Anatomy

Retinal anatomy of the New Zealand kiwi: Structural traits consistent with their nocturnal behavior
Kiwi (Apteryx spp.) have a visual system unlike that of other nocturnal birds, and have specializations to their auditory, olfactory and tactile systems. Eye size, binocular visual fields and visual brain centers in kiwi are proportionally the smallest yet recorded among birds. Given the many unique features of the kiwi visual system, we examined the laminar organization of the kiwi retina to d...


Post-coital genital injury in healthy women: A review
Female genital injury following penile sexual intercourse in healthy women is a matter of importance and debate in many parts of society. However, the literature on the subject is sparse. There are a few studies regarding minor injury that does not require treatment in adult, pre-menopausal women, a single study of adolescent women, and none regarding post-menopausal women. Larger lesions requi...
Development of the lateral plate mesoderm in medaka Oryzias latipes and Nile tilapia Oreochromis niloticus: insight into the diversification of pelvic fin position
The position of the pelvic fins among teleost fishes has tended to shift rostrally during evolution. This positional shift seems to have led to the diversification of feeding behavior and allowed adaptation to new environments. To understand the developmental basis of this shift in pelvic fin position among teleosts, we investigated the embryonic development of the lateral plate mesoderm, which...


Pyramidal lobe of the thyroid gland and the thyroglossal duct remnant: a study using human fetal sections
To investigate developmental changes in the thyroglossal duct, we observed serial sagittal sections of 8 embryos (crown-rump length (CRL) 6-12mm; approximately 5-6 weeks of gestation) as well as serial horizontal or cross-sections of 70 embryos and fetuses (CRL 15-110mm; 6-15 weeks). In the sagittal sections, the thyroglossal duct was identified as a small sheet or mass of relatively large cell...
Occlusal load distribution through the cortical and trabecular bone of the human mid-facial skeleton in natural dentition: A three-dimensional finite element study
Understanding of the occlusal load distribution through the mid-facial skeleton in natural dentition is essential because alterations in magnitude and/or direction of occlusal forces may cause remarkable changes in cortical and trabecular bone structure. Previous analyses by strain gauge technique, photoelastic and, more recently, finite element (FE) methods provided no direct evidence for occl...


Functional morphology of the Neandertal scapular glenoid fossa
Neandertals and Homo sapiens are known to differ in scapular glenoid fossa morphology. Functional explanations may be appropriate for certain aspects of glenoid fossa morphology; however other factors – e.g., allometry, evolutionary development – must be addressed before functional morphology is considered. Using three dimensional geometric morphometrics, shape of the scapular glenoid fossa...
Morphometry, geometry, function, and the future
The proliferation of geometric morphometrics in biological anthropology and more broadly throughout the biological sciences has resulted in a multitude of studies that adopt landmark-based approaches for addressing a variety of questions in evolutionary morphology. In some cases, particularly in the realm of systematics, the fit between research question and analytical design is quite good. Fun...

Functional geometric morphometric analysis of masticatory system ontogeny in papionin primates
The three-dimensional configuration of the primate masticatory system is constrained by the need to maximize bite forces while avoiding distraction of the temporomandibular joint (TMJ). Within these bounds, shape variation has predictable effects on functional capacities such as mechanical advantage and gape. In this study, geometric morphometric analysis is used to investigate the ontogeny of ...
Exploring Eucladoceros ecomorphology using geometric morphometrics
An increasingly common method for reconstructing paleoenvironmental parameters of hominin sites is ecological functional morphology (ecomorphology). This study provides a geometric morphometric study of cervid rearlimb morphology as it relates to phylogeny, size, and ecomorphology. These methods are then applied to an extinct Pleistocene cervid, Eucladoceros, which is found in some of the earli...

Pelvic form and locomotor adaptation in strepsirrhine primates
The pelvic girdle is a complex structure with a critical role in locomotion, but efforts to model the mechanical effects of locomotion on its shape remain difficult. Traditional approaches to understanding form and function include univariate adaptive hypothesis-testing derived from mechanical models. Geometric morphometric (GM) methods can yield novel insight into overall three-dimensional sha...
Geometric morphometrics of hominoid infraspinous fossa shape
Recent discoveries of early hominin scapulae from Ethiopia (Dikika, Woranso-Mille) and South Africa (Malapa) have motivated new examinations of the relationship between scapular morphology and locomotor function. In particular, infraspinous fossa shape has been shown to significantly differ among hominoids. However, this region presents relatively few homologous landmarks, such that traditional...

The relation between geometric morphometrics and functional morphology, as explored by Procrustes interpretation of individual shape measures pertinent to function
A frequent concern in today's functional morphology is the relation of a landmark configuration to some a priori index or suite of indices of function. When an index is itself a generic mathematical or biomechanical shape function of landmark locations, meaning a dimensionless expression that has a nonzero gradient everywhere in the feasible region of morphospace, the question becomes sharper: ...
Form, function, and geometric morphometrics
Geometric morphometrics (GM) has increasingly become an important tool in assessing and studying shape variation in a wide variety of taxa. While the GM toolkit has unparalleled power to quantify shape, its uses in studies of functional morphology have been questioned. Here we assess the state of the field of GM and provide an overview of the techniques available to assess shape, including aspe...
Covariation in the human masticatory apparatus
Many studies have described shape variation of the modern human cranium in relation to subsistence, but patterns of covariation within the masticatory apparatus (MA) remain largely unexplored. The patterns and intensity of shape covariation, and how this is related to diet, is essential for understanding the evolution of functional masticatory adaptations of the human cranium. Within a worldwid...
Three-dimensional geometric morphometric analysis of talar morphology in extant gorilla taxa from highland and lowland habitats
Western gorillas (Gorilla gorilla) are known to climb significantly more often than eastern gorillas (Gorilla beringei), a behavioral distinction attributable to major differences in their respective habitats (i.e., highland vs lowland). Genetic evidence suggests that the lineages leading to these taxa began diverging from one another between approximately 1 and 3 million years ago. Thus, goril...