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Recent advances in molecular phylogenetics and a series of important palaeobotanical discoveries have revolutionized our understanding of angiosperm diversification. Yet, the origin and early evolution of their most characteristic feature, the flower, remains poorly understood. In particular, the structure of the ancestral flower of all living angiosperms is still uncertain. Here we report model-based reconstructions for ancestral flowers at the deepest nodes in the phylogeny of angiosperms, using the largest data set of floral traits ever assembled. We reconstruct the ancestral angiosperm flower as bisexual and radially symmetric, with more than two whorls of three separate perianth organs each (undifferentiated tepals), more than two whorls of three separate stamens each, and more than five spirally arranged separate carpels. Although uncertainty remains for some of the characters, our reconstruction allows us to propose a new plausible scenario for the early diversification of flowers, leading to new testable hypotheses for future research on angiosperms.

The Cradle of Humankind (Gauteng, South Africa) provides an important fossil record of the evolutionary history of PlioPleistocene hominins. Cooper's Cave deposits have yielded a rich fossil faunal assemblage, as well as six remains attributed to Paranthropus robustus. This study provides the first taxonomic, taphonomic and palaeoecological description of the micromammal material from the 1.4 Ma assemblage of Cooper's D. The taphonomic signature of the assemblage indicates an accumulation by tytonid owls (probably Tyto alba) and advanced postdepositional disturbance probably related to trampling by the occupants of the cave, sorting of the bones along slope, and burying. The taxonomic analysis undertaken here at genus level describes at least 22 taxa of small mammals, including one extinct genus Proodontomys. This assemblage is dominated by Mystromys and Otomys, two rodent genera adapted to grassland habitats which are among the most common among pliopleistocene micromammal faunas from the region. The palaeoecological analysis suggests an open landscape with a predominance of grassland and savanna vegetation, and the proximity of rocky outcrops and a perennial river. These results support previous indications of a shift in the African climate and vegetation towards more open habitats during the Early Pleistocene. [ABSTRACT FROM AUTHOR]

Among tetrapods, grasping is an essential function involved in many vital behaviours. The selective pressures that led to this function were widely investigated in species with prehensile hands and feet. Previous studies namely highlighted a strong effect of item properties but also of the species habitat on manual grasping behaviour. African savannah elephants (Loxodonta africana) are known to display various prehensile abilities and use their trunk in a large diversity of habitats. Composed of muscles and without a rigid structure, the trunk is a muscular hydrostat with great freedom of movement. This multitasking organ is particularly recruited for grasping food items while foraging. Yet, the diet of African savannah elephants varies widely between groups living in different habitats. Moreover, they have tusks alongside the trunk which can assist in grasping behaviours, and their tusk morphologies are known to vary considerably between groups. Therefore, in this study, we investigate the food grasping techniques used by the trunk of two elephant groups that live in different habitats: an arid study site in Etosha National Park in Namibia, and an area with consistent water presence in Kruger National Park in South Africa. We characterised the tusks profiles and compared the grasping techniques and their frequencies of use for different foods. Our results show differences in food‐grasping techniques between the two groups. These differences are related to the food item property and tusk profile discrepancies highlighted between the two groups. We suggest that habitat heterogeneity, particularly aridity gaps, may induce these differences. This may reveal an optimisation of grasping types depending on habitat, food size and accessibility, as well as tusk profiles. [ABSTRACT FROM AUTHOR]

Objectives: The shape of the trapezium and first metacarpal (Mc1) markedly influence thumb mobility, strength, and the manual abilities of extant hominids. Previous research has typically focused solely on trapezium‐Mc1 joint shape. Here we investigate how morphological integration and shape covariation between the entire trapezium (articular and non‐articular surfaces) and the entire Mc1 reflect known differences in thumb use in extant hominids. Materials and Methods: We analyzed shape covariation in associated trapezia and Mc1s across a large, diverse sample of Homo sapiens (n = 40 individuals) and other extant hominids (Pan troglodytes, n = 16; Pan paniscus, n = 13; Gorilla gorilla gorilla, n = 27; Gorilla beringei, n = 6; Pongo pygmaeus, n = 14; Pongo abelii, n = 9) using a 3D geometric morphometric approach. We tested for interspecific significant differences in degree of morphological integration and patterns of shape covariation between the entire trapezium and Mc1, as well as within the trapezium‐Mc1 joint specifically. Results: Significant morphological integration was only found in the trapezium‐Mc1 joint of H. sapiens and G. g. gorilla. Each genus showed a specific pattern of shape covariation between the entire trapezium and Mc1 that was consistent with different intercarpal and carpometacarpal joint postures. Discussion: Our results are consistent with known differences in habitual thumb use, including a more abducted thumb during forceful precision grips in H. sapiens and a more adducted thumb in other hominids used for diverse grips. These results will help to infer thumb use in fossil hominins. [ABSTRACT FROM AUTHOR]