Valerie Burke DeLeon

Valerie Burke DeLeon
University of Florida | UF · Department of Anthropology

Ph.D., Functional Anatomy and Evolution

About

132
Publications
15,241
Reads
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2,168
Citations
Additional affiliations
August 2005 - August 2014
Johns Hopkins University
Position
  • Professor (Assistant)
July 2005 - June 2014
Johns Hopkins Medicine
Position
  • Research Assistant

Publications

Publications (132)
Article
Full-text available
Bones of the skull are traditionally categorized as derived from either endochondral or intramembranous bone. In our previous work, we have observed the interaction of different tissue types in growth of the skull. We find the dichotomy of intramembranous and endochondral bone to be too restrictive, limiting our interpretation of sources of biologi...
Article
Full-text available
Tusks are ever‐growing teeth present in mammals of the clade Paenungulata. Unlike the perpetually growing incisors of rodents, tusks are not used in mastication, and in at least some paenungulatans, the tusk is composed of dentin alone in adults. Few studies have provided tissue‐level information on tusks of adult paenungulatans with embedding tech...
Article
The study of primate auditory morphology is a significant area of interest for comparative anatomists, given the phylogenetic relationships that link primate hearing and the morphology of these auditory structures. Extensive literature addresses the form‐to‐function relationship of the auditory system (outer, middle, and inner ear) in primates and,...
Article
Full-text available
Biological variation in the mammalian skull is the product of a series of factors including changes in gene expression, developmental timing, and environmental pressures. When considering the diversity of extant mammalian crania, it is important to understand these mechanisms that contribute to cranial growth and in turn, how differences in cranial...
Article
Systems of the body develop in a modular manner. For example, neural development in primates is generally rapid, whereas dental development varies much more. In the present study, we examined development of the skull, teeth, and postcrania in a highly specialized leaping primate, Galago moholi . Eighteen specimens ranging from birth to adult were s...
Poster
Full-text available
ABSTRACT. Primates exhibit a simplified turbinal skeleton compared to many other mammals. The plasticity of morphological (shape) and topological (structure) characteristics can make it challenging to identify homologous phenotypes in adults. Since turbinal development resembles the placental bauplan, inferring homology from developmental series re...
Article
Full-text available
Collections of human remains in scientific and private institutions have a long tradition, though throughout history there has often been variable regard for the respect and dignity that these tissues demand. Recent public scandals around the use of human remains, coupled with an increasing community awareness around accountability in such instance...
Article
Full-text available
Individuals with Kabuki syndrome type 1 (KS1) often have hearing loss recognized in middle childhood. Current clinical dogma suggests that this phenotype is caused by frequent infections due to the immune deficiency in KS1 and/or secondary to structural abnormalities of the ear. To clarify some aspects of hearing loss, we collected information on h...
Article
Paranasal sinuses of living apes and humans grow with positive allometry, suggesting a novel mechanism for bone enlargement. Here, we examine the paranasal sinuses of the owl monkey (Aotus spp.) and a tamarin (Saguinus midas) across postnatal development. The prediction that paranasal sinuses grow disproportionately faster than the main nasal chamb...
Article
Herein, we compared the developmental maturity of the cranium, limbs, and feeding apparatus in a perinatal common vampire bat relative to its mother. In addition, we introduce a method for combining two computed tomographic imaging techniques to three‐dimensionally reconstruct endocasts in poorly ossified crania. The Desmodus specimens were scanned...
Article
The nasal capsule, as the most rostral part of the chondrocranium, is a critical point of connection with the facial skeleton. Its fate may influence facial form, and the varied fates of cartilage may be a vehicle contributing to morphological diversity. Here, we review ontogenetic changes in the cartilaginous nasal capsule of mammals, and make new...
Article
Objectives The aim of the present study is to broaden our knowledge of the ontogeny of cranial base cartilaginous joints in primates. Materials and Methods A cross-sectional age sample of 66 specimens from four platyrrhine and three strepsirrhine genera were studied using microcomputed tomography, histology, and immunohistochemistry. Specimens wer...
Conference Paper
The fibroblast growth factor and receptor system (FGF/FGFR) regulates cell proliferation and differentiation for various tissue types in the body – including osseous tissue. Mutations in the FGFR2 gene are associated with craniosynostosis, leading to alterations of the shape of bones in the head and face. We have previously demonstrated premature f...
Conference Paper
Mutations in the FGF/FGFR2 gene result in the premature fusion of fibrous and cartilaginous joints in the skull. This results in profound morphological changes in the skulls of both humans and mice with these mutations. Previous studies have indicated that morphological integration of the skull is expected to become more pronounced in dysmorphic sy...
Presentation
Most primates are characterized by orbital convergence, the displacement of the orbits toward the rostral midline. In platyrrhine primates and tarsiers, this convergence is so extreme that orbits meet in the midline at the apical interorbital septum. This produces a spatial separation of the anterior cranial fossa and the nasal cavity. The olfactor...
Poster
Primate auditory structures are morphologically indicative of taxonomy and phylogeny. The tympanic cavity houses the three articulating ear ossicles: malleus, incus, and stapes. The ossicles amplify sound waves from mechanical vibrations to the cochlea, a sensory organ, where it can then be interpreted by the organism. All primates are characterize...
Article
Natural and artificial endocasts have been used for decades to enable researchers to visualize the endocranial space and approximate the morphology of internal soft tissue structures. Producing an endocast of the newborn primate skull is made difficult by the large fontanelle spaces between growing bones. As there is no definitive endocranial bound...
Conference Paper
The mammalian feeding system is made up of multiple components that influence facial variation, including the masticatory muscles, bony jaw apparatus, and teeth. However, it is not fully understood how the development of these components are coordinated and are impacted by life history and diet. Bats are the only mammals that continue to nurse unti...
Article
Previous studies have demonstrated a link between subarcuate fossa size and locomotor behavior in primates. This fossa contains the petrosal portion of the paraflocculus, a portion of the brain associated with mobility and motor control. Studies have determined that the size of the fossa is larger in primate species that have more complex forms of...
Article
Our current knowledge of brain growth in non-human primates is based on comparisons of brain weights in cadaveric newborns compared to adults. Previous work has revealed most strepsirrhine primates (e.g., lemurs and lorises) defer much of their brain growth to the postnatal timeframe. No studies have examined brain growth across postnatal ages, to...
Presentation
Postorbital septation is a character that unites haplorhine primates. As a result, evidence of postorbital septation is expected for fossil primates that may be ancestral to both modern tarsiers and modern anthropoids. Our previous work on newborn primates has indicated that postorbital septation in tarsiers is secondary to growth of their large ey...
Article
Full-text available
Diffusible iodine-based contrast-enhanced computed tomography (diceCT) has emerged as a viable tool for discriminating soft tissues in serial CT slices, which can then be used for three-dimensional analysis. This technique has some potential to supplant histology as a tool for identification of body tissues. Here, we studied the head of an adult fr...
Article
Full-text available
Our knowledge of nasal cavity anatomy has grown considerably with the advent of micro‐computed tomography (CT). More recently, a technique called diffusible iodine‐based contrast‐enhanced CT (diceCT) has rendered it possible to study nasal soft tissues. Using diceCT and histology, we aim to (a) explore the utility of these techniques for inferring...
Article
Full-text available
The sphenoid bone articulates with multiple basicranial, facial, and calvarial bones, and in humans its synchondroses are known to contribute to elongation of the skull base and possibly to cranial base angulation. Its early development (embryological, early fetal) has frequently been studied in a comparative context. However, the perinatal events...
Article
Full-text available
The analysis of textiles as trace evidence is an important area of focus in the field of forensic science, because enhanced understanding of the decomposition of textiles may point to more accurate methods for estimating the post mortem interval (PMI) of remains found in association with these materials. This research is especially crucial in areas...
Article
Full-text available
Living primates show a complex trend in reduction of nasal cavity spaces and structures due to moderate to severe constraint on interorbital breadth. Here we describe the ontogeny of the posterior end of the primate cartilaginous nasal capsule, the thimble shaped posterior nasal cupula (PNC), which surrounds the hind end of the olfactory region. We...
Article
Full-text available
Cranial synchondroses are cartilaginous joints between basicranial bones or between basicranial bones and septal cartilage, and have been implicated as having a potential active role in determining craniofacial form. However, few studies have examined them histologically. Using histological and immunohistochemical methods, we examined all basicrani...
Article
Full-text available
Ectotympanic bone morphology is commonly used as a large‐scale phylogenetic indicator across primates. Less well‐understood is the intraspecies variation in this characteristic and the dynamic ways in which it affects and is affected by overall basicranial shape. This study attempts to clarify relationships between the external ear canal and basicr...
Article
Full-text available
Nasal turbinals, delicate and complex bones of the nasal cavity that support respiratory or olfactory mucosa (OM), are now easily studied using high resolution micro‐computed tomography (μ‐CT). Standard μ‐CT currently lacks the capacity to identify OM or other mucosa types without additional radio‐opaque staining techniques. However, even unstained...
Article
Full-text available
The range of cranial morphology seen in domestic dogs (Canis lupus familiaris) is a direct result of thousands of years of selective breeding. This article is the first to investigate how selection for reduced faces in brachycephalic dogs impacted the neuroanatomy of the canine brain through the analysis of endocasts. Previous research has demonstr...
Article
It has been hypothesized that the human sphenoid bone is uniquely truncated, which in turn contributes to a reduction of forward midfacial growth. If so, the perinatal fusion of the intrasphenoidal synchondrosis (ISS) in humans may contribute to midfacial reduction. However, there is a lack of detailed knowledge on sphenoid development of non‐human...
Article
The purpose of this study is to describe basicranial and brain growth in sub‐adult cotton‐top tamarin ( Saguinus oedipus ) and compare their growth with greater bushbabies ( Otolemur spp.) based on computed tomographic (CT) imaging. Bilateral synchondroses (alisphenoid‐basisphenoid synchrondrosis, ABS) have been identified within the middle cranial...
Article
The basicranium of anthropoid primates is more flexed than in lemurs and lorises (strepsirrhines), which has implications for orientation of facial growth. Differential growth among cranial synchondroses is one suggested mechanism for variation in basicranial development. In this study, we measured length of bony elements of the cranial base using...
Article
Domestic dogs ( Canis lupus familiaris ) exhibit a wide range of cranial morphologies. This diversity in skull shape is largely the result of modern selective breeding practices. This project investigates the impact of selection for facial reduction on canine neuroanatomy. Previous research has indicated that the breeding for reduced faces in dogs...
Book
Cambridge Core - Evolutionary Biology - Skeletal Anatomy of the Newborn Primate - by Timothy D. Smith
Article
Full-text available
Previous descriptive work on deciduous dentition of primates has focused disproportionately on great apes and humans. To address this bias in the literature, we studied 131 subadult nonhominoid specimens (including 110 newborns) describing deciduous tooth morphology and assessing maximum hydroxyapatite density (MHD). All specimens were CT scanned a...
Article
"Macrosmatic" mammals have dedicated olfactory regions within their nasal cavity and segregated airstreams for olfaction and respiratory air-conditioning. Here we examine the 3D distribution of olfactory surface area (SA) and nasal airflow patterns in the pygmy slow loris (Nycticebus pygmaeus) to determine the degree to which their complex nasal ca...
Article
Kabuki syndrome 1 (KS1) is a Mendelian disorder of the epigenetic machinery caused by mutations in the gene encoding KMT2D, which methylates lysine 4 on histone H3 (H3K4). KS1 is characterized by intellectual disability, postnatal growth retardation, and distinct craniofacial dysmorphisms. A mouse model (Kmt2d+/bGeo) exhibits features of the human...
Article
Full-text available
Through artificial selection, humans have altered the morphology of domestic dogs and created the range of morphological traits present in the diverse dog breeds seen today. This article tests how artificial breeding for extreme facial reduction affects the craniodental complex in domestic dogs (Canis lupus familiaris). These brachycephalic dog bre...
Preprint
Full-text available
Kabuki syndrome 1 (KS1) is a Mendelian disorder of the epigenetic machinery caused by mutations in the gene encoding KMT2D, which methylates lysine 4 on histone H3 (H3K4). KS1 is characterized by intellectual disability, postnatal growth retardation, and distinct craniofacial dysmorphisms. A mouse model ( Kmt2d +/βGeo ) exhibits features of the hum...
Article
Ectotympanic bone morphology is a classic characteristic used to differentiate primates and identify fossil affinities, often depicted as either a ring or tube falling along strict phylogenetic lines. Though ectotympanic bone morphology has been frequently cited in academic literature, the way in which this bone lengthens within and across taxa is...
Article
Recently, we described bilateral synchondroses (alisphenoid‐basisphenoid synchondrosis, ABS) within the middle cranial fossa of strepsirrhine primates (lemurs, bushbabies, lorises). These exist as growth centers in late fetal or newborn strepsirrhines, whereas in similarly‐aged monkeys, they are not present. It is unclear whether these joints are c...
Article
Recent work on development of primates indicates the body develops in a highly modular manner; that is, different systems (e.g., neural versus muscular) have different rates of growth and may be influenced by independent selective pressures. Here, we investigate age‐related changes in limb muscle mass, limb bone length, as well as the relative stat...
Poster
Full-text available
Abstract: Trans-Atlantic slave trade migrations instigated processes of systematic rupture that led to the widespread geographical dispersion of African descent peoples. The skeletal diversity observed in African descendants is reflective of this history, and its study through geometric morphometrics provides a useful means of tracing migration-bou...
Conference Paper
Full-text available
Physiological stress is affected by numerous biocultural factors and has a high impact on developmental stability, producing biomarkers such as fluctuating asymmetry. Analyzing differences in the pattern and degree of stress markers in a population can yield information about the overall health of a population and differences in exposure among subg...
Article
Tooth size of newborn primates negatively correlates with gestational length, and also varies with diet. In this study, we examine the effects of these variables on hydroxyapatite (HA) density of the mandibular teeth in newborn primates. Forty‐eight newborn primates (24 species) were microCT scanned at 70 kVp/114 μA at a resolution of 20.5 μm. From...
Article
The sphenoethmoidal synchondrosis or prespheno‐septal synchondrosis (PSept) is a chondrocranial joint_that does not fuse in humans until age six or seven and is suggested to fuse near birth in non‐human primates. As such, the PSept may play a role in variation in basicranial angulation or midfacial protrusion. Here, we assess indicators of cartilag...
Poster
Full-text available
Abstract: The skeletal framework for the vocal tract in non-human primates provides a functional model for interpreting differences in vocal behavior. Previous studies have shown that ontogeny substantially influences vocal tract morphology, but this work has focused primarily on the position of the larynx rather than on the structure of the hyoid...
Article
Basicranial synchondroses are crucial for elongation of the length of the skull and may contribute to basicranial angulation. Most studies have focused on midline synchondroses (e.g., sphenooccipital). More recently, however, evidence has emerged suggesting an important role for lateral basicranial regions in maintaining the functional spatial rela...
Article
Through artificial selection, humans have altered the morphology of domestic dogs and produced the broad range of morphological variation seen in modern dog breeds. The purpose of this study was to analyze the effects of artificial selection for short faces in domestic dogs ( Canis lupus familiaris ). The morphological characteristics associated wi...
Article
Objectives: Dental eruption schedules have been closely linked to life history variables. Here we examine a sample of 50 perinatal primates (28 species) to determine whether life history traits correlate with relative tooth size at birth. Materials and methods: Newborn primates were studied using serial histological sectioning. Volumes of decidu...
Article
Full-text available
Integration of the sphenoid and ethmoid bones during early postnatal development is poorly described in the literature. A uniquely prolonged patency of sphenoethmoidal synchondrosis, or prespheno-septal synchondrosis (PSept) has been attributed to humans. However, the sphenoethmoidal junction has not been studied using a comparative primate sample....
Poster
Full-text available
Abstract: Vocal tract morphology varies throughout non-human primate taxa, directly impacting sound productions that are unique both to species and to individuals. Previous studies have compared whole vocal apparatuses or hyoids in order to contextualize the vocal tract in relation to body size, or the morphological differences across taxa. Howeve...
Article
Traditional nonmetric methods of ancestry assessment posit orbital rim shape varies among ancestral groups. This pilot study uses morphometric analysis of 3D orbital variation to test discrimination among individuals of primarily European, African, and Asian ancestry. Although the size and nature of the sample analyzed limit inferences for other sa...
Chapter
Bone is the tissue most frequently recovered archaeologically and is the material most commonly studied by biological anthropologists, who are interested in how skeletons change shape during growth and across evolutionary time. This volume brings together a range of contemporary studies of bone growth and development to highlight how cross-discipli...
Article
We introduce a new method to geometrically reconstruct eye volume and placement in small-bodied primates based on the three-dimensional contour of the intraorbital surface. We validate it using seven species of living primates, with dry skulls and wet dissections, and test its application on seven species of Paleogene fossils of interest. The metho...
Article
Bony structure of the postorbital region is a key trait distinguishing major clades of primates. Strepsirrhines share a postorbital bar, and anthropoids share a complete postorbital septum. At issue is whether the partial postorbital septum of tarsiers unites living tarsiers more closely with anthropoids than with certain large-eyed Eocene fossils....
Article
Living primates have relatively large eyes and support orbital tissues with a postorbital bar (POB) and/or septum. Some mammals with large eyes lack a POB, and presumably rely on soft tissues. Here, we examined the orbits of four species of strepsirrhine primates (Galagidae, Cheirogaleidae) and three species of fruit bats (Pteropodidae). Microdisse...
Article
The nasal cavity of strepsirrhine primates (lemurs and lorises) has the most primitive arrangement of extant primates. In nocturnal species, the numerous turbinals of the ethmoid bear a large surface area of olfactory mucosa (OM). In the present study, we examine turbinal development in four genera of diurnal or cathemeral lemuriformes. In addition...
Article
The sphenoid is often considered to be the keystone of the skull. Many cranial traits are used to distinguish phylogenetic groups among primates, and the sphenoid is an influential element in these differences. Because of the importance of the sphenoid for the integration of face, vault, and cranial base, we expected that many of these traits would...
Article
The nasal cavity of strepsirrhine primates (lemurs and lorises) has the most primitive arrangement of extant primates. The numerous turbinals of the ethmoid bear a large surface area of olfactory mucosa (OM), although to date this has only been carefully studied in smaller nocturnal species. In the present study, we examine turbinal development in...
Conference Paper
Mammalian crania demonstrate conserved patterns of morphological integration and simultaneously possess varying magnitudes (degrees) of integration. Thus, it has been posited that plasticity in magnitudes of integration allow for adaptive diversification, while conserved patterns of integration reflect stabilizing selection within the population. T...
Article
In this report we provide data on dental eruption and tooth germ maturation at birth in a large sample constituting the broadest array of non-human primates studied to date. Over 100 perinatal primates, obtained from natural captive deaths, were screened for characteristics indicating premature birth, and were subsequently studied using a combinati...
Article
As a component of the primate shoulder, the clavicle is expected to reflect locomotor adaptations. Whereas previous work has generally focused on clavicular length and torsion, the shape of clavicular curvature may better distinguish taxa and provide additional information about upper limb use in locomotion. This study uses three-dimensional geomet...
Article
The technique of forensic facial approximation, or reconstruction, is one of many facets of the field of mummy studies. Although far from a rigorous scientific technique, evidence-based visualization of antemortem appearance may supplement radiological, chemical, histological, and epidemiological studies of ancient remains. Published guidelines exi...
Conference Paper
Full-text available
The tarsier has a characteristic bell-shaped dental arcade, wherein the postcanine dentition are displaced laterally, creating a wide posterior palate. This unique shape has been associated with the expansion of the orbital floors due to hypertrophied eyeballs in Tarsius and, to a lesser extent, in Aotus (Rossie et al., 2006; Rosenberger, 2011). On...
Article
Three-dimensional reconstructions of imaging data are an increasingly common approach for studying anatomical structure. However, certain aspects of anatomy, including microscopic structure and differentiating tissue types, continue to benefit from traditional histological analyses. We present here a detailed methodology for combining data from mic...
Article
Formative assessment has been shown to improve medical student performance and retention, but many learners lack access to formative assessments because faculty members have limited time to create such resources, and acquiring existing commercial review banks is expensive. In response, we developed a collaborative learning platform for medical stud...
Article
Midfacial reduction in primates has been explained as a byproduct of other growth patterns, especially the convergent orbits. This is at once an evolutionary and developmental explanation for relatively short snouts in most modern primates. Here, we use histological sections of perinatal nonhuman primates (tamarin, tarsier, loris) to investigate ho...
Article
Full-text available
Neuroanatomic phenotypes are often assessed using volumetric analysis. Although powerful and versatile, this approach is limited in that it is unable to quantify changes in shape, to describe how regions are interrelated, or to determine whether changes in size are global or local. Statistical shape analysis using coordinate data from biologically...
Article
The purpose of this study was to test for differences in brain shape among children with cleft palate only (n = 22), children with cleft lip and palate (n = 35), and controls (n = 39) using Euclidean distance matrix analysis. Sixteen percent of interlandmark distances differed between children with cleft palate only and controls, 10% differed betwe...
Article
Full-text available
Unlabelled: Forensic clinicians are routinely asked to estimate the age of cutaneous bruises. Unfortunately, existing research on noninvasive methods to date bruises has been mostly limited to relatively small, homogeneous samples or cross-sectional designs. Purpose: The purpose of this prospective, foundational study was to examine change in br...
Article
The widespread availability of high resolution computed tomography (CT) provides an unprecedented ability to view skeletal material of minute size, including subadult specimens. Here, we describe a novel approach of coregistering microCT scans of late fetal nonhuman primates with serial histological sections. We use three primates (loris, tarsier,...
Article
Extant primates are notable for their relatively convergent, or forward‐facing orbits, although some other mammals exhibit similarities, such as a postorbital bar supporting the eye laterally. Here, we use a novel approach of co‐registering micro‐computed tomography (CT) scans of late fetal nonhuman primates with serial histological sections, to in...
Article
Among primates, partial or complete posterior closure of the orbit has been widely accepted as a shared derived characteristic justifying an exclusive tarsier-anthropoid clade, while some regard the tarsier lateral orbit as an elaborated postorbital bar (POB). To test these competing hypotheses while minimizing the confounding effect of tarsier orb...
Article
Among primates, partial or complete posterior closure of the orbit has been widely accepted as a shared derived characteristic justifying an exclusive tarsier-anthropoid clade, while some regard the tarsier lateral orbit as an elaborated postorbital bar (POB). To test these competing hypotheses while minimizing the confounding effect of tarsier orb...
Article
Full-text available
Introduction and hypothesis: The objective of this study was to determine whether the three-dimensional shape of the bony pelvis differs between women with and without pelvic floor disorders (PFDs). We predict that the levator ani attachment points for the pelvic floor are further displaced from one another in affected relative to unaffected women...