Eric Roberts | James Cook University (original) (raw)

Papers by Eric Roberts

Research paper thumbnail of A new Cretaceous lungfish (Dipnoi: Ceratodontidae) from the Rukwa Rift Basin, Tanzania

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Research paper thumbnail of Morphological diversification of ampullariid gastropods (Nsungwe Formation, Late Oligocene, Rukwa Rift Basin, Tanzania) is coincident with onset of East African rifting

Papers in Palaeontology

A new freshwater gastropod fauna is described from the late Oligocene Nsungwe Formation of the Ru... more A new freshwater gastropod fauna is described from the late Oligocene Nsungwe Formation of the Rukwa Rift Basin, Tanzania. Six new species of ampullariids are established including five species of Lanistes (L. microovum, L. nsungwensis, L. rukwaensis, L. songwellipticus and L. songweovum) and one species of Carnevalea (C. santiapillaii). These taxa occupy a morphospace region comparable to nearly half of extant Lanistes, a common and widespread genus in Africa and Madagascar. Palaeoecological evidence indicates that Nsungwe ampullariids inhabited fluvial, pond and paludal environments. Among these species are the oldest high‐spired and fluvially adapated Lanistes taxa. We suggest that Nsungwe Lanistes rapidly diversified in concert with habitat heterogeneity associated with the initiation of rifting along the western branch of the East African Rift System (EARS). Taxonomy, evolution and the biogeographical affinities of Nsungwe Formation freshwater gastropods contributes significantly to expanding the undersampled Palaeogene invertebrate fossil record of continental Africa.

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Research paper thumbnail of Large palaeophiid and nigerophiid snakes from Paleogene Trans-Saharan Seaway deposits of Mali

Acta Palaeontologica Polonica

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Research paper thumbnail of Proterozoic 40Ar/39Ar ages from cave deposits of the Malapa, Sterkfontein and Dinaledi fossil sites, Cradle of Humankind, South Africa

South African Journal of Geology

We have explored the use of 40 Ar / 39 Ar dating on Mn ooids and peloids, and fragments of indura... more We have explored the use of 40 Ar / 39 Ar dating on Mn ooids and peloids, and fragments of indurated, extremely fine-grained mudstone occurring in cave sediments in the Cradle of Humankind (CoH) UNESCO world heritage site, to obtain ages of fossil-bearing cave sediments. Samples analysed were from the Malapa site (envisaged as a testing ground because it was previously dated with high precision by the uranium-lead method and paleomagnetism), the floor of the Dinaledi Chamber in Rising Star Cave, as well as boreholes 2 and 3 of the Sterkfontein Cave. The 40 Ar/ 39 Ar apparent ages of the dated samples turned out to be unrelated to cave formation processes, rendering the Malapa-based validation irrelevant. The results do, however, provide insight into aspects of the origin of the cave sediments and dated material. Most samples yielded disturbed 40 Ar/ 39 Ar spectra. The apparent pooled gas ages for the Mn ooids analysed from Malapa range between 476 ± 13 Ma and 1964 ± 13 Ma. Of 5 ooids from Sterkfontein, one yielded 1597 ± 13 Ma, while the rest range between 1960 ± 35 Ma and 2081 ± 13 Ma, the latter being a plateau age. Peloidal Mn nodules from Dinaledi Chamber samples yielded apparent ages between 1975 ± 9 Ma and 2096 ± 13 Ma. Indurated mudstone fragments were analysed from Sterkfontein and for 3 out of 4 samples, the apparent pooled gas ages range from 1970 ± 14 Ma to 2059 ± 13 Ma (one yielded 1623 ± 15 Ma). We conclude that ooids, peloids and indurated mudstone fragments are derived from higher levels in the Transvaal Supergroup stratigraphy, trapped in karst features over time as these were eroded, and finally washed into the caves.

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Research paper thumbnail of Homo naledi and Pleistocene hominin evolution in subequatorial Africa

eLife, May 9, 2017

New discoveries and dating of fossil remains from the Rising Star cave system, Cradle of Humankin... more New discoveries and dating of fossil remains from the Rising Star cave system, Cradle of Humankind, South Africa, have strong implications for our understanding of Pleistocene human evolution in Africa. Direct dating of Homo naledi fossils from the Dinaledi Chamber (Berger et al., 2015) shows that they were deposited between about 236 ka and 335 ka (Dirks et al., 2017), placing H. naledi in the later Middle Pleistocene. Hawks and colleagues (Hawks et al., 2017) report the discovery of a second chamber within the Rising Star system (Dirks et al., 2015) that contains H. naledi remains. Previously, only large-brained modern humans or their close relatives had been demonstrated to exist at this late time in Africa, but the fossil evidence for any hominins in subequatorial Africa was very sparse. It is now evident that a diversity of hominin lineages existed in this region, with some divergent lineages contributing DNA to living humans and at least H. naledi representing a survivor from ...

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Research paper thumbnail of New fossil remains of Homo naledi from the Lesedi Chamber, South Africa

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Research paper thumbnail of A new tyrannosaur with evidence for anagenesis and crocodile-like facial sensory system

Scientific Reports, 2017

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Research paper thumbnail of Depositional environment of the Lower Cretaceous (upper Albian) Winton Formation at Isisford, central-west Queensland, inferred from sandstone concretions

Journal of Sedimentary Research, 2016, v. 86: 1067–1082

Numerous vertebrate and plant fossils have been found in ex-situ sandstone concretions near Isisf... more Numerous vertebrate and plant fossils have been found in ex-situ sandstone concretions near Isisford in central-west Queensland since the mid-1990s. These concretions are found in the Lower Cretaceous portion (upper Albian, 100.5–102.2 Ma) of the Winton Formation. The lower most Winton Formation is thought to have formed in a fluvial channel or flood-basin setting proximal to the Eromanga Sea, but due to the scarcity of good exposures, the local depositional environment at Isisford has not been ascertained. Minimal compression of vertebrate and plant fossils, a lack of grain suturing, predominantly cement-supported fabric, and fractures running through calcite cement, as well as fossil bone and framework grains, indicates that concretions formed during early diagenesis (pre- compactional or syndepositional). Calcite stable-isotope δ18OvPDB values range from -12.25 to -4‰, indicating mixed marine and meteoric pore waters, and δ13CvPDB values range from -5.3 to 4.1‰, indicative of bot...

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Research paper thumbnail of Lithological and facies analysis of the Roseneath and Murteree shales, Cooper Basin, Australia

Journal of Natural Gas Science and Engineering, 2016

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Research paper thumbnail of Faunal diversity in the late Oligocene Nsungwe Formation, Rukwa Rift Basin, southwestern Tanzania

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Research paper thumbnail of Mineralogical modelling and petrophysical parameters in Permian gas shales from the Roseneath and Murteree formations, Cooper Basin, Australia

Petroleum Exploration and Development, 2016

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Research paper thumbnail of Sampson Grand Staircase-Escalante National Monument: A New and Critical Window into the World of Dinosaurs

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Research paper thumbnail of Deliberate body disposal by hominins in the Dinaledi Chamber, Cradle of Humankind, South Africa

Homo naledi is a new species recently named from material recovered from the Dinaledi Chamber, in... more Homo naledi is a new species recently named from material recovered from the Dinaledi Chamber, inside the Rising Star cave (Berger et al., 2015). Comprising 1550 remains attributed to a minimum number of 15 individuals of all age groups, it was postulated by Dirks et al. (2015) that the unique assemblage could be the result of deliberate disposal of the dead by this small-brained and previously unknown species of hominin. Alternative taphonomic hypotheses, such as accumulation via a natural death trap or by predators, transport by water, occupation of the cave by the hominins, or catastrophic event, were rejected on the basis that (i) the fossil assemblage is composed exclusively of hominin remains (with the exception of a few micromammal and bird bones), (ii) it was recovered in a deep, dark, underground cave chamber never accessible to non-hominins and (iii) no evidence of vertebrate damage (e.g., no carnivore or rodent gnawing) was identified. Furthermore, based on the results of their taphonomic analysis, Dirks et al. (2015: 1) proposed that “hominin individuals reached the chamber complete, with disarticulation occurring during/after deposition”. This has far-reaching implications for understanding the conditions surrounding the emergence of mortuary behaviours in our lineage. Mortuary practices, that is, specific responses by the living members of a group towards their dead, are not exclusive to humans. This is supported by the various reactions towards deceased individuals observed among non-hominin primates, and especially chimpanzees (e.g., Teleki, 1973; Anderson et al., 2010; Biro et al., 2010; Pettitt, 2011). These practices may predate the emergence of the genus Homo if the 3.2 million year old open air

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Research paper thumbnail of Variations in iron oxide, iron sulphide and carbonate concretions and their distributions in fluvio-deltaic and nearshore sandstones: cretaceous examples from the Kaiparowits Plateau, Utah and San Juan Basin, New Mexico

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Research paper thumbnail of Organic petrography and thermal maturity of the Permian Roseneath and Murteree shales in the Cooper Basin, Australia

International Journal of Coal Geology, 2016

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Research paper thumbnail of U-Pb LA-ICPMS detrital zircon geochronology of the Upper Cretaceous Winton Formation, Queensland, Australia: implications for regional tectonics, sedimentary provenance and vertebrate palaeontology

This study utilizes detrital zircon geochronology to constrain the depositional age, tectonic set... more This study utilizes detrital zircon geochronology to constrain the depositional age, tectonic setting, basin evolution, and stratigraphic context of the poorly understood Winton Formation, northeastern Australia (Fig.1). To develop better context for Australia’s most significant dinosaur-bearing succession, we analyzed 10 samples from different stratigraphic levels and key fossil locations throughout the Winton and underlying units (basin wide). Detrital zircon ages were obtained by U-Pb LA-ICPMS dating and the results were subjected to seven different metrics to interpret maximum depositional age. The results considerably improved upon earlier palynological age constraints, suggesting that most of the key vertebrate fossil localities in the Winton Formation are no older than earliest Turonian to latest Cenomanian (92-94 Ma) (Fig.2). The most abundant detrital zircon population clusters between 92-115 Ma, suggesting that much of the volcanic-rich sediment that characterizes the Wint...

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Research paper thumbnail of Basin-Scale Controls on Continental Vertebrate Taphonomy: Insights from the Campanian of Laramidia

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Research paper thumbnail of Criteria for identifying bone modification by termites in the fossil record

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Research paper thumbnail of Paleontological Exploration in Africa

Developments in Primatology: Progress and Prospects, 2008

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Research paper thumbnail of Embryology of Early Jurassic dinosaur from China with evidence of preserved organic remains

Nature, 2013

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Research paper thumbnail of A new Cretaceous lungfish (Dipnoi: Ceratodontidae) from the Rukwa Rift Basin, Tanzania

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Morphological diversification of ampullariid gastropods (Nsungwe Formation, Late Oligocene, Rukwa Rift Basin, Tanzania) is coincident with onset of East African rifting

Papers in Palaeontology

A new freshwater gastropod fauna is described from the late Oligocene Nsungwe Formation of the Ru... more A new freshwater gastropod fauna is described from the late Oligocene Nsungwe Formation of the Rukwa Rift Basin, Tanzania. Six new species of ampullariids are established including five species of Lanistes (L. microovum, L. nsungwensis, L. rukwaensis, L. songwellipticus and L. songweovum) and one species of Carnevalea (C. santiapillaii). These taxa occupy a morphospace region comparable to nearly half of extant Lanistes, a common and widespread genus in Africa and Madagascar. Palaeoecological evidence indicates that Nsungwe ampullariids inhabited fluvial, pond and paludal environments. Among these species are the oldest high‐spired and fluvially adapated Lanistes taxa. We suggest that Nsungwe Lanistes rapidly diversified in concert with habitat heterogeneity associated with the initiation of rifting along the western branch of the East African Rift System (EARS). Taxonomy, evolution and the biogeographical affinities of Nsungwe Formation freshwater gastropods contributes significantly to expanding the undersampled Palaeogene invertebrate fossil record of continental Africa.

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Research paper thumbnail of Large palaeophiid and nigerophiid snakes from Paleogene Trans-Saharan Seaway deposits of Mali

Acta Palaeontologica Polonica

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Research paper thumbnail of Proterozoic 40Ar/39Ar ages from cave deposits of the Malapa, Sterkfontein and Dinaledi fossil sites, Cradle of Humankind, South Africa

South African Journal of Geology

We have explored the use of 40 Ar / 39 Ar dating on Mn ooids and peloids, and fragments of indura... more We have explored the use of 40 Ar / 39 Ar dating on Mn ooids and peloids, and fragments of indurated, extremely fine-grained mudstone occurring in cave sediments in the Cradle of Humankind (CoH) UNESCO world heritage site, to obtain ages of fossil-bearing cave sediments. Samples analysed were from the Malapa site (envisaged as a testing ground because it was previously dated with high precision by the uranium-lead method and paleomagnetism), the floor of the Dinaledi Chamber in Rising Star Cave, as well as boreholes 2 and 3 of the Sterkfontein Cave. The 40 Ar/ 39 Ar apparent ages of the dated samples turned out to be unrelated to cave formation processes, rendering the Malapa-based validation irrelevant. The results do, however, provide insight into aspects of the origin of the cave sediments and dated material. Most samples yielded disturbed 40 Ar/ 39 Ar spectra. The apparent pooled gas ages for the Mn ooids analysed from Malapa range between 476 ± 13 Ma and 1964 ± 13 Ma. Of 5 ooids from Sterkfontein, one yielded 1597 ± 13 Ma, while the rest range between 1960 ± 35 Ma and 2081 ± 13 Ma, the latter being a plateau age. Peloidal Mn nodules from Dinaledi Chamber samples yielded apparent ages between 1975 ± 9 Ma and 2096 ± 13 Ma. Indurated mudstone fragments were analysed from Sterkfontein and for 3 out of 4 samples, the apparent pooled gas ages range from 1970 ± 14 Ma to 2059 ± 13 Ma (one yielded 1623 ± 15 Ma). We conclude that ooids, peloids and indurated mudstone fragments are derived from higher levels in the Transvaal Supergroup stratigraphy, trapped in karst features over time as these were eroded, and finally washed into the caves.

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Research paper thumbnail of Homo naledi and Pleistocene hominin evolution in subequatorial Africa

eLife, May 9, 2017

New discoveries and dating of fossil remains from the Rising Star cave system, Cradle of Humankin... more New discoveries and dating of fossil remains from the Rising Star cave system, Cradle of Humankind, South Africa, have strong implications for our understanding of Pleistocene human evolution in Africa. Direct dating of Homo naledi fossils from the Dinaledi Chamber (Berger et al., 2015) shows that they were deposited between about 236 ka and 335 ka (Dirks et al., 2017), placing H. naledi in the later Middle Pleistocene. Hawks and colleagues (Hawks et al., 2017) report the discovery of a second chamber within the Rising Star system (Dirks et al., 2015) that contains H. naledi remains. Previously, only large-brained modern humans or their close relatives had been demonstrated to exist at this late time in Africa, but the fossil evidence for any hominins in subequatorial Africa was very sparse. It is now evident that a diversity of hominin lineages existed in this region, with some divergent lineages contributing DNA to living humans and at least H. naledi representing a survivor from ...

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Research paper thumbnail of New fossil remains of Homo naledi from the Lesedi Chamber, South Africa

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Research paper thumbnail of A new tyrannosaur with evidence for anagenesis and crocodile-like facial sensory system

Scientific Reports, 2017

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Research paper thumbnail of Depositional environment of the Lower Cretaceous (upper Albian) Winton Formation at Isisford, central-west Queensland, inferred from sandstone concretions

Journal of Sedimentary Research, 2016, v. 86: 1067–1082

Numerous vertebrate and plant fossils have been found in ex-situ sandstone concretions near Isisf... more Numerous vertebrate and plant fossils have been found in ex-situ sandstone concretions near Isisford in central-west Queensland since the mid-1990s. These concretions are found in the Lower Cretaceous portion (upper Albian, 100.5–102.2 Ma) of the Winton Formation. The lower most Winton Formation is thought to have formed in a fluvial channel or flood-basin setting proximal to the Eromanga Sea, but due to the scarcity of good exposures, the local depositional environment at Isisford has not been ascertained. Minimal compression of vertebrate and plant fossils, a lack of grain suturing, predominantly cement-supported fabric, and fractures running through calcite cement, as well as fossil bone and framework grains, indicates that concretions formed during early diagenesis (pre- compactional or syndepositional). Calcite stable-isotope δ18OvPDB values range from -12.25 to -4‰, indicating mixed marine and meteoric pore waters, and δ13CvPDB values range from -5.3 to 4.1‰, indicative of bot...

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Research paper thumbnail of Lithological and facies analysis of the Roseneath and Murteree shales, Cooper Basin, Australia

Journal of Natural Gas Science and Engineering, 2016

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Research paper thumbnail of Faunal diversity in the late Oligocene Nsungwe Formation, Rukwa Rift Basin, southwestern Tanzania

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Mineralogical modelling and petrophysical parameters in Permian gas shales from the Roseneath and Murteree formations, Cooper Basin, Australia

Petroleum Exploration and Development, 2016

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Sampson Grand Staircase-Escalante National Monument: A New and Critical Window into the World of Dinosaurs

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Deliberate body disposal by hominins in the Dinaledi Chamber, Cradle of Humankind, South Africa

Homo naledi is a new species recently named from material recovered from the Dinaledi Chamber, in... more Homo naledi is a new species recently named from material recovered from the Dinaledi Chamber, inside the Rising Star cave (Berger et al., 2015). Comprising 1550 remains attributed to a minimum number of 15 individuals of all age groups, it was postulated by Dirks et al. (2015) that the unique assemblage could be the result of deliberate disposal of the dead by this small-brained and previously unknown species of hominin. Alternative taphonomic hypotheses, such as accumulation via a natural death trap or by predators, transport by water, occupation of the cave by the hominins, or catastrophic event, were rejected on the basis that (i) the fossil assemblage is composed exclusively of hominin remains (with the exception of a few micromammal and bird bones), (ii) it was recovered in a deep, dark, underground cave chamber never accessible to non-hominins and (iii) no evidence of vertebrate damage (e.g., no carnivore or rodent gnawing) was identified. Furthermore, based on the results of their taphonomic analysis, Dirks et al. (2015: 1) proposed that “hominin individuals reached the chamber complete, with disarticulation occurring during/after deposition”. This has far-reaching implications for understanding the conditions surrounding the emergence of mortuary behaviours in our lineage. Mortuary practices, that is, specific responses by the living members of a group towards their dead, are not exclusive to humans. This is supported by the various reactions towards deceased individuals observed among non-hominin primates, and especially chimpanzees (e.g., Teleki, 1973; Anderson et al., 2010; Biro et al., 2010; Pettitt, 2011). These practices may predate the emergence of the genus Homo if the 3.2 million year old open air

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Variations in iron oxide, iron sulphide and carbonate concretions and their distributions in fluvio-deltaic and nearshore sandstones: cretaceous examples from the Kaiparowits Plateau, Utah and San Juan Basin, New Mexico

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Organic petrography and thermal maturity of the Permian Roseneath and Murteree shales in the Cooper Basin, Australia

International Journal of Coal Geology, 2016

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Research paper thumbnail of U-Pb LA-ICPMS detrital zircon geochronology of the Upper Cretaceous Winton Formation, Queensland, Australia: implications for regional tectonics, sedimentary provenance and vertebrate palaeontology

This study utilizes detrital zircon geochronology to constrain the depositional age, tectonic set... more This study utilizes detrital zircon geochronology to constrain the depositional age, tectonic setting, basin evolution, and stratigraphic context of the poorly understood Winton Formation, northeastern Australia (Fig.1). To develop better context for Australia’s most significant dinosaur-bearing succession, we analyzed 10 samples from different stratigraphic levels and key fossil locations throughout the Winton and underlying units (basin wide). Detrital zircon ages were obtained by U-Pb LA-ICPMS dating and the results were subjected to seven different metrics to interpret maximum depositional age. The results considerably improved upon earlier palynological age constraints, suggesting that most of the key vertebrate fossil localities in the Winton Formation are no older than earliest Turonian to latest Cenomanian (92-94 Ma) (Fig.2). The most abundant detrital zircon population clusters between 92-115 Ma, suggesting that much of the volcanic-rich sediment that characterizes the Wint...

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Research paper thumbnail of Basin-Scale Controls on Continental Vertebrate Taphonomy: Insights from the Campanian of Laramidia

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Criteria for identifying bone modification by termites in the fossil record

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Paleontological Exploration in Africa

Developments in Primatology: Progress and Prospects, 2008

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Embryology of Early Jurassic dinosaur from China with evidence of preserved organic remains

Nature, 2013

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