Osteological Traits Research Articles

The Maya Ajawtaak and Teotihuacan Hegemony c. 150–600 ce

This study considers the role played by Teotihuacan in the emergence of the office of the Classic Maya ajawtaak, or ‘lords’. I argue that the synthesis of this office at the site of Tikal was influenced by the building of Teotihuacan's Pyramid of the Feathered Serpent between about 180 and 230 ce. Prior to and in concert with this building's construction, Teotihuacanos orchestrated the sacrifice of an estimated 200 or more individuals, some number of whom resided beyond the Basin of Mexico before burial. Osteological traits consistent with origins in the Maya region are present among these sacrifices. The Pyramid of the Feathered Serpent features mirror and obsidian icons, which later grew to prominence in the self-presentations of the ajawtaak. I note that around the time of this monument's construction, Tikal's obsidian corpus changed in ways that paralleled similar, earlier changes that had occurred to obsidian procurement strategies at Teotihuacan. I conclude that from about 200 ce, some Classic ajawtaak observed the religion that cohered with the building of Teotihuacan's Temple of the Feathered Serpent. The ajawtaak occupied a unique positionality in Early Classic Mesoamerica that was neither essentially Teotihuacan nor essentially Maya, but a dynamic syncretism of the two ethnicities.

The osteology of the lacertid genus Darevskia Arribas, 1999 (Squamata, Lacertidae)

A total of 230 cleared and alizarin stained and 136 radiographed specimens of Darevskia belonging to 47 nominal taxa (species, subspecies or singular clades) including the seven parthenogenetic ones and a triploid hybrid were studied. Sixteen osteological characters in all the tried species were analyzed. These characters by corporal regions were: skull characters: 1.—number of premaxillary teeth; 2.—number of maxillary teeth; 3.—number of dentary teeth; 4.—teeth morphology; 5.—presence of anterolateral process in the postfrontal bone; 6.—presence of anteromedial process in the postorbital bone; 7.—comparative lengths of the postorbital and postfrontal bones; 8.—overlap degree between the postorbital and the squamosal bones. Postcranial characters: 9.—existence of visible (ossified) ribs associated with the third presacral vertebrae; 10.—sternal/xiphisternal costal formula and presence of inscriptional ribs; 11.—number of presacral vertebrae; 12.—number of posterior dorsal vertebrae (short presacral ribs); 13.—presence and form of the sternal fontanelle; 14.—form of the clavicles (emarginated or marginated); 15.—interclavicle form; 16.—morphology of first autotomic vertebrae of the tail. Our goals were to characterize osteologically the different species of Darevskia, to contrast their relationships traced from osteological traits with the available genetic-derived phylogenies of the group, to compare the osteological characteristics of the parthenogenetic species with their bisexual parental species, and to comment on their parentage and character polarity. Finally, we aimed to search for osteological characteristics of the different groups within Darevskia, diagnosing them for the first time. The results, commented on by characters, are available in the main text, and taxa characteristics are easily consultable and condensed in Table 1. Osteological characteristics of Darevskia, together with available phylogenetic trees, have permitted us to define some new groups within Darevskia (raddei, chlorogaster, defilippi, and parvula new groups) (Appendix 3), which are reciprocally monophyletic and have diagnostic characteristics. All of them are diagnosed and named as subgenera to be used if necessary, instead of the partial, old and not always comprehensive groups.

The interglenoid tubercle of the atlas is ancestral to lissamphibians.

Lissamphibians, represented today by frogs, salamanders, and caecilians, diverged deep in the tetrapod tree of life. Extensive morphological adaptations to disparate lifestyles have made linking extant lissamphibians to one another and to their extinct relatives difficult and controversial. However, the discovery of a feature on the atlas of the frog Xenopus laevis, may add to the small set of osteological traits that unite lissamphibians. In this study, we combine our observations of atlas development in X. laevis with a deep examination of atlantal interglenoid tubercle (TI) occurrence in fossil taxa. The TI is shown herein to occur transiently on the ossifying atlas of roughly one-third of X. laevis tadpoles but is absent in adults of this species. In ancestral character state estimations (ACSE), within the evolutionary context of lissamphibians as dissorophoid temnospondyls, this feature is found to be ancestrally shared among lissamphibians, its presence is uncertain in stem batrachians, and then the TI is lost in extant caecilians and frogs. However, our data suggests apparent TI loss around the origin of frogs may be explained by its ontogenetically transient nature. The only nonamphibian tetrapods with a TI are "microsaurs," and this similarity is interpreted as one of many convergences that resulted from convergent evolutionary processes that occurred in the evolution of "microsaurs" and lissamphibians. The TI is thus interpreted to be ancestral to lissamphibians as it is found to be present in some form throughout each extant lissamphibian clade's history.

Reconstructing the origin and early evolution of the snake brain.

Snakes represent one-eighth of terrestrial vertebrate diversity, encompassing various lifestyles, ecologies, and morphologies. However, the ecological origins and early evolution of snakes are controversial topics in biology. To address the paucity of well-preserved fossils and the caveats of osteological traits for reconstructing snake evolution, we applied a different ecomorphological hypothesis based on high-definition brain reconstructions of extant Squamata. Our predictive models revealed a burrowing lifestyle with opportunistic behavior at the origin of crown snakes, reflecting a complex ancestral mosaic brain pattern. These findings emphasize the importance of quantitatively tracking the phenotypic diversification of soft tissues-including the accurate definition of intact brain morphological traits such as the cerebellum-in understanding snake evolution and vertebrate paleobiology. Furthermore, our study highlights the power of combining extant and extinct species, soft tissue reconstructions, and osteological traits in tracing the deep evolution of not only snakes but also other groups where fossil data are scarce.

Analysis of tail morphology and osteology in Ethiopian indigenous sheep

Sheep adaptive diversity, including tail morphology, has been shaped by various factors, including natural and/or artificial selection for different traits. The Horn of Africa has historically been a major livestock entry point on the African continent from the Near Eastern centers of initial domestication. Ethiopia, in particular, possesses a marked sheep diversity, including the presence of breeds with four distinct tail morphotypes (short fat-tail, long fat-tail, fat-rump, and thin-tail) that do not co-exist elsewhere. The origin and development of the fat-tail, as well as the fat-rump, are still poorly known, and the osteological and metrical differences between the fat-tail morphotypes have never been studied. Here, we characterized the phenotypic diversity of Ethiopian sheep tails from morphological and osteological perspectives. Three tail measurements and 14 osteological traits were recorded in six breeds (Menz, Washera, Afar, Blackhead Somali, Bonga, and Gumz), representative of the four sheep tail morphotypes. Both linear discriminant and principal component analyses categorize the six sheep breeds into four distinct tail morphotypes. Analysis of variance of the morphological and osteological traits shows significant differences (P < 0.05) between the four tail morphotypes. The highest mean values of tail length, total caudal vertebrae length and the number of caudal vertebrae were recorded in the thin-tailed sheep, followed by the long fat-tailed sheep, whereas the lowest average values were recorded in the fat-rumped and short fat-tailed sheep. These traits are significantly and positively correlated with each other. Based on regression model analysis, it is possible to use tail length alone as a predictive tool to estimate the sheep tail osteology without killing the animal. Moreover, based on measurements of sheep caudal vertebrae, the osteologist can estimate other osteological traits and the tail length of that sheep, further differentiating its tail morphotypes. Significant differences (P < 0.05) were also observed in individual caudal vertebra length and breadth, tail breadth and tail circumference, and flat and concave-shaped caudal vertebrae between the short-tailed and long-tailed sheep. Our results provide important phenotypic baselines for genome diversity and adaptation studies and an osteological baseline for archeozoological work aiming to understand the history of sheep farming and breed development in past societies.

Effects of the Habitat and Genotype on Osteological Traits in Landlocked and Anadromous Ecological Forms of Atlantic Salmon Salmo salar Linnaeus, 1758

Studies of speciation and intraspecific differentiation in salmonid fishes are traditionally based on analysis of osteological traits. In the current study the variation of osteological traits was compared between two Atlantic salmon forms: anadromous and landlocked. Each form was represented by three samples: one from a wild population, and two from hatcheries; i.e., we studied six samples in total. In total, 45 osteological characters were analyzed. Differences between the forms were found to be genetically determined to a substantial extent. The factor “origin” explained 48% of the total morphological difference between the fish samples; the factor “habitat”, 32%; and their interaction, 14%. Phenotypic plasticity of the anadromous form was observed to be lower than that of the landlocked form. We consider that the higher phenotypic plasticity may compensate for a decrease in genetic diversity which is observed in landlocked forms of the species.

The functional diversity of marsupial limbs is influenced by both ecology and developmental constraint

Abstract Extant marsupials are less ecologically diverse than placentals, and this is reflected by placentals exhibiting a greater diversity of locomotor modes, including powered flight and fully aquatic swimming. One proposed explanation for this discrepancy is that the development of more disparate marsupial forelimbs is prevented by the neonate’s crawl to the pouch, which requires precocious forelimb development for climbing adaptations. To test predictions of this Developmental Constraint Hypothesis (DCH), we pursue a comparative morphometric study on osteological traits of mammalian limbs, with an emphasis on functional differentiation of marsupial limbs among locomotor modes. We apply multivariate analyses to a large dataset of limb metrics and a diverse sample of mammals, with the placental sample limited to taxa whose locomotor modes are exhibited in marsupials. Overall, we do not find consistent evidence in support of the DCH. Diprotodontia serves as an exception, with comparisons of their forelimbs to hind limbs supporting the DCH. Our results suggest that developmental constraints on marsupial forelimbs may have limited marsupial diversity to some degree. Despite this, the marsupial locomotor groups show unexpectedly high levels of morphological differentiation relative to placentals of the same locomotor modes, indicating that ecological functions may overcome developmental constraints on a macroevolutionary scale.

Osteological development of a small and fast metamorphic frog, Microhyla fissipes (Anura, Neobatrachia, Microhylidae).

Describing osteological development is of great importance for understanding vertebrate phenotypic variations, form-functional transitions and ecological adaptations. Anurans exhibit dramatic changes in their morphology, habitat preferences, diet and behaviour between the tadpole and frog stages. However, the anatomical details of their cranial and postcranial development have not been extensively studied, especially in Microhylidae. In this work, we studied the microhylid Microhyla fissipes, commonly known as the ornamented pygmy frog, a small-sized frog with fast metamorphosis. Its osteological development was comprehensively described based on 120cleared and stained specimens, including six tadpoles for each stage between 28 and 45, six juveniles and six adults. Additionally, 22 osteological traits of these specimens involved in food acquisition, respiration, audition and locomotion were selected and measured to reflect the changes in tadpole ecological functions during metamorphosis. Our study provides the first detailed qualitative and quantitative developmental information about these structures. Our results have confirmed that skeletal elements (viz., neopalatines, omosternum, clavicles and procoracoids) absent in adults are not detected during development. Our data reveal that morphologically, radical transformations of the cranial structures related to feeding and breathing are completed within stages 42-45 (72h), but the relative length and width of these skeletons have changed in earlier stages. The postcranial skeletons correlated with locomotion are well developed before stage 42 and approach the adult morphology at stage 45. Indeed, the relative length of the pectoral girdle and forelimb reaches the adult level at stage 42 and stage 45, respectively, whereas that of the vertebral column, pelvic girdle and hind limbs increases from their appearance until reaching adulthood. Based on published accounts of 19species from Neobatrachia, Mesobatrachia and Archaeobatrachia, cranial elements are among the first ossified skeletons in most studied species, whereas sphenethmoids, neopalatines, quadratojugals, mentomeckelians, carpals and tarsals tend to ossify after metamorphosis. These results will help us to better understand the ecomorphological transformations of anurans from aquatic to terrestrial life. Meanwhile, detailed morphological and quantitative accounts of the osteological development of Microhyla fissipes will provide a foundation for further study.

Comparative osteology of the fossorial frogs of the genus Synapturanus (Anura, Microhylidae) with the description of three new species from the Eastern Guiana Shield

The genus Synapturanus includes three nominal species of fossorial Amazonian frogs. A previous study combining molecular, morphological and acoustic data suggested that there may be six times more species than currently recognized. Herein we describe and name three of these new species and compare their osteology. Synapturanus zombie sp. nov. occurs in French Guiana and Amapá (Brazil), Synapturanus mesomorphus sp. nov. in Guyana and adjacent Venezuela, and Synapturanus ajuricaba sp. nov. in the northern part of the Brazilian states of Amazonas and Pará. These species are readily differentiated from congeners by a combination of external morphological characters such as body size, development of fringes on fingers and coloration, by advertisement call variables, and by osteological traits. Along with osteological reinforcement of the skull, atlas and scapular region, the reduction of the size of phalanges, more developed fringes on fingers, smaller eyes and larger body size, altogether suggest an overall increase of the fossorial habits in the easternmost species. In contrast, the relatively conserved morphology of the posterior part of the body across the genus suggests that fossoriality mostly involves the anterior part. Furthermore, the fusion of tarsal bones in the species of the western clade may indicate locomotory adaptation to more epigean habits.

Rethinking the evidence for early horse domestication at Botai

Despite its transformative impact on human history, the early domestication of the horse (Equus caballus) remains exceedingly difficult to trace in the archaeological record. In recent years, a scientific consensus emerged linking the Botai culture of northern Kazakhstan with the first domestication of horses, based on compelling but largely indirect archaeological evidence. A cornerstone of the archaeological case for domestication at Botai is damage to the dentition commonly linked with the use of bridle mouthpieces, or “bit wear.” Recent archaeogenetic analyses reveal, however, that horse remains from Botai are not modern domesticates but instead the Przewalski’s horse, E. przewalskii—warranting reevaluation of evidence for domestication. Here, we compare osteological traits hypothesized to have been caused by horse transport at Botai with wild Pleistocene equids in North America. Our results suggest that damage observed in Botai horse teeth is likely generated by natural disturbances in dental development and wear, rather than through contact with bridle equipment. In light of a careful reconsideration of the mid-Holocene archaeological record of northern Eurasia, we suggest that archaeological materials from Botai are most effectively explained through the regularized mass harvesting of wild Przewalski’s’ horses—meaning that the origins of horse domestication may lie elsewhere.

Osteomorphological Features of the Carcass of Inia geoffrensis (Cetacea: Iniidae)

Osteological studies can have implications that allow direct biological inferences to be made, such as locomotion, as well as indirect ones, such as species distribution, evolution and ecology. This study was aimed at describing some osteological traits of Inia geoffrensis (Blainvillei, 1817), Macapá/AP. A nearly complete carcass was found in a local forest. Information about the killing was collected through community reports. After collecting bones and information, the carcass was taken to the Laboratory of Zoology at the Federal University of Amapá for cleaning and examination. The cleaning process was carried out following the step-by-step maceration protocol and measurements of bones were taken with a measuring tape (2 m) and ruler (50 cm), except for cervical vertebrae, which were measured with a caliper (15 cm). To find the limbs in the carcass, an identification guide and a bone chart of aquatic mammals were used. Based on the observed data, the animal was a female, determined by the genital cleft. Examination of the occipital bone revealed an adult with complete bone fusion, obliterated sutures on the external surface of the skull. The carcass was nearly complete, with the entire face measuring 55 cm. Further studies are needed on environmental education about cetaceans, local awareness with the assistance of inspectors and competent authorities for the conservation of freshwater dolphins in the region and studies on carcasses for the maintenance of the species.

Detailed Structure of the Skeleton, Muscles, and Connective-Tissue Elements in the Head of Silver Carp Hypophthalmichthys molitrix (Cyprinidae) in Relationship with the Functional Features of Its Visceral Apparatus

The structure of some muscles, ligaments, the aponeurotic system, and osteological traits of the visceral apparatus in silver carp Hypophthalmichthys molitrix is considered in detail. A number of the revealed traits of the jaw apparatus indicate its adaptation to pulsed suction filtration. The functional features of the feeding apparatus are analyzed based on the anatomical study and data published in literature.

Revision of Gymnotus (Gymnotiformes: Gymnotidae) from the Upper Madeira Basin of Bolivia and Peru, with descriptions of two new species.

Banded Knifefishes (Gymnotus, Gymnotidae) comprise the most species-rich genus of Neotropical electric fishes, with 41 species currently described from throughout the humid Neotropics, from Mexico to Argentina. Despite substantial alpha-taxonomic work in recent years, the diversity of Gymnotus in some regions remains poorly understood. Here we describe the Gymnotus fauna of the Upper Madeira basin of Bolivia and Peru from examination of more than 240 adult specimens. Species are delimited and described using body proportions (traditional morphometrics), fin-ray, squamation and laterosensory-pore counts (meristics), quantitative shape differences (geometric morphometrics), osteological traits, and color patterns. Comparisons of standardized linear measures as well as multivariate statistical methods validate the presence in the Upper Madeira basin of three previously described species, two with wide-spread geographic distributions throughout Greater Amazonia (G. carapo and G. coropinae), and one (G. chaviro) endemic to southwestern Amazonia. We also diagnose and describe two new species that are endemic to the Upper Madeira basin: G. eyra n. sp., morphologically most similar to G. mamiraua from lowland Amazonia, and G. riberalta n. sp., morphologically most similar to G. pantanal from the Paraguay-Paraná basin. The five Gymnotus species from the Upper Madeira basin are not monophyletic, each species being more closely related to a different species from another region; i.e. the Gymnotus species from the Upper Madeira represents a polyphyletic assemblage. These descriptions to 43 the number of valid Gymnotus species.

Reconstruction of Socioeconomic Status in the Medieval (14th–15th Century) Population of Grevenmacher (Luxembourg) Based on Growth, Development and Diet

AbstractNumerous historical sources describe many aspects of the estate‐based society in medieval times; the detection of socioeconomic status within populations through skeletal remains is a topic of growing interest in anthropological studies. In medieval times, it was common for members of high social rank to be buried within or next to a church. This was certainly the case in Grevenmacher (Luxembourg), where remains of a church building and an adjacent cemetery from the 13th until the beginning of the 15th century were subjected to archaeological and anthropological analysis. By integrating archaeological and anthropological elements, as well as stable isotope analysis, we documented osteological manifestations as indicators of diet differentials in two subsamples (first group consists out of 56 individuals, second one out of 184 individuals) from the medieval cemetery of Grevenmacher. We could distinguish two subsamples that we assumed as different in their socioeconomic status with regards to the burials' position in the cemetery and burial characteristics. Differences in osteological traits such as bone length, stature and body mass indicated differences in diet between sample groups. To substantiate these outcomes, stable isotopic analysis (δ13C, δ15N) were made; the results displayed a clear separation between the sample groups on the basis of their diet. Therefore, we were able to confirm certain individuals in the medieval population of Grevenmacher in relationship to their socioeconomic status. Copyright © 2017 John Wiley &amp; Sons, Ltd.

Molecular and morphological data reveal three new cryptic species of Chiasmocleis (Mehely 1904) (Anura, Microhylidae) endemic to the Atlantic Forest, Brazil.

Three new cryptic species of Chiasmocleis from the Atlantic Forest of Brazil are described. Two of these species occur in the northeastern states of Sergipe and Bahia, whereas the third species is found in the southeastern state of São Paulo. The new species can be distinguished from other congeneric species by the molecular data, as evidenced in the phylogeny, and by a combination of morphological characters including: size, foot webbing, dermal spines, and coloration patterns. Chiasmocleis species differ in osteological traits, therefore we also provide an osteological description of each new species and comparsions with data reported for other species in the genus.

Ecological associations of autopodial osteology in Neotropical geckos.

Coevolution of form and function inspires investigation of associations between morphological variation and the exploitation of specific ecological settings. Such relationships, based mostly on traits of external morphology, have been extensively described for vertebrates, and especially so for squamates. External features are, however, composed by both soft tissues and bones, and these likely play different biomechanical roles during locomotion, such as in the autopodia. Therefore, ecological trends identified on the basis of external morphological measurements may not be directly correlated with equivalent variation in osteology. Here, we investigate how refined parameters of autopodial osteology relate to ecology, by contrasting climbing and nonclimbing geckos. Our first step consisted of inferring how external and osteological morphometric traits coevolved in the group. Our results corroborate the hypothesis of coevolution between external and osteological elements in the autopodia of geckos, and provides evidence for associations between specific osteological traits and preferred locomotor habit. Specifically, nonclimbers exhibit longer ultimate and penultimate phalanges of Digit V in the manus and pes and also a longer fifth metatarsal in comparison with climbers, a pattern discussed here in the context of the differential demands made upon locomotion in specific ecological contexts. Our study highlights the relevance of osteological information for discussing the evolution of ecological associations of the tetrapod autopodium. J. Morphol. 278:290-299, 2017. © 2017 Wiley Periodicals, Inc.

Comparative anatomy of the caudal skeleton of lantern fishes of the genus Triphoturus Fraser-Brunner, 1949 (Teleostei: Myctophidae)

The caudal skeleton provides important information for the study of the systematics and ecomorphology of teleostean fish. However, studies based on the analysis of osteological traits are scarce for fishes in the order Myctophiformes. This paper describes the anatomy of the caudal bones of 3 Triphoturus species: T. mexicanus (Gilbert, 1890), T. nigrescens (Brauer, 1904) and T. oculeum (Garman, 1899). A comparative analysis was performed on cleared and stained specimens to identify the differences and similarities of bony elements and the organization of the caudal skeleton among the selected species. Triphoturus mexicanus differs from T. oculeum in the presence of medial neural plates and a foramen in the parhypural, while T. nigrescens differs from their congeners in a higher number of hypurals (2 + 4 = 6) and the separation and number of cartilaginous elements. This osteological description of the caudal region allowed updates to the nomenclature of bony and cartilaginous elements in myctophids. Further, this study allows for the recognition of structural differences between T. mexicanus and T. oculeum, as well as the major morphological distinction between T. nigrescens and their sister species.

Cranial morphology of European passerine bird families (Aves, Passeriformes)

Abstract The subject of this study focuses on the cranial morphology of 24 native European passerine bird families. In addition to the discussion of taxonomical questions regarding to the examination of beak, orbit, cranium and mandible, the author aims to provide guidance to the determination of raptors’ prey remains. Most of the studied bird families are well-distinguishable using the knowledge on the mentioned osteological traits except some less-specialised families.

Another look at tarsometatarsi of early penguins

AbstractThe tarsometatarsus, a compound bone from the lower leg in birds, is the most important skeletal element in fossil penguin taxonomy, especially in the case of early members of this group. However, any attempt to go beyond the problem of mere classification obviously requires the better understanding of osteological traits under consideration. This in turn touches on the issue of interplay between bone and concomitant soft-tissue structures, such as muscles, tendons and vessels. This paper focuses on the more holistic comprehension of the tarsometatarsal section of the Eocene penguin foot, based on the analysis of the myology and the vascular system of its modern counterparts. A number of graphical reconstructions are provided with a discussion of the role of the hypotarsus and intermetatarsal foramina.

Anatomy of the Crus and Pes of Neotropical Iguanian Lizards in Relation to Habitat use and Digitally Based Grasping Capabilities

Ecomorphological studies of lizards have explored the role of various morphological traits and how these may be associated with, among other things, habitat use. We present an analysis of selected traits of internal morphology of the hind limbs of Neotropical iguanian lizards and their relationship to habitat use. Considering that one of the most widely-held hypotheses relating to the origin of grasping is associated with the exploitation of the narrow-branch arboreal habitat, we include subdivisions of this designation as two of our ecologically defined categories of habitat exploitation for analysis, and compare lizards assigned to these categories to the features displayed by terrestrial lizards. The influence of phylogeny in shaping the morphology of lizards was assessed by using the comparative method. K values were significant for several osteological traits. Most of the K values for the variables based upon muscle and tendon morphometric characters (13 out 21), by contrast, had values <1, suggesting that their variation cannot be explained by phylogeny alone. Results of our phylogenetic and conventional ANCOVA analyses reveal that the characters highlighted through the application of the comparative method are not absolutely related to habitat in terms of the categories considered here. It appears that the bauplan of the lizard pes incorporates a morphological configuration that is sufficiently versatile to enable exploitation of almost all of the available habitats. As unexpected as conservation of internal gross morphology appears, it represents a means of accommodating to environmental challenges by apparently permitting adequacy for all situations examined.