[PaleoMammalogy • 2016] Microleo attenboroughi • A Tiny New Marsupial Lion (Marsupialia, Thylacoleonidae) from the early Miocene of Australia

Microleo attenboroughi 

Gillespie, Archer & Hand, 2016  

Illustration: Peter Schouten   palaeo-electronica.org

ABSTRACT

Microleo attenboroughi, a new genus and species of diminutive marsupial lion (Marsupialia: Thylacoleonidae), is described from early Miocene freshwater limestones in the Riversleigh World Heritage Area, northwestern Queensland, Australia. A broken palate that retains incomplete cheektooth rows demonstrates that this new, very small marsupial lion possessed the elongate, trenchant P3 and predominantly subtriangular upper molars characteristic of thylacoleonids, while other features of the premolar support its placement in a new genus. Phylogenetic analysis suggests that Microleo attenboroughi is the sister taxon to all other thylacoleonids, and that Thylacoleonidae may lie outside Vombatomorphia as the sister taxon of all other wombat-like marsupials including koalas. However, given limited data about the cranial morphology of M. attenboroughi, Thylacoleonidae is concluded here, conservatively, to be part of the vombatomorphian clade. This new thylacoleonid brings to three the number of marsupial lion species that have been recovered from early Miocene deposits at Riversleigh and indicates a level of diversity previously not seen for this group. It is likely that the different size and morphology of the three sympatric taxa reflects niche partitioning and hence reduced competition. Thylacoleonids may have been the dominant arboreal predators of Cenozoic Australia.

 Keywords: Thylacoleonidae; marsupial lion; new genus; new species; early Miocene; Riversleigh

SYSTEMATIC PALAEONTOLOGY

Class MAMMALIA Linnaeus, 1758

Superorder MARSUPIALIA Illiger, 1811

Order DIPROTODONTIA Owen, 1866

Suborder VOMBATIFORMES Woodburne, 1984

Family THYLACOLEONIDAE Gill, 1872

Genus MICROLEO gen. nov.

zoobank.org/24A55B6E-B7DE-4665-836A-907BD13819DB

Type Species. Microleo attenboroughi new genus and species

Etymology. From micro meaning small (Greek) and leo meaning lion (Latin). The species name honours Sir David Attenborough for his dedication and enthusiasm in promoting the natural history of the world and the palaeontological treasures of the Riversleigh World Heritage Area in particular.

Microleo attenboroughi new genus and species

 zoobank.org/922FDD25-1D5D-40AD-9F49-94B57853CE51

Microleo attenboroughi n. gen. et sp., Holotype QM F41143: 

 FIGURE 1. 1) right maxilla and 2) left maxilla in occlusal view, stereo images; 3) interpretive drawing of right maxilla; 4) interpretive drawing of left maxilla. 5) Paratype QM F42676, occlusal views of m3 (stereophotos). 

FIGURE 2.  right maxilla. 1) buccal view; 2) interpretive drawing in buccal view; 3) lingual view; 4 ) interpretive drawing in lingual view.

Abbreviations: aabc, accessory anterobuccal cusp; abc, anterobuccal blade; ac, anterior cusp; alc, anterolingual crest; lb, longitudinal blade; mcl, metaconule; mcus, medial cusp; me, metacone; pa, paracone; pbb, posterobuccal basin; pbc, posterobuccal crest; pc, posterior cusp; plc, posterolingual crest; pr, protocone. Scale bar equals 5 mm.

palaeo-electronica.org

 Holotype. QM F41143, an incomplete palate consisting of partial left and right maxillae (Figure 1.1-4, Figure 2). The left maxilla preserves M2-3, roots for P3-M1, alveoli for M4, and the maxillary root of the zygomatic arch. The right maxilla preserves P3-M2, alveoli for P1-2 and M1. QM F42676, paratype, is a left m3 (Figure 1.5).

Type Locality and Horizon. The Type Locality is Neville’s Garden Site, D Site Plateau, Riversleigh World Heritage Area, Boodjamulla National Park, northwestern Queensland. Neville’s Garden Site is early Miocene in age (radiometrically dated at 18.24±0.29 Ma and 17.85±0.13 Ma: Archer et al., 1997; Arena, 2004; Travouillon et al., 2006; Woodhead et al., 2016).

Diagnosis. Microleo attenboroughi is attributed to Thylacoleonidae on the basis of its bicuspid, blade-like P3 and its weakly-crenulated, subtriangular bunodont molars. Microleo attenboroughi is smaller than all other thylacoleonids (see below). Generic distinction is based primarily on its unique P3 morphology.

FIGURE 3. Cladistic relationships of Microleo attenboroughi within Thylacoleonidae and Vombatiformes: 1) strict consensus tree of nine most parsimonious trees obtained in the phylogenetic analysis (tree length = 272 steps; see Appendices 1, 2); 2) time-tree of thylacoleonid phylogeny. 

Anna K. Gillespie, Michael Archer and Suzanne J. Hand. 2016. A Tiny New Marsupial Lion (Marsupialia, Thylacoleonidae) from the early Miocene of Australia. Palaeontologia Electronica 19.2.29A: 1-25. palaeo-electronica.org/content/2016/1490-new-marsupial-lion

http://zoobank.org/723FFDDC-F477-4BAB-9891-297A2959A2DB

[PaleoMammalogy • 2016] Malleodectidae fam. nov. • A New Family of Bizarre Durophagous Carnivorous Marsupials from Miocene Deposits in the Riversleigh World Heritage Area, northwestern Queensland, Australia

Malleodectes mirabilis using its massive, ball-peen-like P3 to break into what were perhaps one of this unique Miocene marsupial’s favourite meals — Riversleigh escargots. 

Illustration by Peter Schouten. DOI: 10.1038/srep26911

Abstract

A new specimen of the bizarrely specialised Malleodectes mirabilis from middle Miocene deposits in the Riversleigh World Heritage Area provides the first and only information about the molar dentition of this strange group of extinct marsupials. Apart from striking autapomorphies such as the enormous P3, other dental features such as stylar cusp D being larger than B suggest it belongs in the Order Dasyuromorphia. Phylogenetic analysis of 62 craniodental characters places Malleodectes within Dasyuromorphia albeit with weak support and without indication of specific relationships to any of the three established families (Dasyuridae, Myrmecobiidae and Thylacinidae). Accordingly we have allocated Malleodectes to the new family, Malleodectidae. Some features suggest potential links to previously named dasyuromorphians from Riversleigh (e.g., Ganbulanyi) but these are too poorly known to test this possibility. Although the original interpretation of a steeply declining molar row in Malleodectes can be rejected, it continues to seem likely that malleodectids specialised on snails but probably also consumed a wider range of prey items including small vertebrates. Whatever their actual diet, malleodectids appear to have filled a niche in Australia’s rainforests that has not been occupied by any other mammal group anywhere in the world from the Miocene onwards.

Systematic Palaeontology

Subclass: Marsupialia Illiger, 1811

Order: Dasyuromorphia Gill, 1872

Family Malleodectidae nov.

Included genera: Malleodectes Arena et al. (2011)

Familial diagnosis: Medium-sized (~1 kg; see below), durophagous, carnivorously-adapted marsupials that differ from all others in the following combination of features: large, caniniform, laterally compressed C1; narrow, premolariform P1 adpressed against the base of C1; asymmetric P2 with wide, diamond-shaped (in occlusal view) posterior region, posteriorly-sloping crown and low, narrow, attenuated anterior region; uniquely (among known dasyuromorphians) large dP3 (similar in size to M1) with three cusps and a functional postmetacrista; enormous, subrounded, dome-shaped, essentially unicuspid, four-rooted P3 that is wider and longer than M1 and M2 (and probably M3), with (M. moenia) or without (M. mirabilis) a tiny cuspule near the posterior edge of the crown; M1 relatively (compared to M2) hypsodont, longer and wider than M2, with StB and StD directly buccal to the paracone and metacone respectively, StD taller than StB, a deep vertical fissure on the buccal flank of the crown, no anterior ectoloph crest, StE present on posterior ectoloph ridge, poorly-developed straight (M1) centrocrista and no posterior cingulum; M2 more conventionally dasyuromorphian-like with v-shaped centrocrista but with conules better developed than in most undoubted dasyuromorphians.

Etymology: The family name derives from the type genus Malleodectes.

Materials: In addition to specimens noted by Arena et al. (2011) we describe here QM F57925, juvenile cranial material including fragmentary left nasal and? frontal bones and a left maxilla with C1, P1, dP3, P3 crown (unerupted), M1–2, alveoli for P2 and M3. QM F57925 is from AL90 Site, a middle Miocene deposit that has been radiometrically dated as 14.64 ± 0.47 Ma old, and which contains a fauna correlating with mid- to late- Riversleigh Faunal Zone C17,18,19,27. AL90 has been interpreted to be a cave deposit, the original entrance of which acted as a natural pit-fall trap27,28,29.

Estimated body mass: Using the “dasyuromorphian-only” dataset of Myers30, the most accurate regression equation that can be used to calculate body mass for Malleodectes mirabilis is the occlusal area of M2. This gives an estimated body mass (including the smearing estimate) of 896 g.

Description of QM F57925, Malleodectes mirabilis

QM F57925 is identified here as Malleodectes mirabilis and is differentiated from M. moenia based on the following features of P3: absolutely smaller; less rounded; lower-crowned; and lacking a posterior cuspule19. Comparison of P3 with that of the holotype of M. mirabilis (QM F50847) and that which Wroe12 originally referred to Ganbulanyi djadjinguli but which Arena et al. (2011) identified as M. moenia, was enabled through digital extraction of the unerupted P3 from micro-CT images (Fig. 3). All P3s referred here to species of Malleodectes are compared in Fig. 4. P3 of QM F57925 is 5.4 mm wide, 6.7 mm long and most closely approximates P3 in M. mirabilis (5.6 wide; 6.5 mm long) rather than the larger M. moenia (6.5 mm wide; 7.1 mm long).

Malleodectes mirabilis using its massive, ball-peen-like P3 to break into what were perhaps one of this unique Miocene marsupial’s favourite meals — Riversleigh escargots.

Illustration by Peter Schouten.  DOI: 10.1038/srep26911

Conclusion

Although malleodectids are only known on the basis of partial upper dentitions, they clearly represent one of the most distinctive groups of marsupials yet discovered. Because they are known from such limited material and because of the many autapomorphic features they exhibit, relatively few of the preserved features clarify their phylogenetic relationships. The features that are available (most obviously, the larger size of stylar cusp D relative to stylar cusp B on M1–2), suggest, albeit tentatively, that malleodectids are dasyuromorphians. Our phylogenetic analysis confirms this assessment, placing Malleodectes within Dasyuromorphia in a polytomy that also includes dasyurids, thylacinids, the fossil forms Barinya and Mutpuracinus, and the sole known myrmecobiid Myrmecobius fasciatus. In terms of dental function, the well-developed molar dentition of Malleodectes suggests that it ate more diverse foods than just snails. The blades on the molars as well as the wear on anterior teeth suggest that small vertebrates were also part of the malleodectid diet. In combination, the large but laterally compressed C1, laterally compressed, delicate P1, hypertrophied, hammer-like P3 and tribosphenic molars with oblique shearing blades suggest that they occupied a niche in Australia’s Miocene rainforests that no other known mammalian group has managed to occupy since.

M. Archer, S. J. Hand, K. H. Black, R. M. D. Beck, D. A. Arena, L. A. B. Wilson, S. Kealy and T.-t. Hung. 2016. A New Family of Bizarre Durophagous Carnivorous Marsupials from Miocene Deposits in the Riversleigh World Heritage Area, northwestern Queensland. Scientific Reports. 6, Article number: 26911. DOI: 10.1038/srep26911

Remains of bizarre group of extinct snail-eating Australian marsupials d... http://bit.ly/1WPDgSa via @UNSWnews @EurekAlertAAAS

Derrick A. Arena, Michael Archer, Henk Godthelp, Suzanne J. Hand and Scott Hocknull. 2011. Hammer-toothed ‘marsupial skinks' from the Australian Cenozoic. Proc. Roy. Soc. B. 278, 3529–3533.  DOI:  10.1098/rspb.2011.0486
http://blogs.scientificamerican.com/tetrapod-zoology/hammer-toothed-skink-smash/

[PaleoOrnithology • 2016] Dromornis murrayi • The Extinct Flightless Mihirungs (Aves, Dromornithidae): Cranial Anatomy, A New Species, and Assessment of Oligo-Miocene Lineage Diversity

ABSTRACT

Giant flightless fowl (Aves, Dromornithidae) similar to the Northern Hemisphere gastornithids and weighing up to 350–650 kg evolved on Gondwana and existed in what is now Australia from the Eocene to the late Quaternary. Understanding cranial morphology of dromornithids has until now been based almost wholly on species of Dromornis, with that of species in three other genera either previously unknown or very fragmentary. Here we rectify this deficiency and describe a well-preserved cranium from the middle Miocene Bullock Creek Local Fauna referred to Ilbandornis woodburnei, rich, fragmentary crania, quadrates, pterygoids, and mandibles for the Oligo-Miocene Barawertornis tedfordi Rich, and additional material of the species of Ilbandornis. The morphological similarity of this cranial material suggests that the emu-sized B. tedfordi is a smaller precursor to and differs little from species of Ilbandornis. Dromornis murrayi, n. sp., from late Oligocene–Early Miocene sites at Riversleigh, based on cranial and postcranial elements, is the oldest and smallest species in its genus. Placed in the context of other data, these observations suggest that the dromornithids comprised only two lineages throughout the Oligo-Miocene. The Barawertornis-Ilbandornis lineage attained maximum diversity in the middle Miocene Bullock Creek and late Miocene Alcoota local faunas (LF), with two species in each, but the Dromornis lineage seems to have been monotypic throughout its temporal range. The low diversity of these giant galloanseres in Australia mirrors that of the giant herbivorous ratites (ostriches and kin), which similarly have low diversity where they coevolved with diverse mammalian faunas.

Dromornis murrayi, A newly discovered flightless bird, reached 1.5 metres high and weighed up to 250 kilograms.

Illustration: Brian Choo/ Flinders University

Trevor H. Worthy, Warren D. Handley, Michael Archer and Suzanne J. Hand. 2016. The Extinct Flightless Mihirungs (Aves, Dromornithidae): Cranial Anatomy, A New Species, and Assessment of Oligo-Miocene Lineage Diversity. Journal of Vertebrate Paleontology.  DOI: 10.1080/02724634.2015.1031345

ResearchGate.net/publication/295198845_The_extinct_flightless_mihirungs_Aves_Dromornithidae_cranial_anatomy_a_new_species_and_assessment_of_Oligo-Miocene_lineage_diversity

http://zoobank.org/urn:lsid:zoobank.org:pub:591C910A- 882F-46B6-900D-20078E5A537B

Researcher discovers ancestor of biggest bird ever http://phy.so/375346820 via @physorg_com

Dromornis murrayi http://www.abc.net.au/news/2016-02-19/dromornis-murrayi/7185478 via @ABCNews

[PaleoMammalogy • 2013] Obdurodon tharalkooschild • A New, Giant Platypus (Monotremata, Ornithorhynchidae) from the Riversleigh World Heritage Area, Australia

Obdurodon tharalkooschild, a middle to late Cenozoic giant toothed platypus from the the World Heritage fossil deposits of Riversleigh, Australia. At about one meter (more than 3 feet) in length and with powerful teeth (inset: the holotype, a first lower molar), it would have been capable of killing much larger prey, such as lungfish and even small turtles, than its much smaller living relative.

 Illustration: Peter Schouten.

Fossil of Largest Known Platypus Discovered in Australia

  — No living mammal is more peculiar than the platypus. It has a broad, duck-like bill, thick, otter-like fur, and webbed, beaver-like feet. The platypus lays eggs rather than gives birth to live young, its snout is covered with electroreceptors that detect underwater prey, and male platypuses have a venomous spur on their hind foot. Until recently, the fossil record indicated that the platypus lineage was unique, with only one species inhabiting Earth at any one time. This picture has changed with the publication of a new study in the latest issue of the Journal of Vertebrate Paleontology that describes a new, giant species of extinct platypus that was a side-branch of the platypus family tree.

......................

http://www.sciencedaily.com/releases/2013/11/131104152715.htm

http://www.agenciasinc.es/Noticias/Un-ornitorrinco-gigante-habitaba-Australia-hace-entre-15-y-5-millones-de-anos

Giant turtle-devouring duck-billed platypus discovered

http://news.mongabay.com/2013/1104-hance-giant-platypus.html

Pian, R., M. Archer, and S.J. Hand. 2013. A New, Giant Platypus, Obdurodon tharalkooschild, sp. nov. (Monotremata, Ornithorhynchidae), from the Riversleigh World Heritage Area, Australia. Journal of Vertebrate Paleontology. 33(6):1-5.

[Paleomammalogy • 2012] Herds Overhead: Nimbadon lavarackorum (Diprotodontidae), Heavyweight Marsupial Herbivores in the Miocene Forests of Australia

This is an artist’s reconstruction of Nimbadon lavarackorum mother and juvenile (Art: Peter Schouten)

Abstract 

The marsupial family Diprotodontidae (Diprotodontia, Vombatiformes) is a group of extinct large-bodied (60–2500 kg) wombat-like herbivores that were common and geographically widespread in Cenozoic fossil deposits of Australia and New Guinea. Typically they are regarded to be gregarious, terrestrial quadrupeds and have been likened in body form among placental groups to sheep, rhinoceros and hippopotami. Arguably, one of the best represented species is the zygomaturine diprotodontid Nimbadon lavarackorum which is known from exceptionally well-preserved cranial and postcranial material from the middle Miocene cave deposit AL90, in the Riversleigh World Heritage Area, northwestern Queensland. Here we describe and functionally analyse the appendicular skeleton of Nimbadon lavarackorum and reveal a far more unique lifestyle for this plesiomorphic and smallest of diprotodontids. Striking similarities are evident between the skeleton of Nimbadon and that of the extant arboreal koala Phascolarctos cinereus, including the powerfully built forelimbs, highly mobile shoulder and elbow joints, proportionately large manus and pes (both with a semi-opposable digit I) and exceedingly large, recurved and laterally compressed claws. Combined with the unique (among australidelphians) proportionately shortened hindlimbs of Nimbadon, these features suggest adept climbing ability, probable suspensory behaviour, and an arboreal lifestyle. At approximately 70 kg, Nimbadon is the largest herbivorous mammal to have occupied the forest canopies of Australia - an ecological niche that is no longer occupied in any Australian ecosystem and one that further expands the already significant niche diversity displayed by marsupials during the Cenozoic.

Citation: Black KH, Camens AB, Archer M, Hand SJ. 2012. Herds Overhead: Nimbadon lavarackorum (Diprotodontidae), Heavyweight Marsupial Herbivores in the Miocene Forests of Australia. PLoS ONE. 7(11): e48213. doi: 10.1371/journal.pone.0048213

Research Sheds More Light on Enigmatic, Long-Extinct Nimbadon

According to a new research led by Dr Karen Black of the University of New South Wales, Nimbadon lavarackorum – a large bear-like animal that lived in Australia’s lush forests 15 million years ago – was well suited to life in the treetops: it used massive sharp claws to haul its hefty body up trees, hugging the trunk like a bear, and its huge hands and long arms let it hang from branches like an orangutan.

http://www.sci-news.com/paleontology/article00739.html