Huge Reservoir of Helium Found in Tanzania

A new approach to gas exploration has discovered a huge helium gas field, which could address the increasingly critical shortage of this vital yet rare element.

Helium doesn't just make your voice squeaky - it is critical to many things we take for granted, including MRI scanners in medicine, welding, industrial leak detection and nuclear energy. However, known reserves are quickly running out. Until now helium has never been found intentionally - being accidentally discovered in small quantities during oil and gas drilling.

Now, a research group from Oxford and Durham universities, working with Helium One, a helium exploration company headquartered in Norway, has developed a brand new exploration approach. The first use of this method has resulted in the discovery of a world-class helium gas field in Tanzania.

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Elaphrosaurus bambergi: a Reevaluated Noasaurid Abelisauroid From Late Jurassic Tanzania

The theropod dinosaur Elaphrosaurus bambergi Janensch, 1920, from the Late Jurassic of Tendaguru, Tanzania

Authors:

Rauhaut et al

Abstract:

Theropod dinosaurs from the Late Jurassic of Gondwana are still poorly known, with Elaphrosaurus bambergi Janensch, 1920, from the late Kimmeridgian of Tendaguru, Tanzania, being the only taxon represented by more than isolated remains from Africa. Having long been considered a coelurosaurian, more specifically an ornithomimosaur, Elaphrosaurus is currently regarded as a basal ceratosaur. Here, we revise the osteology and phylogenetic position of this important taxon. Elaphrosaurus shows many unusual osteological characters, including extremely elongated and constricted cervical vertebrae, an expansive shoulder girdle with strongly modified forelimbs, a relatively small ilium, and elongate hindlimbs with a very small ascending process of the astragalus that is fused to the tibia. We found this taxon to share many derived characters with noasaurids, such as: strongly elongate cervical and dorsal vertebrae; low, rectangular neural spines in the mid-caudal vertebrae; presence of only an anterior centrodiapophyseal lamina in anterior caudal vertebrae; presence of a wide, U–shaped notch between the glenoid and the anteroventral hook in the coracoid; a laterally flared postacetabular blade of the ilium; a flat anterior side of the distal tibia; and a reduced shaft of metatarsal II. Our analysis placed Elaphrosaurus within a dichotomous Noasauridae as part of a Jurassic subclade, here termed Elaphrosaurinae, that otherwise includes taxa from eastern Asia. These results underscore the long and complex evolutionary history of abelisauroids, which is still only beginning to be understood.

A Pleistocene Quaternary Petrified Forest From Olduvai Gorge, Tanzania

In situ ∼2.0 Ma trees discovered as fossil rooted stumps, lowermost Bed I, Olduvai Gorge, Tanzania

Authors:

Habermann et al

Abstract:

The discovery of fossil rooted tree stumps in lowermost Lower Bed I from the western Olduvai Basin, Tanzania, age-bracketed by the Naabi Ignimbrite (2.038 ± 0.005 Ma) and Tuff IA (1.88 ± 0.05 Ma), provides the first direct, in situ, and to date oldest evidence of living trees at Olduvai Gorge. The tree relicts occur in an interval dominated by low-viscosity mass flow and braided fluvial sediments, deposited at the toe of a largely Ngorongoro Volcano-sourced volcaniclastic fan apron that comprised a widely spaced network of ephemeral braided streams draining northward into the Olduvai Basin. Preservation of the trees occurred through their engulfment by mass flows, post-mortem mold formation resulting from differential decay of woody tissues, and subsequent fluvially-related sediment infill, calcite precipitation, and cast formation. Rhizolith preservation was triggered by the interaction of root-induced organic and inorganic processes to form rhizocretionary calcareous root casts. Phytolith analyses were carried out to complete the paleoenvironmental reconstruction. They imply a pronounced seasonality and indicate a wooded landscape with grasses, shrubs, and sedges growing nearby, comparable to the low, open riverine woodland (unit 4c) along the Garusi River and tributaries in the Laetoli area. Among the tree stump cluster were found outsized lithic clasts and those consisting of quartzite were identified as Oldowan stone tool artifacts. In the context of hominin activity, the identification of wooded grassland in association with nearby freshwater drainages and Oldowan artifacts significantly extends our paleoenvironmental purview on the basal parts of Lower Bed I, and highlights the hitherto underrated role of the yet poorly explored western Olduvai Gorge area as a potential ecologically attractive setting and habitat for early hominins.

Evidence of Local Volcanic Eruptions From Orosirian PaleoProterozoic Tanzania

Age and geochemistry of coeval felsic volcanism and plutonism in the Palaeoproterozoic Ndembera Group of southwestern Tanzania: Constraints from SHRIMP U-Pb zircon and Sm-Nd data

Authors:

Bahame et al

Abstract:

The Ndembera metavolcanic rocks represent a continuum of compositions ranging from intermediate to more siliceous calc-alkaline trachyandesites-dacites-trachytes-rhyolites which have been intruded by largely metaluminous, calc-alkaline I-type granites in the Palaeoproterozoic Usagaran Belt of southewestern Tanzania. SHRIMP U-Pb zircon age data show that the Ndembera metavolcanic rocks were extruded at 1871 ± 30 Ma, an event that was largely coeval with the emplacement of cross-cutting microcline-biotite rich granites at 1896 ± 29 Ma.

Despite some compositional differences, both the granites and metavolcanic rocks share similar geochemical features including very coherent REE patterns characterized by enrichment of the LREE relative to the HREE (La/YbCN = 13.6-32.8 (average = 23.9) for metavolcanic rocks and La/YbCN = 10.8-38.2 (average = 21.8) for granites), negative Eu anomalies (Eu/Eu* = 0.45-1.01 (average = 0.83) for volcanic rocks and Eu/Eu* = 0.48-0.70 (average = 0.60) for granites), negative Ta, Ti and Nb anomalies (Nb/Lapm = 0.14-0.29 (average = 0.20 for volcanic rocks and Nb/Lapm = 0.01-0.37 (average = 0.16) for granites). The metavolcanic rocks have ɛNd(1871Ma) values of -0.03 to -4.89 and TDM ages of 2243 - 2714 which are broadly similar to those of the granites (ɛNd(1896 Ma) values of -3.56 to -4.59 and TDM ages of 2469 - 2646 Ma).

The geochemical similarities between the Ndembera volcanic rocks and granites, coupled with their similar emplacement age, suggest that the two rock suites were derived by the same processes in the same tectonic setting from an isotopically similar source. These geochemical features coupled with the paucity of mafic rocks suggest the derivation of the pluto-volcanic suite by crustal anatexis of basic meta-igneous rocks mixed with a minor metasedimentary component in an intra-continental setting. The more siliceous compositions in the suite may have formed by subsequent fractionation involving hornblende, plagioclase, biotite, titanite and apatite as indicated by the negative correlation between SiO2 and MgO, Fe2O3, Al2O3, CaO, TiO2 and P2O5, low Sr contents and negative Eu and Ti anomalies.

The ∼1.87 Ga coeval felsic volcanic and granitic magmatic event documented in the Ndembera Group is also a feature of the nearby Ubendian belt to the west pointing to a Palaeoproterozoic regional thermal event that occurred in southwestern and western Tanzania.

A new Emydopoid Dicynodont From Upper Permian Tanzania

Distinctive emydopoid dicynodont (Therapsida, Anomodontia) mandibles from the Permian Ruhuhu and Usili formations (Songea Group), Ruhuhu Basin, Tanzania

Authors:

Angielczyk et al

Abstract:

Dicynodont therapsids were discovered in the Permian Usili Formation (Ruhuhu Basin, Tanzania) in the 1930s and in the Permian Ruhuhu Formation in the 1960s, with further collections being made in 2007, 2008, and 2012. Here we describe two fragmentary mandibles that represent a new morphotype of emydopoid dicynodont. One specimen was collected in the middle fossiliferous horizon of the Ruhuhu Formation, and the other originated in the overlying Usili Formation. Three synapomorphies support the placement of these specimens in the emydopoid subclade Kingoriidae: mandibular fenestra occluded by the dentary; curved ridge that follows the profile of the symphysis present on the edge between the anterior and lateral surfaces of the dentary; and posterior dentary sulcus absent. The specimens may represent a new dicynodont species, a previously known species for which mandibular material was unknown, or an intraspecific variant of Dicynodontoides nowacki. Regardless of which of these options is correct, the specimens constitute the first taxon with a stratigraphic range extending from the likely middle Permian middle fossiliferous horizon of the Ruhuhu Formation into the late Permian Usili Formation. They also improve our understanding of the middle Ruhuhu tetrapod fauna, which previously consisted only of Endothiodon tolani.

Endothiodon tolani: a new Endothiodont Dicynodont From Middle Permian Tanzania

A new endothiodont dicynodont (Therapsida, Anomodontia) from the Permian Ruhuhu Formation (Songea Group) of Tanzania and its feeding system

Athors:

Cox et al

Abstract:

Cranial material of the dicynodont Endothiodon from the middle fossiliferous horizon of the Permian Ruhuhu Formation (Ruhuhu Basin, Tanzania) is described as a new species, E. tolani. Endothiodon tolani is distinguished from other Endothiodon species by the absence of a pineal boss and the presence of tusks in most specimens. Although some parts of the Ruhuhu Formation probably correlate with the Eodicynodon or Tapinocephalus assemblage zones of the South African Karoo Basin, it is uncertain whether E. tolani is older than E. bathystoma or E. mahalanobisi. There is less evidence for extensive anteroposterior translation of the mandible in E. tolani than in other dicynodonts. The jaw joint is specialized for allowing some medial-lateral motion. Mastication involved unilateral chewing. Flexure of the postdentary bones relative to the fused dentaries permitted the posterolaterally directed rows of teeth on one side of the skull and mandible to move past one another. The long tooth rows and prominent horn-covered ridges and grooves on the palate and mandible of Endothiodon are unique among dicynodonts. Comparisons with other taxa suggest that its feeding system may have been specialized for cutting three-dimensional objects such as stems or rhizomes. The dicynodont feeding system is very stereotyped throughout the clade's history, but Endothiodon escaped the constraints that affected other dicynodonts, allowing it to evolve a unique skull morphology. This evolutionary flexibility did not translate into high taxonomic richness (we recognize only three species of Endothiodon), but Endothiodon was able to achieve high levels of relative abundance in some basins.

Abajudon kaayai & Endothiodon oosthuizeni: Two New Wordian/Capitanian Permian Dicynodonts From Tanzania

New dicynodonts (Therapsida, Anomodontia) and updated tetrapod stratigraphy of the Permian Ruhuhu Formation (Songea Group, Ruhuhu Basin) of southern Tanzania

Authors:

Angielczyk et al

Abstract:

Permian tetrapod fossils were discovered in the Tanzanian Ruhuhu Formation in 1963, but they have received far less attention than the tetrapods of the overlying Usili (formerly Kawinga) Formation. Here, we describe two dicynodonts collected in the Ruhuhu Formation in 2008. Abajudon kaayai, gen. et sp. nov., is represented by a partial skull and mandible and is characterized by autapomorphic upper teeth that are triangular in cross-section, have procurved tips, and bear a deep groove on the mesial surface. Although it shows similarities to taxa such as Endothiodon and Chelydontops, the exact relationships between A. kaayai and other dicynodonts are uncertain. The second specimen also consists of a partial skull and mandible. We refer it to cf. Endothiodontia based on the medial placement of the long maxillary tooth rows, the presence of depressions on the palatine pad, a long posterior dentary sulcus, and similarities of the mandibular dentition. Tetrapods occur in three fossiliferous horizons in the Ruhuhu Formation. The likely Middle Permian lower horizon includes dinocephalians, temnospondyls, and the dicynodonts described here. The middle horizon includes a new, tusked species of Endothiodon and at least one other dicynodont. The upper horizon appears to sample an assemblage similar to that of the Usili Formation and therefore may be of Late Permian age. The discovery of Middle Permian fossils in Tanzania and Zambia provides the opportunity to test whether southern Gondwana was characterized by a cosmopolitan tetrapod fauna for an extended period of time before the biogeographic restructuring caused by the end-Permian mass extinction.

Nundasuchus songeaensis: a new Anisian Triassic Pseudosuchian Archosaur From Tanzania

A new archosaur from the Manda beds (Anisian, Middle Triassic) of southern Tanzania and its implications for character state optimizations at Archosauria and Pseudosuchia

Authors:

Nesbitt et al

Abstract:

The presence of early pseudosuchians and avemetatarsalians in Anisian beds of Africa demonstrates that the archosaur radiation was well underway by the beginning of the Middle Triassic. The rapid radiation produced a variety of forms, but many of the unique, well-diagnosed Late Triassic clades (e.g., Aetosauria, Ornithosuchidae) lack diagnosable members from the Middle Triassic. Here, we introduce a new Middle Triassic archosaur, Nundasuchus songeaensis, gen. et sp. nov., with an unusual mix of apomorphic character states found within Pseudosuchia and just outside Archosauria. The holotype consists of partial skeleton, including representative postcranial elements and parts of the skull. We added Nundasuchus songeaensis, gen. et sp. nov., into the two most comprehensive early archosaur phylogenetic data sets available, and in both analyses the new taxon falls within Pseudosuchia. However, a number of plesiomorphic archosaurian character states (e.g., posterolaterally directed tuber of the calcaneum) optimize as local autapomorphies of the new taxon within Pseudosuchia in our analyses. Therefore, we tested alternative hypotheses of relationships for the new taxon by utilizing constraint trees. The analyses resulted in little change in the relationships and structure of other Triassic archosaur clades, but changed optimizations of certain character states and character support at the base of Pseudosuchia and Archosauria. Our analyses suggest that the complex evolution of character-state changes at the base of Archosauria is inhibiting our understanding of the relationships of early Pseudosuchia and, in turn, Archosauria.

Rukwatitan bisepultus: a new Endemic Titanosaurian Sauropod from Albian/Cenomanian Cretaceous Tanzania

Ohio University paleontologists have identified a new species of titanosaurian, a member of the large-bodied sauropods that thrived during the final period of the dinosaur age, in Tanzania. Although many fossils of titanosaurians have been discovered around the globe, especially in South America, few have been recovered from the continent of Africa.

The new species, named Rukwatitan bisepultus, was first spotted by scientists embedded in a cliff wall in the Rukwa Rift Basin of southwestern Tanzania. Using the help of professional excavators and coal miners, the team unearthed vertebrae, ribs, limbs and pelvic bones over the course of two field seasons.

CT scans of the fossils, combined with detailed comparisons with other sauropods, revealed unique features that suggested an animal that was different from previous finds—including those from elsewhere in Africa, according to a study the team published today in the Journal of Vertebrate Paleontology.

"Using both traditional and new computational approaches, we were able to place the new species within the family tree of sauropod dinosaurs and determine both its uniqueness as a species and to delineate others species with which it is most closely related," said lead author Eric Gorscak, a doctoral student in biological sciences at Ohio University.

Rukwatitan bisepultus lived approximately 100 million years ago during the middle of the Cretaceous Period. Titanosaurian sauropods, the group that includes Rukwatitan, were herbivorous dinosaurs known for their iconic large body sizes, long necks and wide stance. Although not among the largest of titanosaurians, Rukwatitan is estimated to have a forelimb reaching 2 meters and may have weighed as much as several elephants.

The dinosaur's bones exhibit similarities with another titanosaurian, Malawisaurus dixeyi, previously recovered in Malawi. But the two southern African dinosaurs are distinctly different from one another, and, most notably, from titanosaurians known from northern Africa, said co-author Patrick O'Connor, a professor of anatomy in the Ohio University Heritage College of Osteopathic Medicine.

The fossils of middle Cretaceous crocodile relatives from the Rukwa Rift Basin also exhibit distinctive features when compared to forms from elsewhere on the continent.

"There may have been certain environmental features, such as deserts, large waterways and/or mountain ranges, that would have limited the movement of animals and promoted the evolution of regionally distinct faunas," O'Connor said. "Only additional data on the faunas and paleo environments from around the continent will let us further test such hypotheses."

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Tropical Sea Surface Temperatures may Have Exceeded 40 C During Paleocene–Eocene Thermal Maximum

Extreme warming of tropical waters during the Paleocene–Eocene Thermal Maximum

Authors:

Aze et al

Abstract:

The Paleocene–Eocene Thermal Maximum (PETM), ca. 56 Ma, was a major global environmental perturbation attributed to a rapid rise in the concentration of greenhouse gases in the atmosphere. Geochemical records of tropical sea-surface temperatures (SSTs) from the PETM are rare and are typically affected by post-depositional diagenesis. To circumvent this issue, we have analyzed oxygen isotope ratios (δ18O) of single specimens of exceptionally well-preserved planktonic foraminifera from the PETM in Tanzania (∼19°S paleolatitude), which yield extremely low δ18O, down to less than –5‰. After accounting for changes in seawater chemistry and pH, we estimate from the foraminifer δ18O that tropical SSTs rose by greater than 3 °C during the PETM and may have exceeded 40 °C. Calcareous plankton are absent from a large part of the Tanzania PETM record; extreme environmental change may have temporarily caused foraminiferal exclusion.

Crustal Formation in the NeoArchean and PaleoProterozoic of Tanzania

Neoarchean and Paleoproterozoic crust formation in the Ubendian Belt of Tanzania: Insights from zircon geochronology and geochemistry

Authors:

Kazimoto et al

Abstract:

LA-ICP-MS U-Pb zircon geochronological and geochemical data of meta-igneous and metasedimentary rock types of the Katuma Block of the Paleoproterozoic Ubendian Belt in Tanzania are used to unravel the crustal evolution of this metalliferous terrain. The protoliths of the metabasites and orthogneisses previously considered to be Paleoproterozoic are in fact mostly Neoarchean in age (2713 ± 11 Ma to 2638 ± 5 Ma), from which the oldest rocks experienced their first metamorphism during the same Neoarchean orogenic cycle at ca. 2650 Ma. A second event of mafic magmatism (2021 ± 11 Ma) was concomitant with the migmatization of the Neoarchean orthogneisses and was succeeded by granitic intrusions at 1990–1940 Ma. All rocks of the Katuma Block experienced their main metamorphic reworking during several Paleoproterozoic orogenic events, which were recognized by dating of various metamorphic zircon growth zones and the age of magmatic events dated at ca. 2050, 1960 and 1880 Ma. The detritus of the high-grade metasedimentary rocks derived from Neoarchean (Katuma Block or Tanzania Craton?) and Paleoproterozoic provenances and the minimum age for the deposition is constrained by its first metamorphism at ca. 1960 Ma. The Neoarchean and Paleoproterozoic metabasites, gabbronorites and orthogneisses are sub-alkaline in composition displaying a REE and trace element geochemistry akin to those of rocks formed in modern-arc settings. On the basis of the geochemical data, the presence of eclogites, deformation and metamorphic ages, we suggest that in Paleoproterozoic time the Katuma Block was again at an active continental margin, below which a Paleoproterozoic oceanic lithosphere was subducting.

Mesoproterozoic Metamorphism in Tanzania, Africa

Mesoproterozoic high-grade metamorphism in pelitic rocks of the northwestern Ubendian Belt: Implication for the extension of the Kibaran intra-continental basins to Tanzania

Authors:

Boniface et al

Abstract:

Paleoproterozoic basement rocks are thought to form the northwestern end of the Ubendian Belt in Tanzania that disappears towards the north below a Mesoproterozoic sedimentary cover. The northwestern end of the Ubendian Belt is known to constitute three litho-tectonic terranes of Katuma, Wakole and Ubende. Through dating of zircon (SHRIMP U–Pb) and monazite (U–Th–total Pb electron microprobe ages) of high-grade metasedimentary rocks of the Wakole Terrane we have detected solely Mesoproterozoic ages, showing no sign of reworking of older Paleoproterozoic basement. These findings signify that the Wakole Terrane hosts younger sediments of Mesoproterozoic times metamorphosed to high-grade P–T conditions (peaked at 670–680 °C/8.5–8.9 kbar).

Two distinct phases of Mesoproterozoic metamorphic events separated by 160 Ma have been dated at 1166 ± 14 Ma and 1007 ± 6 Ma (SHRIMP U–Pb zircon). Zircon ages are supported by in-situ dating of monazite with ages at 1170 ± 10 Ma, and 1022 ± 5–1016 ± 10 Ma. The first age is closely related to the period of S-type granitoid emplacement at about 1200 Ma in the Karagwe-Ankolean and Kibaran Belts. The second age cluster overlaps with a period of global Mesoproterozoic orogenic cycle, also recorded in the neighboring Irumide and Kibaran Belts. This age group is associated with the assembly of the hypothetical Mesoproterozoic Rodinia Supercontinent.

The recent model for the evolution of the Kibaran Belt suitably explains the spatial and temporal settings of Mesoproterozoic metasedimentary rocks of the Wakole Terrane overlying the Paleoproterozoic Ubendian Belt. Due to its proximity to the Kibaran Belt and by being bound by the Paleoproterozoic Terranes of Ubende and Katuma, it can be interpreted that the Wakole Terrane metasediments initially were deposited in an intra-continental basin that was later squeezed between these old terranes by the regional ca. 1000 Ma compressional event recorded in the Irumide, Kibaran and Karagwe-Ankolean Belts.

Oldest Record of Azhdarchid Pterosaurs in Africa From Kimmeridgian/Tithonian Jurassic Tanzania

New pterosaur material from the Upper Jurassic of Tendaguru (Tanzania), Africa

Authors:

Costa et al

Abstract:

The pterosaur fossil record from Africa is exceedingly scarce and one of the least known for any continental land mass. The specimens here described are housed at the Naturkundemuseum of the Humboldt University and consist of two cervical vertebrae, a coracoid and a wing metacarpal recovered from the Upper Jurassic Tendaguru Formation, Tanzania. Due to the general morphology and the absence of a lateral pneumatic foramen in both vertebrae, as well as the presence of a longitudinal depression, not previously reported in pterosaurs, we consider these specimens as representatives of a new species of Azhdarchidae. Moreover, because the coracoid, which bears three well-developed pneumatic foramina, has a well-excavated depression that is medially positioned at the posterior face of the acrocoracoid process, we regard this as a new basal pterodactyloid species. The wing metacarpal is greatly elongated and clearly belongs to Pterodactyloidea. Its elongation and slender aspect, as well as the sub-triangular shape of its proximal articular end, likely place it within the Tapejaroidea. The material here described shows the potential of these deposits to provide more informative pterosaur material and provisionally extends the oldest record of azhdarchids to the Kimmeridgian–Tithonian of Africa.

Aenigmastropheus parringtoni: a new Basal Wuchiapingian Permian Archosauromorph of Tanzania

The Origin and Early Evolution of Sauria: Reassessing the Permian Saurian Fossil Record and the Timing of the Crocodile-Lizard Divergence

Authors:

Ezcurra et al

Abstract:

Sauria is the crown-group of Diapsida and is subdivided into Lepidosauromorpha and Archosauromorpha, comprising a high percentage of the diversity of living and fossil tetrapods. The split between lepidosauromorphs and archosauromorphs (the crocodile-lizard, or bird-lizard, divergence) is considered one of the key calibration points for molecular analyses of tetrapod phylogeny. Saurians have a very rich Mesozoic and Cenozoic fossil record, but their late Paleozoic (Permian) record is problematic. Several Permian specimens have been referred to Sauria, but the phylogenetic affinity of some of these records remains questionable. We reexamine and review all of these specimens here, providing new data on early saurian evolution including osteohistology, and present a new morphological phylogenetic dataset. We support previous studies that find that no valid Permian record for Lepidosauromorpha, and we also reject some of the previous referrals of Permian specimens to Archosauromorpha. The most informative Permian archosauromorph is Protorosaurus speneri from the middle Late Permian of Western Europe. A historically problematic specimen from the Late Permian of Tanzania is redescribed and reidentified as a new genus and species of basal archosauromorph: Aenigmastropheus parringtoni. The supposed protorosaur Eorasaurus olsoni from the Late Permian of Russia is recovered among Archosauriformes and may be the oldest known member of the group but the phylogenetic support for this position is low. The assignment of Archosaurus rossicus from the latest Permian of Russia to the archosauromorph clade Proterosuchidae is supported. Our revision suggests a minimum fossil calibration date for the crocodile-lizard split of 254.7 Ma. The occurrences of basal archosauromorphs in the northern (30°N) and southern (55°S) parts of Pangea imply a wider paleobiogeographic distribution for the group during the Late Permian than previously appreciated. Early archosauromorph growth strategies appear to be more diverse than previously suggested based on new data on the osteohistology of Aenigmastropheus.

An Anisian Triassic Silesaurid was Very Large

A large-bodied silesaurid from the Lifua Member of the Manda beds (Middle Triassic) of Tanzania and its implications for body-size evolution in Dinosauromorpha

Authors:

Barrett et al

Abstract:

Many dinosaur lineages were characterised by wide ranges of body-size, ranging from taxa that were < 1 m in length to the largest of all terrestrial vertebrates. On the other hand, the closest relatives of dinosaurs, the non-dinosaurian dinosauromorphs, such as Marasuchus and lagerpetids, were small-bodied animals with little variation in body-size. Here, we describe a partial femur of an unexpectedly large-bodied silesaurid (non-dinosaurian dinosauriform) from the Lifua Member of the Manda beds (?late Anisian) from southwestern Tanzania. This specimen (NHMUK R16303) is estimated to have had a femoral length of approximately 345 mm, which exceeds that of many Triassic and Lower Jurassic dinosaurs, and is either a large individual of the contemporary Asilisaurus kongwe or represents a new and otherwise unknown silesaurid taxon. In either case, it shows that body-size increases were more prevalent among early dinosauromorphs than realised previously. Moreover, silesaurid size increase occurred in parallel with that in early dinosaurs, alongside the convergent acquisition of other features related to locomotion and herbivory. However, Late Triassic faunas including large-bodied sauropodomorph and theropod dinosaurs lack similarly-sized non-dinosaurian dinosauromorphs, whereas the Lifua Member fauna includes both a large silesaurid and the early ?dinosaur Nyasasaurus, which overlapped in size.

Ruhuhuaria reiszi: a New Procolophonoid Reptile From Anisian Triassic Tanzania

Ruhuhuaria reiszi, a new procolophonoid reptile from the Triassic Ruhuhu Basin of Tanzania

Authors:

Linda Akiko Tsuji, Gabriela Sobral and Johannes Müller

Abstract:

The Middle Triassic Lifua Member of the Manda Formation (Ruhuhu Basin, southwestern Tanzania) hosts a diverse fauna dominated by therapsids and archosauromorphs. Reexamination of fossils from previous expeditions in addition to new field collections has brought many new taxa to light. Discovered in the collections of the Cambridge Museum of Zoology, Ruhuhuaria reiszi gen. et sp. nov. is the first procolophonoid reptile described from the Ruhuhu Basin. Although the fossil is poorly preserved, CT scanning reveals crucial diagnostic morphology, in particular the highly labio-lingually expanded tooth bases and enlarged anterior dentary teeth. A phylogenetic analysis shows Ruhuhuaria is nested within the owenettids, but results in an otherwise poorly resolved tree. The discovery of Ruhuhuaria provides further evidence of the persistence of owenettids into the Middle Triassic, and their coexistence with procolophonids well into the Triassic.

Asperoris mnyama: New Anisian Triassic Archosauriform From Tanzania

A New Archosauriform (Reptilia: Diapsida) from the Manda Beds (Middle Triassic) of Southwestern Tanzania

Authors:

Sterling J. Nesbitt, Richard J. Butler and David J. Gower

Abstract:

Background

Archosauria and their closest relatives, the non-archosaurian archosauriforms, diversified in the Early and Middle Triassic, soon after the end-Permian extinction. This diversification is poorly documented in most Lower and Middle Triassic rock sequences because fossils of early groups of archosauriforms are relatively rare compared to those of other amniotes. The early Middle Triassic (? late Anisian) Manda beds of southwestern Tanzania form an exception, with early archosaur skeletons being relatively common and preserved as articulated or associated specimens. The Manda archosaur assemblage is exceptionally diverse for the Middle Triassic. However, to date, no non-archosaurian archosauriforms have been reported from these rocks.

Methodology/Principal Findings

Here, we name a new taxon, Asperoris mnyama gen. et sp. nov., from the Manda beds and thoroughly describe the only known specimen. The specimen consists of a well-preserved partial skull including tooth-bearing elements (premaxilla, maxilla), the nasal, partial skull roof, and several incomplete elements. All skull elements are covered in an autapomorphic highly rugose sculpturing. A unique combination of character states indicates that A. mnyama lies just outside Archosauria as a stem archosaur within Archosauriformes, but more precise relationships of A. mnyama relative to other early archosauriform clades (e.g., Erythrosuchidae) cannot be determined currently.
Conclusions/Significance

Asperoris mnyama is the first confirmed non-archosaurian archosauriform from the Manda beds and increases the morphological and taxonomic diversity of early archosauriforms known from the Middle Triassic. The direct association of A. mnyama with species referable to Archosauria demonstrates that non-archosaurian archosauriforms were present during the rise and early diversification of Archosauria. Non-archosaurian archosauriforms and archosaurs co-occur in fossil reptile assemblages across Pangaea from the late Early Triassic to the end of the Late Triassic.

Mandagomphodon hirschsoni: a Traversodont Cynodont From Anisian Triassic Tanzania

The Traversodontid Cynodont Mandagomphodon hirschsoni from the Middle Triassic of the Ruhuhu Valley, Tanzania

Author:

James Hopson

Abstract:

Mandagomphodon hirschsoni (gen. nov., comb. nov.) is one of three species of traversodontid cynodont placed in Scalenodon [type species S. angustifrons (Parrington, 1946)] by Crompton (1972). It is based on a partial skull and lower jaws from the Middle Triassic of the Ruhuhu Valley, southwestern Tanzania. The upper postcanine teeth were used to diagnose species of Scalenodon, but newer traversodontid material indicates that the three species represent distinct genera. Material of “S.” hirschsoni, except for the postcanines, has not been described. It is unusual among traversodontids in having only three upper incisors, which are enlarged and procumbent. Three enlarged, procumbent anterior lower teeth are interpreted as two incisors and a canine. Analysis of postcanine wear facets indicates that the power stroke of the lower teeth was entirely in a posterior direction, including a slightly downward and backward grinding movement at the end of the stroke.

Turonian Cretaceous Probably Did Not Experience a Glaciation Event

For years, scientists have thought that a continental ice sheet formed during the Late Cretaceous Period more than 90 million years ago when the climate was much warmer than it is today. Now, a University of Missouri researcher has found evidence suggesting that no ice sheet formed at this time. This finding could help environmentalists and scientists predict what the earth's climate will be as carbon dioxide levels continue to rise.

"Currently, carbon dioxide levels are just above 400 parts per million (ppm), up approximately 120 ppm in the last 150 years and rising about 2 ppm each year," said Ken MacLeod, a professor of geological sciences at MU. "In our study, we found that during the Late Cretaceous Period, when carbon dioxide levels were around 1,000 ppm, there were no continental ice sheets on earth. So, if carbon dioxide levels continue to rise, the earth will be ice-free once the climate comes into balance with the higher levels."

In his study, MacLeod analyzed the fossilized shells of 90 million-year-old planktic and benthic foraminifera, single-celled organisms about the size of a grain of salt. Measuring the ratios of different isotopes of oxygen and carbon in the fossils gives scientists information about past temperatures and other environmental conditions. The fossils, which were found in Tanzania, showed no evidence of cooling or changes in local water chemistry that would have been expected if a glacial event had occurred during that time period.

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Pre Monkey-Ape Split Primates From Chattian Oligocene Tanzania Found?

From the human perspective, few events in evolution were more momentous than the split among primates that led to apes (large, tailless primates such as today's gorillas, chimpanzees, and humans) and Old World monkeys (which today include baboons and macaques). DNA studies of living primates have estimated that the rift took place between 25 million and 30 million years ago, but the earliest known fossils of both groups date no earlier than 20 million years ago. Now, a team working in Tanzania has found teeth and partial jaws from what it thinks are 25-million-year-old ancestors of both groups. If the interpretations hold up, the finds would reconcile the molecular and fossil evidence and possibly provide insights into what led to the split in the first place.

Researchers have long been frustrated by a paucity of fossils from this key period in evolution, which sits at the borderline between two major geological epochs: the Miocene (about 23 million to 5 million years ago) and the Oligocene (about 34 million to 23 million years ago). The earliest known fossils of early apes and Old World monkeys date from the early Miocene and have been found in just a handful of sites in Kenya, Uganda, and North Africa. Meanwhile, molecular studies of existing primates consistently suggest that these two groups arose during the Oligocene, leading scientists to wonder whether the molecular dates are wrong or if paleontologists have been looking in the wrong places.

For more than a decade, researchers from the United States and Tanzania have been combing Tanzania's Rukwa Rift Basin, searching for fossils of all kinds. During the 2011 and 2012 seasons, a team led by Nancy Stevens, a vertebrate paleontologist at Ohio University in Athens, discovered fossils that it identified as belonging to two previously unknown species of primates: one, an apparent ape ancestor the team has named Rukwapithecus fleaglei; the other, a claimed Old World monkey ancestor dubbed Nsungwepithecus gunnelli. (The species were named after two notable primatologists, John Fleagle of Stony Brook University in New York, and Gregg Gunnell, who is now at Duke University in Durham, North Carolina.)

Both specimens, consisting of teeth and partial jaws, were found in Rukwa Rift sediments dated by several techniques, including the often used argon-argon method, to 25.2 million years ago. The team identified them as ape and Old World monkey ancestors from the features of their molars, which paleontologists routinely use to tell primates apart. For example, Stevens says, Nsungwepithecus "has a much more triangular outline" of its last lower molar than Rukwapithecus, and there are "a number of other major differences in the shape and position of the cusps and crests that run along the chewing surface of the teeth." The two species also show other dental features that group them with later Old World monkeys and apes, but are still different enough to be classified as separate—and more ancient—species.

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