Eric Roberts

Colorado School of Mines · Department of Geology and Geological Engineering

The Campanian Two Medicine Formation of northwestern Montana, USA, is richly fossiliferous, and discoveries made within the unit over the past century have greatly advanced our appreciation of dinosaur paleobiology and evolution. Previously undifferentiated from a lithostratigraphic perspective, the formation is now subdivided into four new members...

Long-term trends in fisheries catch are useful to monitor effects of fishing on wild populations. However, fisheries catch data are often aggregated in multi-species complexes, complicating assessments of individual species. Non-target species are often grouped together in this way, but this becomes problematic when increasingly common shifts towar...

Paleosols are unrivaled terrestrial archives of paleoclimatic, paleoecological, and paleoenvironmental conditions, yet their full utility and potential for unlocking critical information about past ecosystems, as well as their comparability with other records, is dependent upon the quality and thoroughness of such studies. To help standardize commu...

Recent excavations in the Rising Star Cave System of South Africa have revealed burials of the extinct hominin species Homo naledi. A combination of geological and anatomical evidence shows that hominins dug holes that disrupted the subsurface stratigraphy and interred the remains of H. naledi individuals, resulting in at least two discrete feature...

Recent excavations in the Rising Star Cave System of South Africa have revealed burials of the extinct hominin species Homo naledi. A combination of geological and anatomical evidence shows that hominins dug holes that disrupted the subsurface stratigraphy and interred the remains of H. naledi individuals, resulting in at least two discrete feature...

The East Africa Rift System records a key interval in the evolution of modern African ecosystems, documenting significant floral changes and faunal dispersals in the context of environmental shifts. To date, Miocene- to-Pliocene data from eastern Africa have been derived primarily from richly fossiliferous rift basins along the far north of the Eas...

Recent excavations in the Rising Star Cave System of South Africa have revealed burials of the extinct hominin species Homo naledi. A combination of geological and anatomical evidence shows that hominins dug holes that disrupted the subsurface stratigraphy and interred the remains of H. naledi individuals, resulting in at least two discrete feature...

The Canning Basin is a prospective hydrocarbon frontier basin and is unusual for having limited offshore seismic and well data in comparison with its onshore extent. In this study, seismic mapping was conducted to better resolve the continuity of 13 key stratigraphic units from onshore to offshore to delineate prospective offshore hydrocarbon-beari...

The spectacular fossil fauna and flora preserved in the Upper Cretaceous terrestrial strata of North America’s Western Interior Basin record an exceptional peak in the diversification of fossil vertebrates in the Campanian, which has been termed the ‘zenith of dinosaur diversity’. The wide latitudinal distribution of rocks and fossils that represen...

We name and describe a new iguanodontian dinosaur from the Early Cretaceous Kirkwood Formation, Eastern Cape Province, South Africa. This dinosaur is one of only two ornithopod dinosaurs known from the Cretaceous of southern Africa, and is unique in being represented primarily by hatchling to young juvenile individuals as demonstrated by bone histo...

A second K/Pg boundary interval in the northern sector of the Antarctic Peninsula on Vega Island has been proposed, yet current temporal resolution of these strata prohibits direct testing of this hypothesis. To not only test for the existence of a K/Pg boundary on Vega Island but also provide increased age resolution for the associated vertebrate...

The Western Branch of the East African Rift System has experienced multiple episodes of basin development and intraplate alkaline volcanism since the Jurassic, however the geodynamic processes and lithospheric evolution involved in this protracted geological history remains poorly defined. Here, we present SmNd, LuHf, and RbSr isotopic data of igne...

We describe the sedimentology, geochronology, and geochemistry of the Early Cretaceus Sao Khua Formation of the Khorat Basin, northeastern Thailand, and report a temporal range adjustment for its dinosaurian assemblage. Facies analysis and architectural studies reveal that sedimentation occurred within a floodplain setting fed by large meandering b...

The Nambour Basin provides the easternmost record of Jurassic sedimentation for Australia. U-Pb detrital zircon age spectra constrain basin infill as Early-Middle Jurassic (ca. 195-163 Ma). Early Jurassic samples are dominated by 650–500 Ma detrital zircon sourced from the Lachlan Orogen of southeastern Australia. Distal Jurassic upland associated...

The Great Australian Superbasin, incorporating the Great Artesian Basin, is host to one of the largest artesian groundwater systems on Earth. However, despite the crucial nature of this resource to Australian agriculture, industry and rural communities, key aquifer units remain poorly studied, apart from the exposed eastern/southeastern portions of...

This study presents the first African pedogenic carbonate estimated atmospheric CO2 concentrations for the Early to Late Cretaceous transition. Pedogenic carbonates have been used extensively as proxies to reconstruct past climates, yet few studies have focused on the climatic conditions of Africa during the Mesozoic. The paucity of paleoclimate da...

The Western Interior of North America preserves one of the most complete successions of Upper Cretaceous marine and non-marine strata in the world; among these, the Cenomanian-Campanian units of the Kaiparowits Plateau in southern Utah are a critical archive of terrestrial environments and biotas. Here we present new radioisotopic ages for the Camp...

Early Cretaceous magmatic rocks of the central east coast of Australia are recognized as a lithologically, geochemically, and geochronologically distinctive rock package herein named the Morton Igneous Association. The association embraces small plutons and hypabyssal intrusions within the Jurassic and Lower Cretaceous Nambour and Maryborough basin...

During the Early Cretaceous, Australia was flooded by the epicontinental Eromanga Sea, deposits of which occur across the Great Australian Superbasin. However, the mid‐Cretaceous retreat of this shallow sea, and the resultant palaeogeographic and sediment distribution patterns, are poorly understood. This study chronicles the Eromanga Sea’s northwa...

The fossil record of macroscelidean mammals is notoriously patchy, with a significant spatial and temporal gap separating faunas from the early Oligocene localities of northern Africa and the early Miocene localities of eastern and southern Africa. Here we describe fossil macroscelideans representing Myohyracinae and Rhynchocyoninae recovered from...

The tectonic setting of the Australian sector of the eastern Gondwanan margin during the Jurassic and Cretaceous is enigmatic. Whether this involved convergent tectonism and a long-lived continental magmatic arc or rift-related extension unrelated to subduction is debated. The paucity of Australian Jurassic–Cretaceous igneous outcrops makes resolvi...

The upper Paleozoic–lower Mesozoic strata in the northeastern Galilee Basin are important for their hydrocarbon and groundwater potential; however, despite numerous previous investigations, the nature of this stratigraphic interval remains enigmatic. This study integrates lithostratigraphy, palynology and U–Pb zircon geochronology of well-exposed P...

The Cretaceous Period is considered the archetypical greenhouse interval, yet there is mounting evidence for intermittent cooler climatic phases throughout this geologic span. Few continental climate histories exist for the Cretaceous south of the paleoequator, and fewer still for Africa during this time. The Cretaceous Galula Formation is one of t...

Tyrannosaurids are hypothesized to be gregarious, possibly parasocial carnivores engaging in cooperative hunting and extended parental care. A tyrannosaurid (cf. Teratophoneus curriei ) bonebed in the late Campanian age Kaiparowits Formation of southern Utah, nicknamed the Rainbows and Unicorns Quarry (RUQ), provides the first opportunity to invest...

Sedimentary deposits of the Great Australian Superbasin, extensively developed across eastern Australia and covering almost a fifth of the continent, chronicle a rich record of palaeoenvironmental changes in northeastern Gondwana through the Jurassic and basal Cretaceous (Berriasian to Barremian). However, aside from the Surat Basin in the southeas...

Rising Star Cave in the Cradle of Humankind, South Africa, contains one of the richest hominin-bearing deposits in the world, and is the type locality for the Homo naledi fossils. This paper provides a stratigraphic and geochronological framework, within which published and future fossil finds from Rising Star Cave can be placed. Detailed mapping o...

Extant snake faunas have their origins in the mid-Cenozoic, when colubroids replaced booid-grade snakes as the dominant species. Based on fossils from North America and Europe, the timing of this faunal changeover is thought to have occurred in the early Neogene, after a period of global cooling opened environments suitable for more active predator...

Lungfish (Dipnoi) date back to the Devonian, and some fossil taxa as well as extant African lungfishes are known for their ability to aestivate, tolerating low-oxygen environments associated with seasonal drying. Extant lungfish are separated into two families: Lepidosirenidae (Protopterus in Africa and Lepidosiren in South America) and Neoceratodo...

The incipient phases of continental rift development remain enigmatic, as early rift sequences are rarely exposed, or poorly preserved in the geologic record. Here, we present petrographic and geochemical analyses of heavy mineral separates from pervasively weathered volcanic horizons intercalated within syn-rift sedimentary deposits from the Rukwa...

Although Jurassic-Early Cretaceous sedimentary systems were extensively developed on northeastern Gondwana, deciphering their paleogeography has been complicated by poor exposure and the lack of a robust chronostratigraphic framework. The southeastern margin of the Carpentaria Basin, northeastern Australia is one of the few regions where these sedi...

Although knowledge of Mesozoic marine reptiles from Antarctica has improved considerably in recent years, associated and well-preserved skeletal material of these animals remains uncommon. Here we describe a largely complete, closely associated plesiosaur pelvic girdle recovered from the uppermost Cretaceous (Maastrichtian) Sandwich Bluff Member of...

Lithostratigraphic investigation of the richly fossiliferous Kaiparowits Formation in southern Utah reveals the presence of a previously unidentified stratigraphic unit herein named the Upper Valley Member. The 255-m-thick Upper Valley Member is latest Campanian to earliest Maastrichtian in age and records a significant sedimentological change in t...

Porcupine Gorge, in the Hughenden region of northern Queensland, preserves one of the most impressive and continuous upper Palaeozoic-Mesozoic sedimentary basin successions in Australia.The data herein reveals new insights into the stratigraphy and tectonic history of the north-eastern Galilee and Eromanga basins.

Cape Marsh, located on the eastern end of Robertson Island to the east of the Antarctic Peninsula, exposes an isolated outcrop of Late Cretaceous sedimentary strata. The outcrop is approximately 120 km southwest of the much better-studied exposures of similar age on and around James Ross Island (JRI); as such, its remoteness has complicated both lo...

Provides new age and geological context to perhaps the two most important Jurassic vertebrate fauna discovered in Australia - a pre-Cretaceous sauropod (Rhoetosaurus brownei) and a temnospondyl amphibian (Siderops kehli) - from south-east Queensland.

Although the fossil record of non-avian dinosaurs from the Cretaceous of Antarctica is the poorest of any continent, fossils representing at least five major taxonomic groups (Ankylosauria, early-diverging Ornithopoda, Hadrosauridae, Titanosauria, and Theropoda) have been recovered. All come from Upper Cretaceous (Coniacian–Maastrichtian) marine an...

Unconsolidated mud clast breccia facies in the hominin‐bearing (Homo naledi) Rising Star Cave, Cradle of Humankind, South Africa, are interpreted to have formed through a process termed sedimentary autobrecciation in this study. This process, by which most of the angular mud clast breccia deposits are thought to have formed autochthonously to para‐...

Dissection provides a unique opportunity to integrate anatomical and clinical education. Commonly, cadavers are randomly assigned to courses, which may result in skewed representation of patient populations. The primary aim of this study was to determine if the anatomical donors studied by students at the University of Massachusetts Medical School...

Australia’s Jurassic vertebrate fossil record remains extremely sparse with only two dinosaur taxa and two temnospondyl amphibians identified to date. Of these, the spectacular and extremely well-preserved giant amphibian, Siderops kehli, and the only known pre-Cretaceous sauropod in Australia, Rhoetosaurus brownei, are perhaps the most important....

An epicontinental sea bisected West Africa periodically from the Late Cretaceous to the early Eocene, in dramatic contrast to the current Sahara Desert that dominates the same region today. Known as the Trans-Saharan Seaway, this warm and shallow ocean was a manifestation of globally elevated sea level associated with the rapid break-up of the supe...

African clawed frogs in the genus Xenopus are found today throughout sub-Saharan Africa and, because of their widespread use as model organisms in biological research, as introduced populations around the world (Measey et al., 2012; Evans et al., 2015). Because all members of the family Pipidae, including Xenopus, are predominantly aquatic frogs wi...

The Wadi Milk Formation is one of the best known dinosaur-bearing units in central Africa. The age of this important formation is assumed to be Late Cretaceous. We have shown for the first time that the Wadi Milk Formation is of Campanian age or younger.

The Turkana Basin of northwestern Kenya is well known for its rich Neogene–Quaternary vertebrate fossil record; however, it also represents one of the few locations in sub-Saharan Africa where Cretaceous vertebrate fossils, including dinosaurs and other archosaurs, are preserved. These Cretaceous deposits are colloquially referred to as the ‘Turkan...

The Turkana Basin of northwestern Kenya is well known for its rich Neogene–Quaternary vertebrate fossil record; however, it also represents one of the few locations in sub-Saharan Africa where Cretaceous vertebrate fossils, including dinosaurs and other archosaurs, are preserved. These Cretaceous deposits are colloquially referred to as the ‘Turkan...

The tectonic and geologic history of eastern Australia was characterized by a long-lived convergent margin during the Paleozoic to at least the early Mesozoic, which was followed by rifting and development of the Coral Sea Basin during the Cenozoic. However, the mid-late Mesozoic history of eastern Australian remains elusive because the former cont...

The breakup of eastern Gondwana during the Late Cretaceous was preceded by extensive volcanism, as evidenced by volcanic records along eastern Australia and surrounding regions; these include the Whitsunday Volcanic Province1,2, the volcaniclastic sediments of the Great Artesian Basin1,3, Otway and Gippsland Basins1 and New Caledonia4, and dredge a...

We describe the first record of a fossil gekkotan from the Late Oligocene Nsungwe Formation in the Rukwa Rift Basin, Tanzania. The specimen consists of an almost complete maxilla containing 23 tooth positions, with 10 teeth still in place. Typical gekkotan features include the tall facial process along with a posteriorly sloping angle, and the pres...

The Paleogene was a time of high diversity for snakes, and was characterized by some of the largest species known to have existed. Among these snakes were pan-Tethyan marine species of Nigerophiidae and Palaeophiidae. The latter family included the largest sea snake, Palaeophis colossaeus, known from the Trans-Saharan Seaway of Mali during the Eoce...

Lotosaurus adentus is an unusual sail-backed, edentulous poposauroid pseudosuchian primarily known from a single, nearly monospecific bonebed discovered and excavated in the 1970s in the Middle-Upper Triassic Badong Formation of Sangzhi County, Hunan Province, South China. Renewed interest in this unique taxon prompted exposure of an additional 90...

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...

Brittleness and plasticity indices in hydrocarbon reservoirs are calculated to understand how rocks behave under stress, and for assessing the fracturing performance of clay-rich shale reservoirs and assessing borehole stability. Evaluating shale plasticity/brittleness requires careful analysis of clay mineral composition in target shales and the d...

The complex and destructive geodynamics of Australia’s northeast plate margin has left very little preserved crust of Jurassic and Cretaceous age. This provides a challenge for understanding the pre-Cenozoic plate dynamics of the region. However, evidence of semi-continuous Jurassic-Cretaceous volcanism along the eastern margin of Australia exists...

This study uses magnetostratigraphy to help constrain the age of the paleontologically important Galula Formation (Rukwa Rift Basin, southwestern Tanzania). The formation preserves a Cretaceous vertebrate fauna, including saurischian dinosaurs, a putative gondwanatherian mammal, and notosuchian crocodyliforms. With better dating, the Galula Formati...

Papua New Guinea forms part of the complex and convergent Late Cenozoic north Australian plate boundary. As a result of destructive plate boundary processes, understanding pre-Cenozoic plate dynamics in the region is challenging. However, recent findings have documented traces of Australian crust offshore mainland Australia, including sites in Vanu...

The paleobiogeographic significance of continental Africa during the middle and Late Cretaceous is not well understood, in part due to incomplete sampling from large portions of the landmass during these intervals. Intensified field efforts in the Galula Formation exposed in southwestern Tanzania have revealed a diverse vertebrate fauna, including...

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 flo...

The Winton Formation of central Queensland is recognized as a quintessential source of mid-Cretaceous terrestrial faunas and floras in Australia. However, sedimentological investigations linking fossil assemblages and palaeoenvironments across this unit remain limited. The intent of this study was to interpret depositional environments and improve...

Porcupine Gorge, located in the Hughenden Region of northern Australia, preserves an unmatched sedimentary archive of late Palaeozoic-late Mesozoic depositional environments and basin histories. This record is greatly augmented by investigation of stratigraphic drill cores from the region housed at the Geological Survey of Queensland. A detrital zi...

Porcupine Gorge and the surrounding Hughenden Region of northern Queensland preserve an unmatched sedimentary archive of late Palaeozoic-late Mesozoic basin histories. Of great stratigraphic interest are the coaliferous Upper Permian Betts Creek Beds and the overlying Middle Triassic Warang Sandstone (Fig. 1). Recent stratigraphic and sedimentary p...

The crocodylian-line archosaur clade Poposauroidea contains two major subgroups. The geographically wide- spread Ctenosauriscidae represent an Early-Middle Triassic radiation of sail-backed taxa with a plesiomorphic, carnivorous dentition, whereas several predominantly Late Triassic and North American taxa form an advanced clade of bipedal, non-sai...

Postcranial measurements. DOI: http://dx.doi.org/10.7554/eLife.24232.047

Canonical variates analysis of carpal morphology. DOI: http://dx.doi.org/10.7554/eLife.24232.048

Traits of the LES1 cranium in comparison to H. naledi and other hominin species. DOI: http://dx.doi.org/10.7554/eLife.24232.045

Cranial and mandibular measurements. DOI: http://dx.doi.org/10.7554/eLife.24232.046

Taphonomic observations by specimen from the Lesedi Chamber. DOI: http://dx.doi.org/10.7554/eLife.24232.049

ELife digest Species of ancient humans and the extinct relatives of our ancestors are typically described from a limited number of fossils. However, this was not the case with Homo naledi. More than 1500 fossils representing at least 15 individuals of this species were unearthed from the Rising Star cave system in South Africa between 2013 and 2014...

ELife digest Species of ancient humans and the extinct relatives of our ancestors are typically described from a limited number of fossils. However, this was not the case with Homo naledi. More than 1500 fossils representing at least 15 individuals of this species were unearthed from the Rising Star cave system in South Africa between 2013 and 2014...

ELife digest Species of ancient humans and the extinct relatives of our ancestors are typically described from a limited number of fossils. However, this was not the case with Homo naledi. More than 1,500 fossils representing at least 15 individuals of this species were unearthed from the Rising Star cave system in South Africa between 2013 and 201...

This paper presents a detailed sedimentologic investigation of a newly identified, fossiliferous Late Neogene sedimentary succession in the Rukwa Rift Basin, southwestern Tanzania. This synrift deposit is a rare and significant new example of a fossiliferous succession of this age in the Western Branch of East Africa Rift System. The unit, informal...

We have explored the use of 40Ar/39Ar 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...

A new species of tyrannosaurid from the upper Two Medicine Formation of Montana supports the presence of a Laramidian anagenetic (ancestor-descendant) lineage of Late Cretaceous tyrannosaurids. In concert with other anagenetic lineages of dinosaurs from the same time and place, this suggests that anagenesis could have been a widespread mechanism ge...