australia

MICHAEL ARCHER, KAREN BLACK AND KERRY NETTLE

School of Biological Science, University of New South Wales, Sydney N.S.W. 2052

Archer, M., Black, K. and Nettle, K. (1997). Giant Ringtail Possums (Marsupialia, Pseudocheiridae) and Giant Koalas (Phascolarctidae) from the late Cainozoic of Australia. Proceedings of the Linnean Society of New South Wales 117: 3-16

While seven pseudocheirids have been described from the late Oligocene to early Miocene and five from the Pliocene of Australia, none are known to have been confined to the Pleistocene. We describe here a giant ringtail, Pseudokoala cathysantamaria n. sp., from the early Pleistocene Portland Local Fauna (lower Nelson Bay Fm) of Victoria. We review the generic distinction of the Miocene—Pliocene Corracheirus Pledge, 1992 and conclude that it is a junior synonym of Pseudokoala Turnbull and Lundelius, 1970. The palaeohabitat for all species of Pseudokoala appears to have been rainforest. A second pseudocheirid in the Portland Local Fauna is most similar in morphology and size to the still-living Pseudocheirus peregrinus, a species whose habitat range also includes rainforest. We describe the first known upper and additional lower molars for the giant koala Cundokoala yorkensis Pledge, 1992, from a Pleistocene deposit in Wellington Caves, New South Wales, a taxon previously only known from Pliocene sediments of South Australia. The Portland giant ringtail and Wellington giant koala add two more families to the already extensive list that exhibited Pleistocene gigantism. Previously, only one other lineage (tree kangaroos) of arboreal mam- mals has been known to have undergone gigantism.

Manuscript received 6 June 1996, accepted for publication 23 October 1996.

KEYWORDS: Koalas, Phascolarctidae, Pleistocene gigantism, Pseudocheiridae, Quaternary, ringtail possums.

INTRODUCTION

The record for ringtail possums (Pseudocheiridae) begins in the late Oligocene. From sediments of this age in South Australia, Woodburne et al. (1987a) and Pledge (1987b) describe four species of Pildra, two of Marlu and one of Paljara. Archer (1992) reports over twelve additional unnamed taxa from the Oligo-Miocene sediments of Riversleigh, northwestern Queensland. Archer and Bartholomai (1978) note a Pseudochirops from the late Miocene of Alcoota, Northern Territory. Turnbull and Lundelius (1970; augmented by Turnbull et al. 1987) describe Pseudokoala from the early Pliocene Hamilton Local Fauna as well as two species of ‘Pseudocheirus’ which may (Archer 1984) represent the otherwise modern genus Petauroides. Another species of Pseudochirops, from the early Pliocene Bluff Downs Local Fauna of northeastern Queensland, is under study (B. Mackness and M. Archer). Pledge (1992) describes a giant species of Corracheirus from the late Miocene to Pliocene Curramulka Local Fauna of southern South Australia as well as a single tooth of another large pseudocheirid from the Plio-Pleistocene Cement Mills Local Fauna of southeastern Queensland. Until now, how- ever, no giant pseudocheirids have been reported from undoubted Pleistocene sediments. The tooth described here as Pseudokoala cathysantamaria, from early Pleistocene

Proc. LINN. Soc. N.S.W., 117. 1997

4 GIANT RINGTAIL POSSUMS AND GIANT KOALAS

deposits at Portland, Victoria, is the only ringtail possum confined to the Pleistocene and the only giant ringtail known from the Quaternary.

Fossil koalas (Phascolarctidae) are similarly known from late Oligocene and younger sediments. Stirton (1957), Stirton, Tedford and Woodburne (1967), Woodburne et al. (1987b) and Springer (1987) describe six species in the Oligo-Miocene genera Perikoala, Litokoala and Madakoala. Black and Archer (in press) name another Miocene genus from Riversleigh and Black (in prep.) reports additional Miocene taxa from Riversleigh. Pledge (1992) describes a Miocene to Pliocene species of the giant Cundokoala. Bartholomai (1968) describes a large Plio-Pleistocene Queensland species of the modern genus Phascolarctos. Pledge (1987a) describes another large Phascolarctos from the early Pliocene of South Australia. We describe here isolated teeth, from Pleistocene deposits of Wellington Caves, New South Wales, that appear to represent the same Miocene/Pliocene South Australian species described by Pledge (1992) as Cundokoala yorkensis. The Wellington material includes the first known upper molars for this taxon.

Material described is registered in the palaeontological collections of three institu- tions as follows: AM F numbers represent the Australian Museum fossil collection; P numbers represent the palaeontological collections of the Museum of Victoria; SAM P numbers represent the palaeontological collections of the South Australian Museum. Dental terminology used here follows Luckett (1993) for molar homology, Flower (1867) for premolar homology and Archer (1984) and Woodburne et al. (1987a,b) for molar morphology.

SYSTEMATICS

Class Mammalia Linneaus, 1758 Superorder Marsupialia [liger, 1811 Order Diprotodontia Owen, 1866 Superfamily Phalangeroidea Weber, 1928 Family Pseudocheiridae Winge, 1893

Pseudokoala Turnbull and Lundelius, 1970

Type species: Pseudokoala erlita Turnbull and Lundelius, 1970

Additional species: Pseudokoala curramulkensis (Pledge, 1992) and Pseudokoala cathysantamaria n. sp.

Revised generic distribution: Corra Lynn Cave, Yorke Peninsula, South Australia; Hamilton Local Fauna, south- western Victoria; Portland Local Fauna, Nelson Bay Formation, Portland, Victoria.

Revised age range for the genus:

The Hamilton Local Fauna is interpreted (Rich et al. 1991) to be early Pliocene in age. The Curramulka Local Fauna is interpreted (Pledge 1992) to be late Miocene to Pliocene in age; the Nelson Bay Formation is interpreted (Flannery and Hann 1984) to be early Pleistocene in age.

Revised generic diagnosis: Species of Pseudokoala are distinguished from Marlu praecursor by their continu-

ous postmetacristid and preentocristid, and posthypocristid which does not extend to the

Proc. LINN. SOC. N.S.W., 117. 1997

M. ARCHER, K. BLACK AND K. NETTLE 5

lingual side of the crown. They are distinguished from M. kutjamarpensis by their con- tinuous postmetacristid and preentocristid, connection of the cristid obliqua to the metacristid and their truncated posthypocristid. They are distinguished from species of Pildra and Paljara in their lack of an entostylid, presence of a buccal buttress on the pro- toconid, en echelon overlap of the postmetacristid and preentocristid, large size, and truncated posthypocristid. They are distinguished from species of Pseudocheirus, Petauroides and Hemibelideus in having a truncated posthypocristid, being much larger in size, having a second buccal buttress on the protoconid, not having steep entoconid blades and in lacking a protostylid. They are distinguished from species of Pseudochirops in having a truncated posthypocristid, being larger in size, having a sec- ond buccal buttress on the protoconid, not having steep entoconid blades, having the cristid obliqua connected to the metacristid, and in lacking a protostylid.

Pseudokoala curramulkensis (Pledge, 1992)

Emendation of dental homology for the paratype and referred specimen: Pledge (1992) notes three specimens including the Holotype. The homology of the

teeth (using the M1-4 molar homology system of Luckett 1993) given in table 5 needs emendation as follows. SAM P29901 (referred specimen) is a right dentary fragment with M> (not Mj) and alveoli for M; and M3_4. SAM P31792 (Paratype) is a left den- tary fragment with M>_3 (not Mj_>) and alveoli for M, and Mg.

Pseudokoala cathysantamaria n. sp.

Holotype: P173650, an isolated LM, (Fig. 1).

Type Locality: Interpreted to be Nelson Bay, Portland, Victoria, although no specific locality details

are recorded in the Museum of Victoria Palaeontology register (B. Thompson, pers. comm. to M. Archer), nor are there any details on the specimen label. However, it is regis- tered within a series of fossils, including P173649 (a dentary of Pseudocheirus sp. cf. P. peregrinus; see below), for all of which the locality data is Nelson Bay, Portland, Victoria.

Age: Marine invertebrates from the Lower Nelson Bay Formation, the probable source of the Holotype, are early Pleistocene in age (Flannery and Hann 1984).

Etymology: In honour of Cathy Santamaria for her constant interest and much appreciated

encouragement for palaeontological research in Australia.

TABLE |

Measurements of Pseudokoala material. All measurements in millimetres.

Specimen P3 MI M2 M3 M4 EW, a AWE Wan Iad AWE <P TR AWAD RAV) INN PAW AMPLY) MV P173650 10.7 5.20 5.60

SAM P26542 10.9 4.51 5.20

Proc. LINN. Soc. N.S.W., 117. 1997

6 GIANT RINGTAIL POSSUMS AND GIANT KOALAS

Figure 1. A-A’, Holotype of Pseudokoala cathysantamaria n.sp, Museum of Victoria P173650, occlusal stere- opair of left Mj, from the early Pleistocene of Portland, Victoria; B, Pseudokoala erlita, NMV P54159, left My, occlusal stereopair; C, Pseudocheirus sp. cf. peregrinus, Museum of Victoria P173649, a right dentary frag- ment with M1_y, from the early Pleistocene of Portland, Victoria . Bar indicates 5mm.

Species diagnosis:

Pseudokoala cathysantamaria is a giant ringtail possum with molar teeth at least 20% larger than those of P. erlita (Turnbull et al. 1987) but comparable in size (Table 1) to P. curramulkensis (Pledge 1992; see below). It is also distinguished from P. erlita by hav- ing an extra anterior vertical buttress (as well as a posterior one) on the buccal flank of the protoconid, an anterobuccal vertical trigonid cleft anterior to the extra vertical buttress, an anterolingual basal cingulum and cingular pocket, a lingually convex metacristid, posterior elongation of the postentocristid, and mesostylids between the bases of the hypoconid and protoconid. Although the missing anterior half of Mj for P. curramulkensis prohibits com- parisons in this area, the tooth of P. curramulkensis 1s smaller, appears to lack at least the posterior mesostylid, may lack the anterior flexure on the cristid obliqua, and has a much shorter postentocristid. In this feature, the three species appear to form a gradient with the postentocristid of P. erlita the least extended and that of P. cathysantamaria the most.

Proc. LINN. SOc. N.S.W., 117. 1997

M. ARCHER, K. BLACK AND K. NETTLE 7

Description: The Holotype (Fig. 1) is the least worn of any Pseudokoala specimen known

enabling details of dental morphology in the genus to be clarified. M, has a large, medi- ally situated protoconid (as in P. erlita) which is connected by a steep anterior paracristid to a tiny possible paraconid (not evident in P. erlita and unknown for P. curramulkensis), and by a gently inclined posterior metacristid to a poorly distinguished metaconid (as in at least P. erlita). Two prominent, vertical buccal buttresses subtend the protoconid. There is a tiny, anterolingual basin defined by a small, basal anterolingual cingulum, an anterobuccal cingula and a marked, vertical, anterobuccal trigonid cleft. Between the cristid obliqua and posterior buccal buttress are two basal mesostylids.

The following features of P. cathysantamaria are also evident (where they can be checked) in the holotype of P. curramulkensis and P. erlita. There is no protostylid. At the posterior end of the metacristid is a topographically defined metastylid immediately buccal to the anterior end of the preentocristid. The cristid obliqua does not run directly to the metacristid but instead veers anterobucally to tangentially contact the metacristid. There are pronounced crenulations on the lingual side of the cristid obliqua. There is en echelon overlap of the postmetacristid over the preentocristid. The paracristid, metacristid and postentocristid are elongate and together define a composite blade that extends the length of the whole tooth. The entoconid blades are not steeply inclined. There is no entostylid. The posthypocristid is truncated at the lingual end before it reach- es the postentocristid. It stops far short of the posterolingual corner of the tooth, leaving the posterior end of the postentocristid (which extends posteriorly further than the same crest in the other species of Pseudokoala) to define the edge of the crown. In terms of relative height on the crown, the protoconid is just higher than the metaconid which is higher than the entoconid which is higher than the metastylid which is higher than the hypoconid which is higher than the paraconid.

Discussion:

Estimates of body size for Pseudokoala cathysantamaria, based on tooth and body size in Phascolarctos cinereus, suggest that this ringtail may have weighed 9-10 kg, far larger than any living ringtail possum. However, it is only slightly larger than the Curramulka giant ringtail described by Pledge (1992) as Corracheirus curra- mulkensis. Pledge (1992) suggests that species of Corracheirus (viz. C. curramulken- sis) are differentiated from those of Pseudokoala (viz. P. erlita) by three features: 1, larger size; 2, having the postprotocristid continuous with the cristid obliqua rather than extending to the metastylid; and 3, having a continuous entocristid with a simple metastylid flexure.

Large size is not normally regarded to be a basis for establishment of a monotypic genus (in this case for curramulkensis Pledge). Considering the second feature, there are three specimens of P. curramulkensis noted in the type description: the Holotype with part of M; and M>_4, and SAM P29901 with M> which support the distinction with the postprotocristid appearing to make no contact with the metastylid; and SAM P31792 with M>_3 where the postprotocristid bypasses (but is touched by) the cristid obliqua to make contact with the metastylid flexure. Consequently, this feature appears to be vari- able and does not distinguish species of Corracheirus from those of Pseudokoala. Considering the third distinguishing feature, the Holotype and SAM P29901 do support the suggestion that the preentocristid is continuous with metacristid via a simple metastylid flexure. However, the condition in SAM P31792 is much closer to the P. erlita condition in that there is only a very tenuous direct connection linking the preentocristid and the metacristid via a fine and low bridge of enamel buccal to the metastylid. In this specimen, the preentocristid and metacristid really overlap en echelon, with the preen- tocristid passing anterobuccal to the posterior end of the metacristid to make contact with the postprotocristid, a condition closer to that seen in P. erlita.

Proc. LINN. Soc. N.S.W., 117. 1997

GIANT RINGTAIL POSSUMS AND GIANT KOALAS

. LINN. SOC. N.S.W., 117. 1997

M. ARCHER, K. BLACK AND K. NETTLE 9

Conversely, comparison of SAM P31792 with the M3 or g of P. erlita illustrated in Turnbull, Rich and Lundelius (1987, Fig. 2C) suggests basic overall similarity in all key features (except, possibly, the degree to which the metacristid is lingually concave and the degree of posterior development of the postentocristid; see below). Corracheirus cur- ramulkensis, P. erlita and P. cathysantamaria also exhibit a striking synapomorphy of Mj: truncation of the posthypocristid such that it stops well short of the lingual side of the crown and does not contact any other structure. This condition differs from all other pseudocheirids where the posthypocristid closely approximates the postentocristid (or the entostylid) at or near the lingual margin of the tooth. All three taxa also exhibit a tenden- cy to posteriorly extend the postentocristid, a feature best-developed in M}. Finally, all three taxa appear to be united in their tendency towards gigantism. For these reasons, we suggest that Corracheirus Pledge, 1992 is better regarded as junior synonym of Pseudokoala Turnbull and Lundelius, 1970 which then contains three species: erlita Turnbull and Lundelius, 1970; curramulkensis Pledge, 1992; and cathysantamaria Archer, Black and Nettle (this paper), erlita being the type species of the genus.

Within Pseudokoala, P. cathysantamaria appears to be the sister-group of P. curra- mulkensis, these two sharing as synapomorphies extreme gigantism and greater posterior development of the postentocristid. Although the trigonid 1s unknown for P. curra- mulkensis, that of P. cathysantamaria shows two prominent buccal buttresses in contrast to one in P. erlita, the second buttress being an autapomorphic condition (or perhaps a synapomorphic condition shared with P. curramulkensis). The single buttress of P. erlita may be the homologue of the vertical protostylid ridge in the same position in species of Marlu (or the homologue of the protostylid in, e.g., species of Pseudochirops, Pseudocheirus, Pseudocheirulus).

Species of Pseudokoala share distinctive features of M, with species of Marlu Woodburne, Tedford and Archer, 1987 including: failure of the cristid obliqua to directly contact the postmetacristid (a deep crevice intervening); a crenulated cristid obliqua; en echelon overlapping of the postmetacristid and the preentocristid (in M. kutjamarpensis but not M. praecursor); a vertical buttress but no protostylid on the buccal flank of the protoconid; no entostylid; and gently inclined (rather than steeply inclined) entoconid blades. This intergeneric relationship was originally suggested by Woodburne, Tedford and Archer (1987; Fig. 23) on the basis of synapomorphies exhibited primarily by the upper molars. The new species P. cathysantamaria exhibits the same combination of synapomorphies, lending support to the hypothesis of a Pseudokoala/Marlu clade.

Marked differences between species of Marlu and Pseudokoala include the trun- cated posthypocristid of species of Pseudokoala and their better-developed entoconid blades. Differences in the nature of the connection between the preentocristid and metacristid vary within at least P. curramulkensis (see above) making intergeneric con- trasts here of questionable value.

In terms of patristic relationships, the early Miocene Marlu kutjamarpensis exhibits no features that would preclude it being ancestral to the Pliocene/Pleistocene species of Pseudokoala.

Pseudocheirus Ogilby, 1837

Pseudocheirus sp. cf. P. peregrinus (Boddaert, 1785) Specimen: P173649, a right dentary with Mj_4 (Fig. 1).

Locality: Nelson Bay, Portland, Victoria. Label data also records: ‘Monash Univ. field trip (1973?) and “# 280 004’.

Proc. LINN. Soc. N.S.W., 117. 1997

10 GIANT RINGTAIL POSSUMS AND GIANT KOALAS

Age: The marine invertebrate assemblage of the Lower Nelson Bay Formation, source

of P173649, is early Pleistocene in age (e.g., Flannery and Hann 1984).

Description: P173649 is a Pseudocheirus peregrinus-sized ringtail possum (Table 2) with over-

all similarity to P. peregrinus and P. occidentalis. It is, however, distinguished from these modern species (most individuals but not all, these features being somewhat variable in at least P. occidentalis) in that: the preentocristid is connected to the metastylid on M>_4. and the metaconid on My is less distinct. It is distinguished from Pseudocheirulus her- bertensis in that: the preentocristid is connected to the metastylid; the M, lingual parastylid is not developed; and there is no notch between the postmetacristid and metastylid. It is distinguished from P. caroli and P. forbesi in that: the preentocristid is connected to the metastylid; the Mj, lingual parastylid is not developed; the preen- tocristid is strongly bladed; and there is no notch between postmetacristid and metastylid. It is distinguished from P. canescens and P. mayeri in that: the preentocristid is connected to the metastylid; the preentocristid is strongly bladed; and there is no notch between postmetacristid and metastylid. It is distinguished from Hemibelideus lemuroides in that: the buccal shelf is not prominent; and the M, metaconid is less distinct. It is distin- guished from Petauroides volans in that: the preentocristid is connected to the metastylid; there is no entostylid ridge; and the M; metaconid is less distinct. It is distin- guished from Pseudochirops albertisii in: not having a protostylid basin on Mj; lacking a prominent buccal shelf; lacking an entostylid ridge; lacking a posterobuccal trigonid basin; and in having a less distinct My metaconid. It is distinguished from P. corinnae in that: the preentocristid is connected to the metastylid; it lacks a protostylid basin on Mj; it lacks a prominent buccal shelf; it lacks an entostylid ridge; it has no posterobuccal trigonid basin; and the M, metaconid is less distinct. It is distinguished from P. cupreus in: not having a protostylid basin on M}; lacking a prominent labial shelf, the My cristid obliqua is not angulate, no entostylid ridge, no posterobuccal trigonid basin; and in hav- ing a less distinct metaconid on M}. It is distinguished from P. archeri in: not having a protostylid basin on Mj; having an Mg cristid obliqua that is not angulate; lacking an entostylid ridge; lacking a posterobuccal trigonid basin; and in having a less distinct metaconid on Mj}. It is distinguished from Petropseudes dahli in: not having a proto- stylid basin on Mj; lacking a prominent buccal shelf; lacking a posterobuccal trigonid basin; and in having a less distinct metaconid on Mj. It is distinguished from the species of all extinct ringtail genera in having: a well-developed My protostylid; a preentocristid connected to the metastylid; a strongly bladed preentocristid; an entoconid that is posi- tioned anterior to the hypoconid; a protoconid positioned lingual to the midline of My; and a less distinct metaconid on M}).

TABLE 2

Measurements of Pseudocheirus material. All measurements in millimetres.

Specimen P3 MI M2 M3 M4 LE W L AW PW L AW PW L AW PW L AW PW MY P173649 AMG) SK ZA AV) AI) 230) AO), Dolls) D2 EB) AK} 21S)

AM M4046 3.51 1.58 Syke) IA, DP 3.84 2.12 2.54 4.03 2.37 2.60 4.74 2.43 2.30

The early Pleistocene habitat of Portland: The presence of an ektopodontid and Pseudokoala cathysantamaria in the Portland

assemblage suggests a rainforest component in the palaeoenvironment. All ektopodon-

Proc. LINN. SOC. N.S.W., 117. 1997

M. ARCHER, K. BLACK AND K. NETTLE 1]

tids occur in assemblages that have been interpreted (e.g. Archer, Hand and Godthelp 1995) to represent rainforest communities or communities that include rainforest: the late Oligocene Ditjimanka and Ngama Local Faunas, South Australia; the early and middle Miocene assemblages of Riversleigh, Queensland; the ?early or middle Miocene Kutjamarpu LF, South Australia; and the early Pliocene Hamilton LF, Victoria. The late Miocene to Pliocene Curramulka LF of South Australia, which contains Pseudokoala curramulkensis, is also regarded (Pledge 1992) to represent wet sclerophyll forest and/or rainforest, as is the Hamilton assemblage (Turnbull and Lundelius 1970, Turnbull, Rich and Lundelius 1987) which contains P. erlita. The occurrence in the Portland assemblage of Pseudocheirus sp., cf: P. peregrinus does not conflict with this interpretation because, although primarily an inhabitant of dense understorey vegetation, some modern popula- tions of P. peregrinus extend well into rainforest.

Order Diprotodontia Owen, 1866

Suborder Vombatiformes Woodburne, 1984 Infraorder Phascolarctomorphia Aplin and Archer, 1987 Family Phascolarctidae Owen, 1839

Cundokoala yorkensis Pledge, 1992

Holotype: SAM P24904, left dentary with Mj_4 and alveolus for P3.

Referred material

(Fig. 2) and (Table 3): SAM P24905, partial left Mz in its alveolus.

AM F98885, L MI: AM F98886, R M;; AM F98887, L Mj; AM F98888, L Mp; AM F98889, R My; and AM F98890, L M3.

TABLE 3

Measurements of all known specimens of Cundokoala yorkensis. All measurements in millimetres. Abbreviations: L, length; AW, anterior width; PW, posterior width. Specimen p3 M! M2 M3 1 L WwW L AW PW L AW PW L AW PW L AW PW

AM F98885 12 I2Be 0

P3 M M> M3 My,

ee Wie Ihe AW PWat sees ar AWARE tenet MAW PWe te iMilnen AWA Wy P24904 mS 720 8 “TO el TO Ra ey ae AM F98886 mS 65 G0 AM F98887 11.5 6.9 68 AM F98888 MA 72 7.0 AM F98889 ms 7 GO

AM F98890 WAs Fos) @.7/

Revised distribution: Cundokoala yorkensis is known from Corra Lynn Cave, the Curramulka Local Fauna, Yorke Peninsula, South Australia and now Wellington Caves, New South Wales.

Proc. LINN. Soc. N.S.W., 117. 1997

12 GIANT RINGTAIL POSSUMS AND GIANT KOALAS

Revised age range: The Curramulka Cave site of the typical material is interpreted by Pledge (1992) to

be Miocene to Pliocene in age. The exact locality and age for all but one (AM F98886) of the Wellington Caves specimens is unknown. They were collected from the surface of spoils piles dumped outside the newly restored entrance to the Phosphate Mine. The material on these piles had been obtained during excavation of tourist paths in the Wellington Caves complex in late 1995. The source of the material for each pile was not certainly known but thought by excavation workers at the site to be various localities within the Phosphate Mine and Bone Cave. Although most of the taxa recovered to date from the Wellington Caves complex of sediments have been interpreted to be Pleistocene in age, Hand, Dawson and Augee (1988), L. Dawson et al. (in prep.) and Osborne (1983) have demonstrated that some deposits in the Wellington Caves complex (e.g., in the entrance doline of Big Sink and others in the Phosphate Mine) are Pliocene in age. Therefore the age of the Cundokoala yorkensis material obtained from the spoils piles could be Pliocene, Pleistocene or both.

AM F98886, however, was obtained by one of us (MA) in company with H. Godthelp, A. Gillespie, A. Musser et al. from a newly-excavated pathway in the Phosphate Mine. Material excavated at the same time included an isolated lower molar of Diprotodon sp. cf: D. optatum (only known from the Pleistocene), a dentary of Protemnodon sp. cf. P. roechus (only known from the Pleistocene), abundant dentary and maxilla fragments of Aepyprymnus rufescens (Pleistocene and living species) and a dentary of Onychogalea unguifera (living species). Although other taxa obtained at the same time have yet to be identified, nothing contradicts a Pleistocene age for this assemblage. We would conclude, pending a thorough analysis of the rest of the fauna from this deposit, that Wellington Caves C. yorkensis 1s Pleistocene in age, giving the species a Pliocene-Pleistocene age range.

Revised diagnosis Cundokoala yorkensis differs from all other phascolarctids: in being larger; having

higher-crowned teeth; and in having a relatively short, massive dentary. It differs from all other phascolarctids except species of Phascolarctos in having: a larger paraconule and neometaconule on M°*; a more lingually positioned protoconid and a larger protostylid on Mj; well-developed lingual columnar stylids on the metaconid and entoconid of Mq_ 4; and a well-developed buccal cingulum and metastylid fold on Mj_y4. It differs from species of Litokoala in: lacking the posterobuccal crest which extends from the apex of the metaconid in Mj_ 4: lacking an anteriorly displaced entoconid (relative to the hypoconid) on Mg; lacking an anteriorly displaced metaconid (relative to the protoconid) on the My; and in having | the postprotocristid and cristid obliqua of My meeting in the transverse median valley on My (in contrast to the parallel arrangement seen in Litokoala kanunkaensis) It differs from species of Madakoala and Perikoala: in having: a larger PUSH on M’; a more crenulate, less linearly-oriented paraconule and neometaconule on M°; a paraconule that connects anterobuccally to the anterior cingulum on M°; an entostylid ridge on Mj_4; a more lingual junction of the postprotocristid and cristid obli- qua; and in lacking protoconid-metaconid and hypoconid-entoconid crests.

Description The new Wellington Caves materials (AM F98885 to AM F98890) augment under-

standing about the morphology of this species. AM F98885 is an unworn, relatively square selenodont M° that tapers posteriorly. It is morphologically very similar to the M* of species of Phascolarctos and differs mainly in being relatively wider anteriorly. The para- cone and metacone are similar in height and are the tallest cusps on the tooth followed by the metaconule and protocone. The apex of the protocone lies lingually opposite that of the paracone. The apex of the metaconule lies lingually opposite and slightly anterior to that of the metacone. The lingual bases of the paracone and metacone and the anterolingual base

Proc. LINN. SOc. N.S.W., 117. 1997

M. ARCHER, K. BLACK AND K. NETTLE 13

of the protocone are highly crenulate. The protocone and metacone and their associated crests are slightly obliquely (anterolingually) oriented. The tooth is bisected bucco-lingual- ly by a deep transverse median valley and antero-posteriorly by a relatively deep longitudi- nal valley. The buccal tooth margin is mildly convex sloping anterolingually at the anterolingual tooth margin and curving posterolingually around the buccal margin of the metacone. The lingual bases of the protocone and metaconule slope gently towards the base of the crown. The lingual bases of the paracone and metacone slope more steeply into the longitudinal tooth valley. The triangular buccal surface of the paracone 1s reduced rela- tive to the metacone as is the paracone buccal margin. The buccal basin of the paracone is closed and deep. The buccal basin of the metacone is comparatively shallower but remains closed. A ridge-like stylar shelf extends along the length of the buccal tooth margin. The relative heights of stylar cusps in descending order are as follows: stylar cusp C, B, A, D and E. The preparacrista, postparacrista, premetacrista and postmetacrista which make up the buccal selene of the tooth, are distinct linear crests which extend from the apices of the paracone and metacone respectively. The lingual selene is offset posteriorly and is com- posed of a relatively linear preprotocrista and premetaconule crista and a crescentic post- metacrista and highly crescentic postprotocrista. The postprotocrista and premetaconule- crista meet in the transverse median valley at a point slightly lingual to the longitudinal val- ley. The parastyle is poorly developed. It exists as a slight swelling of the anterior cingulum at the anterobuccal corner of the tooth. A shallow pocket is created between the anterior cingulum and the anterior base of the paracone. Lingually, the pocket is defined by a small, crenulate, but distinct paraconule which lies at the anterolingual base of the paracone. A short, non-cuspate, spur-like protostyle which originates from the preprotocrista at a point slightly lingual to the longitudinal valley, extends posteriorly along the buccal base of the protocone, terminating opposite the protocone apex. A well developed anterolingual paracrista connects the paraconule posteriorly to the apex of the paracone. A similarly well- developed posterolingual paracrista extends from the apex of the paracone into the junction of the transverse median and longitudinal valleys wherein it divides into two spurs which become part of the crenulation pattern of the tooth.

A small, crenulate, non-cuspate neometaconule lies in the longitudinal tooth valley at the anterolingual base of the metacone. It is connected to the metacone base by a weak anterolingual metacrista, which originates approximately half way down the base of the metacone. A posterolingual metacrista is absent. A crenulate, cingulum-like shelf runs along the anterior and anterolingual base of the protocone forming a shallow pocket between the cingulum and the protocone base. A weak anterolingually directed crest extends from the apex of the protocone to meet the anterolingual cingulum. A similar, but deeper pocket occupies the anterolingual base of the metaconule and is bounded by the posterior base of the protocone anteriorly, the anterior base of the metaconule posteriorly, the junction of the premetaconule crista and postprotocrista buccally, and a short, crescentic lingual cingulum lingually. The lingual cingulum effectively closes off the lingual exit of the transverse medi- an valley and is continuous with a weak crest that extends anterolingually from the apex of the metaconule. Weak buccally directed spurs extend from the apices of the protocone and metaconule, fading down their respective bases towards the longitudinal valley. A well developed posterior cingulum is continuous with the postmetaconulecrista lingually and buccally and meets stylar cusp E at the posterobuccal tooth corner.

The Mj of the holotype is poorly worn and the anterolingual tooth corner is miss- ing. Consequently, much of the crown morphology of the trigonid has been lost. In AMF98886 the preprotocristid is a well defined, linear crest which terminates anteriorly in a small paraconid. The preprotostylidcristid extends anterolingually to terminate at the base of the paraconid. Pledge (1992), in his description of the holotype Mj, suggests that C. yorkensis differs from all other phascolarctids in having a fine anterobuccal spur of the preprotocristid meet the preprotostylidcristid at the anterior tooth margin. Its absence in AM F98886 suggests this is a variable feature within the species, and the prepro-

Proc. LINN. SOc. N.S.W., 117. 1997

14 GIANT RINGTAIL POSSUMS AND GIANT KOALAS

tocristid spur is most probably part of the crenulation pattern of the tooth. A well-devel- oped posterobuccal ridge extends from the protostylid apex in AM F98886. This crest is only vaguely discernible in the holotype. The buccal cingulum is better developed in AM F98886. The postprotocristid meets the anterior base of the cristid obliqua at a slightly more lingual position than in the holotype. The lingual columnar stylids of the metaconid and entoconid are large, crenulate and well preserved in AM F98886 whereas they are only represented by slight swellings in the holotype. The entostylid is a well-developed, cuspate swelling on the terminus of the postentocristid at the posterolingual tooth corner in AM F98886. AM F98887, AM F98888 and AM F98889 (M>) are morphologically similar to but smaller than the M> of the holotype. Again, the holotype is highly worn, the apices of all major cusps are missing and the lingual tooth margin is damaged such that the columnar stylids are not preserved and the entostylid is missing. In contrast, all of the Wellington Caves M> specimens show little or no wear. The columnar stylids are large, particularly that of the metaconid. The postentocristid curves lingually to the pos- terolingual tooth corner where it terminates in a well developed entocristid. The ento- conulid, like in the holotype, is poorly developed. Well developed lingually directed crests extend from the apices of the protoconid and hypoconid and terminate just prior to reaching the longitudinal valley. These crests are not present in the holotype. The M3, AM F98890, is largely unworn and is slightly smaller than the M3 of the holotype. The postmetaconid, preentocristid and postentocristid are more arcuate than in the holotype. The lingual buttresses of the metaconid and entoconid are better developed however the buccal bases of these cusps are more greatly expanded in the holotype. The metastylid is larger and the metastylid fold is more pronounced. The lingual faces of the protoconid and hypoconid are more steeply sloping and the lingually directed crests associated with these cusps are well developed (however they are absent in the holotype). Following an analysis of variation in dentitions of the modern species, it is evident that the above men- tioned morphological differences between the referred material and the holotype fall within the boundaries of normal intraspecific variation.

DISCUSSION

Pseudokoala cathysantamaria 1s an enormous ringtail possum and Cundokoala yorkensis an enormous koala. With the addition of these two to the Pleistocene of Australia, all families of Australian herbivorous mammals are now known to have had giants in the Pleistocene megafauna. They also significantly increase the ranks of known arboreal megafaunal species. Apart from one modestly large koala (Phascolarctos stir- toni Bartholomai, 1968), the only undoubted megafaunal arboreal species previously known from the Pleistocene was Bohra paulae Flannery and Szalay, 1982, a gigantic tree kangaroo from Wellington Caves, New South Wales.

ACKNOWLEDGMENTS

We thank the Australian Research Committee, the University of New South Wales, the Queensland Museum, National Estate Programs (Queensland), the Riversleigh Society, Queensland National Parks and Wildlife Service, Australian Geographic Society, Royal Zoological Society of New South Wales, Linnean Society of New South Wales and private individuals for support that has enabled discovery and preparation of the diverse koalas and ringtail possums of Riversleigh. Henk Godthelp, Anna Gillespie and Anne Musser (all of the University of New South Wales) helped collect material from Wellington Caves. Armstrong Osborne (University of Sydney) and Michael Augee (University of New South Wales) organised the opportunity to examine the Wellington deposits. Mathew Crowther (University of New South Wales) confirmed the identifica- tions of other Wellington mammals excavated with the tooth of Cundokoala yorkensis. Neville Pledge (South Australian Museum) and Tom Rich (Museum of Victoria) made materials available for study. Betty Thompson (Museum of Victoria) confirmed collection details of Portland materials. Suzanne Hand and Jenni Brammall (University of New South Wales) read and constructively criticised a draft of this paper.

Proc. LINN. SOC. N.S.W., 117. 1997

M. ARCHER, K. BLACK AND K. NETTLE 15

REFERENCES

Archer, M. (1984). The Australian marsupial radiation. In “Vertebrate zoogeography and evolution in Australasia’ (Eds M. Archer and G. Clayton) pp. 633-808. (Hesperian Press: Perth).

Archer, M. (1992). Ringtail possums (Pseudocheiridae, Marsupialia) from the Tertiary deposits of Riversleigh. The Beagle 9: 257-258.

Archer, M. and Bartholomai, A. (1978). Tertiary mammals of Australia: a synoptic review. Alcheringa 2: 1-19.

Archer, M., Hand, S.J., and Godthelp, H. (1995). Tertiary environmental and biotic change in Australia. In ‘Paleoclimate and evolution, with emphasis on human origins’ (Eds E.S. Vrba, G.H. Denton, T.C. Partridge, L.H. Burckle) pp. 77-90. (Yale University Press: New Haven).

Bartholomai, A. (1968). A new fossil koala from Queensland and a reassessment of the taxonomic position of the problematical species, Koalemus ingens DeVis. Memoirs of the Queensland Museum 15: 65-73.

Black, K. and Archer, M. (in press). Nimiokoala, a new genus and species of koala (Marsupialia, Phascolarctidae) from Riversleigh, northwestern Queensland, with a review of Litokoala Stirton, Tedford and Woodburne, 1967. Memoirs of the Queensland Museum.

Flannery, T.F. and Hann, L. (1984). A new macropodine genus and species (Marsupialia: Macropodidae) from the Early Pleistocene of southwestern Victoria. Australian Mammalogy 7: 193-204.

Flannery, T.F. and Szalay, F. (1982). Bohra paulae, a new giant fossil tree kangaroo (Marsupialia, Macropodidae) from New South Wales, Australia. Australian Mammalogy 5: 83-94.

Flower, W.H. (1867). On the development and succession of teeth in the Marsupialia. Philosophical Transactions of the Royal Society, London 157: 631-641.

Hand, S.J., Dawson, L., and Augee, M. (1988). Macroderma koppa, a new Tertiary species of false vampire bat (Microchiroptera: Megadermatidae) from Wellington Caves, New South Wales. Records of the Australian Museum 40: 343-351.

Luckett, W.P. (1993). An ontogenetic assessment of dental homologies in therian mammals. In ‘Mammal phy- logeny: Mesozoic differentiation, multituberculates, monotremes, early therians, and marsupials’ (Eds BS. Szalay, M.J. Novacek, M.C. McKenna) pp. 182-204. (Springer-Verlag: New York).

Osborne, R.A.L (1983). Cainozoic stratigraphy at Wellington Caves, New South Wales. Proceedings of the Linnean Society of New South Wales 107: 131-147.

Pledge, N.S. (1987a). Phascolarctos maris, a new species of koala (Marsupialia: Phascolarctidae) from the Early Pliocene of South Australia. In ‘Possums and opossums: studies in evolution’ (Ed. M. Archer) pp. 327-330. (Surrey Beatty and Sons Pty Ltd: Sydney).

Pledge, N.S. (1987b). Pseudocheirids (Marsupialia: Pseudocheiridae) from the Middle Miocene Ngama Local Fauna of northern South Australia. In ‘Possums and opossums: studies in evolution’ (Ed. M. Archer) pp. 639-679. (Surrey Beatty and Sons Pty Ltd: Sydney).

Pledge, N.S. (1992). The Curramulka Local Fauna: a new late Tertiary fossil assemblage from Yorke Peninsula, South Australia. The Beagle 9: 115-142.

Rich, T.H., Archer, M., Hand, S.J., Godthelp, H., Muirhead, J., Pledge, N.S., Flannery, T.F., Woodburne, M.O., Case, J.A., Tedford, R., Turnbull, W.D., Lundelius Jr, E.L., Rich, L.S.V., Whitelaw, M.J., Kemp, A. and Rich, P.V. (1991). Appendix 1: Australian Mesozoic and Tertiary terrestrial mammal localities. In “Vertebrate palaeontology of Australasia’ (Eds P. Vickers-Rich, J.M. Monaghan, R.F. Baird, T.H. Rich ) pp. 1005-1058. (Pioneer Design Studio: Melbourne).

Springer, M.S. (1987). Lower molars of Litokoala (Marsupialia: Phascolarctidae) and their bearing on phasco- larctid evolution. In ‘Possums and opossums: studies in evolution’ (ed M. Archer) pp. 319-325. Surrey Beatty and Sons Pty Ltd: Sydney.

Springer, M.S. (1993). Phylogeny and rates of character evolution among ringtail possums (Pseudocheiridae: Marsupialia). Australian Journal of Zoology 41: 273-291.

Stirton, R.A. (1957). A new koala from the Pliocene Palankarinna Fauna of South Australia. Records of the South Australian Museum 13: 71-81.

Stirton, R.A., Tedford, R.H. and Woodburne, M.O. (1967). A new Tertiary formation and fauna from the Tirari Desert, South Australia. Records of the South Australian Museum 15: 427-462.

Turnbull, W.D. and Lundelius Jr, E.L. (1970). The Hamilton Fauna, a late Pliocene mammalian fauna from the Grange Burn, Victoria, Australia. Fieldianna: Geology 19: 1-163.

Turnbull, W.D., Rich, T.H.V. and Lundelius Jr, E.L. (1987). Pseudocheirids (Marsupialia: Pseudocheiridae) of the Early Pliocene Hamilton Local Fauna, southwestern Victoria. In ‘Possums and opossums: studies in evolution’ (Ed. M. Archer) pp. 689-713. (Surrey Beatty and Sons Pty