Lithostratigraphy of the Elliot Formation (Karoo Supergroup), South Africa

The Late Triassic to Early Jurassic Elliot Formation is part of the Stormberg Group (Karoo Supergroup) of South Africa. The unit is significant palaeontlologically, because it preserves not only a range of vertebrate fossils, but also a plethora of ichnofossil and encompasses the boundary of Triassic and Jurassic in Southern Africa. The Formation is considered a stratigraphic equivalent of the Upper Omingonde Formation, Etjo Basin, Namibia, with the Bodibeng Sandstone Formation, Tuli Basin, Botswana, with the upper Mosolotsane Formation, Kalahari Karoo Basin. All Upper Triassic-Lower Jurassic continental red beds of South Africa, irrespective of their geographic locality relative to the main Karoo Basin are now termed Elliot Formation due to their very similar lithologic character and stratigraphic position.http://sajg.geoscienceworld.orgam2016Geolog

Possible trace fossils of putative termite origin in the Lower Jurassic (Karoo Supergroup) of South Africa and Lesotho

Complex structures in the sandstones of the Lower Jurassic aeolian Clarens Formation (Karoo Supergroup) are found at numerous localities throughout southern Africa, and can be assigned to five distinct architectural groups: (1) up to 3.3-m high, free-standing, slab-shaped forms of bioturbated sandstones with elliptical bases, orientated buttresses and an interconnecting large burrow system; (2) up to 1.2-m high, free-standing, irregular forms of bioturbated sandstones with 2-cm to 4-cm thick, massive walls, empty chambers and vertical shafts; (3) about 0.15-m to 0.25-m high, mainly bulbous, multiple forms with thin walls (larger than 2 cm), hollow chambers with internal pillars and bridges; (4) about 0.15-m to 0.2-m (maximum 1-m) high, free-standing forms of aggregated solitary spheres associated with massive horizontal, orientated capsules or tubes, and meniscate tubes; and (5) about 5 cmin diameter, ovoid forms with weak internal shelving in a close-fitting cavity. Based on size, wall thickness, orientation and the presence of internal chambers, these complex structures are tentatively interpreted as ichnofossils of an Early Jurassic social organism; the different architectures are reflective of the different behaviours of more than one species, the history of structural change in architectural forms (ontogenetic series) or an architectural adaptation to local palaeoclimatic variability. While exact modern equivalents are unknown, some of these ichnofossils are comparable to nests (or parts of nests) constructed by extant termites, and thus these Jurassic structures are very tentatively interpreted here as having been made by a soil-dwelling social organism, probably of termite origin. This southern African discovery, along with reported Triassic and Jurassic termite ichnofossils from North America, supports previous hypotheses that sociality in insects, particularity in termites, likely evolved prior to the Pangea breakup in the Early Mesozoic

First Lower Jurassic vertebrate burrow from southern Africa (upper Elliot Formation, Karoo Basin, South Africa)

Vertebrate burrows are common ichnofossils in the Permo-Triassic of the main Karoo Basin in South Africa. They are generally attributable to one of several lineages of therapsid, including the derived clade known as cynodonts. Despite the presence of cynodont species in the Upper Triassic and Lower Jurassic of the Karoo Supergroup, vertebrate burrows have never been reported from this part of the succession. Recent fieldwork recovered a semi-elliptical burrow cast in the Lower Jurassic upper Elliot Formation (Stormberg Group) on the farm Edelweiss 698 (Free State). The horizontal and vertical diameters of the burrow cast are ~ 18 and ~ 7 cm, respectively. This semi-horizontal, straight to slightly sinuous tunnel is ~ 50 cm long with a ramp angle of  20 cm deep) desiccation cracks, invertebrate trace fossils, calcareous rhizoconcretions, and spherical-to-elongated carbonate nodules. These and other associated sedimentary features provide evidence for a semi-arid, fluvio-lacustrine palaeoenvironment during the burrowing activity. Based on comparisons to fossil and modern burrows, this burrow cast is interpreted as a vertebrate burrow, and is the first record of vertebrate fossorial activity within the Lower Jurassic of southern Africa. The ancient burrow architect has yet to be positively identified. However, given the size and morphology of the burrow and the occurrence of similar sized fossil cynodont therapsids that inhabited the main Karoo Basin in the earliest Jurassic, the potential burrow-maker may be tentatively linked to the Cynodontia (e.g., Pachygenelus - an advanced tritheledontid).Fil: Bordy, E.M.. University Of Cape Town;Fil: Sciscio, L.. University Of Cape Town;Fil: Abdala, Nestor Fernando. University of the Witwatersrand; Sudáfrica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: McPhee, B.W.. University of the Witwatersrand; SudáfricaFil: Choiniere, J.N.. University of the Witwatersrand; Sudáfric

Revising dating estimates and the antiquity of eusociality in termites using the fossilized birth-death process

International audienceDeciphering the timing and tempo of lineage diversification of organisms has greatly benefited from advances in Bayesian phylogenetic analyses using morphological data. Those advances, however, have not been used for termites despite a rich fossil record. Here, we estimate divergence times for living and fossil termites using the fossilized birth–death (FBD) process on a previously published morphological matrix expanded with two new fossils that we describe (see Appendices 1 & 2). Those fossils, based on soldier specimens, are the ‘mid’-Cretaceous mastotermitid Milesitermesengeligen. et sp. nov., and the Middle Eocene Reticulitermesgrimaldiisp. nov. The latter is the oldest occurrence of a Rhinotermitidae soldier and the first termite soldier described from Baltic amber. Our dating estimates provide new stem- and crown-ages for termites, suggesting older ages than previously thought for several lineages. Importantly, crown-Isoptera—and therefore eusociality—may have arisen ~200 Ma. We conclude with further directions to keep improving our understanding of the timing of differentiation in termites.Page 2 of 77Systematic Entomolog