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Leslea Hlusko
  • Berkeley, California, United States
ObjectivesThe aim of this study is to assess a new assemblage of papionin fossils (n = 143) recovered from later Pleistocene sediments in the Middle Awash study area in the Afar Rift of Ethiopia.Materials and MethodsWe collected metric... more
ObjectivesThe aim of this study is to assess a new assemblage of papionin fossils (n = 143) recovered from later Pleistocene sediments in the Middle Awash study area in the Afar Rift of Ethiopia.Materials and MethodsWe collected metric and qualitative data to compare the craniodental and postcranial anatomy of the papionin fossils with subspecies of modern Papio hamadryas and with Plio‐Pleistocene African papionins. We also estimated sex and ontogenetic age.ResultsThe new fossils fit well within the range of morphological variation observed for extant P. hamadryas, overlapping most closely in dental size and proportions with the P. h. cynocephalus individuals in our extant samples, and well within the ranges of P. h. anubis and P. h. hamadryas. The considerable overlap in craniodental anatomy with multiple subspecies precludes subspecific diagnosis. We therefore referred 143 individuals to P. hamadryas ssp. The majority of the individuals assessed for ontogenetic age fell into middle‐ and old‐adult age categories based on the degree of dental wear. Males (26%) were better represented than females (12%) among individuals preserving the canine‐premolar honing complex.DiscussionThese new near‐modern P. hamadryas fossils provide a window into population‐level variation in the later Pleistocene. Our findings echo previous suggestions from genomic studies that the papionin family tree may have included a ghost population and provide a basis for future testing of hypotheses regarding hybridization in the recent evolutionary history of this taxon.
ObjectivesThe aim of this study is to introduce and systematically assess a new assemblage of colobine fossils (n = 360) recovered from Late Pleistocene (ca. 100,000 years ago) sediments in the Middle Awash research area, Afar Rift,... more
ObjectivesThe aim of this study is to introduce and systematically assess a new assemblage of colobine fossils (n = 360) recovered from Late Pleistocene (ca. 100,000 years ago) sediments in the Middle Awash research area, Afar Rift, Ethiopia.Materials and MethodsWe describe the colobine fossils relative to extant colobine taxa and Middle Pleistocene fossil samples from “Andalee” and Asbole, Ethiopia using linear dental, cranial, and postcranial metrics, as well as qualitative features. We also document the ontogenetic and sex profiles of this sample.ResultsBased on morphological affinities to extant and fossil Colobus, we refer these 360 individuals to Colobus cf. guereza. The majority of the individuals (76%) fall into young‐ and middle‐adult age categories. Females are slightly better represented than males, although the majority of individuals (84%) could not be assigned to sex.DiscussionDetails of the last half million years of Colobus morphological evolution have remained obscu...
SynopsisPrevious genotype:phenotype mapping of the mouse and primate dentition revealed the presence of pre- and post-canine modules in mice and anthropoid primates, as well as molar and premolar submodules in anthropoid primates. We... more
SynopsisPrevious genotype:phenotype mapping of the mouse and primate dentition revealed the presence of pre- and post-canine modules in mice and anthropoid primates, as well as molar and premolar submodules in anthropoid primates. We estimated phenotypic correlation matrices for species that sample broadly across Mammalia to test the hypothesis that these modules exist across a broader range of taxa and thereby represent a conserved mammalian trait. We calculated phenotypic correlation matrices from linear dental measurements of 419 individual specimens representing 5 species from 4 mammalian orders: Artiodactyla (Odocoileus hemionus), Carnivora (Canis latrans and Ursus americanus), Didelphimorphia (Didelphis virginiana), and Primates (Colobus guereza). Our results based on hierarchical clustering indicate a generally higher correlation within incisors and among post-canine teeth. However, the post-canine phenotypic correlation matrices do not consistently exhibit the premolar and m...
Evolution favored teeth with thicker enamel over sharply crested teeth in hominins confronted with tough diets
Research Interests:
Synopsis The ectodysplasin pathway has been a target of evolution repeatedly. Genetic variation in the key genes of this pathway (EDA, EDAR, and EDARADD) results in a rich source of pleiotropic effects across ectodermally-derived... more
Synopsis The ectodysplasin pathway has been a target of evolution repeatedly. Genetic variation in the key genes of this pathway (EDA, EDAR, and EDARADD) results in a rich source of pleiotropic effects across ectodermally-derived structures, including teeth, hair, sweat glands, and mammary glands. In addition, a non-canonical Wnt pathway has a very similar functional role, making variation in the WNT10A gene also of evolutionary significance. The adaptation of mammals to aquatic environments has occurred independently in at least 4 orders, whose species occupy a wide geographic range (from equatorial to polar regions) and exhibit great phenotypic variation in ectodermally-derived structures, including the presence or absence of fur and extreme lactational strategies. The role of the ectodysplasin pathway in the adaptation to aquatic environments has been never explored in mammalian species. In the present study, we analyze the genetic variation in orthologous coding sequences from E...
Colleagues often refer to Alan Walker as the Eric Clapton (one of the most influential musicians of the late twentieth century) of palaeoanthropology in recognition of the artistry of his science. His field discoveries filled major gaps... more
Colleagues often refer to Alan Walker as the Eric Clapton (one of the most influential musicians of the late twentieth century) of palaeoanthropology in recognition of the artistry of his science. His field discoveries filled major gaps in our knowledge of primate evolution, such as elucidating the Miocene world of <i>Proconsul</i> and finding the transitional 'Black Skull' of <i>Australopithecus aethiopicus</i> and the skeleton of a <i>Homo erectus</i> boy. In addition to discovering these remarkable fossils, Alan was essential in bringing a palaeobiological approach to the laboratory interpretation of their bony morphology. He used the relationships between form and function in living species as a baseline for understanding the past, he pioneered dental microwear analysis to infer diet and was an early-adopter of the use of microCT to explore the internal structure of primate ear bones. Beyond these scientific accomplishments, however, it was Alan's grace and generosity that truly set him apart from his peers. As the patriarch of an extensive intellectual family of students, postdocs and colleagues, Alan taught by example how to be intellectually creative, brave, meticulous, generous and kind. His legacy will long be felt in both the science and the culture of palaeoanthropology.
Advances in genetics and developmental biology are revealing the relationship between genotype and dental phenotype (G:P), providing new approaches for how paleontologists assess dental variation in the fossil record. Our aim was to... more
Advances in genetics and developmental biology are revealing the relationship between genotype and dental phenotype (G:P), providing new approaches for how paleontologists assess dental variation in the fossil record. Our aim was to understand how the method of trait definition influences the ability to reconstruct phylogenetic relationships and evolutionary history in the Cercopithecidae, the Linnaean Family of monkeys currently living in Africa and Asia. We compared the two-dimensional assessment of molar size (calculated as the mesiodistal length of the crown multiplied by the buccolingual breadth) to a trait that reflects developmental influences on molar development (the inhibitory cascade, IC) and two traits that reflect the genetic architecture of postcanine tooth size variation (defined through quantitative genetic analyses: MMC and PMM). All traits were significantly influenced by the additive effects of genes and had similarly high heritability estimates. The proportion of...
ABSTRACTHistological analysis of teeth can yield information on an organism’s growth and development, facilitating investigations of diet, health, environment, and long-term responses to selective pressures. In the Americas, an... more
ABSTRACTHistological analysis of teeth can yield information on an organism’s growth and development, facilitating investigations of diet, health, environment, and long-term responses to selective pressures. In the Americas, an extraordinary abundance of Late Pleistocene fossils including teeth has been preserved in petroleum seeps, constituting a major source of information about biotic changes and adaptations at the end of the last glacial period. However, the usefulness of these fossils for histological studies is unclear, due to the unknown taphonomic effects of long-term deposition in petroleum. Here, we compare histological and chemical analyses on dire wolf (Canis dirus) teeth obtained from two different environments, i.e. a petroleum seep (Rancho La Brea tar pits, California) and a carstic sinkhole (Cutler Hammock sinkhole, Florida). Optical and scanning electron microscopy (SEM) together with X-ray diffraction (XRD) analysis revealed excellent preservation of dental microst...
Colleagues often refer to Alan Walker as the Eric Clapton (one of the most influential musicians of the late twentieth century) of palaeoanthropology in recognition of the artistry of his science. His field discoveries filled major gaps... more
Colleagues often refer to Alan Walker as the Eric Clapton (one of the most influential musicians of the late twentieth century) of palaeoanthropology in recognition of the artistry of his science. His field discoveries filled major gaps in our knowledge of primate evolution, such as elucidating the Miocene world of Proconsul and finding the transitional ‘Black Skull’ of Australopithecus aethiopicus and the skeleton of a Homo erectus boy. In addition to discovering these remarkable fossils, Alan was essential in bringing a palaeobiological approach to the laboratory interpretation of their bony morphology. He used the relationships between form and function in living species as a baseline for understanding the past, he pioneered dental microwear analysis to infer diet and was an early-adopter of the use of microCT to explore the internal structure of primate ear bones. Beyond these scientific accomplishments, however, it was Alan's grace and generosity that truly set him apart fr...

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