Alana C Sharp

Verified

Alana verified their affiliation via an institutional email.

Learn more

Verified

Alana verified their affiliation via an institutional email.

Learn more

• PhD
• Senior Lecturer at University of Liverpool

The crania of leporid lagomorphs are uniquely fenestrated, including the posterior cranial bones and the lateral portion of the maxilla. The functional significance of the highly fenestrated rostrum has received considerably little attention, despite being absent in other mammalian herbivores with a long rostrum. This unique feature is of particula...

Bats are unique among mammals for evolving powered flight. However, very little data are available on the muscle properties and architecture of bat flight muscles. Diffusible iodine contrast‐enhanced computed tomography (diceCT) is an established tool for 3D visualisation of anatomy and is becoming a more readily accessible and widely used techniqu...

Artiodactyls exhibit a striking diversity of the cervical vertebral column in terms of length and overall mobility. Using finite element analysis, this study explores the morphology at the cervico‐thoracic boundary and its performance under loads in artiodactyls with different habitual neck postures and body sizes. The first thoracic vertebra of 36...

Cranial sutures are fibrocellular joints between the skull bones that are progressively replaced with bone throughout ontogeny, facilitating growth and cranial shape change. This transition from soft tissue to bone is reflected in the biomechanical properties of the craniofacial complex. However, the mechanical significance of cranial sutures has o...

Although a functional relationship between bone structure and mastication has been shown in some regions of the rabbit skull, the biomechanics of the whole cranium during mastication have yet to be fully explored. In terms of cranial biomechanics, the rabbit is a particularly interesting species due to its uniquely fenestrated rostrum, the mechanic...

The crania of leporid lagomorphs are uniquely fenestrated, including the posterior cranial bones and the lateral portion of the maxilla. The functional significance of the highly fenestrated rostrum has received considerably little attention, despite being absent in other mammalian herbivores with a long rostrum. This unique feature is of particula...

Natural dentition commonly fails, leading to dental implant replacements. Current dentistry utilises standardised implants lacking the root morphology of the posterior dentition. However, the functional significance of tooth root morphology is little understood; studies are lacking despite strong evidence of tooth root variation between individuals...

Sutures are mesenchymal joints positioned at the interface between adjacent cranial bones. Their role includes establishing craniofacial shape via intramembranous bone growth, permitting the rapid brain expansion observed within the first year of life and facilitating skull deformation during parturition. However, the mechanical function of sutures...

The skull of modern leporid lagomorphs (rabbits and hares) is highly modified from other mammals, including their closest relatives the pikas (Ochotonidae), with a suite of unique features including fenestration of the rostrum and posterior cranial bones, a pronounced ventral flexion of the facial region, and an intracranial joint that suggests som...

Lagomorphs are remarkably conserved over evolutionary time. The largest morphological distinction is between the two extant families: Ochotonidae (pikas) and Leporidae (rabbits and hares). Palaeolagus is an Eocene/Oligocene early leporid, with a cranium that is morphologically ochotonid-like posteriorly and leporid-like anteriorly. Here, we use f...

Background The leporid lagomorphs (rabbits and hares) are adapted to running and leaping (some more than others) and consequently have unique anatomical features that distinguish them from ochotonid lagomorphs (pikas) and from their rodent relatives. Two traits that have received some attention are fenestration of the lateral wall of the maxilla an...

The crania of leporid lagomorphs are uniquely fenestrated, including the posterior cranial bones and the lateral portion of the maxilla. The posterior fenestrations have been linked to locomotion; however, the functional significance of the highly fenestrated rostrum has received considerably less attention and the mechanical function is still deba...

Craniofacial sutures are unique joints consisting of soft connective tissues between the skull bones. They are important sites for bone growth during development, and for absorption of mechanical stress, but their mechanical function is not well understood. Craniosynostosis is a congenital condition causing premature fusion of one or more cranial s...

Due to their global distribution, invasive history, and unique characteristics, European rabbits are recognizable almost anywhere on our planet. Although they are members of a much larger group of living and extinct mammals [Mammalia, Lagomorpha (rabbits, hares, and pikas)], the group is often characterized by several well-known genera (e.g., Oryct...

Background Muscular variations are potentially symptomatic and may complicate imaging interpretation. Intrinsic foot musculature and extrinsic tendon insertion variations are common. Distinct supernumerary muscles are rare. We report a novel anomalous intrinsic foot muscle on the medial longitudinal arch. Case presentation An accessory muscle was...

Cranial morphology in lepidosaurs is highly disparate and characterized by the frequent loss or reduction of bony elements. In varanids and geckos, the loss of the postorbital bar is associated with changes in skull shape, but the mechanical principles underlying this variation remain poorly understood. Here, we seek to determine how the overall cr...

Little is known about how the large brains of mammals are accommodated into the dazzling diversity of their skulls. It has been suggested that brain shape is influenced by relative brain size, that it evolves or develops according to extrinsic or intrinsic mechanical constraints, and that its shape can provide insights into its proportions and func...

The amount and value of digital resources available for anatomical education and research is continuously growing with more advanced imaging technologies. Computed tomography (CT) and magnetic resonance imaging (MRI) have been used extensively in anatomy to build 3D models and compare digital dissection methods with traditional dissection. Diffusib...

Little is known about how the large brains of mammals are accommodated into the dazzling diversity of their skulls. It has been suggested that brain shape is influenced by relative brain size, that it evolves or develops according to extrinsic or intrinsic mechanical constraints, and that its shape can provide insights into its proportions and func...

The chondrocranium is the cartilage component of the vertebrate braincase. Among jawed vertebrates it varies greatly in structure, mineralisation, and in the extent to which it is replaced by bone during development. In mammals, birds, and some bony fish, most of the chondrocranium is replaced by bone whereas in lizards, amphibians, and chondrichth...

Paleontologists and paleoanthropologists have long debated relationships between cranial morphology and diet in a broad diversity of organisms. While the presence of larger temporalis muscle attachment area (via the presence of sagittal crests) in carnivorans is correlated with durophagy (i.e. hard-object feeding), many primates with similar morpho...

Osteoderms are hard tissues embedded in the dermis of vertebrates and have been suggested to be formed from several different mineralized regions. However, their nano architecture and micro mechanical properties had not been fully characterized. Here, using electron microscopy, µ-CT, atomic force microscopy and finite element simulation, an in-dept...

Background: Within-species skull shape variation of marsupial mammals is widely considered low and strongly size-dependent (allometric), possibly due to developmental constraints arising from the altricial birth of marsupials. However, species whose skulls are impacted by strong muscular stresses - particularly those produced through mastication o...

Mammals have evolved diverse craniofacial morphology to adapt to a wide range of ecological niches. The skull of modern leporid lagomorphs (rabbits and hares) is highly modified from other mammals as it is structurally specialized for providing intracranial movement, or cranial kinesis. Increasing evidence suggests that cranial kinesis, coupled wit...

Background Within-species skull shape variation of marsupial mammals is widely considered low and strongly size-dependent (allometric), possibly due to developmental constraints arising from the altricial birth of marsupials. However, species whose skulls are impacted by strong muscular stresses – particularly those produced through mastication of...

The falx cerebri and the tentorium cerebelli are two projections of the dura mater in the cranial cavity which ossify to varying degrees in some mammalian species. The idea that the ossification of these structures may be necessary to support the loads arising during feeding has been proposed and dismissed in the past, but never tested quantitative...

The falx cerebri and the tentorium cerebelli are two membranous projections of the dura mater in the cranial cavity which are ossified to varying degrees in certain mammalian species. The hypothesis that ossification of these structures may be necessary to support the loads arising during feeding has been the subject of debate, but never assessed q...

Normal cranial growth and development rely on appropriate tissue interactions. Soft tissues like the brain and eyes develop first, becoming enclosed by fibrous capsules (e.g. periosteum, dura) within which the skeletal units develop, and are maintained and shaped. However, with the exception of the jaw muscles, most biomechanical models do not take...

The role of soft tissues in skull biomechanics remains poorly understood. Not least, the chondrocranium, the portion of the braincase which persists as cartilage with varying degrees of mineralization. It also remains commonplace to overlook the biomechanical role of sutures despite evidence that they alter strain distribution. Here, we examine the...

Australia was inhabited by a diverse array of large Pleistocene vertebrates including the last representatives of the family Diprotodontidae. The best-known members of this group of quadrupedal herbivores are the rhino-sized Diprotodon optatum and hippo-like Zygomaturus trilobus. By comparison, Nototherium inerme, although first described in 1845,...

Leaellynasaura amicagraphica was a small, bipedal, herbivorous Australian dinosaur that lived about 106 million years ago within the Antarctic Circle of that time. Although three cranial elements of Leaellynasaura exist, they are too delicate to be removed from the rock in which they are embedded. Synchrotron computed tomography (CT) provides a uni...

The lizard species Salvator 'Tupinambis' merianae and Varanus ornatus evolved independently in South America and Africa but share similar ecology and feeding behaviour, despite having notable differences in their skull structure. Tupinambis has a compact, relatively short and wide snout, whereas that of Varanus is more slender and narrow. In additi...

The lizard species Salvator ‘ Tupinambis ’ merianae and Varanus ornatus evolved independently in South America and Africa but share similar ecology and feeding behaviour, despite having notable differences in their skull structure. Tupinambis has a compact, relatively short and wide snout, whereas that of Varanus is more slender and narrow. In addi...

Introduction The names Abductor hallucis (AH) and Abductor digiti minimi (ADM) suggest abduction as a primary function. This has been questioned. Instead, AH is proposed to deepen the foot arch, and a sling of fascia around the muscle belly has been reported, changing its direction of pull. We investigated the structures, attachments and fascial re...

Sharp, A.C. 2016. A quantitative comparative analysis of the size of the frontoparietal sinuses and brain in vombatiform marsupials. Memoirs of Museum Victoria 74: 331–342. Cranial sinuses result from the resorption and deposition of bone in response to biomechanical stress during a process known as pneumatisation. The morphology of a pneumatic b...

Trusler, P.W. and Sharp, A.C. 2016. Description of new cranial material of Propalorchestes (Marsupialia: Palorchestidae) from the Middle Miocene Camfield Beds, Northern Territory, Australia. Memoirs of Museum Victoria 74: 291–324. Additional material referable to Propalorchestes novaculacephalus from the middle Miocene Camfield Beds is described....

Multibody dynamics is a powerful modelling tool which is becoming increasingly popular for the simulation and analysis of jaw muscle function. It can be used to apply varying muscle forces to predict joint and bite forces during static and dynamic motions as well as investigating muscle activation patterns and how they vary to produce specific move...

The giant extinct marsupial Diprotodon optatum has unusual skull morphology for an animal of its size, consisting of very thin bone and large cranial sinuses that occupy most of the internal cranial space. The function of these sinuses is unknown as there are no living marsupial analogues. The finite element method was applied to identify areas of...

Marsupial herbivores exhibit a wide variety of skull shapes and sizes to exploit different ecological niches. Several studies on teeth, dentaries, and jaw adductor muscles indicate that marsupial herbivores exhibit different specializations for grazing and browsing. No studies, however, have examined the skulls of marsupial herbivores to determine...

Wombats are unique among marsupials in having one pair of upper incisors, and hypsodont molars for processing tough, abrasive vegetation. Of the three extant species, the most abundant, the common wombat (Vombatus ursinus), has had the least attention in terms of masticatory muscle morphology, and has never been thoroughly described. Using MRI and...

Cranial sinuses result from the resorption and deposition of bone in response to biomechanical stress during a process known as pneumatisation. The morphology of a pneumatic bone represents an optimisation between strength and being light weight. The presence of very large sinuses has been described in a number of extinct marsupial megafauna, the s...

The morphology and arrangement of the jaw adductor muscles in vertebrates reflects masticatory style and feeding processes, diet and ecology. However, gross muscle anatomy is rarely preserved in fossils and is, therefore, heavily dependent on reconstructions. An undeformed skull of the extinct marsupial, Diprotodon optatum, recovered from Pleistoce...