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Robin M D Beck - One of the best experts on this subject based on the ideXlab platform.
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an emerging consensus in the evolution phylogeny and systematics of marsupials and their fossil relatives Metatheria
Journal of Mammalogy, 2019Co-Authors: Mark D B Eldridge, Robin M D Beck, Darin A Croft, Kenny J. TravouillonAbstract:Marsupials and their fossil relatives, which collectively comprise Metatheria, have been of scientific interest for centuries, with many aspects of their evolution and systematics subject to intense research and debate. Here, we review progress over the last 25 years, which has included the description of many new species (modern and fossil), and major improvements in understanding of their phylogenetic relationships, as well as the overall evolutionary history and biogeography of Marsupialia (crown-clade) and Metatheria (total-clade). Significant advances have included the deployment of increasingly sophisticated molecular, morphological, and total evidence analyses, which have resolved most previously disputed relationships among and within the modern marsupial orders. A broad systematic consensus is now emerging, although several major areas of contention remain, particularly among fossil Metatherians. New modern species continue to be described at an impressive rate, with almost 50 named in the last 25 years, and many more await discovery. There has also been an explosion in the discovery and description of fossil marsupials and non-marsupial Metatherians (~270 species), principally from Australasia and the Americas but also from Antarctica, Europe, and Asia. Most are represented by dental specimens only, but some consist of complete and well-preserved material, which has led to major improvements in our understanding of the evolution of cranial and postcranial morphology. Improvements in the fossil record and advances in methods for inferring divergence times have helped clarify when and where key events occurred in Metatherian evolution, and the patterns of subclade diversification. We also have improved understanding of biogeographical relationships among Metatherians on different landmasses. Despite enormous progress, numerous key uncertainties remain due to major gaps in the fossil record (e.g., Antarctica, Late Cretaceous, and early Paleogene of Australia) and a comparative lack of studies that directly combine molecular and fossil data. Future advances will largely depend on improvements in the fossil record and studies that better integrate neontological and paleontological evidence.
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The Osteology and Systematics of the Enigmatic Australian Oligo-Miocene Metatherian Yalkaparidon (Yalkaparidontidae; Yalkaparidontia; ?Australidelphia; Marsupialia)
Journal of Mammalian Evolution, 2014Co-Authors: Robin M D Beck, Henk Godthelp, Ken P. Aplin, Kenny J. Travouillon, Michael ArcherAbstract:We provide the first detailed description of the osteology of the enigmatic Oligo-Miocene Australian Metatherian Yalkaparidon . This taxon exhibits a number of unusual craniodental apomorphies but appears to be plesiomorphic within Metatheria in retaining four molars, rather than three as previously reported. We demonstrate that the only known skull of Yalkaparidon almost certainly represents a single individual. We also tentatively refer a number of isolated tarsals to the genus. Maximum parsimony analyses of a 258 character morphological matrix (with information from the tarsals described here either included or excluded) place Yalkaparidon within the superordinal clade Australidelphia, but Bayesian analyses of the same matrix are less well resolved, placing Yalkaparidon within Marsupialia but without unequivocally supporting australidelphian affinities. Bayesian analyses of a total evidence matrix that combines the morphological data with 9 kb of sequence data from five nuclear protein-coding genes (APOB, BRCA1, IRBP, RAG1 and VWF), 78 indels, and 53 retroposon insertion characters are similarly poorly resolved and do not clarify the supraordinal relationships of Yalkaparidon beyond suggesting that it is probably a member of Marsupialia. However, if the tarsal remains are correctly attributed to Yalkaparidon , then membership of Australidelphia seems likely, as these specimens exhibit characteristic australidelphian apomorphies. We conclude that the ordinal status of Yalkaparidon remains justified based on current evidence, and we present a revised diagnosis for Yalkaparidontia. We maintain the two currently recognized species, Y. coheni and Y. jonesi , but present revised specific diagnoses. We suggest a revised phylogenetic definition for Marsupialia, and provide phylogenetic definitions for Eomarsupialia (the clade comprising all extant Australian marsupial orders) and for the clade comprising Dasyuromorphia, Peramelemorphia, and Notoryctemorphia to the exclusion of Diprotodontia; we propose the name Agreodontia for the latter clade.
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The Osteology and Systematics of the Enigmatic Australian Oligo-Miocene Metatherian Yalkaparidon (Yalkaparidontidae; Yalkaparidontia; ?Australidelphia; Marsupialia)
Journal of Mammalian Evolution, 2014Co-Authors: Robin M D Beck, Henk Godthelp, Ken P. Aplin, Kenny J. Travouillon, Michael ArcherAbstract:We provide the first detailed description of the osteology of the enigmatic Oligo-Miocene Australian Metatherian Yalkaparidon . This taxon exhibits a number of unusual craniodental apomorphies but appears to be plesiomorphic within Metatheria in retaining four molars, rather than three as previously reported. We demonstrate that the only known skull of Yalkaparidon almost certainly represents a single individual. We also tentatively refer a number of isolated tarsals to the genus. Maximum parsimony analyses of a 258 character morphological matrix (with information from the tarsals described here either included or excluded) place Yalkaparidon within the superordinal clade Australidelphia, but Bayesian analyses of the same matrix are less well resolved, placing Yalkaparidon within Marsupialia but without unequivocally supporting australidelphian affinities. Bayesian analyses of a total evidence matrix that combines the morphological data with 9 kb of sequence data from five nuclear protein-coding genes (APOB, BRCA1, IRBP, RAG1 and VWF), 78 indels, and 53 retroposon insertion characters are similarly poorly resolved and do not clarify the supraordinal relationships of Yalkaparidon beyond suggesting that it is probably a member of Marsupialia. However, if the tarsal remains are correctly attributed to Yalkaparidon , then membership of Australidelphia seems likely, as these specimens exhibit characteristic australidelphian apomorphies. We conclude that the ordinal status of Yalkaparidon remains justified based on current evidence, and we present a revised diagnosis for Yalkaparidontia. We maintain the two currently recognized species, Y. coheni and Y. jonesi , but present revised specific diagnoses. We suggest a revised phylogenetic definition for Marsupialia, and provide phylogenetic definitions for Eomarsupialia (the clade comprising all extant Australian marsupial orders) and for the clade comprising Dasyuromorphia, Peramelemorphia, and Notoryctemorphia to the exclusion of Diprotodontia; we propose the name Agreodontia for the latter clade.
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An ‘ameridelphian’ marsupial from the early Eocene of Australia supports a complex model of Southern Hemisphere marsupial biogeography
Naturwissenschaften, 2012Co-Authors: Robin M D BeckAbstract:Recent molecular data strongly support the monophyly of all extant Australian and New Guinean marsupials (Eomarsupialia) to the exclusion of extant South American marsupials. This, together with available geological and fossil evidence, has been used to argue that the presence of marsupials in Australia is simply the result of a single dispersal event from South America during the latest Cretaceous or Palaeocene, without subsequent dispersals between the two continents. Here, I describe an isolated ankle bone (calcaneus) of a Metatherian from the early Eocene Tingamarra Local Fauna in northeastern Australia. Strikingly, this specimen, QM F30060, lacks the ‘continuous lower ankle joint pattern’ (CLAJP), presence of which is a highly distinctive apomorphy of the marsupial clade Australidelphia, which includes Eomarsupialia, the living South American microbiotherian Dromiciops and the Tingamarran fossil marsupial Djarthia . Comparisons with a range of marsupials and stem-Metatherians strongly suggest that the absence of the CLAJP in QM F30060 is plesiomorphic, and that this specimen represents the first unequivocal non-australidelphian (‘ameridelphian’) Metatherian known from Australia. This interpretation is confirmed by phylogenetic analyses that place QM F30060 within (crown-group) Marsupialia, but outside Australidelphia. Based on these results, the distribution of marsupials within Gondwana cannot be explained by simply a single dispersal event from South America and Australia. Either there were multiple dispersals by marsupials (and possibly also stem-Metatherians) between South America and Australia, in one or both directions, or, alternatively, there was a broadly similar Metatherian fauna stretching across southern South America, Antarctica and Australia during the Late Cretaceous–early Palaeogene.
Michael Archer - One of the best experts on this subject based on the ideXlab platform.
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The Osteology and Systematics of the Enigmatic Australian Oligo-Miocene Metatherian Yalkaparidon (Yalkaparidontidae; Yalkaparidontia; ?Australidelphia; Marsupialia)
Journal of Mammalian Evolution, 2014Co-Authors: Robin M D Beck, Henk Godthelp, Ken P. Aplin, Kenny J. Travouillon, Michael ArcherAbstract:We provide the first detailed description of the osteology of the enigmatic Oligo-Miocene Australian Metatherian Yalkaparidon . This taxon exhibits a number of unusual craniodental apomorphies but appears to be plesiomorphic within Metatheria in retaining four molars, rather than three as previously reported. We demonstrate that the only known skull of Yalkaparidon almost certainly represents a single individual. We also tentatively refer a number of isolated tarsals to the genus. Maximum parsimony analyses of a 258 character morphological matrix (with information from the tarsals described here either included or excluded) place Yalkaparidon within the superordinal clade Australidelphia, but Bayesian analyses of the same matrix are less well resolved, placing Yalkaparidon within Marsupialia but without unequivocally supporting australidelphian affinities. Bayesian analyses of a total evidence matrix that combines the morphological data with 9 kb of sequence data from five nuclear protein-coding genes (APOB, BRCA1, IRBP, RAG1 and VWF), 78 indels, and 53 retroposon insertion characters are similarly poorly resolved and do not clarify the supraordinal relationships of Yalkaparidon beyond suggesting that it is probably a member of Marsupialia. However, if the tarsal remains are correctly attributed to Yalkaparidon , then membership of Australidelphia seems likely, as these specimens exhibit characteristic australidelphian apomorphies. We conclude that the ordinal status of Yalkaparidon remains justified based on current evidence, and we present a revised diagnosis for Yalkaparidontia. We maintain the two currently recognized species, Y. coheni and Y. jonesi , but present revised specific diagnoses. We suggest a revised phylogenetic definition for Marsupialia, and provide phylogenetic definitions for Eomarsupialia (the clade comprising all extant Australian marsupial orders) and for the clade comprising Dasyuromorphia, Peramelemorphia, and Notoryctemorphia to the exclusion of Diprotodontia; we propose the name Agreodontia for the latter clade.
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The Osteology and Systematics of the Enigmatic Australian Oligo-Miocene Metatherian Yalkaparidon (Yalkaparidontidae; Yalkaparidontia; ?Australidelphia; Marsupialia)
Journal of Mammalian Evolution, 2014Co-Authors: Robin M D Beck, Henk Godthelp, Ken P. Aplin, Kenny J. Travouillon, Michael ArcherAbstract:We provide the first detailed description of the osteology of the enigmatic Oligo-Miocene Australian Metatherian Yalkaparidon . This taxon exhibits a number of unusual craniodental apomorphies but appears to be plesiomorphic within Metatheria in retaining four molars, rather than three as previously reported. We demonstrate that the only known skull of Yalkaparidon almost certainly represents a single individual. We also tentatively refer a number of isolated tarsals to the genus. Maximum parsimony analyses of a 258 character morphological matrix (with information from the tarsals described here either included or excluded) place Yalkaparidon within the superordinal clade Australidelphia, but Bayesian analyses of the same matrix are less well resolved, placing Yalkaparidon within Marsupialia but without unequivocally supporting australidelphian affinities. Bayesian analyses of a total evidence matrix that combines the morphological data with 9 kb of sequence data from five nuclear protein-coding genes (APOB, BRCA1, IRBP, RAG1 and VWF), 78 indels, and 53 retroposon insertion characters are similarly poorly resolved and do not clarify the supraordinal relationships of Yalkaparidon beyond suggesting that it is probably a member of Marsupialia. However, if the tarsal remains are correctly attributed to Yalkaparidon , then membership of Australidelphia seems likely, as these specimens exhibit characteristic australidelphian apomorphies. We conclude that the ordinal status of Yalkaparidon remains justified based on current evidence, and we present a revised diagnosis for Yalkaparidontia. We maintain the two currently recognized species, Y. coheni and Y. jonesi , but present revised specific diagnoses. We suggest a revised phylogenetic definition for Marsupialia, and provide phylogenetic definitions for Eomarsupialia (the clade comprising all extant Australian marsupial orders) and for the clade comprising Dasyuromorphia, Peramelemorphia, and Notoryctemorphia to the exclusion of Diprotodontia; we propose the name Agreodontia for the latter clade.
Henk Godthelp - One of the best experts on this subject based on the ideXlab platform.
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The Osteology and Systematics of the Enigmatic Australian Oligo-Miocene Metatherian Yalkaparidon (Yalkaparidontidae; Yalkaparidontia; ?Australidelphia; Marsupialia)
Journal of Mammalian Evolution, 2014Co-Authors: Robin M D Beck, Henk Godthelp, Ken P. Aplin, Kenny J. Travouillon, Michael ArcherAbstract:We provide the first detailed description of the osteology of the enigmatic Oligo-Miocene Australian Metatherian Yalkaparidon . This taxon exhibits a number of unusual craniodental apomorphies but appears to be plesiomorphic within Metatheria in retaining four molars, rather than three as previously reported. We demonstrate that the only known skull of Yalkaparidon almost certainly represents a single individual. We also tentatively refer a number of isolated tarsals to the genus. Maximum parsimony analyses of a 258 character morphological matrix (with information from the tarsals described here either included or excluded) place Yalkaparidon within the superordinal clade Australidelphia, but Bayesian analyses of the same matrix are less well resolved, placing Yalkaparidon within Marsupialia but without unequivocally supporting australidelphian affinities. Bayesian analyses of a total evidence matrix that combines the morphological data with 9 kb of sequence data from five nuclear protein-coding genes (APOB, BRCA1, IRBP, RAG1 and VWF), 78 indels, and 53 retroposon insertion characters are similarly poorly resolved and do not clarify the supraordinal relationships of Yalkaparidon beyond suggesting that it is probably a member of Marsupialia. However, if the tarsal remains are correctly attributed to Yalkaparidon , then membership of Australidelphia seems likely, as these specimens exhibit characteristic australidelphian apomorphies. We conclude that the ordinal status of Yalkaparidon remains justified based on current evidence, and we present a revised diagnosis for Yalkaparidontia. We maintain the two currently recognized species, Y. coheni and Y. jonesi , but present revised specific diagnoses. We suggest a revised phylogenetic definition for Marsupialia, and provide phylogenetic definitions for Eomarsupialia (the clade comprising all extant Australian marsupial orders) and for the clade comprising Dasyuromorphia, Peramelemorphia, and Notoryctemorphia to the exclusion of Diprotodontia; we propose the name Agreodontia for the latter clade.
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The Osteology and Systematics of the Enigmatic Australian Oligo-Miocene Metatherian Yalkaparidon (Yalkaparidontidae; Yalkaparidontia; ?Australidelphia; Marsupialia)
Journal of Mammalian Evolution, 2014Co-Authors: Robin M D Beck, Henk Godthelp, Ken P. Aplin, Kenny J. Travouillon, Michael ArcherAbstract:We provide the first detailed description of the osteology of the enigmatic Oligo-Miocene Australian Metatherian Yalkaparidon . This taxon exhibits a number of unusual craniodental apomorphies but appears to be plesiomorphic within Metatheria in retaining four molars, rather than three as previously reported. We demonstrate that the only known skull of Yalkaparidon almost certainly represents a single individual. We also tentatively refer a number of isolated tarsals to the genus. Maximum parsimony analyses of a 258 character morphological matrix (with information from the tarsals described here either included or excluded) place Yalkaparidon within the superordinal clade Australidelphia, but Bayesian analyses of the same matrix are less well resolved, placing Yalkaparidon within Marsupialia but without unequivocally supporting australidelphian affinities. Bayesian analyses of a total evidence matrix that combines the morphological data with 9 kb of sequence data from five nuclear protein-coding genes (APOB, BRCA1, IRBP, RAG1 and VWF), 78 indels, and 53 retroposon insertion characters are similarly poorly resolved and do not clarify the supraordinal relationships of Yalkaparidon beyond suggesting that it is probably a member of Marsupialia. However, if the tarsal remains are correctly attributed to Yalkaparidon , then membership of Australidelphia seems likely, as these specimens exhibit characteristic australidelphian apomorphies. We conclude that the ordinal status of Yalkaparidon remains justified based on current evidence, and we present a revised diagnosis for Yalkaparidontia. We maintain the two currently recognized species, Y. coheni and Y. jonesi , but present revised specific diagnoses. We suggest a revised phylogenetic definition for Marsupialia, and provide phylogenetic definitions for Eomarsupialia (the clade comprising all extant Australian marsupial orders) and for the clade comprising Dasyuromorphia, Peramelemorphia, and Notoryctemorphia to the exclusion of Diprotodontia; we propose the name Agreodontia for the latter clade.
Ken P. Aplin - One of the best experts on this subject based on the ideXlab platform.
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The Osteology and Systematics of the Enigmatic Australian Oligo-Miocene Metatherian Yalkaparidon (Yalkaparidontidae; Yalkaparidontia; ?Australidelphia; Marsupialia)
Journal of Mammalian Evolution, 2014Co-Authors: Robin M D Beck, Henk Godthelp, Ken P. Aplin, Kenny J. Travouillon, Michael ArcherAbstract:We provide the first detailed description of the osteology of the enigmatic Oligo-Miocene Australian Metatherian Yalkaparidon . This taxon exhibits a number of unusual craniodental apomorphies but appears to be plesiomorphic within Metatheria in retaining four molars, rather than three as previously reported. We demonstrate that the only known skull of Yalkaparidon almost certainly represents a single individual. We also tentatively refer a number of isolated tarsals to the genus. Maximum parsimony analyses of a 258 character morphological matrix (with information from the tarsals described here either included or excluded) place Yalkaparidon within the superordinal clade Australidelphia, but Bayesian analyses of the same matrix are less well resolved, placing Yalkaparidon within Marsupialia but without unequivocally supporting australidelphian affinities. Bayesian analyses of a total evidence matrix that combines the morphological data with 9 kb of sequence data from five nuclear protein-coding genes (APOB, BRCA1, IRBP, RAG1 and VWF), 78 indels, and 53 retroposon insertion characters are similarly poorly resolved and do not clarify the supraordinal relationships of Yalkaparidon beyond suggesting that it is probably a member of Marsupialia. However, if the tarsal remains are correctly attributed to Yalkaparidon , then membership of Australidelphia seems likely, as these specimens exhibit characteristic australidelphian apomorphies. We conclude that the ordinal status of Yalkaparidon remains justified based on current evidence, and we present a revised diagnosis for Yalkaparidontia. We maintain the two currently recognized species, Y. coheni and Y. jonesi , but present revised specific diagnoses. We suggest a revised phylogenetic definition for Marsupialia, and provide phylogenetic definitions for Eomarsupialia (the clade comprising all extant Australian marsupial orders) and for the clade comprising Dasyuromorphia, Peramelemorphia, and Notoryctemorphia to the exclusion of Diprotodontia; we propose the name Agreodontia for the latter clade.
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The Osteology and Systematics of the Enigmatic Australian Oligo-Miocene Metatherian Yalkaparidon (Yalkaparidontidae; Yalkaparidontia; ?Australidelphia; Marsupialia)
Journal of Mammalian Evolution, 2014Co-Authors: Robin M D Beck, Henk Godthelp, Ken P. Aplin, Kenny J. Travouillon, Michael ArcherAbstract:We provide the first detailed description of the osteology of the enigmatic Oligo-Miocene Australian Metatherian Yalkaparidon . This taxon exhibits a number of unusual craniodental apomorphies but appears to be plesiomorphic within Metatheria in retaining four molars, rather than three as previously reported. We demonstrate that the only known skull of Yalkaparidon almost certainly represents a single individual. We also tentatively refer a number of isolated tarsals to the genus. Maximum parsimony analyses of a 258 character morphological matrix (with information from the tarsals described here either included or excluded) place Yalkaparidon within the superordinal clade Australidelphia, but Bayesian analyses of the same matrix are less well resolved, placing Yalkaparidon within Marsupialia but without unequivocally supporting australidelphian affinities. Bayesian analyses of a total evidence matrix that combines the morphological data with 9 kb of sequence data from five nuclear protein-coding genes (APOB, BRCA1, IRBP, RAG1 and VWF), 78 indels, and 53 retroposon insertion characters are similarly poorly resolved and do not clarify the supraordinal relationships of Yalkaparidon beyond suggesting that it is probably a member of Marsupialia. However, if the tarsal remains are correctly attributed to Yalkaparidon , then membership of Australidelphia seems likely, as these specimens exhibit characteristic australidelphian apomorphies. We conclude that the ordinal status of Yalkaparidon remains justified based on current evidence, and we present a revised diagnosis for Yalkaparidontia. We maintain the two currently recognized species, Y. coheni and Y. jonesi , but present revised specific diagnoses. We suggest a revised phylogenetic definition for Marsupialia, and provide phylogenetic definitions for Eomarsupialia (the clade comprising all extant Australian marsupial orders) and for the clade comprising Dasyuromorphia, Peramelemorphia, and Notoryctemorphia to the exclusion of Diprotodontia; we propose the name Agreodontia for the latter clade.
Francisco J. Goin - One of the best experts on this subject based on the ideXlab platform.
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The fossil record of Antarctic land mammals: commented review and hypotheses for future research
2019Co-Authors: Javier N. Gelfo, Francisco J. Goin, Nicolás Bauzá, Marcelo RegueroAbstract:The fossil record of terrestrial mammals in Antarctica is temporally and geographically constrained to the Eocene outcrops of La Meseta and Submeseta formations in Seymour (Marambio) Island in West Antarctica. The faunal assemblage indicates a clear South American imprint since all the groups have a close phylogenetic relationship with Cretaceous and Paleogene mammals from Patagonia. Despite the presence of several mammalian taxonomic groups: Dryolestida, Gondwanatheria, Eutheria and Metatheria, the presence of other major mammalian taxa should be expected and will probably be confirmed by new findings. Placental mammals with an inferred body mass between 10 to 400 kg in size, are represented by xenarthrans, and two groups of the so called South American native ungulates: Astrapotheria and Litopterna. The Metatheria are the smaller (less than 1 kg) and most abundant components of the fauna. Marsupials are represented by derorhynchid ameridelphians, several microbiotherian australidelphians (both microbiotheriids and woodburnodontids), and ?glasbiid prepidolopod and polydolopid polydolopimorphians. Plus, there are remains of several mammalian teeth of indeterminate phylogenetic affinities. The present knowledge of the Southern Hemisphere mammalian evolution and paleogeographic change through time, indicates that Antarctica played a major role for land mammals, at least since the Jurassic. The actual representation of Paleogene terrestrial mammals in Antarctica is most probably biased, as all the evidence indicates that australosphenidan mammals should be present in this continent since the Jurassic. Citation:Gelfo J N, Goin F J, Bauza N, et al. The fossil record of Antarctic land mammals: commented review and hypotheses for future research. Adv Polar Sci, 2019, 30(3): 274-292, doi: 10.13679/j.advps.2019.0021
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Diversity, Affinities and Adaptations of the Basal Sparassodont Patene (Mammalia, Metatheria)
Ameghiniana, 2019Co-Authors: Caio César Rangel, Edison Vicente Oliveira, Francisco J. Goin, Leonardo M Carneiro, Lílian Paglarelli Bergqvist, María Judith BabotAbstract:Sparassodonts were the main mammalian predators during most of the Cenozoic in South America. The lower Eocene Itaborai Basin/ Formation includes the second oldest fossil records of this group in South America: Patene Simpson and cf. Nemolestes Ameghino. Patene is by far the most abundant sparassodont from this formation, with more than 30 specimens referable to a single taxon, Patene simpsoni Paula Couto. Some specimens recovered from the Quebrada de Los Colorados Formation (formerly Lumbrera Formation – middle Eocene) in Northwestern Argentina have been also referred to P. simpsoni. In order to test the affinities of Patene and the taxonomy of the Argentinean specimens, we performed a review of the genus. Specimens of Patene from Northwestern Argentina show significant differences from the specimen from Brazil, including: smaller size; a relatively larger paraconid; and smaller metaconid, entoconid and hypoconid. As a result, the specimens from the Quebrada de Los Colorados Formation are assigned to a new taxon, Patene coloradensis sp. nov. The results of our phylogenetic analysis recover Patene as a basal sparassodont and support previous hypotheses that exclude Patene from the “Hathliacynidae”. The results also supported the hypothesis that Allqokirus australis Marshall & Muizon and Mayulestes ferox Muizon from the Tiupampa Basin (Santa Lucia Formation, lower Paleocene – Tiupampan SALMA), Bolivia, are the oldest known representatives of the Sparassodonta. The results also supported the monophyly of the Pucadelphyda with the inclusion of the Jaskhadelphyidae and closely related taxa in this group in addition to the Pucadelphyidae and Sparassodonta. The late Cretaceous North American Varalphadon Johanson was not recovered as a representative of the Sparassodonta in our phylogenetic analysis. Based on our results and the current fossil record, the Sparassodonta should be considered an endemic South American lineage.
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austropediomys marshalli gen et sp nov a new pediomyoidea mammalia Metatheria from the paleogene of brazil paleobiogeographic implications
Revista Brasileira De Paleontologia, 2018Co-Authors: Leonardo M Carneiro, Edison Vicente Oliveira, Francisco J. GoinAbstract:The Pediomyiodea has been largely regarded as a Late Cretaceous North American Metatherian lineage; however, some studies have suggested that a few South American taxa could be related to this family. Herein, Austropediomys marshalli gen. et sp. nov. from the Itaborai Basin, Brazil (lower Eocene – Itaboraian SALMA), is described. Austropediomys gen. nov. represents the first report of a pediomyoid Metatherian in the Paleogene of South America backed by a phylogenetic analysis. Several derived features in the upper molars support its belonging to the Pediomyoidea: presence of accessory ‘conular-like’ structures (here named conuloids) lingual to the conules; supernumerary stylar cusps; asymmetric stylar shelf, with parastylar shelf reduced to a narrow rim in M1; straight centrocrista; short and obliquely oriented prepacrista, which contacts StA in M2–3. The presence of ‘conular-like’ structures lingual to the paraconule and metaconule is identified in Austropediomys gen. nov. and in Late Cretaceous pediomyoids as well, and results in the phylogenetic analysis as a synapomorphy of the Pediomyoidea. Austropediomys gen. nov. is autapomorphyc in the presence of enlarged conuloids on protocristae. The record of a pediomyoid in the Paleogene of South America increases the temporal and biogeographical range of this lineage. Also, our results support the hypothesis that several non-related Metatherian lineages dispersed from North to South America via the Caribbean Plate, most probably during the latest Cretaceous, in an island-hopping or sweepstakes model.
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taxonomy affinities and paleobiology of the tiny Metatherian mammal minusculodelphis from the early eocene of south america
Naturwissenschaften, 2016Co-Authors: Edison Vicente Oliveira, Natalia Zimicz, Francisco J. GoinAbstract:With less than 3 g of estimated body mass, the early Eocene Minusculodelphis minimus Paula Couto (Mammalia, Metatheria, Jaskhadelphyidae) is one of the smallest mammals, living or extinct. It has alternatively been regarded as a didelphid or a derorhynchid “ameridelphian,” or even as an eoMetatherian marsupial. Here, we describe a new species of Minusculodelphis coming from the same locality (Itaborai Quarry, Brazil) and age (Itaboraian age) of the type species of the genus. It differs from M. minimus in its larger size and several dental characters. The new species offers data on the upper dentition and femur, which are unknown in the type species. Compared to other Paleogene Metatherians, Minusculodelphis shows closer relationships with Jaskhadelphys, from the early Paleocene of Tiupampa, Bolivia, as well as with Kiruwamaq, from the late Eocene-early Oligocene of Peru. A cladistic analysis places all three genera within the family Jaskhadelphyidae (Metatheria, Order indet.), which includes small to tiny, insectivorous-like Metatherians. We argue that insectivory (soft insects) is the best-supported diet for both species of Minusculodelphis, and that the most probable microhabitat for them was the understorey or leaf litter of tropical, rain forested environments.
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Insights into the Neotropics prior to the Great American Biotic Interchange: new evidence of mammalian predators from the Miocene of Northern Colombia
2016Co-Authors: Catalina Suarez, Francisco J. Goin, Analía M. Forasiepi, Carlos JaramilloAbstract:A new species of Sparassodonta (Mammalia, Metatheria), Lycopsis padillai, sp. nov., is described on the basis of a partial left maxilla with M1–M4 and fragments of lacrimal and jugal. The material comes from the early to early middle Miocene Castilletes Formation, La Guajira Peninsula, Colombia. This specimen represents the northernmost record of a fossil Metatherian in South America and integrates a highly diverse vertebrate association, recently discovered in the north of Colombia. The La Guajira specimen is referred to the genus Lycopsis, as supported by the results of our phylogenetic analysis. This analysis also demonstrates that species of Lycopsis (L. torresi, L. longirostrus, L. viverensis, and L. padillai) constitute a monophyletic group and are placed as the basal taxon of Borhyaenoidea. Lycopsis padillai is a large-sized sparassodont with a body mass of about 22 kg. The presence of Lycopsis from La Guajira extends the geographical distribution of the genus to the entire South America, representing the sparassodont with the widest latitudinal distribution. http://zoobank.org/urn:lsid:zoobank.org:pub:B3127EDAB4BB-4972-81B9-4447CC44EE79 SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP Citation for this article: Suarez, C., A. M. Forasiepi, F. J. Goin, and C. Jaramillo. 2015. Insights into the Neotropics prior to the Great American Biotic Interchange: new evidence of mammalian predators from the Miocene of Northern Colombia. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2015.1029581.
