Evidence in hand: recent discoveries and the early evolution of human manual manipulation

Abstract

For several decades, it was largely assumed that stone tool use and production were abilities limited to the genus Homo . However, growing palaeontological and archaeological evidence, comparative extant primate studies, as well as results from methodological advancements in biomechanics and morphological analyses, have been gradually accumulating and now provide strong support for more advanced manual manipulative abilities and tool-related behaviours in pre- Homo hominins than has been traditionally recognized. Here, I review the fossil evidence related to early hominin dexterity, including the recent discoveries of relatively complete early hominin hand skeletons, and new methodologies that are providing a more holistic interpretation of hand function, and insight into how our early ancestors may have balanced the functional requirements of both arboreal locomotion and tool-related behaviours.

Compound grips in tufted capuchin monkeys (Sapajusspp andSapajus libidinosus)

“…Our understanding of manual dexterity in nonhuman primates lags behind, for example, our understanding of locomotion (Kivell, 2015), despite the emphasis on manual dexterity as a feature of human evolution. Much comparative work regarding manual function has contrasted hand morphology and behavior in chimpanzees and humans (e.g.…”

Biometric variables predict stone tool functional performance more effectively than tool‐form attributes: a case study in handaxe loading capabilities

“…It is important to acknowledge that the present results were generated from a sample of individuals displaying modern human ( Homo sapiens ) hand anatomy and corresponding levels of biometric variation. Given that the precision‐gripping capabilities of H. sapiens are hypothesized to have been selectively favoured over millions of years (Kivell ; Marzke ; Tocheri et al . ), it is arguably the case that the participant sample used here displays lower levels of variation than that observed in early tool using populations, potentially indicating the observed relationships to have been stronger during the Lower Palaeolithic.…”

“…Differences in hand anatomy between modern humans and Lower Palaeolithic hominin species do, however, raise questions about how accurately results can be applied to prehistoric populations. Fossil hand remains from the earliest hypothesized tool‐using hominin species (> 2 Mya) often indicate a transitional anatomy, with some human‐like precision manipulative capabilities (Kivell ; Tocheri et al . ).…”

“…Moreover, effective and efficient stone tool use requirements are widely thought to have affected the evolutionary trajectory of hominin hand anatomy during this period (Hamrick et al . ; Key and Lycett ; Kivell ; Marzke , ; Marzke and Shackley ; Rolian et al . ; Williams‐Hatala et al .…”

“…() further emphasizes the high muscular recruitment and loading required by the thumb and index finger during effective flake and handaxe use. Other work has examined fossil evidence with the aim of identifying the influence that stone tool production and use likely had on hominin manual anatomy (Kivell ; Marzke , ).…”