Anatomical Record : Advances in Integrative Anatomy and Evolutionary Biology

Paranasal sinuses of living apes and humans grow with positive allometry, suggesting a novel mechanism for bone enlargement. Here, we examine the paranasal sinuses of the owl monkey (Aotus spp.) and a tamarin (Saguinus midas) across postnatal development. The prediction that paranasal sinuses grow disproportionately faster than the main nasal chamber is tested. We used diffusible iodine-based contrast-enhanced computed tomography and histology to study sinuses in eight Aotus and three tamarins ranging from newborn to adult ages...

The Hyaenodonta were the most diverse carnivorous mammals in the European Eocene and were classically divided into three subfamilies: Sinopaninae, Arfianinae, and Proviverrinae, with this latter being the most successful of the three, as it exhibited a much larger geographic and temporal range. This classification is currently abandoned, as cladistic analyses of Hyaenodonta showed that several of these groups were paraphyletic. In any case, the former "proviverrines" were European endemic hyaenodontids which occupied the niche of small to medium-sized predators from the Ypresian (MP7) to the Priabonian (MP19)...

Based on histological cross-sections, the chondrocranium of the common musk turtle (Sternotherus odoratus) was reconstructed, described, and compared with other turtles. It differs from that of other turtle chondrocrania by possessing elongated, slightly dorsally orientated nasal capsules with three dorsolateral foramina, which might be homologous to the foramen epiphaniale, and by having an enlarged crista parotica. Additionally, the posterior part of the palatoquadrate is more elongated and more slender than in other turtles, while its ascending process is connected to the otic capsule by appositional bone...

Tigrivia baii gen. et sp. nov. (Coleoptera: Adephaga: Coptoclavidae) is described and named based on a fossil specimen from the Middle Jurassic Daohugou Biota, Nincheng County, Inner Mongolia of China. The fossil is very similar in morphology with the adult Coptoclava longipoda Ping 1928 (Laiyang Formation of Nanligezhuang Village, Laiyang City, Shandong Province, China, Lower Cretaceous, 121 ~ 120 Ma), but differs from C. longipoda by the adjacencies of two procoxae and two mesocoxae. T...

A long neck is an evolutionary innovation convergently appearing in multiple tetrapod lineages, including groups of plesiosaurs, non-archosauriform archosauromorphs, turtles, sauropodomorphs, birds, and mammals. Among all tetrapods both extant and extinct, two Triassic archosauromorphs, Tanystropheus and Dinocephalosaurus, have necks that are particularly elongated relative to the lengths of their trunks. However, the evolutionary history of such hyper-elongated necks in these two archosauromorph clades remains unknown, partially because known close relatives such as Macrocnemus and Pectodens possess only moderately elongated necks...

With their particular body plan within amniotes and their amazing fossil record, turtles represent a great interest for both neontologists and paleontologists with a strong anatomical background. The Turtle Evolution Symposia are regular international meetings that gather scientists working with different aspects related to the evolutionary history of turtles, from their origin and early evolution until recent times. The latest edition of the Turtle Evolution Symposium was organized in 2021 amidst the COVID-19 outbreak and held virtually from the facilities of the Museo Paleontológico Egidio Feruglio in Trelew (Patagonia, Chubut, Argentina)...

Bats form a diverse group of mammals that are highly specialized in active flight and ultrasound echolocation. These specializations rely on adaptations that reflect on their morphoanatomy and have been tentatively linked to brain morphology and volumetry. Despite their small size and fragility, bat crania and natural braincase casts ("endocasts") have been preserved in the fossil record, which allows for investigating brain evolution and inferring paleobiology. Advances in imaging techniques have allowed virtual extraction of internal structures, assuming that the shape of the endocast reflects soft organ morphology...

Prozostrodon brasiliensis and Therioherpeton cargnini are non-mammaliaform cynodonts that lived ~233 million years ago (late Carnian, Late Triassic) in western Gondwana. They represent some of the earliest divergent members of the clade Prozostrodontia, which includes "tritheledontids", tritylodontids, "brasilodontids", and mammaliaforms (including Mammalia as crown group). Here, we studied the endocranial anatomy (cranial endocast, nerves, vessels, ducts, ear region, and nasal cavity) of these two species...

Skulls of the Mongolian ankylosaurids Shamosaurus, Tarchia, and Saichania were scanned for information about their internal anatomy. Computed tomography (CT) imaging of the Tarchia skull revealed substantial internal anatomical differences from known Campanian North American taxa, particularly in the morphology of the airway. In addition, unexpected anomalies were detected within the airway and sinuses. The anomalies include multiple bilaterally distributed, variably sized hyperdense (mineralized) concretions within the airway and sinuses, the largest of which, positioned in the right nasal cavity medial to the supraorbitals, has an asymmetric ovoid shape that tapers caudally and which is partially encased within a hemispherical trabeculated osseous proliferation (sinus exostosis)...

This article provides an ontogenetically-based comparative description of the Guercy 3 partial child's maxilla with Rdm2 -RM1 and unerupted RI2 -RP4 from Baume Moula-Guercy (MIS 5e) and examines its affinities to European and Middle Eastern Middle-to-Late Pleistocene (≈MIS 14-MIS 1) Homo. Description of the Guercy 3 maxilla and dentition (7.0 year ± 0.9 month) is based on observations of original fossils, casts, CT scans, literature descriptions, and virtual reconstructions...

Bite force is a performance metric commonly used to link cranial morphology with dietary ecology, as the strength of forces produced by the feeding apparatus largely constrains the foods an individual can consume. At a macroevolutionary scale, there is evidence that evolutionary changes in the anatomical elements involved in producing bite force have contributed to dietary diversification in mammals. Much less is known about how these elements change over postnatal ontogeny. Mammalian diets drastically shift over ontogeny-from drinking mother's milk to feeding on adult foods-presumably with equally drastic changes in the morphology of the feeding apparatus and bite performance...

The recovery of additional mandibular fossils from the Atapuerca Sima de los Huesos (SH) site provides new insights into the evolutionary significance of this sample. In particular, morphological descriptions of the new adult specimens are provided, along with standardized metric data and phylogenetically relevant morphological features for the expanded adult sample. The new and more complete specimens extend the known range of variation in the Atapuerca (SH) mandibles in some metric and morphological details...

A new Old World trident bat (Rhinonycteridae) is described from an early Miocene cave deposit in the Riversleigh World Heritage Area, northwestern Queensland, Australia. Living rhinonycterids comprise a small family of insect-eating, nasal-emitting rhinolophoid bats from Africa, Madagascar, Seychelles, the Middle East, and northern Australia. The new fossil species is one of at least 12 rhinonycterid species known from the Oligo-Miocene cave deposits at Riversleigh. We refer the new species to the genus Xenorhinos (Hand, Journal of Vertebrate Paleontology, 18, 430-439, 1998a) because it shares a number of unusual cranial features with the type and only other species of the genus, X...

Neochelys is an exclusively European Eocene podocnemidid genus belonging to a linage that reached this continent at the early Eocene. The so far available anatomical information about it is relatively abundant, especially considering that of its shell, at least partially preserved for the eight valid species currently considered. By contrast, the skull of very few representatives of the taxon has been identified. Neochelys arenarum is one of the species for which the cranial anatomy is known. It corresponds to the oldest species of this genus, coming from the MP7 zone of the Ypresian (early Eocene) of Southern France...

One of the most remarkable features in sauropod dinosaurs relates to their pneumatized skeletons permeated by a bird-like air sac system. Many studies described the late evolution and diversification of this trait in mid to late Mesozoic forms but few focused on the origin of the invasive respiratory diverticula in sauropodomorphs. Fortunately, it is possible to solve this thanks to the boom of new species described in the last decade as well as the broad accessibility of new technologies. Here we analyze the unaysaurid sauropodomorph Macrocollum itaquii from the Late Triassic (early Norian) of southern Brazil using micro-computed tomography...

The nasal septum is the only element of the chondrocranium which never completely ossifies. The persistence of this nonarticular cartilage has given rise to a variety of theories concerning cranial mechanics and growth of the midface. Previously, using pigs, we demonstrated that the septum is not a strut supporting the snout and that septal growth seems capable of stretching the overlying nasofrontal suture, a major contributor to snout elongation. Here we investigate whether abnormalities of the septum are implicated in cases of midfacial hypoplasia, in which growth of the midface is inadequate...

Hagfish (Myxinoidea) are a deep-sea taxon of cyclostomes, the extant jawless vertebrates. Many researchers have examined the anatomy and embryology of hagfish to shed light on the early evolution of vertebrates; however, the diversity within hagfish is often overlooked. Hagfish have three lineages, Myxininae, Eptatretinae, and Rubicundinae. Usually, textbook illustrations of hagfish anatomy reflect the morphology of the Myxininae lineage, especially Myxine glutinosa, with its single pair of external branchial pores...

Great environmental changes may affect the survival capability of a variety of organisms. Testudinidae is the most diverse family of terrestrial chelonians within the whole order (Testudines). Interestingly, however, the number of extinct species overcome the extant ones. In order to understand better how the diversification process of this family occurred, this work used the PyRate software, which estimates both the preservation and diversification processes in a continuous time interval. For such, the software used a list of fossil occurrences obtained from the Paleobiology Database whereas the extant species list was obtained from Catalogue of Life...

Understanding the origins of the vertebrate brain is fundamental for uncovering evolutionary patterns in neuroanatomy. Regarding extinct species, the anatomy of the brain and other soft tissues housed in endocranial spaces can be approximated by casts of these cavities (endocasts). The neuroanatomical knowledge of Rhynchocephalia, a reptilian clade exceptionally diverse in the early Mesozoic, is restricted to the brain of its only living relative, Sphenodon punctatus, and unknown for fossil species. Here, we describe the endocast and the reptilian encephalization quotient (REQ) of the Triassic rhynchocephalian Clevosaurus brasiliensis and compare it with an ontogenetic series of S...

Glossectomy is a surgical procedure performed to remove all or part of the tongue in patients with cancer. The removal of a significant part of the tongue has a marked effect on speech and swallowing function, as patients may lose not only the tongue muscles but also the median lingual septum (MLS). Therefore, to achieve successful tongue regeneration, it is necessary to investigate the developmental processes of not only the tongue muscles but also the MLS. This study was conducted to clarify the mutual development of the tongue muscles and the MLS in human fetuses...