Academia.edu no longer supports Internet Explorer.

To browse Academia.edu and the wider internet faster and more securely, please take a few seconds to upgrade your browser.

Log In
Sign Up

Figure 21 – uploaded by Karen Black

See full PDF downloadDownload figure

Fig.22 The largest marsupial known, the three-tonne diprotodontid Diprotodon optatum from the Australian Pleistocene (P. Murray). While this dry-country megafaunal species may have looked wombat-like, diprotodontids were only distantly related to the much smaller, fossorial vombatids The Rise of Australian Marsupials: A Synopsis of Biostratigraphic, Phylogenetic, Palaeoecologic... — Figure 22 The largest marsupial known, the three-tonne diprotodontid Diprotodon optatum from the Australian Pleistocene (P. Murray). While this dry-country megafaunal species may have looked wombat-like, diprotodontids were only distantly related to the much smaller, fossorial vombatids The Rise of Australian Marsupials: A Synopsis of Biostratigraphic, Phylogenetic, Palaeoecologic...

Related Figures (68)

The Rise of Australian Marsupials: A Synopsis of Biostratigraphic, Phylogenetic, Palaeoecologic... maculatus (G. Settle); (c) Thylacine Thylacinus cynocephalust (Tasmanian Museum and Art Gallery); and (d) Numbat Myrmecobius fasciatus (D. Whitford). Most of Australia’s car- nivores (e.g., b—d) are now either extinct or endangered Fig.1 Representatives of extant (and recently extinct f) dasyuromorphian families (Table 1): (a, b) Dasyuridae; (c) Thylacinidae; (d) Myrmecobiidae. (a) Kimberley Planigale Planigale subtilissima (M. Archer); (b) Tiger Quoll Dasyurus

Fig. 2 Representative extant members of peramelemorphian families (Table 1). (a) Thylacomyidae, Greater Bilby Macrotis lagotis (R. Scott); (b) Peramelidae, Eastern Barred Bandicoot Perameles gunni (Wikimedia Commons, Noodle Snacks); and (c) Peroryctidae Peroryctes longicaudata (T. Flannery). These families proliferated only after rainfall in Australia began to steeply decline in the late Miocene

The Rise of Australian Marsupials: A Synopsis of Biostratigraphic, Phylogenetic, Palaeoecologic... Commons, Aviceda); (f) Acrobatidae, Acrobates pygmaeus (D. Andrew); and (g) Burramyidae, Cercartetus nanus (D. Whitford). All of these families have representatives extend- ing back to late Oligocene and some (e.g., macropodids and pseudocheirids) have massively increased in diversity since the late Miocene Fig.3 Representatives of extant members of diprotodon- tian families (Table 1). (a) Phascolarctidae, Phascolarctos cinereus (Wikimedia Commons, Sanjay ach); (b) Vombatidae, Vombatus ursinus (Wikimedia Commons, Materialscientist); (c) Pseudocheiridae, Pseudocheirus archeri (M. Archer); (d) Macropodidae, Macropus parryi (M. _ Archer); (e) Phalangeridae, Spilocuscus maculatus (Wikimedia

Fig.4 A modern representative of the order Notoryctemorphia containing the sole family Notoryctidae, the Southern Marsupial Mole Notoryctes typhlops (M. Gillam). While today only known from deserts in central Australia, their ancestors appear to have first evolved in lush rainforests

Fig.5 Key events in the evolution of Australian marsupials. In contrast to the relatively rich record of events and evolutionary outcomes for marsupials spanning the last 26 Ma, no marsupial fossils have been found in Australia older than those in the 55 Ma Tingamarra LF, and none is known from that time until 26 Ma. (Abbreviations: Ma, million years ago; yBP, years before present)

Table 1 Marsupial classification used in this study Table 1 (continued)

placentals, and rodents in the late Cenozoic, marsu- pials filled the majority of herbivorous as well as all of the insectivorous, carnivorous and omnivorous mammalian roles.

Fig. 7 Sole living representative of the australidelphian order Microbiotheria, Dromiciops gliroides. Microbiotheriids, which only survive today in South America, are a vital evolutionary link between the marsupials of South America, Antarctica and Australia (J.A.W. Kirsch) Amrine-Madsen et al. 2003; Horovitz and Sanchez- Villagra 2003; Asher et al. 2004; Cardillo et al. 2004; Nilsson et al. 2004; Drummond et al. 2006; Phillips et al. 2006; Sanchez-Villagra et al. 2007; Beck 2008a; Beck et al. 2008b; Meredith et al. 2008a; Phillips and Pratt 2008; Meredith et al. 2009).

The Rise of Australian Marsupials: A Synopsis of Biostratigraphic, Phylogenetic, Palaeoecologic... Fig.6 A tiny bright red dot in a vast landscape of the past. Henk Godthelp (UNSW) searches in the late Cretaceous (below him) to Paleogene sediments (above him) in the Grand Baranca, Patagonia, Argentina, for traces of the first marsupials that reached South America (M. Archer)

Fig.8 Site of the early Eocene Tingamarra LF, near Murgon, southeastern Queensland (K. Black; inset H. Godthelp). From this ‘pit in a paddock’, in 55 myo sediments that accumulated long before Australia had finally separated from Antarctica 35 Ma, have come Australia’s oldest marsupials such as Djarthia as well as the world’s first songbirds and possibly the oldest bat

The Rise of Australian Marsupials: A Synopsis of Biostratigraphic, Phylogenetic, Palaeoecologic... and australidelphian marsupials (Australian plus ubiquitous microbiotheres) demonstrates higher familial diversity of mar- supials in Australia. Despite the calculated antiquity based on molecular divergence, apart from microbiotheriids none of the other australidelphian families are known as fossils prior to the late Oligocene Fig.9 Phylogeny and divergence estimates for modern marsu- pial groups based on nuclear gene sequence data of Meredith et al. (2009). Node numbers and divergence dates are listed in Table 2. Abbreviations: L.CRET, late Cretaceous; MZ, Mesozoic; Oligo, Oligocene; Paleo, Paleocene; Pl, Pliocene. The basic dichotomy between the ‘ameridelphian’ (South America)

Fig. 10 Upper molars of chulpasiines Chulpasia mattaueri (a) and C. jimthorselli (b) from Chulpas in southern Peru and Murgon in southeastern Queensland respectively (S. Hand). Although the family relationships of these early Cenozoic mar- supials are unclear, they represent the first marsupial genus known to have spanned three continents which also reflects the forested corridor that at this time linked all three

The Rise of Australian Marsupials: A Synopsis of Biostratigraphic, Phylogenetic, Palaeoecologic... Fig. 11 Comparison of isolated anklebones of the Australian early Eocene Djarthia murgonensis with an extant aus- tralidelphian marsupial and an extant ameridelphian marsupial. Astragali (a, c, e) and calcanea (b, d, f) of the ‘ameridelphian’ didelphid Thylamys elegans (a—b), Djarthia murgonensis (c—d) and the australidelphian microbiotheriid Dromiciops australis (e-f). Astragali illustrated in dorsal (top), distal (middle) and ventral (bottom) views. Calcanea illustrated in dorsal (top) and distal (bottom) views. Scale bar, 1 mm. Presence of the contin- uous lower ankle joint pattern (CLAPJ) and subdivision of the calcaneocuboid facet into three distinct facets are australidel- phian synapomorphies (after Beck et al. 2008b). The differences between the ankle bones of these two great groups of marsupials are also reflected in molecular and other system differences

convergent on placental golden moles (chrysochlo- rids). Archer (1976c) suggested possible affinities to diprotodontians based on some similarities in middle ear construction and soft anatomical features. Description of the first known extinct notoryctid from early Miocene sediments of the Riversleigh World Heritage fossil deposits of Qld (Archer et al. 2011) may help shed light on the ordinal affinities of the

Table 2 Divergence times (Ma) and confidence intervals (in parentheses) for marsupials based on recent relaxed molecular clock analyses

Zone A vertebrate assemblages (= System A of Archer The late Oligocene (26-23 Ma) fossil record of Australia is well represented by deposits in cen- tral (Etadunna and Namba Fms, S.A.) and northern Australia (Riversleigh, Qld, Kangaroo Well and Pwerte Marnte Marnte, N.T.; Figs. 13 and 15a). The Etadunna and Namba Fms have been dated as between 24 and 26 Ma using radiometry, magnetostratigraphy and biocorrelation of forams and pollens (Lindsay 1987; Woodburne et al. 1985, 1993). Riversleigh’s Faunal Zone A vertebrate assemblages (= System A of Archer

The Rise of Australian Marsupials: A Synopsis of Biostratigraphic, Phylogenetic, Palaeoecologic... Fig.15 Map of Australasian fossil mammal-bearing deposits. (a) Tertiary deposits; (b) Pleistocene deposits. Conspicuous challenges are the almost total lack of Tertiary deposits from Western Australia and the single site known from New Guinea. The richest, longest records for the Tertiary come from Queensland, South Australia and the Northern Territory. Pleistocene sites, however, are most abundant in Victoria, New South Wales and South Australia

during the late Eocene with consequent development of the Drake Passage, the cold Antarctic circumpolar current began to churn its way around the south- ern oceans (Scher and Martin 2006). Global oceanic circulation patterns began to change, affecting cli- mates worldwide. Glaciers began to form in Antarctica and global sea temperatures cooled, which had a major impact on climate in the southern hemisphere (White 2006). Australia had entered an ‘icehouse’ phase resulting in low temperatures, reduced rainfall and consequent declining biodiversity (Frakes et al. 1987; McGowran and Li 1994). Late Oligocene forests were less diverse than those of the early Eocene and Oligocene and were dominated by casuarinaceans, myrtaceans and species of Nothofagus with araucari- aceans and podocarpaceans prominent in southeastern Australia. With the advent of greater seasonality in the Oligocene, sclerophyll taxa such as species of

Table 3 Generic and species-level diversity (genus/species) of Australasian marsupial families from the late Oligocene to recent

Fig. 18 Nimbacinus dicksoni skull and dentary emerging from a partially processed limestone block from Riversleigh’s AL90 deposit (A. Gillespie). This fox-sized thylacinid was found as an intact skeleton curled up in the relaxed posture of an animal that had died in its sleep about 15 Ma. It lay adjacent to a similarly well-preserved skeleton of an archaic kangaroo Thylacinids (with the thylacoleonids) appear to be the dominant marsupi Oligocene and much of t al carnivores of the late he Miocene, with numer- ous fossil taxa being described in the last two decades (Archer 1982b; M uirhead and Archer 1990; Muirhead 1992, 1997; Muirhead and Wroe 1998; Wroe 1996b, 2001; Wroe and Megirian 2000, 2006 from late Oligocene depos bulli Muirhead and Wroe, and Musser 2001; Murray b). The oldest thylacinids its include Badjicius turn- 1998 from White Hunter LF, Faunal Zone A, Rivers eigh; Nimbacinus dicksoni Muirhead and Archer, 1990 from Faunal Zones A-C, Riversleigh (Fig. 18); Nim bacinus sp. cf N. dicksoni

Fig.17 Well-preserved skull of the oldest-known undoubted dasyurid Barinya wangala from Riversleigh (R. Arnett). Because they have been preserved in freshwater limestone, preservation of many of the Oligocene and Miocene skulls from Riversleigh is unusually good

Fig. 20 The partial right dentary of a very strange numbigilgid marsupial (drawing J. Muirhead). The relationships of this group are a mystery; they may be peramelemorphians (Fig. 19) or they may represent an entirely different order. However there is noth- ing like this taxon in any of the other known marsupial orders. Strange features include the complex extra cusps and blades on the molars and the two-cusped second premolar Fig. 19 Phylogenetic interrelationships of peramelemorphians including extinct groups based on dental morphology. The dashed line indicates tentative relationships of the enigmatic numbigilgids to this order of marsupials (Fig. 20). Yaraloids, all of which vanished before the Pleistocene, are more archaic than any of the living groups most of which do not have a fos- sil record until the Pliocene. However, these almost certainly began to diversify during the relatively poorly documented late Miocene

Undoubted peramelemorphians are currently divided into two superfamilies: Perameloidea, con taining the three extant families Thylacomylidae Peroryctidae and Peramelidae; and Yaraloidea, con taining the extinct family Yaralidae (Fig. 19). I numbigilgids (containing Numbigilga ernielundeliusi Fig. 20) are peramelemorphians (a possibility dis cussed by Beck et al. 2008a), their relationship:

Fig. 21 Yaralid bandicoots are among the most common mar- supials found in the rich early to mid Miocene fossil deposits ot Riversleigh (K. Atkinson). Sometimes, as in this case where the specimen has been partially exposed by dissolution of limestone in dilute acetic acid, skeletons are preserved with associatec elements found next to each other Yaralids are a geographically widespread group of plesiomorphic, short-snouted bandicoots (Long et al. 2002) including one of the oldest known (with the pos- sible exception of the early Eocene Tingamarran taxon discussed above) peramelemorphians, Yarala kida Schwartz, 2006a from the late Oligocene Kangaroo Well LF. Yarala kida is more plesiomorphic and possibly ancestral to the type species, Yarala burch- fieldi Muirhead and Filan, 1995 from early to middle Miocene deposits of Riversleigh (Schwartz 2006a). Peramelemorphians in the late Oligocene Ditjimanka

Fig. 23 The late Miocene palorchestid Palorchestes painei from Alcoota in the Northern Territory. (a) Reconstruction showing the characteristic tapir-like trunk of palorchestids (P. Murray). (b) Rendering of the skull that formed the basis for the cranial reconstruction, showing at the top the tapir-like position of the tips of the nasal bones (P. Murray)

Fig.24 The skull of the early Miocene wynyardiid Namilamadeta superior from Upper Site at Riversleigh (K. Black). Wynyardiids were first known from a Tasmanian specimen that lacked teeth. Until discovery of dentitions in central Australia and Riversleigh their now undoubted relation- ship to vombatiform marsupials was unclear. All of them were extinct by the end of the middle Miocene

Fig. 25 Relationships of extinct families within the suborder Vombatiformes (after Black 2008). This suborder in itself is as or more diverse than the placental order Perissodactyla and included forms that ranged from tapir-like herbivores (palorch- estids) to the most specialised of mammalian carnivores — the marsupial lions (Thylacoleonidae)

Fig. 26 Semi-selenodont dentition of the ilariid Kuterintja ngama from the late Oligocene White Hunter Site at Riversleigh (T. Myers). These vombatiforms, although fox-size, had teeth that were similar to those of the extinct placental anthracotheres. The shapes of teeth indicate probable diet and in this case they almost certainly ate soft leaves possibly of trees

Fig. 27 The only known jaw (and Holotype) of the enigmatic vombatomorphian family Maradidae, Marada arcanum, from the late Oligocene Hiatus Site at Riversleigh (K. Black). In the absence of more information, the ecological role of this marsupial remains a mystery

Fig. 28 Teeth of primitive wombats, all from Riversleigh (M. Archer). They demonstrate, moving left to right from the left tooth, which is early Miocene in age, a steady increase in the height of the crown until by late Miocene time (tooth at for right) they had lost their roots altogether and the teeth erupted con- tinuously throughout life. This evolutionary transition suggests adaptation to an increasingly abrasive diet within 10 million years Overall, survival of a single vombatomorphian fam- ily today (wombats) belies the highly diverse nature The oldest, most plesiomorphic wombat is Rhizophascolonus crowcrofti Stirton et al., 1967 from the Kutjamarpu LF, S.A. and Bone Reef LF, Faunal

Burramyoids The superfamily Burramyoidea, con- taining the single family Burramyidae (Table 3, Fig. 29), was established by Aplin and Archer (1987) in recognition of the degree of morphological

Fig. 30 The extant mountain pygmy-possum Burramys parvus, one of the largest of the burramyids (H. Bates). Having first been discovered and named as a fossil in the 1800s before being discovered alive in 1966 in an alpine ski lodge, this highly spe- cialised possum is now in danger of becoming an extinct fossil again because of growing climate-change-related threats to its alpine habitat

Fig. 31 The strikingly complex, somewhat rodent-like lower teeth of Ektopodon stirtoni, from Mammalon Hill, S.A., are typ- ical of all ektopodontid possums (N. Pledge). These similarities may have led to competition with native rodents and extinction prior to the late Pleistocene

Fig. 33 Reconstruction of an undescribed primitive balbarid kangaroo from the late Oligocene of central Australia (R. Scott). Balbarids were among the most common of the archaic kan- garoos in the forests of the late Oligocene to middle Miocene. Although in the main herbivorous, some would have been omnivorous and others carnivorous (Fig. 32). Flamingos, crocs and fish were abundant in the freshwater lakes that dotted inland Australia at this time

Miocene PIR Site (A. Nelson). The blocks of limestone have been carved using light explosives into blocks that can be more easily transported to UNSW for acid-processing Fig. 34 The Riversleigh World Heritage area of northwestern Queensland. (a) Tertiary freshwater limestone jutting up out of a semi-arid woodland (K. Black). (b) Excavation work at the early

The Rise of Australian Marsupials: A Synopsis of Biostratigraphic, Phylogenetic, Palaeoecologic... The Early Miocene Marsupial Fauna The best-documented early Miocene faunal assem- blages are those of Faunal Zone B from the Riversleigh World Heritage Area, northwestern Qld (Archer et al. 1989, 1994, 1995, 1997, 1999). Within these highly diverse faunal assemblages, alongside more archaic groups some of which were in decline, we see the first appearance of many modern groups such as notoryc- tids, dasyurids, phalangerids and acrobatids as well as extinct families such as yingabalinarids and yalkapari- dontids that are so far unique to Riversleigh (Table 3).

The Rise of Australian Marsupials: A Synopsis of Biostratigraphic, Phylogenetic, Palaeoecologic... deposits compared with only 11 genera and 20 species during the late Oligocene. In direct contrast is an asso- ciated decrease in diversity in the predominantly ter- restrial, large-bodied vombatiforms with the apparent extinction of two families (Ilariidae and Maradidae) and a reduction in generic and species level diver- sity in the remaining families. At least 20 genera and 29 species of vombatiform were present during the late Oligocene, yet only 13 genera and 18 species are recorded from the early Miocene. Macropodoid diver- sity appears to have remained relatively unchanged from the moderate diversity displayed during the late Oligocene (Table 3). deposits compared with only 11 genera and 20 species

Fig. 37 Fossil koalas (phascolarctids) from Riversleigh. (a) Nimiokoala greystanesi from the Miocene had very odd, highly crenulated teeth. (b) A partial skull of Litokoala kutjamarpensis showing enlarged tympanic bullae (K. Black) that suggest it was very sensitive to low-frequency sounds of the kind that modern koalas utter when communicating across large distances

Fig.38 Skull of a small species of marsupial lion (thyla- coleonid), Priscileo roskellyae, from the early Miocene Upper Site of Riversleigh (M. Archer). Although barely cat-size, this at least omnivorous vombatiform marsupial was soon replaced by larger and larger, ever more specialised descendents until by the late Pleistocene marsupial lions were lioness-size

In contrast to petaurids, pseudocheirids represent one of the most successful marsupial radiations of the early middle Miocene. As many as six sympatric species have been reported from the Upper Site LF of Faunal Zone B, Riversleigh (Roberts et al. 2007; Travouillon et al. 2006) and five sympatric species are known from the Kutjamarpu LF (Woodburne et al. 1993). Much of this material (Fig. 39) is currently in the process of being described (Roberts et al. 2009). Published taxa from the Kutjamarpu LF include Pildra tertius Woodburne et al., 1987c; M. kutja- marpensis (ibid.); M. ampelos Roberts et al., 2009; M. syke Roberts et al., 2009; and Paljara tiraren- sae Woodburne et al., 1987c. The latter two species are also known from Faunal Zone B, Riversleigh (Bassarova et al. 2001; Roberts et al. 2009). Additional published species from Faunal Zone B, Riversleigh, include Gawinga aranaea Roberts et al., 2007; Paljara maxbourkei Bassarova et al., 2001; and Paljara nan- cyhawardae Bassarova et al., 2001. This high diver- sity of ringtail possums almost certainly reflects a high diversity of rainforest plants on which they fed. However, not all were necessarily obligate folivores: Fig. 39 Fossil ringtail possum (pseudocheirid) skull from the early Miocene Neville’s Garden Site, Riversleigh (Photo R. Murphy). Although still being acid-etched from the freshwater limestone in which this skull was found, the leaf-eating teeth and wide space for the powerful chewing muscles of a folivore are clear

Fig. 40 Tarsipedids, or honey possums, now only known from W.A., have no pre-Pleistocene fossil record (J. Gould). Having spent millions of years becoming increasingly nectarivorous, their cheekteeth are degenerate. From molecular biology, they appear to be at least distantly related to feather-tail gliders (acrobatids)

Fig. 41 Skull of the early Miocene balbarid kangaroo Balbaroo fangaroo from Riversleigh (A. Gillespie). While the cheek- teeth indicate that it was primarily herbivorous, the enormous, recurved and sharp upper canines suggest it was capable of putting up a good fight to avoid becoming the dinner of carnivo- rous kangaroos and other predators Of special mention, and unique among all kanga- roos, is the unusual condition found in B. fangaroo (Fig. 41) of extraordinary hypertrophied upper canines (Cooke 2000). Enlarged canines that are sexually dimorphic in size are found in modern artiodactyls such as tragulids and moschids. These small-to-tiny deer occupy dense vegetation and the males use their large canines as close-range visual cues of sexual identity, agonistic displays and for defence. By anal- ogy, Cooke (2000, 2006) proposed that the enormous (for a kangaroo) canines (Fig. 41) of B. fangaroo may also be a sexually dimorphic feature in a species that occupied the dense understorey of Riversleigh’s early Miocene rainforests. Cooke (2006) further suggested that like N. gillespiae, B. fangaroo may have been quadrupedal and hence less able to use its forearms and hind legs in fights in contrast to living kangaroos. Consequently, its large canines may have also been used, as they sometimes are in moschids and tragulids, as a defensive weapon. Interestingly, modern tragulids and moschids also have relatively short legs compared with other deer.

The Rise of Australian Marsupials: A Synopsis of Biostratigraphic, Phylogenetic, Palaeoecologic.. of the canopy and possibly the beginning of seasonal variations in conditions. The palaeoenvironment of the late middle Miocene Bullock Creek LF has been interpreted, on the basis of its abundant aquatic and stream bank fauna, as a large meandering river and surrounding floodplain with seasonal fluctuations in water supply. Murray and Megirian (1992) interpret the proximal vegetation to be a mix of shrubs and sedges. Unlike Riversleigh’s Faunal Zone C assemblages, small terrestrial animals and arboreal taxa are scarce (Murray and Megirian 1992; Schwartz and Megirian 2004) and may suggest that species-rich forests were distal to the depositional area. Murray and Vickers-Rich (2004) suggest that the rarer elements of the Bullock Creek LF, such as Faunal Zone C assemblages, small terrestrial animals

Fig.43 The skull and jaw of a middle Miocene leopard-size thylacoleonid, Wakaleo vanderleuri from the Bullock Creek LF, N.T. (P. Murray). Larger than Priscjleo but smaller than Thylacoleo, the species of this genus of marsupial carnivores already have vicious stabbing lower incisors and increasingly elongate shearing premolars

Fig. 44 Skulls of an adult and juvenile diprotodontid Nimbadon lavarackorum from the middle Miocene AL90 Site of Riversleigh (K. Black). Dozens of skulls representing all devel- opmental stages of this sheep-sized herbivore have come from the AL90 cave deposit Several diprotodontid species (e.g. N. lavaracko- rum, Neohelos sp. A, N. stirtoni) exhibit high abun- dance in many of the deposits in which they are found which suggests that each of these species moved together as large ‘mobs’ (Black 1997b; Black and Hand 2010; Murray et al. 2000a, b). Of note is an exceptionally well-preserved N. lavarackorum popu- ation that includes cranial (Fig. 44) and postcranial material (Fig. 45) of pouch-young to mature adults, from AL90 Site at Riversleigh. This material has allowed benchmark studies of intraspecific (e.g. Black and Hand 2010) and ontogenetic (e.g. Black et al. 2010) variation within a fossil marsupial population. As a consequence of the former study, Nimbadon whitelawi Hand et al., 1993 known from a single specimen from the Bullock Creek LF, has since been synonymised with N. lavarackorum (Black and Hand 2010). Nimbadon lavarackorum is small (approx. 75 kg) compared to other mid-Miocene diprotodontids which seems to buck the general trend for increasing body size through time. Black and Hand (2010) sug- gest this plesiomorphic species may represent a relict taxon with phylogenetic relationships to even smaller

The Rise of Australian Marsupials: A Synopsis of Biostratigraphic, Phylogenetic, Palaeoecologic... and Archer to a new genus, Onirocuscus. Crosby and Norris (2003) and Crosby (2007) also suggested that dicksoni Flannery and Archer represented a new as yet undescribed genus of phalangerids. Other middle Miocene phalangerids from Riversleigh include Onirocuscus rupina Crosby, 2007; Onirocuscus inver- sus; and an additional undescribed species referable to the same new genus as ‘Trichosurus’ dicksoni (Fig. 46).

Fig. 46 Partially processed skull and jaws of a middle Miocene phalangerid from Dome Site South at Riversleigh (K. Black). The exquisite preservation of Riversleigh’s fossils may reflect the speed with which they were encased by limestone after falling into carbonate-rich freshwater pools. In some cases, even soft tissues have been fossilised here because of the globally unusual process of bacteria-mediated phosphatisation Burramyoids Both B. brutyi and Cercartetus sp. extend their temporal range into the middle Miocene with levels of abundance similar to those in the early Miocene. Given the rainforest palaeoenvironments of

Fretauroids Ihe middle Miocene petauroid fauna con- sists of Dactylopsila sp. and D. yadjana and a spectacular radiation of ringtail possums (Fig. 47). Fourteen pseudocheirid species have been reported from Riversleigh’s middle Miocene assemblages (Archer 1992; Archer et al. 1999; Bassarova et al. 2001; Archer et al. 2006; Roberts et al. 2008, 2009) including members of Pildra (4 undescribed species); Marlu (M. kutjamarpensis, M. syke, M. ampelos, M. karya Roberts et al. 2009); Paljara (P. nancy- hawardae, P. tirarensae, P. hushae Roberts et al. 2008); and an unnamed genus and species. Two Pseudochirops sp. had previously been reported from Faunal Zone C deposits (Archer et al. 1997, 2006; Roberts et al. 2007) but have since been identified as a new genus that awaits description. Ten sym- patric species are recorded in Riversleigh’s lower Faunal Zone C Dwornamor LF (Archer et al. 2006) whereas only three species are known from the upper Faunal Zone C Henk’s Hollow LF. Pseudocheirids are not known from the Bullock Creek LF, although a bias towards large terrestrial species and aquatic taxa has been demonstrated (Murray and Megirian 1992). Be that as it may, modern woodland/open forest 1992). Be that as it may, modern woodland/open forest

Fig. 48 The skull and dentary of the middle Miocene potoroid Bettongia moyesi, from Two Tree Site at Riversleigh (D. Maitland). While other kinds of archaic kangaroos were com- mon in these ancient forests, potoroids (rat-kangaroos) were extremely rare. However, by Quaternary time they were common in all habitats of Australia from rainforests to deserts Potoroid diversity remains as low as it was in the early Miocene with a single middle Miocene species described and an additional unnamed potoroid iden- tified from the Bullock Creek LF (L. Schwartz ‘per- sonal communication’ to J. Case in Westerman et al. 2002). Bettongia moyesi Flannery and Archer, 1987c from the Two Trees LF of Riversleigh is known from an exceptionally well-preserved skull and asso- ciated dentaries (Fig. 48). This faunal assemblage is the only one at Riversleigh that has produced this taxon. Morphologically, this potoroid is broadly sim- ilar to the living burrowing bettong, Bettongia lesueur 2002). Bettongia moyesi Flannery and Archer, 1987c

The Encore LF of Riversleigh is interpreted to be early late Miocene (~9-—10 myo) in age on the basis Comprehensive studies of the palaeontology and geology of the Alcoota locality (Alcoota and Ongeva LFs) have been undertaken by Woodburne (1967), Murray and Megirian (1992), Murray et al. (1993), Megirian et al. (1996) and Murray and Vickers-Rich (2004). Age estimates for these deposits are based on stage-of-evolution biocorrelation of zygomaturine diprotodontids (Murray et al. 1993; Megirian et al. 1996). The Ongeva LF, which comes from a strati- graphic unit in the Waite Fm that overlies that which produces the Alcoota LF, contains zygomaturines (e.g. Zygomaturus gilli; Megirian et al. 1996) at an equiv- alent stage of evolution to zygomaturines from the Beaumaris LF of Victoria. The Beaumaris LF has been variably interpreted as latest late Miocene or earliest Pliocene (i.e., Cheltenhamian) in age (Rich et al. 1991). Strontium dating of molluscs indicates the deposit is between 4.5 and 5.5 Ma (Dickinson et al. 2002). The Alcoota LF has been traditionally inter- preted as late Miocene (Mitchellian) in age, somewhat older than the Ongeva LF. However, recognition of Kolopsis torus in both the Alcoota and Ongeva LFs (Megirian et al. 1996) and Kolopsis sp. cf. K. torus (Rich et al. 2003) in the Beaumaris LF has led Rich et al. to suggest the Alcoota LF is also Cheltanhamian in age. The Encore LF of Riversleigh is interpreted to be

Fig. 50 Palate of the giant late Miocene thylacinid Thylacinus potens from the Alcoota LF of the N.T. (L. Meier). This wolf- sized carnivorous marsupial was the largest thylacinid ever found. Its large size reflects the increasing size of the late Miocene herbivores, a trend that culminated in the megafaunal giants of the Pleistocene The Rise of Australian Marsupials: A Synopsis of Biostratigraphic, Phylogenetic, Palaeoecologic...

Fig.51 Reconstruction of the largest known marsupial thy- lacine, Thylacinus potens from the late Miocene Alcoota LF, NT (courtesy S. Wroe). In keeping with its role as the king of mam- malian beasts in the late Miocene, it is very rare in the Alcoota deposit

Fig.52 Dentary (two views of the holotype) of the Pleistocene wombat Warendja wakefieldi from McEacherns Cave, Vic. (K. Black). As in all vombatids that have ever-growing, rootless teeth, the premolars and molars constantly erupt to replace tooth material worn away by abrasion. The cheekteeth of early to mid- dle Miocene forest-dwelling vombatids from Riversleigh had roots and crowns. Neither became irrelevant until the climate change of the late Miocene

Fig.53 A possible surviving sthenurine kangaroo, the banded hare-wallaby Lagostrophus fasciatus is an endangered species whose range is now restricted to two islands in Shark Bay, W.A. (J. Gould). While some studies suggest they are too ‘primitive’ to be part of the sthenurine radiation, most researchers agree that they are surviving members of the group that contained species of the extinct genus Troposodon and, as such, unlike any of the other living kangaroos

Fig.54 Reconstruction of the largest known kangaroo, the sthenurine macropodid Procoptodon goliah. It stood 2.5 m tall and is known from many Pleistocene sites in Australia (R. Scott). By the time it was common across much of inland as well as coastal areas of the continent, grasslands and deserts were a feature of the interior. A wisp of smoke in the distance contro- versially suggests that humans may have arrived in time to see some of these now extinct megafaunal giants

Fig.55 Riversleigh’s only known Pliocene deposit. (a) Early Pliocene Rackham’s Roost site (S. Hand) with the pale Pliocene deposit lapping up against the base of the former walls of the cave; (b) reconstruction of Rackham’s Roost faunal assemblage (D. Dunphy). By this time, the forests of northern and inland Australia had opened up, the first rodents had arrived and the first grazing kangaroos had evolved Pliocene (5.3 to 1.8 Ma) mammal deposits are well represented in Australia, occurring in all states except Tasmania and the Northern Territory. The old- est records for marsupials in New Guinea are also Pliocene in age. Pliocene marsupial-bearing deposits (Figs. 13 and 15a) include Queensland’s Rackham’s Roost (Fig. 55), Bluff Downs and Chinchilla LFs; the Bow and Big Sink LFs of central N.S.W.; Quanbun LF of W.A. (Archer et al. 1984; Rich et al. 1991); the Awe LF of P.N.G. (Fig. 56); and numerous local- ities in the Lake Eyre, Frome, Murray, Otway and Port Philip Basins of southeastern Australia such as Palankarinna, Kanunka, Sunlands, Fisherman’s Cliff, Hamilton (Woodburne 1972; Fig. 57) and Dog Rocks LFs (reviewed by Tedford et al. 2006). brief milder greenhouse phase, Nothofagus and other During the Pliocene the global climate fluctuated markedly with the expansion and contraction of north- ern and southern hemisphere ice sheets (Gallagher et al. 2003). Following the cool and dry conditions that characterised the late Miocene, in the early Pliocene there was a brief respite of warmer, wetter conditions before Australia began to dry once more. During this brief milder greenhouse phase, Nothofagus and other

Fig. 56 Early Pliocene Otibanda Formation, the source of the Awe Local Fauna, New Guinea (P. Woolley). The diprotodon- tids and kangaroos in this deposit appear to be most similar to those of the Alcoota LF of the NT suggesting that Australian marsupials first colonised NG sometime during the late Miocene

Fig.58 The pig-footed bandicoot, Chaeropus ecaudatus, a recently extinct peramelid that once lived in central Australia (J. Gould). From studies of gut contents in preserved specimens, it appears to have been the only grazing bandicoot and one of the smallest mammalian grazers known

Fig.59 The palate and mandible of the Pliocene diprotodon- tine Euowenia grata from the Pliocene Chinchilla LF, Qld (K. Black). This cow-sized diprotodontid was highly unusual in appearing to have, like vombatids, only a single pair of upper incisors. The very worn teeth indicate that whatever plant material it was eating was highly abrasive Diprotodontids are represented by at least seven genera and nine species in the Pliocene, this being the highest diversity recorded in the family’s long history. The spread of open forests were evi- dently beneficial for this now-extinct family. Notable Pliocene diprotodontids include the zygomaturines Kolopsis rotundus Plane, 1967 and Kolopsoides cul- tridens Plane, 1967 from the Awe LF of N.G. and Zygomaturus keanei Stirton, 1967c from the Palankarinna LF of S. A. Representative diprotodon- tines include Euowenia grata De Vis, 1887 (Fig. 59) from the Chinchilla LF, Qld and from Pliocene sediments of the Tirari Formation, S. A. (Camens and from the Chinchilla LF, Qld and from Pliocene In Australia, Pliocene marsupial lions (thyla- coleonids) are widely distributed, with the larger Thylacoleo crassidentatus Bartholomai, 1962 repre- sented in the Bow, Chinchilla and Bluff Downs LFs of N.S.W. and Qld, and the much smaller Thylacoleo hilli Pledge, 1977 in the Bow LF and Curramulka LF from N.S.W. and S. A. Among Pliocene assemblages, only the Bow LF of N.S.W. includes two sympatric thylacoleonids — T: crassidentatus and T. hilli.

Fig.60 Petaurids like these living Sugar Gliders, Petaurus breviceps, were probably stimulated into evolving gliding adap- tations by the opening of forests from the late Miocene (A. Easton, Queensland Museum). Like all three groups of gliding marsupials, which occupy open forests to woodlands, its clos- est relatives (in this case Leadbeater’s Possum) are non-gliding possums found in lush forests The petaurid fossil record is relatively poor. In regard to species of Petaurus, this may be because open forest (the current habitat of the gliding petaurids) was not widespread before the early Pliocene. Until the forests had opened up, there would have been lit- tle selection pressure on arboreal possums to develop the ability to glide (Archer and Hand 2006). The first occurrence of the modern genus Petaurus (Fig. 60) is the ability to glide (Archer and Hand 2006). The first tle selection pressure on arboreal possums to develop

Fig.61 Reconstruction of a Pliocene propleopine kangaroo eat- ing the juvenile of an extinct relative (Troposodon sp.) of the living banded hare-wallaby Lagostrophus fasciatus (R. Scott). Propleopines include the carnivorous kangaroos of the early to middle Miocene (Ekaltadeta spp) as well as slender, somewhat bear-like species (Propleopus wellingtonensis) that survived into the late Pleistocene before the subfamily went extinct along with other megafaunal giants

other skeletal remains; (d) articulated Simosthenurus occiden- talis skeleton (S. Bourne). The Naracoorte Caves are part of the Fossil Mammals of Australia World Heritage listing alongside Riversleigh Fig.62 The Naracoorte Caves, all 27 of them, have acted as pit- fall traps, collecting animals for at least 500,000 years including many megafaunal species. (a) The excavation process; (b) recon- structed Thylacoleo carnifex skeleton; (ec) T: carnifex skull and

Peramelemorphians Fig.63 Skull of the Recent Thylacine, Thylacinus cyno- cephalus, alongside a humerus from the Kimberley region of northwestern W.A., and a much larger Pleistocene humerus from Wellington Caves, central N.S.W. (M. Archer). None of the mainland Thylacines appears to have survived much beyond 4,000 yBP after which time they were restricted to Tasmania until Europeans drove them to extinction by 1936

Fig.64 Thylacinus cynocephalus mummified head from the surface of a cave on the Western Australian section of the Nullarbor Plain (John Long and WAM). These individuals are among the last survivors of the mainland Thylacine. Introduction and probably domestication of the comparably sized Dingo (Canis lupus) by unknown people about 4,000 years ago may have led to extinction of the Thylacine on the mainland. Dingos never reached Tasmania

Fig.65 Skull of the short-faced sthenurine macropodid kan- garoo Simosthenrus browneorum from Pleistocene deposits in Naracoorte Caves, S.A. and Mammoth Cave, W.A. (S. Bourne). This giant, boof-headed kangaroo was one of about 55 megafau- nal species alive in the late Pleistocene. Most but not all appear to have been driven to extinction by climate change prior to the arrival of humans

Related topics:

Vertebrate Palaeontology Biogeography Biodiversity Vertebrate Paleontology Climate Change and Biodiversity Quaternary palaeontology Quaternary environments

Connect with 287M+ leading minds in your field

Discover breakthrough research and expand your academic network

Explore
Papers
Topics

Features
Mentions
Analytics
PDF Packages
Advanced Search
Search Alerts

Journals
Academia.edu Journals
My submissions
Reviewer Hub
Why publish with us
Testimonials

Company
About
Careers
Press
Help Center
Terms
Privacy
Copyright
Content Policy

580 California St., Suite 400

San Francisco, CA, 94104

© 2025 Academia. All rights reserved