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Karen H. Black - One of the best experts on this subject based on the ideXlab platform.
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A new family of diprotodontian marsupials from the latest Oligocene of Australia and the evolution of wombats, koalas, and their relatives (Vombatiformes)
Scientific Reports, 2020Co-Authors: Robin M. D. Beck, Karen H. Black, Michael Archer, Julien Louys, Philippa Brewer, Richard H. TedfordAbstract:We describe the partial cranium and skeleton of a new diprotodontian marsupial from the late Oligocene (~26–25 Ma) Namba Formation of South Australia. This is one of the oldest Australian marsupial fossils known from an associated skeleton and it reveals previously unsuspected morphological diversity within Vombatiformes, the clade that includes wombats (Vombatidae), koalas (Phascolarctidae) and several extinct families. Several aspects of the skull and teeth of the new taxon, which we refer to a new family, are intermediate between members of the fossil family Wynyardiidae and wombats. Its postcranial skeleton exhibits features associated with scratch-digging, but it is unlikely to have been a true burrower. Body mass estimates based on postcranial dimensions range between 143 and 171 kg, suggesting that it was ~5 times larger than living wombats. Phylogenetic analysis based on 79 craniodental and 20 postcranial characters places the new taxon as sister to vombatids, with which it forms the superfamily Vombatoidea as defined here. It suggests that the highly derived vombatids evolved from wynyardiid-like ancestors, and that scratch-digging adaptations evolved in vombatoids prior to the appearance of the ever-growing (hypselodont) molars that are a characteristic feature of all post-Miocene vombatids. Ancestral state reconstructions on our preferred phylogeny suggest that bunolophodont molars are plesiomorphic for vombatiforms, with full lophodonty (characteristic of diprotodontoids) evolving from a selenodont morphology that was retained by phascolarctids and ilariids, and wynyardiids and vombatoids retaining an intermediate selenolophodont condition. There appear to have been at least six independent acquisitions of very large (>100 kg) body size within Vombatiformes, several having already occurred by the late Oligocene.
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Bearing up well? Understanding the past, present and future of Australia's koalas
Gondwana Research, 2014Co-Authors: Karen H. Black, Gilbert J. Price, Michael Archer, Suzanne J. HandAbstract:The modern Koala Phascolarctos cinereus is the last surviving member of a once diverse family Phascolarctidae (Marsupialia, Phascolarctomorphia). Nine genera and at least 16 species of koala are known. Late Oligocene sediments of central Australia record the oldest fossils and highest species diversity. Five species are known from the early to middle Miocene rainforest assemblages of the Riversleigh World Heritage Area, Queensland. With the onset of dryer conditions after the middle Miocene climatic optimum (similar to 16 Ma), rainforest habitats contracted resulting in the apparent extinction of three koala lineages (Litokoala, Nimiokoala, Priscakoala). Phascolarctos first appears in the fossil record during the Pliocene and the modem species around 350 ka. Despite a dramatic decline in taxonomic diversity to a single extant species, the fossil record indicates that at most only three koala species coexisted in any given faunal assemblage throughout their 24 million year history. Within these assemblages, the vast majority of extinct koalas are extremely rare (some known from only a single specimen) which may reflect a general rarity within their palaeohabitats compared with the modern species which is represented by an estimated 400,000 individuals spread over most of eastern mainland Australia. Be that as it may, P. cinereus, although once geographically more widespread, occurring for example in Western Australia in the Pleistocene, underwent significant range contractions and localized population extinctions during the stressful climatic conditions of the late Pleistocene and more recently through human-induced habitat destruction. Combined with threats of disease, reduced genetic diversity and climate change, the survival of this iconic Australian marsupial is arguably a cause for concern. (C) 2013 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.
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Understanding morphological variation in the extant koala as a framework for identification of species boundaries in extinct koalas (Phascolarctidae; Marsupialia)
Journal of Systematic Palaeontology, 2013Co-Authors: Karen H. Black, Julien Louys, Gilbert J. PriceAbstract:We document morphological variation (both geographical and sexual) in the dentition of the extant koala, Phascolarctos cinereus, in order to facilitate discrimination of species boundaries in extinct phascolarctids. Considerable variation is evident in dental structures previously used to diagnose several phascolarctid fossil species. Consistent patterns of morphological variation are not evident between sexes or geographic regions, with variation as great between samples as within them. Metric variation is evident between the sexes in upper molar dimensions with Victorian (southern) males significantly larger than Victorian females, although this is not reflected in lower molar dimensions or in the Queensland (northern) sample. Male koalas from southern populations generally display significantly larger molars than their northern counterparts; however this trend is not evident in female upper molar dimensions. In both males and females, some, but not all, lower molar dimensions are larger in southern pop...
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New Tertiary Koala (Marsupialia, Phascolarctidae) from Riversleigh, Australia, with a Revision of Phascolarctid Phylogenetics, Paleoecology, and Paleobiodiversity
Journal of Vertebrate Paleontology, 2012Co-Authors: Karen H. Black, Michael Archer, Suzanne J. HandAbstract:ABSTRACT Here we describe the most plesiomorphic koala yet known. Priscakoala lucyturnbullae, gen. et sp. nov., is the fourth and largest koala species described from Miocene deposits in the Riversleigh World Heritage area, northern Australia. It is known from a maxilla with M1–3 and isolated M2, M3 or M4 and m1. Relationships within the diprotodontian suborder Vombatiformes are clarified using cranial and dental characters based on a data set compiled from new and more complete cranial materials for each of the respective vombatiform families. Monophyly of Phascolarctidae is supported by the development of a protostylid and metastylid on m1. Priscakoala lucyturnbullae is the most plesiomorphic phascolarctid. Inclusion in the analysis of the enigmatic Pliocene genus Koobor, currently classified as Vombatiformes incertae sedis, indicates phascolarctomorphian affinities for the genus.
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Descriptions of koala fossils from the Miocene of Riversleigh, northwestern Queensland and implications for Litokoala (Marsupialia, Phascolarctidae)
Alcheringa: An Australasian Journal of Palaeontology, 2007Co-Authors: Julien Louys, Karen H. Black, Michael Archer, Suzanne J. Hand, Henk GodthelpAbstract:Louys, J., Black, K., Archer, M., Hand, S.J. & Godthelp, H., June, 2007. Descriptions of koala fossils from the Miocene of Riversleigh, northwestern Queensland and implications for Litokoala (Marsupialia, Phascolarctidae). Alcheringa 31, 99‐110. ISSN 0311-5518. Litokoala is revised on the basis of new material from the early to middle Miocene deposits of Riversleigh. A new species of Litokoala is described from the System B Outasite Local Fauna. Litokoala garyjohnstoni sp. nov. possesses a unique combination of both plesiomorphic and apomorphic dental features, making its phylogenetic position within Litokoala difficult to interpret. In some aspects of dental morphology, L. garyjohnstoni is convergent on the early Miocene phascolarctid Nimiokoala greystanesi Black & Archer, 1997. The dentition of a partial skull of Litokoala from Jims Carousel Site, System C is also described. On the basis of this dentition, it is suggested that the morphological variation between L. kutjamarpensis Stirton, 1967 and L. ka...
Gilbert J. Price - One of the best experts on this subject based on the ideXlab platform.
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Bearing up well? Understanding the past, present and future of Australia's koalas
Gondwana Research, 2014Co-Authors: Karen H. Black, Gilbert J. Price, Michael Archer, Suzanne J. HandAbstract:The modern Koala Phascolarctos cinereus is the last surviving member of a once diverse family Phascolarctidae (Marsupialia, Phascolarctomorphia). Nine genera and at least 16 species of koala are known. Late Oligocene sediments of central Australia record the oldest fossils and highest species diversity. Five species are known from the early to middle Miocene rainforest assemblages of the Riversleigh World Heritage Area, Queensland. With the onset of dryer conditions after the middle Miocene climatic optimum (similar to 16 Ma), rainforest habitats contracted resulting in the apparent extinction of three koala lineages (Litokoala, Nimiokoala, Priscakoala). Phascolarctos first appears in the fossil record during the Pliocene and the modem species around 350 ka. Despite a dramatic decline in taxonomic diversity to a single extant species, the fossil record indicates that at most only three koala species coexisted in any given faunal assemblage throughout their 24 million year history. Within these assemblages, the vast majority of extinct koalas are extremely rare (some known from only a single specimen) which may reflect a general rarity within their palaeohabitats compared with the modern species which is represented by an estimated 400,000 individuals spread over most of eastern mainland Australia. Be that as it may, P. cinereus, although once geographically more widespread, occurring for example in Western Australia in the Pleistocene, underwent significant range contractions and localized population extinctions during the stressful climatic conditions of the late Pleistocene and more recently through human-induced habitat destruction. Combined with threats of disease, reduced genetic diversity and climate change, the survival of this iconic Australian marsupial is arguably a cause for concern. (C) 2013 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.
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Understanding morphological variation in the extant koala as a framework for identification of species boundaries in extinct koalas (Phascolarctidae; Marsupialia)
Journal of Systematic Palaeontology, 2013Co-Authors: Karen H. Black, Julien Louys, Gilbert J. PriceAbstract:We document morphological variation (both geographical and sexual) in the dentition of the extant koala, Phascolarctos cinereus, in order to facilitate discrimination of species boundaries in extinct phascolarctids. Considerable variation is evident in dental structures previously used to diagnose several phascolarctid fossil species. Consistent patterns of morphological variation are not evident between sexes or geographic regions, with variation as great between samples as within them. Metric variation is evident between the sexes in upper molar dimensions with Victorian (southern) males significantly larger than Victorian females, although this is not reflected in lower molar dimensions or in the Queensland (northern) sample. Male koalas from southern populations generally display significantly larger molars than their northern counterparts; however this trend is not evident in female upper molar dimensions. In both males and females, some, but not all, lower molar dimensions are larger in southern pop...
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Long-Term Trends in Lineage ‘Health’ of the Australian Koala (Mammalia:Phascolarctidae): Using Paleo-diversity to Prioritize Species for Conservation
Paleontology in Ecology and Conservation, 2012Co-Authors: Gilbert J. PriceAbstract:Understanding phylogenetic diversity over large temporal scales as afforded by the fossil record allows for the identification of the history of taxonomic diversity in extant taxa. Identification of such long-term trends in lineage ‘health’ is a critical, but commonly underutilized method for helping to prioritize species for conservation. The modern Australian koala (Phascolarctos cinereus) is a case in point. It is widely debated whether the modern koala should be an immediate candidate for conservation. Although modern populations have seen recent declines in some regions, in other areas koalas are overabundant, with translocation, contraceptive, and evening culling programs suggested as population control measures. The view from the fossil record is that koalas (family Phascolarctidae) have suffered a dramatic, progressive long-term decline in diversity (e.g., four genera and eight species in the late Oligocene, compared to only one genus and species at present). At no time in the known history of the Phascolarctidae has phylogenetic diversity been as low as today. Climate change, leading to enhanced variability in seasonality, increased aridfication, and habitat change has had a negative impact on phascolarctid diversity through time, and has been a determining factor in the geographic range of the modern koala. Do such observations warrant adding the modern koala to the list of threatened species? Although the answer to this question remains outside the scope of this chapter, it should be remembered that extinction of the extant koala would mark the loss of not only of a single species, but also of an entire family of endemic Australian marsupial.
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Invictokoala monticola gen. et sp. nov. (Phascolarctidae, Marsupialia), a Pleistocene plesiomorphic koala holdover from Oligocene ancestors
Journal of Systematic Palaeontology, 2011Co-Authors: Gilbert J. Price, Scott A. HocknullAbstract:Koalas (Phascolarctidae) are uncommon elements within the Australian fossil record. The earliest representatives are recorded from late Oligocene rainforest assemblages of central Australia. In contrast, the extant Koala Phascolarctos cinereus Blainville, 1816 (the only surviving member of a once diverse family) is found only in eastern Australian open woodlands. Extinction of koalas from rainforests was previously thought to have occurred after the middle Miocene. Recent systematic cave excavations at Mt. Etna, central eastern Queensland, Australia, have revealed several remarkable new middle Pleistocene vertebrate assemblages that are dominated by rainforest-adapted taxa. Within one of the deposits, we have identified a new, but archaic, genus and species of koala. Invictokoala monticola gen. et sp. nov. shares affinities with the most plesiomorphic member of the family, Madakoala Woodburne et al., 1987 (late Oligocene), but is distinguished by possessing higher-crowned upper molars, with a tricsupate (...
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New records of Plio-Pleistocene koalas from Australia: palaeoecological and taxonomic implications
Records of the Australian Museum, 2009Co-Authors: Gilbert J. Price, Jian-xin Zhao, Yuexing Feng, Scott A. HocknullAbstract:ab S tract . Koalas (Phascolarctidae, Marsupialia) are generally rare components of the Australian fossil record. However, new specimens of fossil koalas were recovered during recent systematic excavations from several eastern Plio-Pleistocene deposits of Queensland, eastern Australia, including the regions of Chinchilla, Marmor and Mt. Etna. The new records are significant in that they extend the temporal and geographic range of Plio-Pleistocene koalas from southern and southeastern Australia, to northeastern central Queensland. We provide the first unambiguous evidence of koalas in the Pliocene Chinchilla Local Fauna (phascolarctid indet. and Ph. ?stirtoni): important additions to an increasingly diverse arboreal mammalian assemblage that also includes tree kangaroos. The persistence of koalas and local extinction of tree kangaroos in the Chinchilla region today suggests that significant habitat and faunal reorganization occurred between the Pliocene and Recent, presumably reflecting the expansion of open woodlands and grasslands. Other koala records from the newly U/Th-dated Middle Pleistocene Marmor and Mt. Etna fossil deposits (Phascolarctos sp. and Ph. ?stirtoni), along with independent palaeohabitat proxies, indicate the former presence of heterogeneous habitats comprised of rainforests, open woodlands and grasslands. The lack of such habitat mosaics in those regions today is likely the product of significant Middle Pleistocene climate change.
Michael Archer - One of the best experts on this subject based on the ideXlab platform.
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A new family of diprotodontian marsupials from the latest Oligocene of Australia and the evolution of wombats, koalas, and their relatives (Vombatiformes)
Scientific Reports, 2020Co-Authors: Robin M. D. Beck, Karen H. Black, Michael Archer, Julien Louys, Philippa Brewer, Richard H. TedfordAbstract:We describe the partial cranium and skeleton of a new diprotodontian marsupial from the late Oligocene (~26–25 Ma) Namba Formation of South Australia. This is one of the oldest Australian marsupial fossils known from an associated skeleton and it reveals previously unsuspected morphological diversity within Vombatiformes, the clade that includes wombats (Vombatidae), koalas (Phascolarctidae) and several extinct families. Several aspects of the skull and teeth of the new taxon, which we refer to a new family, are intermediate between members of the fossil family Wynyardiidae and wombats. Its postcranial skeleton exhibits features associated with scratch-digging, but it is unlikely to have been a true burrower. Body mass estimates based on postcranial dimensions range between 143 and 171 kg, suggesting that it was ~5 times larger than living wombats. Phylogenetic analysis based on 79 craniodental and 20 postcranial characters places the new taxon as sister to vombatids, with which it forms the superfamily Vombatoidea as defined here. It suggests that the highly derived vombatids evolved from wynyardiid-like ancestors, and that scratch-digging adaptations evolved in vombatoids prior to the appearance of the ever-growing (hypselodont) molars that are a characteristic feature of all post-Miocene vombatids. Ancestral state reconstructions on our preferred phylogeny suggest that bunolophodont molars are plesiomorphic for vombatiforms, with full lophodonty (characteristic of diprotodontoids) evolving from a selenodont morphology that was retained by phascolarctids and ilariids, and wynyardiids and vombatoids retaining an intermediate selenolophodont condition. There appear to have been at least six independent acquisitions of very large (>100 kg) body size within Vombatiformes, several having already occurred by the late Oligocene.
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Bearing up well? Understanding the past, present and future of Australia's koalas
Gondwana Research, 2014Co-Authors: Karen H. Black, Gilbert J. Price, Michael Archer, Suzanne J. HandAbstract:The modern Koala Phascolarctos cinereus is the last surviving member of a once diverse family Phascolarctidae (Marsupialia, Phascolarctomorphia). Nine genera and at least 16 species of koala are known. Late Oligocene sediments of central Australia record the oldest fossils and highest species diversity. Five species are known from the early to middle Miocene rainforest assemblages of the Riversleigh World Heritage Area, Queensland. With the onset of dryer conditions after the middle Miocene climatic optimum (similar to 16 Ma), rainforest habitats contracted resulting in the apparent extinction of three koala lineages (Litokoala, Nimiokoala, Priscakoala). Phascolarctos first appears in the fossil record during the Pliocene and the modem species around 350 ka. Despite a dramatic decline in taxonomic diversity to a single extant species, the fossil record indicates that at most only three koala species coexisted in any given faunal assemblage throughout their 24 million year history. Within these assemblages, the vast majority of extinct koalas are extremely rare (some known from only a single specimen) which may reflect a general rarity within their palaeohabitats compared with the modern species which is represented by an estimated 400,000 individuals spread over most of eastern mainland Australia. Be that as it may, P. cinereus, although once geographically more widespread, occurring for example in Western Australia in the Pleistocene, underwent significant range contractions and localized population extinctions during the stressful climatic conditions of the late Pleistocene and more recently through human-induced habitat destruction. Combined with threats of disease, reduced genetic diversity and climate change, the survival of this iconic Australian marsupial is arguably a cause for concern. (C) 2013 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.
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New Tertiary Koala (Marsupialia, Phascolarctidae) from Riversleigh, Australia, with a Revision of Phascolarctid Phylogenetics, Paleoecology, and Paleobiodiversity
Journal of Vertebrate Paleontology, 2012Co-Authors: Karen H. Black, Michael Archer, Suzanne J. HandAbstract:ABSTRACT Here we describe the most plesiomorphic koala yet known. Priscakoala lucyturnbullae, gen. et sp. nov., is the fourth and largest koala species described from Miocene deposits in the Riversleigh World Heritage area, northern Australia. It is known from a maxilla with M1–3 and isolated M2, M3 or M4 and m1. Relationships within the diprotodontian suborder Vombatiformes are clarified using cranial and dental characters based on a data set compiled from new and more complete cranial materials for each of the respective vombatiform families. Monophyly of Phascolarctidae is supported by the development of a protostylid and metastylid on m1. Priscakoala lucyturnbullae is the most plesiomorphic phascolarctid. Inclusion in the analysis of the enigmatic Pliocene genus Koobor, currently classified as Vombatiformes incertae sedis, indicates phascolarctomorphian affinities for the genus.
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Cranial Anatomy of Oligo-Miocene Koalas (Diprotodontia: Phascolarctidae): Stages in the Evolution of an Extreme Leaf-Eating Specialization
Journal of Vertebrate Paleontology, 2009Co-Authors: Julien Louys, Ken Aplin, Robin M. D. Beck, Michael ArcherAbstract:ABSTRACT Partial crania of two fossil species of koala (family Phascolarctidae) from Oligo-Miocene deposits in the Riversleigh World Heritage Area, one referable to Litokoala kutjamarpensis and another to Nimiokoala greystanesi, are described. Comparison with the extant koala Phascolarctos cinereus and other diprotodontian marsupials reveals a high degree of similarity in basicranial morphology between fossil and modern phascolarctids but substantial differences in the architecture of the masticatory system. Key specialisations present in Phascolarctos but absent in both Litokoala and Nimiokoala include forward displacement of the palate, enlargement of the occlusal surface of the molar teeth, thickening of the maxillae above the toothrow with resultant lowering of the occlusal plane of the cheekteeth relative to the glenoid fossa, and a decrease in the size of the pterygoid fossae. These extreme aspects of the cranial morphology of Phacolarctos probably reflect its dependence on eucalypt leaves, a nutrie...
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Descriptions of koala fossils from the Miocene of Riversleigh, northwestern Queensland and implications for Litokoala (Marsupialia, Phascolarctidae)
Alcheringa: An Australasian Journal of Palaeontology, 2007Co-Authors: Julien Louys, Karen H. Black, Michael Archer, Suzanne J. Hand, Henk GodthelpAbstract:Louys, J., Black, K., Archer, M., Hand, S.J. & Godthelp, H., June, 2007. Descriptions of koala fossils from the Miocene of Riversleigh, northwestern Queensland and implications for Litokoala (Marsupialia, Phascolarctidae). Alcheringa 31, 99‐110. ISSN 0311-5518. Litokoala is revised on the basis of new material from the early to middle Miocene deposits of Riversleigh. A new species of Litokoala is described from the System B Outasite Local Fauna. Litokoala garyjohnstoni sp. nov. possesses a unique combination of both plesiomorphic and apomorphic dental features, making its phylogenetic position within Litokoala difficult to interpret. In some aspects of dental morphology, L. garyjohnstoni is convergent on the early Miocene phascolarctid Nimiokoala greystanesi Black & Archer, 1997. The dentition of a partial skull of Litokoala from Jims Carousel Site, System C is also described. On the basis of this dentition, it is suggested that the morphological variation between L. kutjamarpensis Stirton, 1967 and L. ka...
Julien Louys - One of the best experts on this subject based on the ideXlab platform.
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A new family of diprotodontian marsupials from the latest Oligocene of Australia and the evolution of wombats, koalas, and their relatives (Vombatiformes)
Scientific Reports, 2020Co-Authors: Robin M. D. Beck, Karen H. Black, Michael Archer, Julien Louys, Philippa Brewer, Richard H. TedfordAbstract:We describe the partial cranium and skeleton of a new diprotodontian marsupial from the late Oligocene (~26–25 Ma) Namba Formation of South Australia. This is one of the oldest Australian marsupial fossils known from an associated skeleton and it reveals previously unsuspected morphological diversity within Vombatiformes, the clade that includes wombats (Vombatidae), koalas (Phascolarctidae) and several extinct families. Several aspects of the skull and teeth of the new taxon, which we refer to a new family, are intermediate between members of the fossil family Wynyardiidae and wombats. Its postcranial skeleton exhibits features associated with scratch-digging, but it is unlikely to have been a true burrower. Body mass estimates based on postcranial dimensions range between 143 and 171 kg, suggesting that it was ~5 times larger than living wombats. Phylogenetic analysis based on 79 craniodental and 20 postcranial characters places the new taxon as sister to vombatids, with which it forms the superfamily Vombatoidea as defined here. It suggests that the highly derived vombatids evolved from wynyardiid-like ancestors, and that scratch-digging adaptations evolved in vombatoids prior to the appearance of the ever-growing (hypselodont) molars that are a characteristic feature of all post-Miocene vombatids. Ancestral state reconstructions on our preferred phylogeny suggest that bunolophodont molars are plesiomorphic for vombatiforms, with full lophodonty (characteristic of diprotodontoids) evolving from a selenodont morphology that was retained by phascolarctids and ilariids, and wynyardiids and vombatoids retaining an intermediate selenolophodont condition. There appear to have been at least six independent acquisitions of very large (>100 kg) body size within Vombatiformes, several having already occurred by the late Oligocene.
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Understanding morphological variation in the extant koala as a framework for identification of species boundaries in extinct koalas (Phascolarctidae; Marsupialia)
Journal of Systematic Palaeontology, 2013Co-Authors: Karen H. Black, Julien Louys, Gilbert J. PriceAbstract:We document morphological variation (both geographical and sexual) in the dentition of the extant koala, Phascolarctos cinereus, in order to facilitate discrimination of species boundaries in extinct phascolarctids. Considerable variation is evident in dental structures previously used to diagnose several phascolarctid fossil species. Consistent patterns of morphological variation are not evident between sexes or geographic regions, with variation as great between samples as within them. Metric variation is evident between the sexes in upper molar dimensions with Victorian (southern) males significantly larger than Victorian females, although this is not reflected in lower molar dimensions or in the Queensland (northern) sample. Male koalas from southern populations generally display significantly larger molars than their northern counterparts; however this trend is not evident in female upper molar dimensions. In both males and females, some, but not all, lower molar dimensions are larger in southern pop...
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Cranial Anatomy of Oligo-Miocene Koalas (Diprotodontia: Phascolarctidae): Stages in the Evolution of an Extreme Leaf-Eating Specialization
Journal of Vertebrate Paleontology, 2009Co-Authors: Julien Louys, Ken Aplin, Robin M. D. Beck, Michael ArcherAbstract:ABSTRACT Partial crania of two fossil species of koala (family Phascolarctidae) from Oligo-Miocene deposits in the Riversleigh World Heritage Area, one referable to Litokoala kutjamarpensis and another to Nimiokoala greystanesi, are described. Comparison with the extant koala Phascolarctos cinereus and other diprotodontian marsupials reveals a high degree of similarity in basicranial morphology between fossil and modern phascolarctids but substantial differences in the architecture of the masticatory system. Key specialisations present in Phascolarctos but absent in both Litokoala and Nimiokoala include forward displacement of the palate, enlargement of the occlusal surface of the molar teeth, thickening of the maxillae above the toothrow with resultant lowering of the occlusal plane of the cheekteeth relative to the glenoid fossa, and a decrease in the size of the pterygoid fossae. These extreme aspects of the cranial morphology of Phacolarctos probably reflect its dependence on eucalypt leaves, a nutrie...
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Descriptions of koala fossils from the Miocene of Riversleigh, northwestern Queensland and implications for Litokoala (Marsupialia, Phascolarctidae)
Alcheringa: An Australasian Journal of Palaeontology, 2007Co-Authors: Julien Louys, Karen H. Black, Michael Archer, Suzanne J. Hand, Henk GodthelpAbstract:Louys, J., Black, K., Archer, M., Hand, S.J. & Godthelp, H., June, 2007. Descriptions of koala fossils from the Miocene of Riversleigh, northwestern Queensland and implications for Litokoala (Marsupialia, Phascolarctidae). Alcheringa 31, 99‐110. ISSN 0311-5518. Litokoala is revised on the basis of new material from the early to middle Miocene deposits of Riversleigh. A new species of Litokoala is described from the System B Outasite Local Fauna. Litokoala garyjohnstoni sp. nov. possesses a unique combination of both plesiomorphic and apomorphic dental features, making its phylogenetic position within Litokoala difficult to interpret. In some aspects of dental morphology, L. garyjohnstoni is convergent on the early Miocene phascolarctid Nimiokoala greystanesi Black & Archer, 1997. The dentition of a partial skull of Litokoala from Jims Carousel Site, System C is also described. On the basis of this dentition, it is suggested that the morphological variation between L. kutjamarpensis Stirton, 1967 and L. ka...
Suzanne J. Hand - One of the best experts on this subject based on the ideXlab platform.
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Bearing up well? Understanding the past, present and future of Australia's koalas
Gondwana Research, 2014Co-Authors: Karen H. Black, Gilbert J. Price, Michael Archer, Suzanne J. HandAbstract:The modern Koala Phascolarctos cinereus is the last surviving member of a once diverse family Phascolarctidae (Marsupialia, Phascolarctomorphia). Nine genera and at least 16 species of koala are known. Late Oligocene sediments of central Australia record the oldest fossils and highest species diversity. Five species are known from the early to middle Miocene rainforest assemblages of the Riversleigh World Heritage Area, Queensland. With the onset of dryer conditions after the middle Miocene climatic optimum (similar to 16 Ma), rainforest habitats contracted resulting in the apparent extinction of three koala lineages (Litokoala, Nimiokoala, Priscakoala). Phascolarctos first appears in the fossil record during the Pliocene and the modem species around 350 ka. Despite a dramatic decline in taxonomic diversity to a single extant species, the fossil record indicates that at most only three koala species coexisted in any given faunal assemblage throughout their 24 million year history. Within these assemblages, the vast majority of extinct koalas are extremely rare (some known from only a single specimen) which may reflect a general rarity within their palaeohabitats compared with the modern species which is represented by an estimated 400,000 individuals spread over most of eastern mainland Australia. Be that as it may, P. cinereus, although once geographically more widespread, occurring for example in Western Australia in the Pleistocene, underwent significant range contractions and localized population extinctions during the stressful climatic conditions of the late Pleistocene and more recently through human-induced habitat destruction. Combined with threats of disease, reduced genetic diversity and climate change, the survival of this iconic Australian marsupial is arguably a cause for concern. (C) 2013 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.
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New Tertiary Koala (Marsupialia, Phascolarctidae) from Riversleigh, Australia, with a Revision of Phascolarctid Phylogenetics, Paleoecology, and Paleobiodiversity
Journal of Vertebrate Paleontology, 2012Co-Authors: Karen H. Black, Michael Archer, Suzanne J. HandAbstract:ABSTRACT Here we describe the most plesiomorphic koala yet known. Priscakoala lucyturnbullae, gen. et sp. nov., is the fourth and largest koala species described from Miocene deposits in the Riversleigh World Heritage area, northern Australia. It is known from a maxilla with M1–3 and isolated M2, M3 or M4 and m1. Relationships within the diprotodontian suborder Vombatiformes are clarified using cranial and dental characters based on a data set compiled from new and more complete cranial materials for each of the respective vombatiform families. Monophyly of Phascolarctidae is supported by the development of a protostylid and metastylid on m1. Priscakoala lucyturnbullae is the most plesiomorphic phascolarctid. Inclusion in the analysis of the enigmatic Pliocene genus Koobor, currently classified as Vombatiformes incertae sedis, indicates phascolarctomorphian affinities for the genus.
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Descriptions of koala fossils from the Miocene of Riversleigh, northwestern Queensland and implications for Litokoala (Marsupialia, Phascolarctidae)
Alcheringa: An Australasian Journal of Palaeontology, 2007Co-Authors: Julien Louys, Karen H. Black, Michael Archer, Suzanne J. Hand, Henk GodthelpAbstract:Louys, J., Black, K., Archer, M., Hand, S.J. & Godthelp, H., June, 2007. Descriptions of koala fossils from the Miocene of Riversleigh, northwestern Queensland and implications for Litokoala (Marsupialia, Phascolarctidae). Alcheringa 31, 99‐110. ISSN 0311-5518. Litokoala is revised on the basis of new material from the early to middle Miocene deposits of Riversleigh. A new species of Litokoala is described from the System B Outasite Local Fauna. Litokoala garyjohnstoni sp. nov. possesses a unique combination of both plesiomorphic and apomorphic dental features, making its phylogenetic position within Litokoala difficult to interpret. In some aspects of dental morphology, L. garyjohnstoni is convergent on the early Miocene phascolarctid Nimiokoala greystanesi Black & Archer, 1997. The dentition of a partial skull of Litokoala from Jims Carousel Site, System C is also described. On the basis of this dentition, it is suggested that the morphological variation between L. kutjamarpensis Stirton, 1967 and L. ka...