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Purpose: This study aimed to examine the anatomical variations and morphometric characteristics of the sulci in the dural venous sinuses within the intracranial cavity, with a particular focus on sex differences and asymmetry. Methods: Thirty fixed cadaveric heads were used to measure the dimensions (length, width, and depth) and spatial relationships of the dural venous sinus sulci within the intracranial cavity, including the distance to the midline, distance to each other, and lateral margin of the skull. Comparisons were made between sexes and sides of the body. Results: A significant difference was observed in the length of the marginal sinus on the right side between sexes (p = 0.028). Various measurements, including the width of the transverse sinus, origin and insertion sites of the superior petrosal sinus, and distances between the sinuses and midline, showed statistically significant differences between the left and right sides (p < 0.05). Furthermore, the width of the inferior petrosal sinus and depth of the sigmoid sinus were notably higher on the right side (p < 0.05). Conclusion: The results suggest an asymmetric distribution of the sigmoid, superior/inferior petrosal, and transverse sinuses in terms of diameter and distance from the midline. Surgeons should consider these anatomical variations during procedures in this region. [ABSTRACT FROM AUTHOR]

The stem lineage of Archosauria is populated by a diverse fossil record that remains notably understudied relative to the crown clade. Prominent among these specimens is a beautifully preserved skull of the early mid-Triassic rhynchosaur Mesosuchus browni [Iziko South African Museum (SAM) 6536], whose phylogenetic position has considerable influence on patterns of pan-archosaurian cranial evolution. We used high-resolution, micro-computed tomography to re-examine the anatomy of this specimen, building on previous studies that were either limited to external observations or restricted to the braincase. A digital segmentation of the cranial elements and primary neurovascular canals of SAM-PK-6536 allows for expanded character scoring and constitutes a foundation for future comparative insights. Our data support the phylogenetically oldest instance of a pneumatized maxilla in a pan-archosaur, bringing the record of antorbital pneumatization into closer alignment with that of the neurocranium. The nasal cavity and primary palate of Mesosuchus includes a complex septomaxilla, a novel element anterior to the vomer, and is likely to have supported a well-developed vomeronasal system. The evolution of this system is discussed in terms of both phylogenetic pattern and how the skeletal architecture of Mesosuchus and other fossils could inform the signalling dynamics that pattern the vomeronasal system during development. [ABSTRACT FROM AUTHOR]

We provide a detailed and first description of the skull, hyoid apparatus, and trachea of the Turks and Caicos rock iguana, Cyclura carinata (Squamata: Iguanidae). Cyclura is a radiation of iguanas restricted to islands of the Caribbean Sea. Species of Cyclura have high rates of endemism, and all species are severely threatened with extinction. Our anatomical description of this threatened iguana is based on high-resolution computed tomography scans of one adult, one putative adult or near adult, and one juvenile specimen, and includes three-dimensional segmented renderings and visualizations. We discuss some observations of intraspecific and ontogenetic variation, and provide a brief comparison with specimens of another species of Cyclura and published descriptions of other iguanas. Our study provides a cranial osteological framework for Cyclura and augments the body of knowledge on iguana anatomy generally. Finally, we posit that our description and future studies may facilitate identification of fossil Cyclura, which could help understand the paleobiogeography of the genus. [ABSTRACT FROM AUTHOR]

• Tetra code is a precise, concise, unambiguous alphanumeric code for position on scalp. • Tetra codes achieve a median precision of 0.7–0.8 mm with 4 alphanumeric characters. • Tetra codes extend coverage on the scalp beyond the cortex to include the cerebellum. • An extension of Tetra codes specifies orientation and angle-of-incidence. [ABSTRACT FROM AUTHOR]

We provide a detailed and first description of the skull, hyoid apparatus, and trachea of the Turks and Caicos rock iguana, Cyclura carinata (Squamata: Iguanidae). Cyclura is a radiation of iguanas restricted to islands of the Caribbean Sea. Species of Cyclura have high rates of endemism, and all species are severely threatened with extinction. Our anatomical description of this threatened iguana is based on high-resolution computed tomography scans of one adult, one putative adult or near adult, and one juvenile specimen, and includes three-dimensional segmented renderings and visualizations. We discuss some observations of intraspecific and ontogenetic variation, and provide a brief comparison with specimens of another species of Cyclura and published descriptions of other iguanas. Our study provides a cranial osteological framework for Cyclura and augments the body of knowledge on iguana anatomy generally. Finally, we posit that our description and future studies may facilitate identification of fossil Cyclura, which could help understand the paleobiogeography of the genus.

The data of 44 scalp acupuncture schools are collected to analyze their commonalities in theoretical foundations, needling sites, techniques, and indications. The integration of these characteristics into an optimized, unified scalp acupuncture protocol has become an inevitable trend. The paper discusses the potential for a unified scalp acupuncture protocol from aspects such as theoretical unification, the relationships between point areas, lines, and sites, and needle numbers. It also explores the primary issues and solutions involved in unifying scalp acupuncture protocols, providing a reference for standardization and unification in scalp acupuncture protocol.

In response to growing curriculum pressures and reduced time dedicated to teaching anatomy, research has been conducted into developing innovative teaching techniques. This raises important questions for neuroanatomy education regarding which teaching techniques are most beneficial for knowledge acquisition and long-term retention, and how they are best implemented. This focused systematic review aims to provide a review of technology-enhanced teaching methods available to neuroanatomy educators, particularly in knowledge acquisition and long-term retention, compared to traditional didactic techniques, and proposes reasons for why they work in some contexts. Electronic databases were searched from January 2015 to June 2020 with keywords that included combinations of 'neuroanatomy,' 'technology,' 'teaching,' and 'effectiveness' combined with Boolean phrases 'AND' and 'OR.' The contexts and outcomes for all studies were summarised while coding, and theories for why particular interventions worked were discussed. There were 4287 articles identified for screening, with 13 studies included for final analysis. There were four technologies of interest: stereoscopic views of videos, stereoscopic views of images, augmented reality (AR), and virtual reality (VR). No recommendation for a particular teaching method was made in six studies (46%) while recommendations (from weak to moderate) were made in seven studies (54%). There was weak to moderate evidence for the efficacy of stereoscopic images and AR, and no difference in the use of stereoscopic videos or VR compared to controls. To date, technology-enhanced teaching is not inferior to teaching by conventional didactic methods. There are promising results for these methods in complex spatial anatomy and reducing cognitive load. Possible reasons for why interventions worked were described including students' engagement with the object, cognitive load theory, complex spatial relationships, and the technology learning curve. Future research may build on the theorised explanations proposed here and develop and test innovative technologies that build on prior research. [ABSTRACT FROM AUTHOR]

The holotype of the Tenerife (Canary Islands) giant rat, Canariomys bravoi, an almost complete cranium from the Late Pleistocene site of Cueva de las Palomas, is described for the first time. This species is characterized by its large size, robust skull with a short rostrum, dorsal inflation at the level of the infraorbital foramen, and moderately high-crowned upper molars which develop partial stephanodonty at advanced wear stages. Canariomys tamarani from Gran Canaria Island, the only other species of this genus known so far, is slightly smaller and further differs in its higher crowned molars with cusps arranged in a lamellar pattern. However, their crania are remarkedly similar and present a distinctive anatomy of the zygomatic plate, which is very high on the rostrum, so that its dorsal border is nearly on level with the zygomatic process of the maxilla instead of considerably below it as usually seen in murines. This is also observed in other insular, often large-sized, murines but certainly evolved in parallel as an adaptation to herbivory. Molar morphology is congruent with recent analyses of ancient molecular data of C. bravoi which place it in the tribe Arvicanthini (mostly African murines), more concretely within the Arvicanthis niloticus species complex. Even though genetic data indicate that both species diverged very recently, just 650,000 years ago, cranial and dental anatomy of C. bravoi are very derived. Conversely, C. tamarani presents a molar morphology reminiscent of that of A. niloticus albeit associated with a similarly highly derived cranial anatomy. [ABSTRACT FROM AUTHOR]

We provide the first detailed description of the cranial anatomy of an early marmotine ground squirrel Csakvaromys (= Spermophilinus) bredai, based on a well-preserved facial skull and associated specimens from the early late Miocene (11.1–9.7 Ma) Grytsiv fauna in western Ukraine. Notable cranial features of C. bredai include a shallow, broad, and elongated facial skull with a straight dorsal profile, massive rostrum, deeply concave lateral lip of the infraorbital foramen, shortened infraorbital canal, large lacrimal foramen, an elongated anteromedial edge of the zygomatic arch extending onto the premaxilla, a broad and flat interorbital region with closed supraorbital foramina, and non-elevated supraorbital margins. Phylogenetic analysis of a 136 craniodental character matrix reconstructs Csakvaromys, together with Palaeosciurus, Protospermophilus, and Sciurotamias, within the subtribal clade Sciurotamiina. We provide the first reliable morphological synapomorphies for Xerinae, and suggest a revised definition for a monophyletic Sciurotamiina, which is supported by a large lacrimal foramen ventrally contributed by the maxilla, the facial tuberosity with a longitudinal crest for the superficial masseter, rudimentary ectopterygoid crest, and the presence of an expansive attachment area for the anterior fibers of the anterior deep masseter muscle. The craniofacial anatomy reveals that C. bredai was a frugivore with a predominantly hard-nut diet and arboreal or semi-arboreal habit. [ABSTRACT FROM AUTHOR]

Leptoreodon is a basal member of the Protoceratidae, an extinct group of artiodactyls variably allied with the Camelidae and the Ruminantia. The basicranial morphology of other protoceratids (Leptotragulus, Protoceras, Syndyoceras) is similar to that of ruminants, supporting the hypothesis that the two clades are closely related. However, study of the basicranium of Leptoreodon major has revealed that protoceratid basicranial morphology is more variable than previously thought. Leptoreodon does share morphological features with some, if not all, other protoceratids, but the taxon also has some features not previously documented in the family. These previously undocumented features resemble the basicranial morphology of camelids rather than ruminants, suggesting that previous hypotheses of protoceratid relationships need to be reexamined.

The skeletal anatomy of the anterior narial region in mammals is complex, comprised of several bony and cartilaginous elements. Because it includes many cartilaginous components, preservation of this area in extant and extinct specimens is often incomplete. This, along with its complexity, means that this region of the cranium is generally understudied, with the exception of humans and a few select mammal species. The present study began with a cranial specimen of the extant Hoffmann's two-toed sloth, Choloepus hoffmanni (Xenarthra, Folivora, Megalonychidae), that possessed several unusual well-preserved narial anomalies. In order to determine whether such features are present in other extant sloths, and if so, how frequently, we examined two- and three-toed sloth specimens from a variety of museum collections. Additionally, we examined museum specimens of extinct sloths known to possess unusual osseous narial structures, with the goal of better understanding the anatomy of the anterior opening of the nasal cavity in all sloths, living and extinct. A diverse series of unusual narial elements were found, including an internasal bone, an ossified anterior nasal septum, an os nariale, an ossified processus lateralis ventralis of the nasal capsule, and an internarial bar of varying composition and completeness. All of these features are present in Choloepus, although they are preserved in museum skulls infrequently, but none were found to be present in the three-toed sloth, Bradypus. An internarial bar, anteriorly elongated ossified nasal septum, and ossified processus lateralis ventralis were observed in several species of extinct mylodontid and megatheriid sloths, and an os nariale was recorded in the extant vermilinguan anteaters Cyclopes and Tamandua. It is not known how much of the variation we document in these features is genuine and how much is due to preservation issues. Given such uncertainty, it is difficult to assess the phylogenetic or functional significance of these features. We believe, however, that this is an area of the skull in Pilosa (sloths and anteaters) that merits further study. [ABSTRACT FROM AUTHOR]

Micro‐computed tomography (microCT) of small animals has led to a more detailed and more accurate three‐dimensional (3D) view on different anatomical structures in the last years. Here, we present the cranial anatomy of two frog species providing descriptions of bone structures and soft tissues of the feeding apparatus with comments to possible relations to habitat and feeding ecology. Calyptocephalella gayi, known for its aquatic lifestyle, is not restricted to aquatic feeding but also feeds terrestrially using lingual prehension. This called for a detailed investigation of the morphology of its feeding apparatus and a comparison to a fully terrestrial species that is known to feed by lingual prehension such as Leptodactylus pentadactylus. These two frog species are of similar size, feed on similar diet but within different main habitats. MicroCT scans of both species were conducted in order to reconstruct the complete anatomical condition of the whole feeding apparatus for the first time. Differences in this regard are evident in the tongue musculature, which in L. pentadactylus is more massively built and with a broader interdigitating area of the two main muscles, the protractor musculus genioglossus and the retractor musculus hyoglossus. In contrast, the hyoid retractor (m. sternohyoideus) is more massive in the aquatic species C. gayi. Moreover, due to the different skull morphology, the origins of two of the five musculi adductores vary between the species. This study brings new insights into the relation of the anatomy of the feeding apparatus to the preferred feeding method via 3D imaging techniques. Contrary to the terrestrially feeding L. pentadactylus, the skeletal and muscular adaptations of the aquatic species C. gayi provide a clear picture of necessities prescribed by the habitat. Nevertheless, by keeping a certain amount of flexibility of the design of its feeding apparatus, C. gayi is able to employ various methods of feeding. [ABSTRACT FROM AUTHOR]

Besanosaurus leptorhynchus Dal Sasso & Pinna, 1996 was described on the basis of a single fossil excavated near Besano (Italy) nearly three decades ago. Here, we re-examine its cranial osteology and assign five additional specimens to B. leptorhynchus, four of which were so far undescribed. All of the referred specimens were collected from the Middle Triassic outcrops of the Monte San Giorgio area (Italy/Switzerland) and are housed in various museum collections in Europe. The revised diagnosis of the taxon includes the following combination of cranial characters: extreme longirostry; an elongate frontal not participating in the supratemporal fenestra; a prominent ‘triangular process’ of the quadrate; a caudoventral exposure of the postorbital on the skull roof; a prominent coronoid (preglenoid) process of the surangular; tiny conical teeth with coarsely-striated crown surfaces and deeply-grooved roots; mesial maxillary teeth set in sockets; distal maxillary teeth set in a short groove. All these characters are shared with the holotype of Mikadocephalus gracilirostris Maisch & Matzke, 1997, which we consider as a junior synonym of B. leptorhynchus. An updated phylogenetic analysis, which includes revised scores for B. leptorhynchus and several other shastasaurids, recovers B. leptorhynchus as a basal merriamosaurian, but it is unclear if Shastasauridae form a clade, or represent a paraphyletic group. The inferred body length of the examined specimens ranges from 1 m to about 8 m. The extreme longirostry suggests that B. leptorhynchus primarily fed on small and elusive prey, feeding lower in the food web than an apex predator: a novel ecological specialisation never reported before the Anisian in a large diapsid. This specialization might have triggered an increase of body size and helped to maintain low competition among the diverse ichthyosaur fauna of the Besano Formation.

Besanosaurus leptorhynchus Dal Sasso & Pinna, 1996 was described on the basis of a single fossil excavated near Besano (Italy) nearly three decades ago. Here, we re-examine its cranial osteology and assign five additional specimens to B. leptorhynchus, four of which were so far undescribed. All of the referred specimens were collected from the Middle Triassic outcrops of the Monte San Giorgio area (Italy/Switzerland) and are housed in various museum collections in Europe. The revised diagnosis of the taxon includes the following combination of cranial characters: extreme longirostry; an elongate frontal not participating in the supratemporal fenestra; a prominent 'triangular process' of the quadrate; a caudoventral exposure of the postorbital on the skull roof; a prominent coronoid (preglenoid) process of the surangular; tiny conical teeth with coarsely-striated crown surfaces and deeply-grooved roots; mesial maxillary teeth set in sockets; distal maxillary teeth set in a short groove. All these characters are shared with the holotype of Mikadocephalus gracilirostris Maisch & Matzke, 1997, which we consider as a junior synonym of B. leptorhynchus. An updated phylogenetic analysis, which includes revised scores for B. leptorhynchus and several other shastasaurids, recovers B. leptorhynchus as a basal merriamosaurian, but it is unclear if Shastasauridae form a clade, or represent a paraphyletic group. The inferred body length of the examined specimens ranges from 1 m to about 8 m. The extreme longirostry suggests that B. leptorhynchus primarily fed on small and elusive prey, feeding lower in the food web than an apex predator: a novel ecological specialisation never reported before the Anisian in a large diapsid. This specialization might have triggered an increase of body size and helped to maintain low competition among the diverse ichthyosaur fauna of the Besano Formation. [ABSTRACT FROM AUTHOR]

The postcranial morphology of the extremely long-necked Tanystropheus hydroides is well-known, but observations of skull morphology were previously limited due to compression of the known specimens. Here we provide a detailed description of the skull of PIMUZ T 2790, including a partial endocast and endosseous labyrinth, based on synchrotron microtomographic data, and compare its morphology to that of other early Archosauromorpha. In many features, such as the wide and flattened snout and the configuration of the temporal and palatal regions, Tanystropheus hydroides differs strongly from other early archosauromorphs. The braincase possesses a combination of derived archosaur traits, such as the presence of a laterosphenoid and the ossification of the lateral wall of the braincase, but also differs from archosauriforms in the morphology of the ventral ramus of the opisthotic, the horizontal orientation of the parabasisphenoid, and the absence of a clearly defined crista prootica. Tanystropheus hydroides was a ram-feeder that likely caught its prey through a laterally directed snapping bite. Although the cranial morphology of other archosauromorph lineages is relatively well-represented, the skulls of most tanystropheid taxa remain poorly understood due to compressed and often fragmentary specimens. The recent descriptions of the skulls of Macrocnemus bassanii and now Tanystropheus hydroides reveal a large cranial disparity in the clade, reflecting wide ecological diversity, and highlighting the importance of non-archosauriform Archosauromorpha to both terrestrial and aquatic ecosystems during the Triassic.

Objectives: The diploic channels are bony passages of veins, running within frontal, parietal, and occipital bones. In this study, we investigate ontogenetic changes of these channels in a sample of nonadult and adult modern humans. Materials and methods: Using computed tomography scans of dried crania, we provide quantitative comparisons of lumen size, branch length, volume, and vascular asymmetries, and correlations with age, cranial size, and bone thickness. Results: The vascular system displays progressive but nonlinear changes throughout ontogeny, becoming even more complex with adulthood. Vascular variables are significantly different in frontal, parietal, and occipital bones for most of the postnatal ontogeny. Diploic channels of the left and right sides are developed similarly. Vascular variables display a nonlinear association with age and cranial size in modern humans. Cranial bone thickness is shown to be a major determinant of lumen size, branch length, and volume. Conclusions: A previous radiographic survey suggested that diploic channels are more developed in adult modern humans than in nonadults. Recent advances in digital anatomy have been used in this study to investigate this craniovascular structure. The complexity of the channels increases during development, with a noticeable boost in adults. Taking into account the potential metabolic differences and constraints associated with modern human brain size and shape, the vascular differences found might be related to endocranial thermoregulation. [ABSTRACT FROM AUTHOR]

Two genera of Miocene beavers (Castoridae), Hystricops and Priusaulax are referred to a new tribe Hystricopini of the subfamily of giant beavers, Castoroidinae based on cranial and dental morphologies. Previously undescribed and more complete specimens of Hystricops demonstrate that it is referable to the Castoroidinae rather than the Castorinae. Along with Priusaulax, it is believed to represent a group of basal castoroidines, distinct from later Castoroidinae by the retention of the primitive morphology of the contact of the lacrimal bone with the jugal on the cranium, as well as more primitive dental morphologies (lower crown-height and simple occlusal pattern of cheek teeth). A partial cranium and several isolated teeth from the Hemingfordian of Colorado, originally referred to Anchitheriomys?, are referred here to a new species, Priusaulax wilsoni sp. nov. Monosaulax senrudi from the Barstovian of Montana is also referred to Priusaulax. Hystricops is limited to the type species H. venustus from the Clarendonian and Barstovian North American Land Mammal Age (NALMA), and H. browni from the Hemphillian NALMA.

Sandownidae is an enigmatic group of Cretaceous–Paleogene turtles with highly derived cranial anatomy. Although sandownid monophyly is not debated, relationships with other turtles remain unclear. Sandownids have been recovered in significantly different parts of the turtle tree: as stem-turtles, stem-cryptodires and stem-chelonioid sea turtles. Latest phylogenetic studies find sandownids as the sister-group of the Late Jurassic thalassochelydians and as stem-turtles. Here, we provide a detailed study of the cranial and mandibular anatomy of Sandownia harrisi from the Aptian of the Isle of Wight, based on high resolution computed tomography scanning of the holotype. Our results confirm a high number of anatomical similarities with thalassochelydians and particularly Solnhofia parsonsi, which is interpreted as an early member of the sandownid lineage. Sandownids + Solnhofia show many cranial modifications related to the secondary palate and a durophagous diet. Sandownia is additionally highly derived in features related to its arterial circulation and neuroanatomy, including the endosseous labyrinth. Our results imply rapid morphological evolution during the early history of sandownids. Sandownids likely evolved in central Europe from thalassochelydian ancestors during the Late Jurassic. The durophagous diet of sandownids possibly facilitated their survival of the Cretaceous/Paleogene mass extinction.

Bothremydidae is a successful lineage of pleurodiran turtles that lived from the Cretaceous to the Paleogene, and are found in most continents of both Laurasia and Gondwana. Despite numerous known cranial remains of this clade, no study on the complete neuroanatomical reconstruction of any of its representatives has been published so far. Tartaruscola teodorii is a French lower Eocene member of Foxemydina (Bothremydini), known by two skulls. It is one of the few bothremydids identified in the Cenozoic record of Europe. The present study includes the complete three-dimensional reconstruction of each of the cranial bones of both the holotype and the paratype of T. teodorii, increasing the anatomical information about this species. The virtual reconstruction of its neuroanatomical structures is presented here, including the cranial cavity, nerves, nasal cavity, inner ears, and carotid arteries. This analysis is the first detailed neuroanatomical study performed for a member of Bothremydidae. In addition, the virtual reconstruction of the neuroanatomical structures of some extant taxa belonging to several pleurodiran lineages (Chelidae, Pelomedusidae and Podocnemididae), are also carried out and analyzed, so that the comparative framework for Pleurodira is remarkably improved.

Allosaurus is one of the best known theropod dinosaurs from the Jurassic and a crucial taxon in phylogenetic analyses. On the basis of an in-depth, firsthand study of the bulk of Allosaurus specimens housed in North American institutions, we describe here a new theropod dinosaur from the Upper Jurassic Morrison Formation of Western North America, Allosaurus jimmadseni sp. nov., based upon a remarkably complete articulated skeleton and skull and a second specimen with an articulated skull and associated skeleton. The present study also assigns several other specimens to this new species, Allosaurus jimmadseni, which is characterized by a number of autapomorphies present on the dermal skull roof and additional characters present in the postcrania. In particular, whereas the ventral margin of the jugal of Allosaurus fragilis has pronounced sigmoidal convexity, the ventral margin is virtually straight in Allosaurus jimmadseni. The paired nasals of Allosaurus jimmadseni possess bilateral, blade-like crests along the lateral margin, forming a pronounced nasolacrimal crest that is absent in Allosaurus fragilis. [ABSTRACT FROM AUTHOR]

Background The phylogenetic placement of Cretaceous marine turtles, especially Protostegidae, is still under debate among paleontologists. Whereas protostegids were traditionally thought to be situated within the clade of recent marine turtles (Chelonioidea), some recent morphological and molecular studies suggest placement along the stem of Cryptodira. The main reason why the evolution of marine turtles is still poorly understood, is in part due to a lack of insights into the cranial anatomy of protostegids. However, a general availability of high-quality fossil material, combined with modern analysis techniques, such as X-ray microtomography, provide ample opportunity to improve this situation. The scope of this study is to help resolve its phylogenetic relationships by providing a detailed description of the external and internal cranial morphology of the extinct protostegid sea turtle Desmatochelys lowii Williston, 1894. Material and Methods This study is based on the well-preserved holotype of Desmatochelys lowii from the Late Cretaceous (middle Cenomanian to early Turonian) Greenhorn Limestone of Jefferson County, Nebraska. The skulls of two recent marine turtles, Eretmochelys imbricata (Linnaeus, 1766) (Cheloniidae) and Dermochelys coriacea Lydekker, 1889 (Dermochelyidae), as well as the snapping turtle Chelydra serpentina (Linnaeus, 1758) (Chelydridae) provide a comparative basis. All skulls were scanned using regular or micro CT scanners and the scans were then processed with the software program Amira to create 3D isosurface models. In total, 81 bones are virtually isolated, figured, and described, including the nature of their contacts. The novel bone contact data is compiled and utilized in a preliminary phenetic study. In addition, an update phylogenetic analysis is conduced that utilizes newly obtained anatomical insights. Results The detailed examination of the morphology of the herein used specimens allowed to explore some features of the skull, to refine the scoring of Desmatochelys lowii in the recent global matrix of turtles, and develop five new characters. The alleged pineal foramen in the type skull of Desmatochelys lowii is shown to be the result of damage. Instead, it appears that the pineal gland only approached the skull surface, as it is in Dermochelys coriacea. Whereas the parasphenoid in confirmed to be absent in hard-shelled sea turtles, ist possible presence in Desmatochelys lowii is unclear. The results of the phenetic study show that Desmatochelys lowii is least similar to the other examined taxa in regards to the nature of its bone contacts, and therefore suggests a placement outside Americhelydia for this protostegid sea turtle. The phylogenetic study results in a placement of Protostegidae along the stem of Chelonioidea, which is a novel position for the group.

The trigeminal nerve is responsible for transmitting sensory information from the face, nasal and mouth cavities, and most of the scalp. Trigeminal neuralgia (TN) is a chronic facial pain disorder characterized by spontaneous paroxysmal pain throughout the distribution of the trigeminal nerve. This study investigated the morphological and morphometric variations of the foramen rotundum (FR) and its association with TN through a retrospective radiological analysis. A cohort of 97 participants from King Fahad University Hospital, Saudi Arabia, comprising 57 TN patients and 40 controls, underwent head CT scans for measurement and analysis. The study revealed significant differences in the FR morphology between TN patients and controls, particularly noting narrower FR measurements among TN individuals, especially in females. The right side demonstrated narrower FR dimensions, potentially correlating with the predominant side of pain in TN patients. While the presence of bony spurs was absent in all participants, variations in FR shape, size, and spatial positioning were observed and compared across genders and groups. These findings provide crucial insights into the potential anatomical factors contributing to TN, emphasizing the importance of understanding FR variations in clinical assessment and management of TN cases. Further research focusing on FR morphology and its clinical implications is recommended to enhance understanding and aid medical professionals in addressing TN-related concerns., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Ismail et al.)

Background: The phylogenetic placement of Cretaceous marine turtles, especially Protostegidae, is still under debate among paleontologists. Whereas protostegids were traditionally thought to be situated within the clade of recent marine turtles (Chelonioidea), some recent morphological and molecular studies suggest placement along the stem of Cryptodira. The main reason why the evolution of marine turtles is still poorly understood, is in part due to a lack of insights into the cranial anatomy of protostegids. However, a general availability of high-quality fossil material, combined with modern analysis techniques, such as X-ray microtomography, provide ample opportunity to improve this situation. The scope of this study is to help resolve its phylogenetic relationships by providing a detailed description of the external and internal cranial morphology of the extinct protostegid sea turtle Desmatochelys lowii Williston, 1894. Material and Methods: This study is based on the well-preserved holotype of Desmatochelys lowii from the Late Cretaceous (middle Cenomanian to early Turonian) Greenhorn Limestone of Jefferson County, Nebraska. The skulls of two recent marine turtles, Eretmochelys imbricata (Linnaeus, 1766) (Cheloniidae) and Dermochelys coriacea Lydekker, 1889 (Dermochelyidae), as well as the snapping turtle Chelydra serpentina (Linnaeus, 1758) (Chelydridae) provide a comparative basis. All skulls were scanned using regular or micro CT scanners and the scans were then processed with the software program Amira to create 3D isosurface models. In total, 81 bones are virtually isolated, figured, and described, including the nature of their contacts. The novel bone contact data is compiled and utilized in a preliminary phenetic study. In addition, an update phylogenetic analysis is conduced that utilizes newly obtained anatomical insights. Results: The detailed examination of the morphology of the herein used specimens allowed to explore some features of the skull, to refine the scoring of Desmatochelys lowii in the recent global matrix of turtles, and develop five new characters. The alleged pineal foramen in the type skull of Desmatochelys lowii is shown to be the result of damage. Instead, it appears that the pineal gland only approached the skull surface, as it is in Dermochelys coriacea. Whereas the parasphenoid in confirmed to be absent in hard-shelled sea turtles, ist possible presence in Desmatochelys lowii is unclear. The results of the phenetic study show that Desmatochelys lowii is least similar to the other examined taxa in regards to the nature of its bone contacts, and therefore suggests a placement outside Americhelydia for this protostegid sea turtle. The phylogenetic study results in a placement of Protostegidae along the stem of Chelonioidea, which is a novel position for the group. [ABSTRACT FROM AUTHOR]

Previously, only three pachycephalosaur specimens have been reported from the Nemegt Formation, two of which are holotypes ( Homalocephale calathocercos and Prenocephale prenes ) and all of which were collected from the classic Nemegt locality. Here, we describe several new cranial specimens from this formation, but which originate from Bügiin Tsav, Guriliin Tsav, and Tsagaan Khushuu localities. The specimens consist of an incomplete frontoparietal dome that is slightly smaller than the holotype of P . prenes , and two specimens that are larger than the holotype –a second incomplete frontoparietal and a complete squamosal with ornamentation. All specimens are referable to P . prenes or cf. Prenocephale . Cranial histology is investigated in an Asian pachycephalosaur for the first time on the basis of these new specimens. The specimens increase the ontogenetic representation for Prenocephale , and show that the squamosal ornamentation pattern is consistent across the known size range. These specimens expand the geographic range of pachycephalosaurs in the Nemegt Formation, and provide new ontogenetic data for P . prenes that reinforces the taxonomic distinction between it and Homalocephale . [ABSTRACT FROM AUTHOR]

Razanandrongobe sakalavae Maganuco, Dal Sasso & Pasini, 2006 is a large predatory archosaur from the Middle Jurassic (Bathonian) of the Mahajanga Basin, NW Madagascar. It was diagnosed on the basis of teeth and a fragmentary maxilla, but its affinities were uncertain. Here we describe new cranial remains (above all, an almost complete right premaxilla and a caudally incomplete left dentary) that greatly improve our knowledge on this enigmatic species and reveal its anatomy to be crocodylomorph. The right premaxilla indicates that the rostrum was deep, wide, and not pointed; it bears five teeth that are sub-vertical and just slightly curved lingually; the mesial teeth are U-shaped in cross-section and have serrated carinae on the lingual side; the aperturae nasi osseae (external bony nares) are confluent and face rostrally; and there is no lateral groove at the premaxillomaxillary suture for reception of a hypertrophied lower caniniform tooth. The preserved portion of the left dentary has an edentulous tip and bears eight large mandibular teeth of which the mesial (1–3) are the largest, but none is a hypertrophied caniniform tooth; the mandibular (dentary) symphysis extends caudally to the level of the third tooth; the splenial is not preserved, but its sutural marks on the dentary indicate that it contributed to the mandibular symphysis for at least 20% of the symphyseal length in dorsal aspect. On the basis of this new data, some previously uncertain features of the holotype maxilla—such as the margin of the suborbital fenestra, the contact surfaces for the palatine, the ectopterygoid, and the jugal—are now apparent. Testing of the phylogenetic position of the species within Crocodylomorpha indicates that R. sakalavae is a mesoeucrocodylian. It also represents one of the earliest events of exacerbated increase in body size along the evolutionary history of the group. In addition, it is by far the oldest notosuchian. A cranial reconstruction of this gigantic predator is also attempted here. The very robust jaw bones of R. sakalavae, coupled with its peculiar dentition, strongly suggest a diet that included hard tissue such as bone and tendon.

Two new plesiosaurian specimens coming from lower Turonian deposits of Goulmima in Morocco are described. The three-dimensional digital reconstructions of both specimens provide details about their skull roof, mandible and atlas-axis complex. In addition, computed tomography allows to reconstruct their braincase, which is a part of the skull poorly known among plesiosaurians due to either poor preservation and/or insufficient preparation, but that offers a large number of characters used in phylogenetical analyses. After descriptions and comparisons, the two specimens D1-8213 and MNHN F-GOU14 are assigned to Libonectes morgani and to an undetermined Polycotylidae, respectively. The presence of the North American taxon Libonectes morgani in the deposits of Goulmima confirms a trans-Atlantic faunal connectivity at that time and that Elasmosauridae were able to exploit the open marine environment for dispersion. Polycotylids have already been described from Goulmima; however, the typical preservation of these specimens in nodules prevented their preparation and the access to their internal anatomy. Here, the use of X-ray computed tomography shows the strong interest to use such a technique and provide new anatomical details. [ABSTRACT FROM AUTHOR]

Two genera of Miocene beavers (Castoridae), Hystricops and Priusaulax are referred to a new tribe Hystricopini of the subfamily of giant beavers, Castoroidinae based on cranial and dental morphologies. Previously undescribed and more complete specimens of Hystricops demonstrate that it is referable to the Castoroidinae rather than the Castorinae. Along with Priusaulax, it is believed to represent a group of basal castoroidines, distinct from later Castoroidinae by the retention of the primitive morphology of the contact of the lacrimal bone with the jugal on the cranium, as well as more primitive dental morphologies (lower crown-height and simple occlusal pattern of cheek teeth). A partial cranium and several isolated teeth from the Hemingfordian of Colorado, originally referred to Anchitheriomys?, are referred here to a new species, Priusaulax wilsoni sp. nov. Monosaulax senrudi from the Barstovian of Montana is also referred to Priusaulax. Hystricops is limited to the type species H. venustus from the Clarendonian and Barstovian North American Land Mammal Age (NALMA), and H. browni from the Hemphillian NALMA. [ABSTRACT FROM AUTHOR]

Objective: In neurosurgical microsurgery, understanding the accurate size of microstructures is essential to perform operation safely and less invasively. We here describe a simple method of measuring the size of microvessels using a digital image as a microscale. Materials and Methods: The digital image was made as a microscale on the computer. We measured the size of intracranial microstructures using the microscale. Results: We accurately measured the size of the vertebral artery perforator of 1 mm or less using the adjusted microscale on the computer. Conclusions: The development of a microscale is easy and renders the measurement of microstructures, sized 1 mm or less, feasible, and accurate. [ABSTRACT FROM AUTHOR]

Ceratopsian dinosaurs arguably show some of the most extravagant external cranial morphology across all Dinosauria. For over a century, ceratopsian dinosaurs have inspired a multitude of cranial functional studies as more discoveries continued to depict a larger picture of the enormous diversity of these animals. The iconic horns and bony frills in many ceratopsians portray a plethora of shapes, sizes, and arrangements across taxa, and their overall feeding apparatus show the development of unique specializations previously unseen in large herbivores. Here, I give a brief updated review of the many functional studies investigating different aspects of the ceratopsian head. The functional role of the horns and bony frills is explored, with an overview of studies investigating their potential for weaponization or defense in either intraspecific or anti-predatory combat, among other things. A review of studies pertaining to the ceratopsian feeding apparatus is also presented here, with analyses of studies exploring their beak and snout morphology, dentition and tooth wear, cranial musculature with associated skull anatomy, and feeding biomechanics., (© 2023 American Association for Anatomy.)

Galianemys is one of the three genera of Cearachelyini (Pleurodira, Bothremydidae) so far defined, being the only one identified in Africa (in the Cenomanian of Morocco). It is represented by two species, Galianemys whitei and Galianemys emringeri, both being identified by several skulls. The other two representatives of Cearachelyini are both South-American forms, and only the species Cearachelys placidoi (from the Albian of Brazil) preserves cranial remains, including a partial skull corresponding to its holotype. However, despite the relatively great number of skulls identified for both Galianemys spp. and Cearachelys placidoi, information about the neuroanatomy of this lineage is very limited. The three-dimensional (3D) reconstruction of the skulls of two specimens belonging to the genus Galianemys, each of them representing a different species, is performed here for the first time. All of the cranial bones of one of them are also virtually reconstructed to accurately characterize them. In addition, the 3D models of the main neuroanatomical structures (i.e., cranial, nasal, and labyrinthic cavities, and nervous and carotid canals) of both specimens were generated, most of them being described in detail for first time in Cearachelyini. Neuroanatomical differences are recognized when the skulls of both species of Galianemys analyzed here are compared. In addition, the comparison between the neuroanatomy of Galianemys spp. and that of other non-Cearachelyini bothremydids allow us to identify some differences between those lineages, but also recognize other shared characters for the entire lineage of Bothremydidae, to providing a more precise characterization within Pleurodira., (© 2022 The Authors. The Anatomical Record published by Wiley Periodicals LLC on behalf of American Association for Anatomy.)

The morphology of the mastoid region in predators is informative about the hunting strategies and capacity of carrying prey. The purpose of this research was to describe the mastoid region and reconstruct the associated musculature of Stipanicicia pettorutii Reig, 1956, a Pleistocene weasel with a distinctive morphology compared to its living relatives, and to make inferences about its predatory abilities. Galictis, a living weasel closely related to Stipanicicia, as well as other earnivorans, were used as comparative models. The muscle insertions identified in Stipanicicia presented a similar or larger development than Galictis. The insertion area of the muscles obliquus capitis cranialis, longissimus capitis, sternocephalicus pars mastoidea and cleidocephalicus pars mastoidea were found to be markedly developed and in a lateralised position with respect to the atlanto-occipital joint in hyaenids and mustelids, and especially in Stipanicicia, suggesting powerful lateral flexion and rotation movements in the fossil. The larger degree of advancement of the mastoid process in mustelids, and secondary in felids, would allow a powerful ventral flexion of the head. Stipanicicia would have exhibited powerful lateral movements and retraction of the head and neck, over restricted extension movements and, therefore, would have been a weasel specialised in subjugating and carrying prey of a relatively large size. [ABSTRACT FROM AUTHOR]

We describe crocodylian remains from the Early Miocene (MN4) site of Els Casots (Subirats, Vallès-Penedès Basin, NE of the Iberian Peninsula). Referral to Diplocynodon (Alligatoroidea: Diplocynodontidae) is justified by several cranial and postcranial features, including: (1) the subequal and confluent alveoli of the maxilla (fourth and fifth) and dentary (third and fourth); (2) the position of the foramen aëreum on the quadrate; (3) the small and ventrally reflected medial hemicondyle of the quadrate; (4) the distinct dorsoventral step on the frontal; and (5) the bipartite ventral osteoderms. Multiple morphological features are consistent with an attribution to Diplocynodon ratelii , previously known from the Early Miocene (MN2) of France, and discount an alternative attribution to other species of the genus, including Diplocynodon ungeri from the Middle Miocene (MN5) of Austria. The described material from Els Casots is smaller in size than the French material of D. ratelii , possibly reflecting an earlier ontogenetic stage. The described remains constitute the first report of D. ratelii and the youngest record of Diplocynodon in the Iberian Peninsula, where only Diplocynodon muelleri and Diplocynodon tormis have been previously reported. The presence of Diplocynodon further supports the lacustrine depositional environment previously inferred for Els Casots and also indicates a relatively high temperature. [ABSTRACT FROM AUTHOR]

ABSTRACT Objectives Maba 1, a partial cranium from Guandong Province (China) tentatively dated between 300 and 130 ka, has been suggested to display a mosaic of archaic and derived features, including facial affinities with Neandertals. This study aims to evaluate whether Maba 1 shows a derived endocranial phenotype, or if it displays a plesiomorphic braincase morphology. Materials and methods We analyzed a set of metric variables on fossil and modern human endocasts using bivariate correlation, principal component analysis, and cluster analyses, to evaluate the morphological affinities of the Maba 1 endocast. Results The cranial capacity, estimated at around 1300 cc, and the endocranial proportions of Maba 1 are within the ranges of modern humans, Neandertals and Homo heidelbergensis. However, the frontal lobes are narrow and the parietal areas are short and flattened, as in H. heidelbergensis and H. erectus. Nonetheless, the position of the frontal lobes relative to the orbits, the morphology of the frontal sinus and the curve of the frontal squama are more derived, being similar to Neandertals and modern humans. Conclusions The endocast displays a general archaic morphology, although with some derived features associated with the spatial relationships with the face. A similar admixture was described for other Middle Pleistocene samples, like Sima de los Huesos. Future phylogenetic studies must re-evaluate the facial skeleton to consider whether its features can be considered as related to the Neandertal lineage. Alternatively, they should be interpreted as the result of homoplasy and parallelism within the genus Homo, and may reflect a predominantly Asian variation. Am J Phys Anthropol 160:633-643, 2016. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Paleogene micromomyids are small (∼10-40 g) euarchontan mammals with primate-like molars and postcrania suggestive of committed claw-climbing positional behaviors, similar to those of the extant arboreal treeshrew, Ptilocercus. Based primarily on evidence derived from dental and postcranial morphology, micromomyids have alternately been allied with plesiadapiforms, Dermoptera (colugos), or Primatomorpha (Primates + Dermoptera) within Euarchonta. Partial crania described here of Paleocene Dryomomys szalayi and Eocene Tinimomys graybulliensis from the Clarks Fork Basin of Wyoming are the first known for the family Micromomyidae. The cranium of D. szalayi exhibits a distinct, small groove near the lateral extreme of the promontorium, just medial to the fenestra vestibuli, the size of which suggests that the internal carotid artery was non-functional, as has been inferred for paromomyid and plesiadapid plesiadapiforms, but not for Eocene euprimates, carpolestids, and microsyopids. On the other hand, D. szalayi is similar to fossil euprimates and plesiadapoids in having a bullar morphology consistent with an origin that is at least partially petrosal, unlike that of paromomyids and microsyopids, although this interpretation will always be tentative in fossils that lack exhaustive ontogenetic data. Micromomyids differ from all other known plesiadapiforms in having an inflated cochlear part of the bony labyrinth and a highly pneumatized squamosal and mastoid region with associated septa. Cladistic analyses that include new cranial data, regardless of how bullar composition is coded in plesiadapiforms, fail to support either Primatomorpha or a close relationship between micromomyids and dermopterans, instead suggesting that micromomyids are among the most primitive known primates. [ABSTRACT FROM AUTHOR]

ABSTRACT Objectives The diploic channels appear to be more developed in humans than in nonhuman primates, suggesting they may be relevant in evolutionary biology. This study is aimed at providing a segmentation procedure for diploic channels and CT analysis, a quantitative description of their variation in modern humans, and paleoanthropological case-studies. Materials and Methods CT data were used for the 2D and 3D visualization, rendering, and measure, of diploic channels in modern and fossil hominids. We analyzed 20 modern human skulls and three Neanderthals. The effect of different resolution factors was evaluated. A specific protocol was designed to segment the vascular network and localize the main branches, reducing the noise of the cancellous bone. Results We provide a quantitative description of the frontal, parietal, and occipital diploic networks in modern humans and in three Neanderthals. There is a correlation in the degree of vascularization among the different vault areas. No side differences can be detected. The diploic network is commonly connected with the meningeal artery at the temporal fossa, with the emissary veins at the occipital bone, and with the venous sinuses at the parieto-occipital areas. The channels are more developed in the parietal areas. The three Neanderthals show a vascular development, which is in the lower range of the modern human variation. Conclusions Modern humans display a large variation in their morphological patterns, being the parietal area the most vascularized. The pattern of the diploic channels may be relevant in anthropology, medicine, and paleontology, taking into account their possible involvement in thermoregulation. Am J Phys Anthropol 159:313-324, 2016. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Introduction Preserving cranial nerve (CN) function during tumor removal at the jugular foramen is challenging. No anatomical study has better defined the relevant dural septations on the inner surface of the jugular foramen. This study was undertaken to elucidate this anatomy. Methods Fourteen cadaveric heads (28 sides) were dissected, and relationships of the meningeal coverings of the jugular foramen and adjacent CNs documented. A classification scheme was created to better describe the dural septations of the inner surface of the jugular foramen. Results Four types of dural septations were noted. Type I: 10 sides (36%) where a dural septation was seen between CNs IX anteriorly and X and XI posteriorly. Of these, the septum was ossified in 20%. Type II (32%) was defined as a jugular foramen with no dural septation. Type III (7%) was defined as septation between CNs IX and X anteriorly and XI posteriorly. Type IV (7 sides, 25%) or the chaotic form was defined asmultiple septations within the jugular foramen that housed and divided CN rootlets. Conclusions The dural septations defined here can be used in future studies to help correlate operative strategy to meningeal morphology within the jugular foramen. [ABSTRACT FROM AUTHOR]