Two unrecognised burnetiamorph specimens from historic Karoo collections

Two historical specimens from Permian rocks of the Karoo Basin represent previously unrecognised members of the rare therapsid group Burnetiamorpha. These specimens cannot be referred to any existing burnetiamorph species, but are left in open nomenclature because of their incompleteness (both are isolated skull roofs). The first specimen is from the Tapinocephalus Assemblage Zone (AZ) and is characterized by heavily pachyostosed supraorbital bosses and a low nasal crest. The second specimen is from the Tropidostoma AZ and is generally similar to the Malawian taxon Lende, but is unique among described burnetiamorphs in having a frontoparietal ‘dome’ that surrounds the pineal foramen. Phylogenetic analysis of burnetiamorphs recovers support for a split between Proburnetia and Burnetia-like burnetiids, here named Proburnetiinae subfam. nov. and Burnetiinae Broom, 1923.Deutsche Forschungsgemeinschaft (KA 4133-1/1) Sofja Kovalevskaja Award from the Alexander von Humboldt Foundation to Jörg Fröbsic

The first skeletal evidence of a dicynodont from the lower Elliot Formation of South Africa

Historical fossil specimens from the lower Elliot Formation are identified as representing a large-bodied dicynodont, the first known from skeletal material in the Late Triassic of South Africa. Although fragmentary, these fossils differ from all other known Triassic dicynodonts and are here described as a new taxon, Pentasaurus goggai gen. et sp. nov. Pentasaurus can be distinguished from other Triassic dicynodonts by a number of mandibular characters, most importantly the well-developed, unusually anteriorly-positioned lateral dentary shelf. Phylogenetic analysis indicates that Pentasaurus is a placeriine stahleckeriid. Placeriines include the latestsurviving dicynodonts but their remains are primarily known from the Northern Hemisphere, with their only previously-known Southern Hemisphere representative being the Middle Triassic Zambian taxon Zambiasaurus. The discovery of a placeriine in the Late Triassic of SouthAfrica supports recent proposals that local climatic conditions, not broad-scale biogeographic patterns, best explain the observed distribution of Triassic tetrapods. The tetrapod fauna of the lower Elliot Formation is highly unusual among Triassic assemblages in combining ‘relictual’ taxa like dicynodonts and gomphodont cynodonts with abundant, diverse sauropodomorph dinosaurs.Deutsche Forschungsgemeinschaft (KA 4133/1-1)JN

Replacement names for the therapsid genera Criocephalus Broom 1928 and Olivieria Brink 1965.

Main articleOur knowledge of premammalian synapsid evolutionary history has benefited from over a hundred years of fossil collecting, especially within the Permo-Triassic sediments of South Africa's Beaufort Group (Rubidge 1995) and the Cis-Ural region of Eastern Europe (Ivachnenko et al. 1997). In the course of our research and discussions we have discovered several errors in the present state of non-mammalian synapsid taxonomy. Here we propose emendations concerning the genera Criocephalus Broom 1928 and Olivieria Brink 1965.Palaeo-Anthropology Scientific Trust; French Embassy in South Africa; Co-operation and Cultural Service

Hippocampal Remapping Is Constrained by Sparseness rather than Capacity

Grid cells in the medial entorhinal cortex encode space with firing fields that are arranged on the nodes of spatial hexagonal lattices. Potential candidates to read out the space information of this grid code and to combine it with other sensory cues are hippocampal place cells. In this paper, we investigate a population of grid cells providing feed-forward input to place cells. The capacity of the underlying synaptic transformation is determined by both spatial acuity and the number of different spatial environments that can be represented. The codes for different environments arise from phase shifts of the periodical entorhinal cortex patterns that induce a global remapping of hippocampal place fields, i.e., a new random assignment of place fields for each environment. If only a single environment is encoded, the grid code can be read out at high acuity with only few place cells. A surplus in place cells can be used to store a space code for more environments via remapping. The number of stored environments can be increased even more efficiently by stronger recurrent inhibition and by partitioning the place cell population such that learning affects only a small fraction of them in each environment. We find that the spatial decoding acuity is much more resilient to multiple remappings than the sparseness of the place code. Since the hippocampal place code is sparse, we thus conclude that the projection from grid cells to the place cells is not using its full capacity to transfer space information. Both populations may encode different aspects of space

A physiologically inspired model for global remapping in the hippocampus

Europe PMC is an archive of life sciences journal literature., A physiologically inspired model for global remapping in the hippocampus

The postcranial anatomy of Gorgonops torvus (Synapsida, Gorgonopsia) from the late Permian of South Africa

The article processing charge was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – 491192747 and the Open Access Publication Fund of Humboldt-Universität zu Berlin.Gorgonopsians are among the most recognizable groups of synapsids from the Permian period and have an extensive but mostly cranial fossil record. By contrast, relatively little is known about their postcranial anatomy. Here, we describe a nearly complete, semi-articulated skeleton of a gorgonopsian (identified as Gorgonops torvus) from the late Permian Endothiodon Assemblage Zone of the South African Karoo Basin and discuss its paleobiological implications. Known gorgonopsian postcrania indicate morphological conservatism in the group, but the skeletal anatomy of Gorgonops does differ from that of other gorgonopsians in some respects, such as in the triangular radiale and short terminal phalanges in the manus, and a weakly developed distinction between pubis and ischium in ventral aspect of the pelvic girdle. Similarities between the specimen described herein and a historically problematic specimen originally referred to “Scymnognathus cf. whaitsi” confirm referral of the latter specimen to Gorgonops. Since descriptions of gorgonopsian postcrania are rare, new interpretations of the lifestyle and ecology of Gorgonopsia can be drawn from our contribution. We conclude that gorgonopsians were likely ambush predators, able to chase their prey over short distances and pin them down with strong forelimbs before using their canines for the kill. This is evidenced by their different fore- and hindlimb morphology; the former stouter and more robust in comparison to the longer, more gracile, back legs. Furthermore, the completeness of the study specimen facilitates calculation of an estimated body mass of approximately 98 kg, similar to that of a modern lioness.Peer Reviewe