Beyond head and wings: Unveiling influence of diet, body size, and phylogeny on the evolution of the femur in phyllostomid bats.

Phyllostomidae, the most diverse family of Neotropical bats, encompass 230 species with varied dietary habits and food acquisition methods. Their feeding niche diversification has shaped skull and wing morphologies through natural selection, reflecting food processing and flight strategies. Yet, evolution of bat hindlimbs, especially in phyllostomids, remains little understood. Previous studies highlighted the femur's morphology as a key to understanding the evolution of quadrupedalism in yangochiropteran bats, including the adept walking observed in vampire bats (Desmodontinae). Here, we aimed to describe the femoral morphological variation in Phyllostomidae, correlating this with body size and assessing the effects of phylogenetic history, dietary habits, and hindlimb usage. Analyzing 15 femoral traits from 45 species across 9 subfamilies through phylogenetically informed methods, we discovered a significant phylogenetic structure in femoral morphology. Allometric analysis indicated that body mass accounts for about 85% of the variance in phyllostomid femoral size and about 11% in femoral shape. Relatively smaller femurs showed to be typical in Stenodermatinae, Lonchophyllinae, and Glossophaginae, in contrast to the larger femurs of Phyllostominae, Desmodontinae, Micronycterinae, and Lonchorrhininae. Furthermore, extensive femur shape variation was detected, with the most distinct morphologies in vampire bats, followed by frugivorous species. Adaptive evolutionary models related to diet more effectively explained variations in femoral relative size and shape than stochastic models. Contrary to the conventional belief of limited functional demand on bat femurs, our findings suggest that femoral morphology is significantly influenced by functional demands associated with diet and food capture, in addition to being partially structured by body size and shared evolutionary history.

An extinct north American porcupine with a South American tail.

New World porcupines (Erethizontinae) originated in South America and dispersed into North America as part of the Great American Biotic Interchange (GABI) 3-4 million years ago.1 Extant prehensile-tailed porcupines (Coendou) today live in tropical forests of Central and South America.2,3 In contrast, North American porcupines (Erethizon dorsatum) are thought to be ecologically adapted to higher-latitude temperate forests, with a larger body, shorter tail, and diet that includes bark.4,5,6,7 Limited fossils8,9,10,11,12,13 have hindered our understanding of the timing of this ecological differentiation relative to intercontinental dispersal during the GABI and expansion into temperate habitats.14,15,16,17,18 Here, we describe functionally important features of the skeleton of the extinct Erethizon poyeri, the oldest nearly complete porcupine skeleton documented from North America, found in the early Pleistocene of Florida. It differs from extant E. dorsatum in having a long, prehensile tail, grasping foot, and lacking dental specializations for bark gnawing, similar to tropical Coendou. Results from phylogenetic analysis suggest that the more arboreal characteristics found in E. poyeri are ancestral for erethizontines. Only after it expanded into temperate, Nearctic habitats did Erethizon acquire the characteristic features that it is known for today. When combined with molecular estimates of divergence times, results suggest that Erethizon was ecologically similar to a larger species of Coendou when it crossed the Isthmus of Panama by the early Pleistocene. It is likely that the range of this more tropically adapted form was limited to a continuous forested biome that extended from South America through the Gulf Coast.

Prey capture kinematics of horned frogs (Anura: Ceratophryidae).

Horned frogs, members of the Ceratophryidae family, encompass a group of anurans varying in size and behavior, yet unified by morphological and behavioral traits enabling them to adopt a megalophagous diet (i.e., large prey feeding). Although the group has been the focus of numerous studies, our understanding of its feeding behavior remains limited. In this study, we characterize the feeding mechanism in five species representing the three extant genera of ceratophryid anurans, both in terrestrial and aquatic environments. We also explore the ability of Chacophrys pierottii to adjust feeding behavior based on prey type. Our findings show that all species are capable of wide mouth opening, displaying an asymmetric feeding cycle. While tongue usage is the primary method for capturing prey on land, ceratophryids may use their forelimbs to manipulate prey into their mouths, exhibiting different behavioral patterns. C. pierottii shows modulation of its feeding kinematics and is also capable of some modulation of its feeding in response to prey properties.

Dancing close together in the woods: mate-guarding behavior might explain sexual dimorphism in Chrysoprasis auriventris auriventris Redtenbacher, 1868 (Coleoptera: Cerambycinae)

ABSTRACT A fortuitous observation of mate-guarding behavior of male Chrysoprasis a. auriventris is presented here. In our observation, a male hold onto the female's body using his forelegs and walks along with her while she lays the eggs into the trunk slits. While guarding the female, the male adopted aggressive postures and attacked rival males that approached her. We suggest that the mate-guarding behavior may explain the male's elongated mid and hindlegs in this species, under a functional perspective. Additionally, a new host plant association was recorded.

The function of wing bullae in mayflies (Insecta: Ephemeroptera) reveals new insights into the early evolution of Pterygota.

BACKGROUND: Mayflies are basal winged insects of crucial importance for the understanding of the early evolution of Pterygota. Unlike all other insects, they have two successive winged stages, the subimago and the imago. Their forewings feature so-called bullae, which are desclerotized spots in the anterior main veins. Up to now, they have been considered to play a major role in wing bending during flight. RESULTS: We investigated bullae by multiple methods to reveal their structure and arrangement and to gain new information on the evolution of insect flight. Bullae are mostly present in the anterior negative wing veins, disrupting the otherwise rigid veins. High-speed videography reveals that mayfly wings do not bend during flight. Likewise, different arrangements of bullae in different species do not correlate with different modes of flying. Observations on the moulting of subimagines unravel that they are essential for wing bending during the extraction of the imaginal wing from the subimaginal cuticle. Bullae define predetermined bending lines, which, together with a highly flexible wing membrane enriched with resilin, permit wing bending during subimaginal moulting. Bullae are only absent in those species that remain in the subimaginal stage or that use modified modes of moulting. Bullae are also visible in fossil mayflies and can be traced back to stemgroup mayflies of the Early Permian, the 270 million years old Protereismatidae, which most probably had bullae in both fore- and hind wings. CONCLUSIONS: Bullae in mayfly wings do not play a role in flight as previously thought, but are crucial for wing bending during subimaginal moulting. Thus, the presence of bullae is a reliable morphological marker for a subimaginal life stage, confirming the existence of the subimago already in Permian Protereismatidae. A thorough search for bullae in fossils of other pterygote lineages may reveal wheather they also had subimagines and at what point in evolution this life stage was lost. In mayflies, however, the subimago may have been retained due to selective advantages in connection with the transition from aquatic to terrestrial life or due to morphological requirements for a specialized mating flight.

Masticatory myology of the llama (Lama glama, Camelidae) and comparisons with other camelids and euungulates.

Camelids are the only living representatives of the Suborder Tylopoda, and present a unique set of osteo-myological masticatory features, differing from all other extant euungulates. They combine selenodont dentition and rumination with a fused symphysis, and roughly plesiomorphic muscle proportions. Despite its potential relevance as an euungulate model in comparative anatomy studies, the available data is strikingly scarce. The present study represents the first description of the masticatory muscles of a Lamini, analyzing the functional morphology of Lama glama and other camelids in a comparative framework. Both sides of the head of three adult specimens from Argentinean Puna were dissected. Descriptions, illustrations, muscular maps, and weighing of all masticatory muscles were performed. Some facial muscles are also described. The myology of llamas confirms that camelids possess relatively large temporalis muscles, with Lama being less extreme than Camelus. This plesiomorphic feature is also recorded in suines and some basal euungulates. Conversely, the direction of the fibers of the M. temporalis is mainly horizontal, resembling grinding euungulates such as equids, pecorans, and some derived suines. Although the M. masseter of camelids and equids do not reach the particularly modified configuration of pecorans, in which it is rostrally extended and arranged horizontally, the posterior sectors of Mm. masseter superficialis and pterygoideus medialis have acquired relatively horizontal disposition in the former lineages, suitable for protraction. The pterygoidei complex presents several bundles, and its relative size is intermediate between suines and derived grinding euungulates. The whole masticatory muscles are relatively light when compared to jaw weight. The evolution of the masticatory muscles and chewing of camelids implied that grinding abilities were reached with less extreme modifications of the topography and/or proportions than pecoran ruminants and equids. A relatively large M. temporalis recruited as a powerful retractor during the power stroke is a key feature of camelids. The relaxed pressure on chewing derived from the acquisition of rumination explains the slenderer build masticatory musculature of camelids compared to other euungulates except ruminants.

Upper beak depression instead of elevation dominates cranial kinesis in woodpeckers.

The value of birds' ability to move the upper beak relative to the braincase has been shown in vital tasks like feeding and singing. In woodpeckers, such cranial kinesis has been thought to hinder pecking as delivering forceful blows calls for a head functioning as a rigid unit. Here, we tested whether cranial kinesis is constrained in woodpeckers by comparing upper beak rotation during their daily activities such as food handling, calling and gaping with those from closely related species that also have a largely insectivorous diet but do not peck at wood. Both woodpeckers and non-woodpecker insectivores displayed upper beak rotations of up to 8 degrees. However, the direction of upper beak rotation differed significantly between the two groups, with woodpeckers displaying primarily depressions and non-woodpeckers displaying elevations. The divergent upper beak rotation of woodpeckers may be caused either by anatomical modifications to the craniofacial hinge that reduce elevation, by the caudal orientation of the mandible depressor muscle forcing beak depressions, or by both. Our results suggest that pecking does not result in plain rigidification at the upper beak's basis of woodpeckers, but it nevertheless significantly influences the way cranial kinesis is manifested.

Ecomorphological variation of the penguin wing.

Penguins (Aves, Sphenisciformes) are pursuit divers that feed mainly on krill, fish, and squid. Although they are opportunistic feeders, some species are more generalists than others and many show dietary preferences toward krill and other crustaceans or fish and squid. Their diving depth seems to follow a body size pattern and relates to the type of item that they prey on. Penguins dive with their wing; hence their wing musculature is responsible for the animal maneuverability and strength while diving. In the present study, ecological traits such as diving depths and prey composition are used to explore if morphology relates to foraging habits. A geometric morphometric approach is used to quantitatively address these morphological differences in the wing apparatus of all extant penguins and a fossil species taking into consideration allometric and phylogenetic factors. Results show that morphological differences among penguins with different diets are significant and strong; groups are well separated with the greatest differences found between piscivorous and crustacivorous penguins. Dive depth has a moderate covariation with morphology and a strong correspondence with wing area. Last, Madrynornis mirandus, an exceptionally well-preserved fossil from the Miocene of Patagonia, is found to be close to the piscivorous and generalist piscivorous species. It is proposed that swimming styles correlate with specific traits of the anatomy of wing and pectoral girdle skeleton and muscles.

Community-scale relationships between body shape and trophic ecology in tropical demersal marine fish of northeast Brazil.

Functional morphology investigates the relationships between morphological characters and external factors, such as environmental, physical and ecological features. Here, we evaluate the functional relationships between body shape and trophic ecology of a tropical demersal marine fish community using geometric morphometrics techniques and modelling, hypothesizing that shape variables could partially explain fish trophic level. Fish were collected over the continental shelf of northeast Brazil (4-9°S). Analysed fish were distributed into 14 orders, 34 families and 72 species. Each individual was photographed in lateral view, and 18 landmarks were distributed along the body. A principal component analysis (PCA) applied on morphometric indices revealed that fish body elongation and fin base shape were the main axes of variation explaining the morphology. Low trophic levels (herbivore and omnivore) are characterized by deep bodies and longer dorsal and anal fin bases, while predators present elongated bodies and narrow fin bases. Fin position (dorsal and anal fins) on the fish body is another important factor contributing to (i) body stability at high velocity (top predators) or (ii) manoeuvrability (low trophic levels). Using multiple linear regression, we verified that 46% of trophic level variability could be explained by morphometric variables, with trophic level increasing with body elongation and size. Interestingly, intermediate trophic categories (e.g., low predators) presented morphological divergence for a given trophic level. Our results, which can likely be expanded to other tropical and nontropical systems, show that morphometric approaches can provide important insights into fish functional characteristics, especially in trophic ecology.

Anatomy of the vertebral column, ribs and sternum in orange rumped agouti (Dasyprocta leporina Linnaeus, 1758): Structural and Functional perspectives.

The axial skeleton of orange rumped agouti, Dasyprocta leporina, was studied for better understanding of its locomotor behaviour. The bones from eight adult agoutis of both sexes were observed for their anatomical features and functional significance. The vertebral formula was found to be C7 T12 L7 S5 Cy5-6 . The well-developed occipital crest, caudally oriented prominent axis spine and well-developed transverse processes from C3 -C7 indicated a highly flexible neck with greater sagittal mobility. Articular facets were horizontal in anterior series while oblique in the posterior series, which enabled them to perform both lateral and sagittal movements during locomotion. The caudally directed thoracic spines, T12 as anticlinal vertebra and prominent mamillary process in the posterior series were suggestive of strong dorso-ventral flexion/extension and rotation. The robust lumbar vertebrae, well-developed transverse processes with cranio-ventral extension, were the feature for powerful sagittal/dorsoventral movement. The presence of spinous processes and well-developed transverse processes in all caudal vertebrae was an indication of a highly movable tail. The ribs were 13 pairs with first seven as sternal and six as asternal. They were laterally compressed in the anterior series as a cursorial adaptation. A strong muscular attachment to vertebrae provides this rodent speed, agility, dexterity and strength suitable for survival in food chain.

Insectivory leads to functional convergence in a group of Neotropical rodents.

The mandible of vertebrates serves as insertion area for masticatory muscles that originate on the skull, and its functional properties are subject to selective forces related to trophic ecology. The efficiency of masticatory muscles can be measured as mechanical advantage on the mandible, which, in turn, has the property of correlating with bite force and shape. In the present work, we quantify the mechanical advantage of the mandible of akodontine rodents, which present a diverse radiation of insectivorous specialists, to assess their relationship to the estimated bite force and diet. We also tested the degree of morphofunctional convergence in response to insectivory on the group. We found the mechanical advantages to be convergent on insectivorous species, and associated with the estimated bite force, with higher mechanical advantages in species with a stronger bite and short, robust mandibles and lower mechanical advantages in insectivorous species with weaker bites and more elongated, dorso-ventrally compressed mandibles. Insectivorous species of Akodontini are functional specialists for the consumption of live prey and may exploit the resources that shrews, moles and hedgehogs consume elsewhere.

Giant steps: adhesion and locomotion in theraphosid tarantulas.

Theraphosid tarantulas are large spiders that bear dense hairy adhesive pads on the distal parts of their legs: scopula and claw tufts. These structures allow them to climb on vertical smooth surfaces and contribute to prey capture. While adult females and juveniles remain most of the time in their burrows, adult males actively walk searching for females during the reproductive period. Adhesion and locomotion thus play important roles in the ecology and reproduction of these animals. In this paper, we review the current state of the knowledge on adhesion and locomotion in tarantulas, focusing on functional and evolutionary morphology.

Ecomorphological Adaptations of Second Maxilliped-setation: Insights from Three Species of Fiddler Crabs from Panama.

The functional morphology of maxilliped-setation in three species of fiddler crabs-Petruca panamensis, Leptuca terpsichores and L. beebei-collected from Panama were studied using a comparative ecomorphological approach. The coverage of spoon-tipped (ST) and plumose (P) setae on the inner surface of the second maxilliped were noted, and the abundance of each setal type was enumerated, with crab carapace width as the covariate. These attributes were then related to the sediment particle size characterization of their respective collection sites for an ecomorphological comparison. All three species have mixed setation, albeit in different proportions of coverage. For L. terpsichores, the ST:P coverage was consistently ca. 70%:30% whereas there was approximately equal coverage of both setal types (i.e., 50% ST:50% P) on the maxillipeds of L. beebei and P. panamensis. Analysis of Covariance (ANCOVA) results of setal counts between the sexes in each species showed that the number of ST and P setae did not differ significantly between males and females, indicating an absence of sexual dimorphism in mouthpart setae. When all three species were compared-sexes combined within each species-ANCOVA results reveal that for any crab of a given size, there were significantly more ST setae on the second maxilliped of L. terpsichores (sediment from sampling site classified as 'moderately-sorted medium sand') than L. beebei (sediment from sampling site classified as 'moderately-sorted fine sand') and P. panamensis (a rocky-habitat species); no significant difference was detected between ST abundance in the latter two species. Current results provide unequivocal quantitative evidence that the abundance of ST setae can be an indicator to differentiate habitats down to the level of different sand-grain size, i.e., medium sand versus fine sand habitats of L. terpsichores and L. beebei, respectively. Both L. beebei and P. panamensis had significantly fewer ST setae than L. terpsichores, possibly because the former two species' habitats have sediments with sand grains that are less coarse than the latter's. On rocks, P. panamensis does not produce pseudofecal pellets as they directly swallow food materials pinched from the rock surfaces without sorting, rendering the role of ST setae of secondary importance. The three species did not differ significantly in P setae abundance, suggesting that the adaptive function of this type of setae to habitat characteristics remains debatable. The significance of ST setae as an ecomorphological adaptation for efficient food extraction from sandy sediments is, thus, evident in L. terpsichores. As for other two species-L. beebei and P. panamensis-that live in environments with finer sediment grain sizes, the adaptive role of ST setae is of diminished functional importance. Fiddler crab species with mixed setal types may have greater potential to exhibit feeding plasticity should their habitats be threatened.

Ecomorphological associations of scapulocoracoid form in Greater Antillean Anolis lizards.

External morphological metrics have featured prominently in comparative studies examining the morphological convergence that characterizes anoline ecomorphs. To what degree the appendicular-skeletal morphology of Greater Antillean island Anolis lizards tracks their diversity and ecological adaptation, however, remains relatively unexplored. Here we employ computed tomographic scanning techniques to visualize in situ the scapulocoracoid of ecomorph representatives (trunk-ground, trunk-crown, crown-giant, twig) from three islands (Jamaica, Hispaniola, and Puerto Rico), and compare its three-dimensional geometry using qualitative-descriptive and quantitative-morphometric techniques. In contrast to our previous, similarly-conducted study of the pelvic girdle of these same species, the form of the scapulocoracoid varies markedly both within and between species, with much of the variation relating to phylogenetic relationship, specimen size, and assigned ecomorph category. Morphometric variation that correlates with size and/or phylogenetic signal varies between species and cannot be eliminated from the data set without markedly reducing its overall variability. The discovered patterns of skeletal variation are consistent with the demands of locomotor mechanics imposed by the structural configuration of the microhabitat of these ecomorphs. Most pertinently the ecomorphs differ in the anteroposterior length of the coracoid, the dorsoventral height of the scapulocoracoid, the dorsoventral height of the scapula in relation to the height of the suprascapula, and the relative positioning of the borders of the scapulocoracoid fenestra. In the examined ecomorph categories these skeletal differences likely relate to microhabitat usage by permitting different degrees of tilting and displacement of the scapulocoracoid in the parasagittal plane and influencing the sizes of muscle origins and the vectors of their actions. These differences relate to the amount of humeral adduction applied during its protraction, and to the structural stability of the shoulder girdle during acrobatic maneuvers, thus influencing the perch diameter that can be effectively negotiated, a critical factor in the microhabitat structure of Anolis ecomorphs.

Morphological responses of three persistent native anuran species after forest conversion into monoculture pine plantations: tolerance or prosperity?

Species loss by habitat replacement operating as an ecological filter is a well-known consequence of modern human activities. In contrast, the ecological and evolutionary response of species overcoming those filters in converted habitats has not been thoroughly explored. Species that persist are subject to novel and potentially stressful conditions that may induce certain morphological changes. We evaluated changes in the functional morphology of three anuran species persisting after the conversion of areas of the Atlantic Forest into pine plantations. We specifically evaluated differences in body size and body condition indices, head width, and hind legs' length between adult individuals from both habitats and sexes. Habitat conversion and sexual dimorphism affected the morphology of the three anurans, with varying effects upon species and traits. Regarding the effect of habitat conversion, Elachistocleis bicolor increased body condition in plantations with no changes in the other traits, Physalaemus cuvieri showed only a marginal increment in residual body mass in plantations, and Odontophrynus americanus exhibited a substantial increment in body size while maintaining its body condition in plantations. Remarkably, none of the results suggested these persistent anurans were stressed by forest conversion. This study shows that habitat conversion may induce intraspecific morphological changes in ecologically relevant traits of persistent species, and that disturbed areas do not necessarily imply stressful, low quality habitats affecting all persistent native species negatively.

Differential locomotor and predatory strategies of Gondwanan and derived Laurasian dromaeosaurids (Dinosauria, Theropoda, Paraves): Inferences from morphometric and comparative anatomical studies.

Tetrapod limbs morphology is a reliable proxy of locomotor capacities. Beyond this, other aspects of life habits, such as predation abilities, can also be relevant to determine main morphofunctional appendicular properties, which ultimately reflect a compromise between different factors of the biological role. Dromaeosauridae is a dinosaur clade belonging to Theropoda, a group of bipedal predators. Dromaeosaurids represent an interesting study case, in which the hindlimbs have been proposed to be involved in both locomotion and predation activity. A peculiar feature characterizing all dromaeosaurids is a modified second pedal digit, which is typically related to predation. This theropod group is closely related to birds and diversified during the Cretaceous Period, mainly in the Northern Hemisphere (Laurasia). However, a subclade of dromaeosaurids, the Unenlagiinae, was recently recognized for Gondwana. Nevertheless, there are morphological differences between derived Laurasian dromaeosaurids (eudromaeosaurs) and unenlagiines. Such differences are observed in the proportions between hindlimb bones and in the presence of a subarctometatarsalian condition in unenlagiines, which is mainly characterized by a proximally constricted metatarsal III. To evaluate the function of these divergent morphologies, we conducted morphometric analyses and comparisons of qualitative morphological aspects, encompassing unenlagiines, other dromaeosaurids, as well as taxa from other theropod groups, including extant birds. The former approach consisted of two phylogenetic principal component analyses, one based on the main measurements of the hindlimb, and the other focused on the lengths of the pedal phalanges. The first analysis drew the unenlagiines close to taxa with long tibiae, as well as long and slender metatarsi. Instead, eudromaeosaurs are closer to taxa with shorter tibiae, and shorter and wider metatarsi. The second analysis showed that eudromaeosaurs and unenlagiines have similar phalangeal proportions, including the elongation of distal phalanges. However, the shorter second phalanx of the pedal digit II of eudromaeosaurs could have increased the force generated by this digit, which was the main predatory tool of the autopodium. This, together with a shorter and wider metatarsus, and a marked hinge-like morphology of the articular surfaces of metatarsals and phalanges, possibly allowed eudromaeosaurs to exert a great gripping strength and hunt large prey. Conversely, the longer and slender subarctometatarsus, and less well-marked hinge joints of unenlagiines possibly gave them greater cursorial capacities. Additionally, the longer second phalanx of digit II allowed unenlagiines fast movements of this digit to hunt smaller and elusive prey. Thus, the distinctive morphological evolutionary pathways of these two dromaeosaurid clades seem to have been influenced by the particular locomotor and predatory specializations that characterized each of these lineages.

Diverticula in Male Lycorea halia Butterflies (Lepidoptera: Nymphalidae: Danaini: Itunina)-Support Organs for Everted Hairpencils with Unique Ultrastructure.

The involvement of the diverticula, a synapomorphy for Itunina, in protrusion and expansion of hairpencils by male Lycorea halia (Hübner, 1816) is demonstrated for the first time. They facilitate maintaining the haemolymph pressure necessary to keep the hairpencils everted. The diverticula are curved hook-like lobes, open to the body cavity and densely filled with tracheae and threads made by units of two staggered cells surrounding a central extracellular fibril bundle. Such complex structures, apparently metabolically active, have not been reported for insects previously and might indicate additional functions, but their functional role(s) remains a puzzle. When a male emerges from pupa, the diverticula are not yet formed; this happens only during the first protrusion of the hairpencils.

My branch is your branch: Talar morphology correlates with relative substrate size in platyrrhines at Tiputini Biodiversity Station, Ecuador.

Given that most species of primates are predominantly arboreal, maintaining the ability to move among branches of varying sizes has presumably been a common selective force in primate evolution. However, empirical evaluations of the relationships between morphological variation and characteristics of substrate geometry, such as substrate diameter relative to an animal's body mass, have been limited by the lack of quantified substrate usage in the wild. Here we use recently published quantitative data to assess the relationships between relative substrate size and talar morphology in nine New World monkey species at the Tiputini Biodiversity Station, Ecuador. Within this sample, both fibular facet angle (the angle between the fibular facet and the trochlear rims) and body-mass-standardized area of the medial tibial facet decrease as average and maximum relative substrate size increases. Correlations between medial tibial facet area and relative substrate size are driven by the inclusion of callitrichids in this sample. Nevertheless, these findings strengthen the hypothesis that variation in fibular facet orientation and medial tibial facet area are functionally correlated with habitual degrees of pedal inversion. They also strengthen the notion that evolutionarily changing body mass could impact habitat geometry experienced by a lineage and thereby substantially impact major trends in primate morphological evolution. This study highlights the importance of empirical data on substrate use in living primates for inferring functional and evolutionary implications of morphological variation.

Microstructural morphology of dermal and oral denticles of the sharpnose sevengill shark Heptranchias perlo (Elasmobranchii: Hexanchidae), a deep-water species.

The dermal denticles are among the unique morphological adaptations of sharks, which have been acquired throughout their long evolutionary process of more than 400 million years. Species-specific morphological characteristics of these structures has been applied specially as tools for functional and taxonomic (family-level) studies. Nevertheless, few studies have explored the diversity of denticle structure in different around the body and oral cavity. In the present study, we described the morphological differences observed in skin and oral cavity of sharpnose sevengill shark Heptranchias perlo, using scanning electron microscopy. Our findings demonstrate substantial variation in morphological structure of the denticles of the body and oral cavity. Overall, the dermal denticles observed across body surface were overlapped, tricuspid, with the central cuspid being more pronounced, pointed, and triangular in shape compared with lateral ones. Unlike, the denticles on the tip of the nose had a smooth crown, with rounded edges, being compact, and overlapped. The oral denticles were found in the ventral and dorsal region of the oral cavity. They also were tricuspid, but with differences in arrangement and ridges. These results suggest a strict functional relationship with the morphological characteristics observed. Such morphological diversity body-region-dependent highlights the need for comparative studies that include oral denticles, since this structure has an important functional role in sharks and can be found in fossil and recent records.

Locomotory adaptations in entoptychine gophers (Rodentia: Geomyidae) and the mosaic evolution of fossoriality.

Pocket gophers (family Geomyidae) are the dominant burrowing rodents in North America today. Their fossil record is also incredibly rich; in particular, entoptychine gophers, a diverse extinct subfamily of the Geomyidae, are known from countless teeth and jaws from Oligocene and Miocene-aged deposits of the western United States and Mexico. Their postcranial remains, however, are much rarer and little studied. Yet, they offer the opportunity to investigate the locomotion of fossil gophers, shed light on the evolution of fossoriality, and enable ecomorphological comparisons with contemporaneous rodents. We present herein a quantitative study of the cranial and postcranial remains of eight different species of entoptychine gophers as well as many contemporary rodent species. We find a range of burrowing capabilities within Entoptychinae, including semifossorial scratch-digging animals and fossorial taxa with cranial adaptations to burrowing. Our results suggest the repeated evolution of chisel-tooth digging across genera. Comparisons between entoptychine gophers and contemporaneous rodent taxa show little ecomorphological overlap and suggest that the succession of burrowing rodent taxa on the landscape may have had more to do with habitat partitioning than competition.