Type
Text
Type
Dissertation
Advisor
Jungers, William L | Demes, Brigitte | Susman, Randall L | Patel, Biren A | Almécija, Sergio.
Date
2016-12-01
Keywords
Morphology -- Biomechanics -- Evolution & development | Bipedalism, Human evolution, Joint congruence, Metatarsals, Phalanges, Shape analysis
Department
Department of Anthropology
Language
en_US
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/77465
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
The transition to our uniquely human gait—terrestrial bipedalism—is the hallmark of our lineage. Abundant fossil evidence confirms that it was the adoption of a terrestrial bipedal gait that first set hominins apart from other apes. Therefore, a thorough understanding of postcranial functional morphology is necessary in order to gain as much insight as possible from the current known fossil material. When compared to our closest relatives, the living apes, it is clear that a suite of morphological changes have occurred in the human postcranial skeleton broadly, including modifications at the vertebral column, shoulder, wrist, hand, pelvis, ankle and foot. The human foot in particular is strikingly different from that of any other primate, and a better understanding of its functional morphology would allow researchers to better reconstruct the locomotor behavior of extinct hominin groups. Despite their theorized importance in bipedal locomotion, the morphological details of the anthropoid forefoot (i.e. | metatarsophalangeal) joints have not been thoroughly quantified. To that end, I present here a detailed morphometric analysis of anthropoid forefoot shape and form using modern 3-dimensional geometric morphometric (3DGM) techniques in a broad phylogenetic context in order to capture functionally meaningful aspects of forefoot shape. The appositional articular surfaces of the metatarsus and proximal pedal phalanges were quantified, and then hypotheses about forefoot functional morphology were tested by exploring shape space, constant and variable-rate models of shape evolution, patterns of forefoot joint covariance, and the correlation between forefoot morphology and kinematic performance. Results revealed several broad patterns in anthropoid forefoot evolution. First, it seems the lateral forefoot began to evolve first, with the hallux retaining a primitive form until relatively late in evolution; a similar pattern was found in the pedal phalanges, which looked more primitive than the metatarsals overall. This staggered timing of forefoot evolution perhaps reflects the importance of arboreal locomotion persisting well into the hominin lineage. Evidence of convergent evolution between highly terrestrial cercopithecoids and hominins was found. Correlations with kinematic data in human and chimpanzee forefoot joints suggest that dorsal robusticity is strongly correlated with forefoot dorsiflexion range of motion. | The transition to our uniquely human gait—terrestrial bipedalism—is the hallmark of our lineage. Abundant fossil evidence confirms that it was the adoption of a terrestrial bipedal gait that first set hominins apart from other apes. Therefore, a thorough understanding of postcranial functional morphology is necessary in order to gain as much insight as possible from the current known fossil material. When compared to our closest relatives, the living apes, it is clear that a suite of morphological changes have occurred in the human postcranial skeleton broadly, including modifications at the vertebral column, shoulder, wrist, hand, pelvis, ankle and foot. The human foot in particular is strikingly different from that of any other primate, and a better understanding of its functional morphology would allow researchers to better reconstruct the locomotor behavior of extinct hominin groups. Despite their theorized importance in bipedal locomotion, the morphological details of the anthropoid forefoot (i.e. | metatarsophalangeal) joints have not been thoroughly quantified. To that end, I present here a detailed morphometric analysis of anthropoid forefoot shape and form using modern 3-dimensional geometric morphometric (3DGM) techniques in a broad phylogenetic context in order to capture functionally meaningful aspects of forefoot shape. The appositional articular surfaces of the metatarsus and proximal pedal phalanges were quantified, and then hypotheses about forefoot functional morphology were tested by exploring shape space, constant and variable-rate models of shape evolution, patterns of forefoot joint covariance, and the correlation between forefoot morphology and kinematic performance. Results revealed several broad patterns in anthropoid forefoot evolution. First, it seems the lateral forefoot began to evolve first, with the hallux retaining a primitive form until relatively late in evolution; a similar pattern was found in the pedal phalanges, which looked more primitive than the metatarsals overall. This staggered timing of forefoot evolution perhaps reflects the importance of arboreal locomotion persisting well into the hominin lineage. Evidence of convergent evolution between highly terrestrial cercopithecoids and hominins was found. Correlations with kinematic data in human and chimpanzee forefoot joints suggest that dorsal robusticity is strongly correlated with forefoot dorsiflexion range of motion. | 311 pages
Recommended Citation
Fernandez, Pedro J., "Form and Function of the Anthropoid Forefoot" (2016). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 3277.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/3277