![]() In contrast, phylogenetic reconstruction of ancestral states is able to provide a detailed suite of behavioral, ecological and life-history characters for each hypothetical ancestor. ![]() Any evolutionary model that uses a single extant species to explain behavioral evolution of early hominins is therefore of limited use. However, numerous behaviors present in extant great apes represent their own terminal autapomorphies (both uniquely derived and homoplastic). Our analyses demonstrate that many fundamental behavioral and life-history attributes of hominids (including humans) are evidently ancient and likely inherited from the common ancestor of all hominids. This analysis allows us to reconstruct the character states of the last common ancestors of Hominoidea, Hominidae, and the chimpanzee–human last common ancestor. Using the widely accepted hominoid phylogenetic tree, we perform a series of character optimization analyses using 65 selected life-history and behavioral characters for all extant hominid species. Here, we argue that while behavioral data on extant great apes are extremely relevant for reconstruction of ancestral behaviors, these behaviors should be reconstructed trait by trait using formal phylogenetic methods. The prominent, chimpanzee-based referential model of early hominin behavior has recently been challenged on the basis of broad multispecies comparisons and newly discovered fossil evidence. The origin of the fundamental behavioral differences between humans and our closest living relatives is one of the central issues of evolutionary anthropology. In addition, a newly discovered scaphoid bone with a fusing os centrale provides further evidence about the nature of hominin hand evolution. ramidus ankle and hallux than previously recognized. The newly recovered fossils document a greater adaptation to bipedality in the Ar. ramidus of having a mixed locomotor adaptation of terrestrial bipedality and arboreal clambering, we broaden our understanding of the nature of its locomotor pattern by documenting better the function of the hip, ankle, and foot. While we reinforce the original functional interpretations of Ar. ramidus fossils from the Gona Project study area, Ethiopia, that includes a fragmentary but informative partial skeleton (GWM67/P2) and additional isolated manual remains. ![]() Here, we present the results of an analysis of additional early Pliocene Ar. ramidus locomotion has been collected from the Aramis area of the Middle Awash Research Project in Ethiopia. To date, all of the fossil evidence of Ar. That chimpanzees and gorillas independently resorted to a more terrestrial existence, with their signature knuckle-walking pattern (Kivell and Schmitt, 2009 Simpson et al., 2018), further complicates our understanding of the evolution of their distinctive locomotor anatomy.įunctional analyses of the 4.4 Ma hominin Ardipithecus ramidus postcrania revealed a previously unknown and unpredicted locomotor pattern combining arboreal clambering and a form of terrestrial bipedality. As noted elsewhere (Latimer et al., 1981 Lovejoy et al., 2009d Sanders et al., 2010 White et al., 2015), the African apes have followed their own evolutionary adaptive history to high canopy foraging and their current locomotor anatomy is not that of our shared ancestor. ![]() The absence of many modern ape traits in the Ardipithecus skeleton, including long medial metacarpals, reduced pollex with absence of the flexor pollicis longus tendon or its transfer to the index finger (Chapman, 1878, 1879 Straus, 1949), complex carpometacarpal articulations (Selby et al., 2016), forelimb elongation, hindlimb and tarsal shortening, and stiffening of the torso, especially the lumbopelvic region (Lovejoy and McCollum, 2010), reinforces our understanding of the degree of specialization by the extant large-bodied apes to high-canopy arboreality. ![]()
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