Bovid ecomorphology and hominin paleoenvironments of the Shungura Formation, lower Omo River Valley, Ethiopia

Abstract

The Shungura Formation in the lower Omo River Valley, southern Ethiopia, has yielded an important paleontological and archeological record from the Pliocene and Pleistocene of eastern Africa. Fossils are common throughout the sequence and provide evidence of paleoenvironments and environmental change through time. This study developed discriminant function ecomorphology models that linked astragalus morphology to broadly defined habitat categories (open, light cover, heavy cover, forest, and wetlands) using modern bovids of known ecology. These models used seven variables suitable for use on fragmentary fossils and had overall classification success rates of > 82%. Four hundred and one fossils were analyzed from Shungura Formation members B through G (3.4 to 1.9 million years ago). Analysis by member documented the full range of ecomorph categories, demonstrating that a wide range of habitats existed along the axis of the paleo-Omo River.

Exploring morphological generality in the Old World monkey postcranium using an ecomorphological framework

“…; Plummer et al. ), as is seen in alcelaphin bovids, for example, as well as the guenons. The advantage of examining phylogenetic signal alongside ecomorphological signal is that it enables more in‐depth consideration of the evolutionary processes that gave rise to ecomorphic adaptations, including evolutionary conservatism, niche filling scenarios and the effects of stabilising selection.…”

“…; Plummer et al. ) but, in brief, each dataset used three or four similar categories: open (animals living and moving in savanna grassland and environments with little tree cover); mixed/intermediate (animals either using environments with greater canopy cover, or exploiting forest edges, or using open and closed environments across their range or within a given region); and forest (exploiting closed environments with considerable canopy cover, either on the ground or, in the case of felids and cercopithecids, in the trees). For the bovid sample (following Kappelman et al.…”

“…; Barr, , ; Scott & Barr, ; Plummer et al. ), including whether traits with a strong phylogenetic signal pose a ‘risk’ when interpreting ecomorphological signal. However, function and phylogeny often travel hand in hand (Louys et al.…”

“…This was not unexpected, as the Chlorocebus clade (phylogenetic similarity) shares terrestrial preferences (function), whereas the Cercopithecus clade is arboreal. There has been increasing debate in the literature over how phylogeny should be assessed and incorporated into classic ecomorphological analyses Barr, 2014Barr, , 2015Scott & Barr, 2014;Plummer et al 2015), including whether traits with a strong phylogenetic signal pose a 'risk' when interpreting ecomorphological signal. However, function and phylogeny often travel hand in hand Plummer et al 2015), as is seen in alcelaphin bovids, for example, as well as the guenons.…”

“…There has been increasing debate in the literature over how phylogeny should be assessed and incorporated into classic ecomorphological analyses Barr, 2014Barr, , 2015Scott & Barr, 2014;Plummer et al 2015), including whether traits with a strong phylogenetic signal pose a 'risk' when interpreting ecomorphological signal. However, function and phylogeny often travel hand in hand Plummer et al 2015), as is seen in alcelaphin bovids, for example, as well as the guenons. The advantage of examining phylogenetic signal alongside ecomorphological signal is that it enables more in-depth consideration of the evolutionary processes that gave rise to ecomorphic adaptations, including evolutionary conservatism, niche filling scenarios and the effects of stabilising selection.…”