The skull of the semi-aquatic neotropical lizard Echinosaura horrida (Gymnophthalmidae: Cercosaurinae) reveals new synapomorphies within Gymnophthalmoidea.

The rough teiid or water cork lizard (Echinosaura horrida) is a small reptile from Colombia and Ecuador placed in a genus that contains eight species and well-known phylogenetic relationships. Here we provide a detailed description and illustrations, bone by bone, of its skull, while we discussed its intraspecific variation by comparing high-resolution computed tomography data from two specimens and the variation within the genus by including previously published data from Echinosaura fischerorum. This allowed to propose putative diagnostic character states for Echinosaura horrida and synapomorphies for Echinosaura. In addition, our discussion includes broader comparisons of new character transformations of the jugal, vomer, orbitosphenoid, and hyoid. These characters are important for diagnosing clades at different levels of the Gymnophthalmoidea phylogeny.

A novel perspective of calvarial development: the cranial morphogenesis and differentiation regulated by dura mater.

There are lasting concerns on calvarial development because cranium not only accommodates the growing brain, but also safeguards it from exogenous strikes. In the past decades, most studies attributed the dynamic expansion and remodeling of cranium to the proliferation of osteoprecursors in cranial primordium, and the proliferation of osteoprogenitors at the osteogenic front of cranial suture mesenchyme. Further investigations identified series genes expressed in suture mesenchymal cells as the markers of the progenitors, precursors and postnatal stem cells in cranium. However, similar to many other organs, it is suggested that the reciprocal interactions among different tissues also play essential roles in calvarial development. Actually, there are increasing evidence indicating that dura mater (DM) is indispensable for the calvarial morphogenesis and osteogenesis by secreting multiple growth factors, cytokines and extracellular matrix (ECM). Thus, in this review, we first briefly introduce the development of cranium, suture and DM, and then, comprehensively summarize the latest studies exploring the involvement of ECM in DM and cranium development. Eventually, we discussed the reciprocal interactions between calvarium and DM in calvarial development. Actually, our review provides a novel perspective for cranium development by integrating previous classical researches with a spotlight on the mutual interplay between the developing DM and cranium.

Occipital-synarcual joint mobility in ratfishes (Chimaeridae) and its possible adaptive role.

The neurocranial elevation generated by axial muscles is widespread among aquatic gnathostomes. The mechanism has two functions: first, it contributes to the orientation of the mouth gape, and second, it is involved in suction feeding. To provide such mobility, anatomical specialization of the anterior part of the vertebral column has evolved in many fish species. In modern chimaeras, the anterior part of the vertebral column develops into the synarcual. Possible biological roles of the occipital-synarcual joint have not been discussed before. Dissections of the head of two species of ratfishes (Chimaera monstrosa and Chimaera phantasma) confirmed the heterocoely of the articulation surface between the synarcual and the neurocranium, indicating the possibility of movements in the sagittal and frontal planes. Muscles capable of controlling the movements of the neurocranium were described. The m. epaxialis is capable of elevating the head, the m. coracomandibularis is capable of lowering it if the mandible is anchored by the adductor. Lateral flexion is performed by the m. lateroventralis, for which this function was proposed for the first time. The first description of the m. epaxialis profundus is given, its function is to be elucidated in the future. Manipulations with joint preparations revealed a pronounced amplitude of movement in the sagittal and frontal planes. Since chimaeras generate weak decrease in pressure in the oropharyngeal cavity when sucking in prey, we hypothesised the primary effect of neurocranial elevation, in addition to the evident lateral head mobility, is accurate prey targeting.

Male proboscis monkey cranionasal size and shape is associated with visual and acoustic signalling.

The large nose adorned by adult male proboscis monkeys is hypothesised to serve as an audiovisual signal of sexual selection. It serves as a visual signal of male quality and social status, and as an acoustic signal, through the expression of loud, low-formant nasalised calls in dense rainforests, where visibility is poor. However, it is unclear how the male proboscis monkey nasal complex, including the internal structure of the nose, plays a role in visual or acoustic signalling. Here, we use cranionasal data to assess whether large noses found in male proboscis monkeys serve visual and/or acoustic signalling functions. Our findings support a visual signalling function for male nasal enlargement through a relatively high degree of nasal aperture sexual size dimorphism, the craniofacial region to which nasal soft tissue attaches. We additionally find nasal aperture size increases beyond dental maturity among male proboscis monkeys, consistent with the visual signalling hypothesis. We show that the cranionasal region has an acoustic signalling role through pronounced nasal cavity sexual shape dimorphism, wherein male nasal cavity shape allows the expression of loud, low-formant nasalised calls. Our findings provide robust support for the male proboscis monkey nasal complex serving both visual and acoustic functions.

Human Malformed Perinatal Anthropological Crania Contribute to New Insight in the Extension of Bone Malformations in Cranial Development.

INTRODUCTION: We describe five abnormal crania which may provide more diagnostic data for assessment of abnormal crania in newborns. METHODS: Five malformed perinatal crania from the Saxtorphian Collection are described using published prenatal abnormal cranial development criteria. These malformations were compared to normal cranial development arising from the migration of neural crest cells. Visual and photographic investigations were performed. RESULTS: The malformed crania were occipital encephalocele, holoprosencephaly, anencephaly, and two without a recognizable diagnosis. The anthropological crania were malformed in the same regions as formerly observed in fetal pathology. These regions were comparable to fields formed during normal cell migration from the neural crest. This has seemingly not previously been demonstrated. One undiagnosed cranium may represent a Treacher Collins syndrome (Case 3). The other undiagnosed cranium (Case 4) could be from a scaphocephalic specimen. DISCUSSION: Sharp borderlines between malformed and non-malformed regions in cranial syndromes may enable improvement in diagnostics.

Desmoplastic fibroma of the pediatric cranium with CTNNB1 mutation: case report and literature review.

PURPOSE: Desmoplastic fibroma (DF) is an uncommon intermediate bone tumor rarely involving the skull with unidentified pathogenesis. We report the first case of pediatric temporoparietal cranial desmoplastic fibroma (DF) with a CTNNB1 gene mutation and review the previous literature. CASE PRESENTATION: A 3-year-old boy had a firm, painless mass on the right temporoparietal region for 22 months. The cranial CT scan showed isolated osteolytic destruction in the outer plate and diploe of the right temporoparietal bone. Gross total resection of the lesion and cranioplasty were performed. After that, a growing epidural hematoma was observed so another operation was performed to remove the artificial titanium plate. Postoperative pathology indicated a DF diagnosis and molecular pathology suggested a missense mutation in exon 3 of the CTNNB1 gene (c.100G > A,p.Gly34Arg). CONCLUSION: Pediatric cranial DF is rare and easy to be misdiagnosed before operation. For cranial DF, lesion resection can be performed and perioperative management should be strengthened. Mutations in the CTNNB1 gene might be one of the molecular pathologic features of DF.

Anatomical and Morphological Structure of the Skull of a Juvenile Specimen of Myotis myotis (Chiroptera: Vespertilionidae).

Few studies analyze the morphology and anatomy of the bat skull, and most of them are incomplete. Some of the difficulties stem from the fact that, in the representatives of the order Chiroptera, the interosseous sutures disappear by fusing together before active flight begins, which takes place over only a few months. This study presents a detailed morphological and anatomical description of the skull of a juvenile specimen of Myotis myotis (Borkhausen, 1797). Juvenile skulls are difficult to preserve and often incomplete. Previously inconsistent terminology related to bones, sutures, and other cranial structures was unified, which will provide insight on the distribution of each structure in both juvenile and adult specimens to be investigated. The description fill in the gaps in knowledge about the cranial structures of Myotis myotis and the representatives of the family Vespertilionidae. This will allow for precise descriptions of the skulls of bats.

What we see is what we touch? Sex estimation on the skull in virtual anthropology.

BACKGROUND: The increased use of virtual bone images in forensic anthropology requires a comprehensive study on the observational errors between dry bones and CT reconstructions. Here, we focus on the consistency of nonmetric sex estimation traits on the human skull. MATERIALS AND METHODS: We scored nine nonmetric traits on dry crania and mandibles (n = 223) of archaeological origin and their CT reconstructions. Additionally, we 3D surface scanned a subsample (n = 50) and repeated our observations. Due to the intricate anatomy of the mental eminence, we split it into two separate traits: the bilateral mental tubercles and the midsagittal mental protuberance. We provide illustrations and descriptions for both these traits. RESULTS: We obtained supreme consistency values between the CT and 3D surface modalities. The most consistent cranial traits were the glabella and the supraorbital margin, followed by the nuchal crest, zygomatic extension, mental tubercles, mental protuberance, mental eminence, mastoid process and ramus flexure, in descending order. The mental tubercles show higher consistency scores than the mental eminence and the mental protuberance. DISCUSSION: The increased interchangeability of the virtual modalities with each other as compared to the dry bone modality could be due to the lack of tactility on both the CT and surface scans. Moreover, tactility appears less essential with experience than a precise trait description. Future studies could revolve around the most consistent cranial traits, combining them with pelvic traits from a previous study, to test for accuracy.

Evaluating the muscle attachment hypothesis for sagittal cresting in Gorilla and Pongo.

Primate mandibular morphology is often associated with jaw functionality of the masticatory complex in the context of variation in diets. Recent research into the disparities between the diet and jaw functionality in male and female hominoids is inconclusive and suggests that sexual dimorphism in the mandible may be influenced by external factors such as temporalis and masseter muscle morphology, which in turn may be influenced by sexual selection. As the muscles associated with mastication (i.e., the type of chewing exhibited by primates and other mammals) encompass the mandible as well as the neurocranium, including the sagittal crest among some individuals, this study investigates sex-specific associations between regions of the mandibular ramus and neurocranium associated with mastication in a dentally mature sample of Gorilla and Pongo. A total of four cranial and mandibular variables were measured in two Gorilla taxa (Gorilla gorilla gorilla and Gorilla beringei graueri) and one Pongo taxon (Pongo pygmaeus pygmaeus) (n = 220). For all three taxa, we investigate (a) whether the degree of sexual dimorphism in cranial regions associated with sagittal cresting (sagittal crest size (SCS) and temporalis muscle attachment area (TMAA)) is proportional to the degree of mandibular ramus area (MRA) and coronoid process height (CPH) sexual dimorphism, (b) whether there are sex differences in scaling relationships between TMAA and MRA, and (c) whether there are sex differences in the strength of association between TMAA and CPH. We show that for G. g. gorilla, variables associated with sagittal cresting show higher sexual dimorphism values than our two mandibular ramus variables, which is not the case for G. b. graueri or for P. p. pygmaeus. All three taxa show similar sex-specific scaling relationships between TMAA and MRA, where for males this relationship does not diverge from isometry, and for females there is a negative allometric relationship. Our findings also show intraspecific sex differences in allometric slopes between MRA and TMAA for all three taxa. Only G. g. gorilla shows a significant association between TMAA and CPH, which is observed in both sexes. Although there are some statistical associations between the cranial and mandibular regions associated with mastication, our results show that among male gorillas and orangutans, patterns of variation in the sagittal crest, TMAA, mandibular ramus and the coronoid process cannot be explained by the muscle attachment hypothesis alone. These findings have implications surrounding the associations between social behaviour and the morphology of the craniofacial complex.

New craniodental fossils of Paranthropus robustus from Kromdraai, South Africa (2014-2017 excavations).

Since the initial discovery of Paranthropus robustus at the site of Kromdraai in 1938, the hypodigm of this species has been expanded by subsequent work at the localities of Swartkrans and Drimolen, with a few fossils also known from Cooper's D, Gondolin and Sterkfontein Member 5. Beginning in 2014, systematic excavations at Kromdraai uncovered a large and previously unknown fossiliferous area, shedding light on Units O and P in the earliest part of the site's stratigraphic sequence. The aim of this paper is to provide detailed descriptions and illustrations of 30 P. robustus craniodental specimens recovered between 2014 and 2017 within the Unit P deposits at Kromdraai. This new sample predates all prior conspecific specimens found at this site (including the holotype of P. robustus from Kromdraai, TM 1517). Its basic dental morphology dimensions and cranial features are compared in a preliminary analysis with other P. robustus samples. The P. robustus sample from Kromdraai Unit P documents previously unknown portions of the P. robustus juvenile cranium. The new dental and cranial remains aid in the exploration of potential morphological distinctions between site-specific P. robustus samples and are compared favorably in size and morphology with the small P. robustus specimens from Drimolen (e.g., DNH 7). These findings do not support the hypothesis that the specimens from Drimolen belong to a different taxonomic group. Instead, they reinforce the presence of a significant degree of sexual dimorphism within P. robustus. The Kromdraai Unit P specimens also contribute to the biodemographic profile of P. robustus. The notable prevalence of infants (i.e., juvenile individuals before the emergence of their first permanent molars) mirrors the natural mortality profiles observed in wild chimpanzees. This suggests a closer resemblance in the processes of accumulation in Kromdraai Unit P and Drimolen than at Swartkrans.

Pervasive cranial allometry at different anatomical scales and variational levels in extant armadillosAlometría craneal generalizada a diferentes escalas anatómicas y niveles de variación en armadillos actuales.

Allometry, i.e., morphological variation correlated with size, is a major pattern in organismal evolution. Since size varies both within and among species, allometry occurs at different variational levels. However, the variability of allometric patterns across levels is poorly known since its evaluation requires extensive comparative studies. Here, we implemented a 3D geometric morphometric approach to investigate cranial allometry at three main variational levels-static, ontogenetic, and evolutionary-and two anatomical scales-entire cranium and cranial subunits-based on a dense intra- and interspecific sampling of extant armadillo diversity. While allometric trajectories differ among distantly related species, they hardly do so among sister families. This suggests that phylogenetic distance plays an important role in explaining allometric divergences. Beyond trajectories, our analyses revealed pervasive allometric shape changes shared across variational levels and anatomical scales. At the entire cranial scale, craniofacial allometry (relative snout elongation and braincase reduction) is accompanied notably by variations of nuchal crests and postorbital constriction. Among cranial subunits, the distribution of allometry was highly heterogeneous, with the frontal and petrosal bones showing the most pervasive shape changes, some of which were undetected at a more global scale. Evidence of widespread and superimposed allometric variations raises questions on their determinants and anatomical correlates and demonstrates the critical role of allometry in morphological evolution.

Pictorial review of the post-operative cranium.

Imaging evaluation of the brain and cranium after cranial surgery is a routine and significant part of the workflow of a radiology department. Various normal expected findings and early and late complications are associated with the post-operative cranium. In this pictorial review, the authors describe the typical imaging features of the spectrum of various conditions associated with cranial surgery with illustrative cases. Contribution: A good knowledge and understanding of the spectrum of imaging appearances in the post-operative cranium is vital for the radiologist to accurately diagnose potential complications and distinguish them from normal post-operative findings, improving patient outcomes and guiding further treatment.

Disentangling Mechanical and Sensory Modules in the Radiation of Noctilionoid Bats.

AbstractWith diverse mechanical and sensory functions, the vertebrate cranium is a complex anatomical structure whose shifts between modularity and integration, especially in mechanical function, have been implicated in adaptive diversification. Yet how mechanical and sensory systems and their functions coevolve, as well as how their interrelationship contributes to phenotypic disparity, remain largely unexplored. To examine the modularity, integration, and evolutionary rates of sensory and mechanical structures within the head, we analyzed hard and soft tissue scans from ecologically diverse bats in the superfamily Noctilionoidea, a clade that ranges from insectivores and carnivores to frugivores and nectarivores. We identified eight regions that evolved in a coordinated fashion, thus recognizable as evolutionary modules: five associated with bite force and three linked to olfactory, visual, and auditory systems. Interrelationships among these modules differ between Neotropical leaf-nosed bats (family Phyllostomidae) and other noctilionoids. Consistent with the hypothesis that dietary transitions begin with changes in the capacity to detect novel food items followed by adaptations to process them, peak rates of sensory module evolution predate those of some mechanical modules. We propose that the coevolution of structures influencing bite force, olfaction, vision, and hearing constituted a structural opportunity that allowed the phyllostomid ancestor to take advantage of existing ecological opportunities and contributed to the clade's remarkable radiation.

Computed tomographic characteristics of frontal sinus ossifying fibroma in a dog.

A 10-year-old female spayed Kelpie cross was presented to The Austin Vet Specialists for further investigation of a mineralized, lobulated frontal sinus mass that had previously been detected radiographically. Computed tomography (CT) revealed a large, expansile, well-defined, heterogeneously mineral attenuating mass invading both frontal sinuses. The mass was surgically debulked via a frontal sinusotomy approach. Histopathology was consistent with ossifying fibroma. This  is the first published report to describe frontal sinus ossifying fibroma in a dog, and the second to describe CT features of ossifying fibroma involving the cranium in a dog.

Twenty Intracranial Skull Base Variations in the Same Specimen.

Anatomists and clinicians often encounter single bony anatomical variations in dry skulls and on imaging. However, a constellation of 20 such variants some that, to our knowledge, have not been previously described is noteworthy. Here, we describe an adult skull with multiple bony variations, and these are detailed and discussed. These included clival canals, an interclinoid bar with resultant foramen at the uppermost aspect of the clivus, middle clinoid process, posterior petroclinoid ligament, pterygoalar plate, septated hypoglossal canal, foramen through the anterior clinoid process, septated foramen ovale, shortened superior orbital fissure, and crista muscularis. Knowledge of individual differences in the structure of the skull may be of use to both anatomists and clinicians in the treatment of intracranial procedures as well as cranial imaging studies. Taken together, such a unique specimen is of archival value.

The Zagreb Skull Collection-The unique identified collection of human skulls from fetuses to centenarians.

Skull anatomy and development have been extensively studied due to their significance in evolutionary biology, forensic anthropology, and clinical medicine. Bone collections are an indispensable resource for conducting such anthropological and anatomical studies. However, worldwide there are only few skull collections containing specimens covering the entire fetal and postnatal period. Herein we describe the Zagreb Skull Collection, an identified collection comprising more than 1100 skulls and skull bone sets from the early fetal period to centenarians. The Zagreb Skull Collection consists of two main parts: the unique Collection of Skull Bones containing 386 sets of separated skull bones from the early fetal period to adulthood and the Collection of Skulls containing 742 skulls (age range 4-101 years). The collection was the core source for numerous anatomical studies on the development, postnatal changes, and anatomical variations of the skull. However, the Zagreb Skull Collection is still an underexploited resource for anthropological, forensic, and anatomical studies with translatability to contemporary clinical practice.

Inferring human neutral genetic variation from craniodental phenotypes.

There is a growing consensus that global patterns of modern human cranial and dental variation are shaped largely by neutral evolutionary processes, suggesting that craniodental features can be used as reliable proxies for inferring population structure and history in bioarchaeological, forensic, and paleoanthropological contexts. However, there is disagreement on whether certain types of data preserve a neutral signature to a greater degree than others. Here, we address this unresolved question and systematically test the relative neutrality of four standard metric and nonmetric craniodental data types employing an extensive computational genotype-phenotype comparison across modern populations from around the world. Our computation draws on the largest existing data sets currently available, while accounting for geographically structured environmental variation, population sampling uncertainty, disparate numbers of phenotypic variables, and stochastic variation inherent to a neutral model of evolution. Our results reveal that the four data types differentially capture neutral genomic variation, with highest signals preserved in dental nonmetric and cranial metric data, followed by cranial nonmetric and dental metric data. Importantly, we demonstrate that combining all four data types together maximizes the neutral genetic signal compared with using them separately, even with a limited number of phenotypic variables. We hypothesize that this reflects a lower level of genetic integration through pleiotropy between, compared to within, the four data types, effectively forming four different modules associated with relatively independent sets of loci. Therefore, we recommend that future craniodental investigations adopt holistic combined data approaches, allowing for more robust inferences about underlying neutral genetic variation.

Analysis of free-fall bullet injury potential in the cranium via finite elements method.

The aim of this study is to analyze the injury potential of the free-falling bullet in the cranium, which is known as a tired bullet in the public, with the finite element method (FEM) In the study, as penetrant 9 × 19 mm FMJ bullets with vertical falling angle, adult human skull and brain tissue were discussed. The results of the analysis with the Finite element method, which is similar to the cases reported before, revealed that free-falling bullets as a result of shooting into the air can cause fatal injuries.

Surgical method for critical sized cranial defects in rat cranium.

Cranial tissue models are a widely used model to show the bone repair and the regeneration ability of candidate biomaterials for tissue engineering purposes. Until now, efficacy studies of different biomaterials for calvarial defect bone regeneration have been reported, generally in small animal models. This paper offers a versatile, reliable, and reproducible surgical method for creating a critical-sized cranial defect in rats including critical steps and tried-and-tested tips. The method proposed here,•Shows a general procedure for in vivo cranial models.•Provide an insight to restore bone tissue repair that may be used in combination with several tissue engineering strategies•Is a crucial technique that may guide in vivo bone tissue engineering.