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2.
J Morphol ; 283(8): 1015-1047, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35673834

RESUMO

The Greater Rhea (Rhea americana, Rheidae) is a flightless paleognath with a wide geographical distribution in South America. The morphology of its shoulder girdle and wings are different from those of flying birds and some characteristics are similar to basal birds and paravian theropods. We present a detailed osteological, myological, and functional study of the shoulder and the wing of the Greater Rhea. Particular features of the anatomy of the pectoral girdle and wing of Rhea include the lack of triosseal canal, reduced origin area of the mm. pectoralis p. thoracica and supracoracoideus and the lack of a propatagium. The wing muscle mass is markedly reduced, reaching only 0.89% of total body mass (BM). Forelimb muscles mass values are low compared to those of flying birds and are congruent with the non-use of wings for active locomotion movements. R. americana does not flap the wings dorso-ventral as typical for flying birds, but predominantly in cranio-caudal direction, following a craniolateral to caudomedial abduction-adduction arc. When the wings are fully abducted, they are inverted L-shaped, with the inner surface caudally faced, and when the wings are folded against the body, they do not perform the complete automatic wing folding nor the circumduction of the manus, a movement performed by extant volant birds. This study complements our knowledge of the axial musculature of the flightless paleognaths and highlights the use of the Greater Rhea as a model, which may help understand the evolution of Palaeognathae, as well as the origin of flapping flight among paravian theropods.


Assuntos
Reiformes , Struthioniformes , Animais , Voo Animal/fisiologia , Osteologia , Asas de Animais/anatomia & histologia
3.
Clin Oral Implants Res ; 33 Suppl 23: 137-144, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35763017

RESUMO

OBJECTIVES: To systematically assess the literature and report on (1) the frequency of occurrence of buccal soft tissue dehiscence (BSTD) at implants, (2) factors associated with the occurrence of BSTD and (3) treatment outcomes of reconstructive therapy for the coverage of BSTD. MATERIALS AND METHODS: Two systematic reviews addressing focused questions related to implant BSTD occurrence, associated factors and the treatment outcomes of BSTD coverage served as the basis for group discussions and the consensus statements. The main findings of the systematic reviews, consensus statements and implications for clinical practice and for future research were formulated within group 3 and were further discussed and reached final approval within the plenary session. RESULTS: Buccally positioned implants were the factor most strongly associated with the risk of occurrence of BSTD, followed by thin tissue phenotype. At immediate implants, it was identified that the use of a connective tissue graft (CTG) may act as a protective factor for BSTD. Coverage of BSTD may be achieved with a combination of a coronally advanced flap (CAF) and a connective tissue graft, with or without prosthesis modification/removal, although feasibility of the procedure depends upon multiple local and patient-related factors. Soft tissue substitutes showed limited BSTD coverage. CONCLUSION: Correct three-dimensional (3D) positioning of the implant is of utmost relevance to prevent the occurrence of BSTD. If present, BSTD may be covered by CAF +CTG, however the evidence comes from a low number of observational studies. Therefore, future research is needed for the development of further evidence-based clinical recommendations.


Assuntos
Implantes Dentários , Procedimentos Cirúrgicos Reconstrutivos , Implantação Dentária Endóssea/métodos , Implantes Dentários/efeitos adversos , Osteologia , Retalhos Cirúrgicos
4.
Clin Oral Implants Res ; 33 Suppl 23: 47-55, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35763021

RESUMO

OBJECTIVES: To assess the literature on (i) the relevance of the presence of a minimum dimension of keratinized peri-implant mucosa (KPIM) to maintain the health and stability of peri-implant tissues, and; (ii) the surgical interventions and grafting materials used for augmenting the dimensions of the KPIM when there is a minimal amount or absence of it. MATERIAL & METHODS: Two systematic reviews complemented by expert opinion from workshop group participants served as the basis of the consensus statements, implications for clinical practice and future research, and were approved in plenary session by all workshop participants. RESULTS: Thirty-four consensus statements, eight implications for clinical practice, and 13 implications for future research were discussed and agreed upon. There is no consistent data on the incidence of peri-implant mucositis relative to the presence or absence of KPIM. However, reduced KPIM width is associated with increased biofilm accumulation, soft-tissue inflammation, greater patient discomfort, mucosal recession, marginal bone loss and an increased prevalence of peri-implantitis. Free gingival autogenous grafts were considered the standard of care surgical intervention to effectively increase the width of KPIM. However, substitutes of xenogeneic origin may be an alternative to autogenous tissues, since similar results when compared to connective tissue grafts were reported. CONCLUSION: Presence of a minimum width of KPIM should be assessed routinely in patients with implant supported restorations, and when associated with pathological changes in the peri-implant mucosa, its dimensions may be surgically increased using autogenous grafts or soft-tissue substitutes with evidence of proven efficacy.


Assuntos
Implantes Dentários , Peri-Implantite , Consenso , Humanos , Membrana Mucosa , Osteologia
6.
Sci Rep ; 12(1): 1954, 2022 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-35145134

RESUMO

Other than repaired fractures, osteoarthritis, and periosteal reaction, the vertebrate fossil record has limited evidence of non-osseous diseases. This difficulty in paleontological diagnoses stems from (1) the inability to conduct medical testing, (2) soft-tissue pathologic structures are less likely to be preserved, and (3) many osseous lesions are not diagnostically specific. However, here reported for the first time is an avian-style respiratory disorder in a non-avian dinosaur. This sauropod presents irregular bony pathologic structures stemming from the pneumatic features in the cervical vertebrae. As sauropods show well-understood osteological correlates indicating that respiratory tissues were incorporated into the post-cranial skeleton, and thus likely had an 'avian-style' form of respiration, it is most parsimonious to identify these pathologic structures as stemming from a respiratory infection. Although several extant avian infections produce comparable symptoms, the most parsimonious is airsacculitis with associated osteomyelitis. From actinobacterial to fungal in origin, airsacculitis is an extremely prevalent respiratory disorder in birds today. While we cannot pinpoint the specific infectious agent that caused the airsacculitis, this diagnosis establishes the first fossil record of this disease. Additionally, it allows us increased insight into the medical disorders of dinosaurs from a phylogenetic perspective and understanding what maladies plagued the "fearfully great lizards".


Assuntos
Evolução Biológica , Dinossauros/fisiologia , Paleontologia , Infecções Respiratórias/fisiopatologia , Animais , Aves/fisiologia , Fósseis/patologia , Osteologia , Filogenia
7.
J Morphol ; 283(4): 510-538, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35094424

RESUMO

Fossoriality evolved early in snakes, and has left its signature on the cranial morphology of many extinct Mesozoic and early Caenozoic forms. Knowledge of the cranial osteology of extant snakes is indispensable for associating the crania of extinct lineages with a particular mode of life; this applies to fossorial taxa as well. In the present work, we provide a detailed description of the cranium of Hypoptophis wilsonii, a member of the subfamily Aparallactinae, using micro-computed tomography (CT). This is also the first thorough micro-CT-based description of any snake assigned to this African subfamily of predominantly mildly venomous, fossorial, and elusive snakes. The cranium of Hypoptophis is adapted for a fossorial lifestyle, with increased consolidation of skull bones. Aparallactines show a tendency toward reduction of maxillary length by bringing the rear fangs forward. This development attains its pinnacle in the sister subfamily Atractaspidinae, in which the rear fang has become the "front fang" by a loss of the part of the maxilla lying ahead of the fang. These dentitional changes likely reflect adaptation to subdue prey in snug burrows. An endocast of the inner ear of Hypoptophis shows that this genus has the inner ear typical of fossorial snakes, with a large, globular sacculus. A phylogenetic analysis based on morphology recovers Hypoptophis as a sister taxon to Aparallactus. We also discuss the implications of our observations on the burrowing origin hypothesis of snakes.


Assuntos
Osteologia , Crânio , Animais , Evolução Biológica , Filogenia , Crânio/anatomia & histologia , Crânio/diagnóstico por imagem , Serpentes/anatomia & histologia , Microtomografia por Raio-X
8.
An Acad Bras Cienc ; 94(1): e20191254, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35043846

RESUMO

Atractus badius has a long and controversial nomenclatural history due to both its antiquity and the brevity of its original description. This species was described based on two syntypes from Java. Later, a lectotype was designated and the distribution range restricted to the Guiana Shield. Although this species has been repeatedly recorded throughout Amazonia and the Andes, these records have been erroneously assigned to A. badius because of a considerable level of confusion in the literature. We found 13 additional specimens of this poorly known snake, expanding our knowledge on its morphological variability, phylogenetic relationships and distribution. In this paper, we report new localities and data on meristic, morphometric, coloration, scales micro-ornamentation, osteology and hemipenial morphology to A. badius. We also determine the phylogenetic position of A. badius as nested in a composite Guiana Shield clade. In addition, we discuss recent advances on the systematics of Atractus and comment on some 'new arrangements' with respect to previously recognized species groups and available morphological evidence. Finally, we highlight the importance of accurate voucher identification before promoting taxonomic changes or implementing nomenclatural acts derived from new phylogenetic hypotheses, and notably propose the synonymy of the recently described A. pyroni with A. roulei.


Assuntos
Genômica , Serpentes , Animais , Brasil , Osteologia , Filogenia , Serpentes/genética
9.
Anat Rec (Hoboken) ; 305(9): 2312-2330, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35068074

RESUMO

In several taxa of Neornithes (crown group birds), the lacrimal/ectethmoid complex exhibits small bones, the comparative osteology of which is poorly studied. Some of these ossicles-which are commonly known as uncinate bones (ossa uncinata or ossa lacrimopalatina)-were already described two centuries ago, but knowledge of their distribution and morphological variability in higher level clades is incomplete. In the present study, a detailed survey of the occurrence of uncinate bones is given, and these ossicles are for the first time reported in the gruiform Psophiidae, some Rallidae, and in the Otidiformes. Their presence in the latter taxon is of particular interest, because in current molecular analyses, the Otidiformes result as close relatives of the Musophagiformes, in which the uncinate bone is particularly large. The uncinate bones of most other neornithine clades, however, appear to have evolved multiple times independently through parallel evolution from the same ligamentous structures. A few earlier authors assumed that the uncinate bone is homologous to the ectopterygoid of non-avian theropods. Although this remains a viable hypothesis, more data on the occurrence of the ectopterygoid in Mesozoic birds are needed for well-supported conclusions. Here, it is noted that the ontogenetic development of the uncinate bone appears to be correlated with that of the ectethmoid, which is another bone in the skull of neornithine birds that is of unknown origin.


Assuntos
Aves , Crânio , Animais , Evolução Biológica , Aves/anatomia & histologia , Fósseis , Cabeça/anatomia & histologia , Osteologia , Filogenia , Crânio/anatomia & histologia
10.
Syst Biol ; 71(4): 875-900, 2022 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-34605923

RESUMO

Generally, the species is considered to be the only naturally occurring taxon. However, species recognized and defined using different species delimitation criteria cannot readily be compared, impacting studies of biodiversity through Deep Time. This comparability issue is particularly marked when comparing extant with extinct species because the only available data for species delimitation in fossils are derived from their preserved morphology, which is generally restricted to osteology in vertebrates. Here, we quantify intraspecific, intrageneric, and intergeneric osteological variability in extant species of lacertid lizards using pairwise dissimilarity scores based on a data set of 253 discrete osteological characters for 99 specimens referred to 24 species. Variability is always significantly lower intraspecifically than between individuals belonging to distinct species of a single genus, which is in turn significantly lower than intergeneric variability. Average values of intraspecific variability and associated standard deviations are consistent (with few exceptions), with an overall average within a species of 0.208 changes per character scored. Application of the same methods to six extinct lacertid species (represented by 40 fossil specimens) revealed that intraspecific osteological variability is inconsistent, which can at least in part be attributed to different researchers having unequal expectations of the skeletal dissimilarity within species units. Such a divergent interpretation of intraspecific and interspecific variability among extant and extinct species reinforces the incomparability of the species unit. Lacertidae is an example where extant species recognized and defined based on a number of delimitation criteria show comparable and consistent intraspecific osteological variability. Here, as well as in equivalent cases, application of those skeletal dissimilarity values to paleontological species delimitation potentially provides a way to ameliorate inconsistencies created by the use of morphology to define species. [Intraspecific variation; Lacertidae; morphological disparity; osteology; species delimitation; taxonomic bias.].


Assuntos
Lagartos , Osteologia , Animais , Biodiversidade , Fósseis , Humanos , Filogenia
11.
Anat Rec (Hoboken) ; 305(6): 1316-1342, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-34591368

RESUMO

This study described the detailed osteological features of the Setouchi salamander Hynobius setouchi. H. setouchi, which is endemic to central Japan, was recently delineated from the wide range of H. nebulosus species based on molecular and external morphological characteristics. However, the osteological features of the species belonging to the genus Hynobius have not been examined, which has hindered the detailed understanding of morphological diversity in the genus. To address this problem, this study elucidated the osteological features of the salamander using micro-computed tomography scanning and whole-mount double staining methods. The articular, a part of the hypobranchial I, a part of coracoid, pubis, carpus, and tarsus were cartilaginous in small-sized individuals and were partially or completely ossified in large-sized individuals. The degree of ossification varied in the operculum, basibranchial II, and ascending process of the palatoquadrate. However, ossification was not associated with body size. The lacrimal, ossified manus, and ossified pes exhibited varying degrees of articulation or fusion irrespective of body size. Moreover, the cranium and tarsus of H. setouchi exhibited several unique characteristics. These osteological characteristics will aid in revising the taxonomy and phylogeny of the Hynobius species.


Assuntos
Osteologia , Urodelos , Animais , Tamanho Corporal , Humanos , Filogenia , Urodelos/anatomia & histologia , Microtomografia por Raio-X
12.
Anat Rec (Hoboken) ; 305(7): 1563-1591, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-34813153

RESUMO

Of the more than 6,000 members of the most speciose avian clade, Passeriformes (perching birds), only the five species of dippers (Cinclidae, Cinclus) use their wings to swim underwater. Among nonpasserine wing-propelled divers (alcids, diving petrels, penguins, and plotopterids), convergent evolution of morphological characteristics related to this highly derived method of locomotion have been well-documented, suggesting that the demands of this behavior exert strong selective pressure. However, despite their unique anatomical attributes, dippers have been the focus of comparatively few studies and potential convergence between dippers and nonpasseriform wing-propelled divers has not been previously examined. In this study, a suite of characteristics that are shared among many wing-propelled diving birds were identified and the distribution of those characteristics across representatives of all clades of extant and extinct wing-propelled divers were evaluated to assess convergence. Putatively convergent characteristics were drawn from a relatively wide range of sources including osteology, myology, endocranial anatomy, integument, and ethology. Comparisons reveal that whereas nonpasseriform wing-propelled divers do in fact share some anatomical characteristics putatively associated with the biomechanics of underwater "flight", dippers have evolved this highly derived method of locomotion without converging on the majority of concomitant changes observed in other taxa. Changes in the flight musculature and feathers, reduction of the keratin bounded external nares and an increase in subcutaneous fat are shared with other wing-propelled diving birds, but endocranial anatomy shows no significant shifts and osteological modifications are limited. Muscular and integumentary novelties may precede skeletal and neuroendocranial morphology in the acquisition of this novel locomotory mode, with implications for understanding potential biases in the fossil record of other such transitions. Thus, dippers represent an example of a highly derived and complex behavioral convergence that is not fully associated with the anatomical changes observed in other wing-propelled divers, perhaps owing to the relative recency of their divergence from nondiving passeriforms.


Assuntos
Aves Canoras , Animais , Evolução Biológica , Voo Animal , Fósseis , Osteologia , Natação , Asas de Animais/anatomia & histologia
13.
Anat Rec (Hoboken) ; 305(5): 1168-1200, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-34496139

RESUMO

Rhynchosaurs are bulky quadrupedal herbivores that achieved a cosmopolitan distribution during the Middle and Late Triassic. Rhynchosaurids are characterized by a pair of premaxillae modified into an edentulous beak that had a bone-to-bone occlusion with the tips of the dentaries, and a specialized masticatory apparatus composed of groove(s) on the maxilla and ridges(s) on the dentary. The Argentinian fossil record of rhynchosaurs is abundant, but only two nominal species have been named so far. One of them, the hyperodapedontine Hyperodapedon sanjuanensis, is the most abundant tetrapod of the Ischigualasto Formation of northwestern Argentina. However, the anatomy of H. sanjuanensis remains poorly studied. The repreparation and computed tomographic (CT) scanning of its holotypic skull (MACN-Pv 18185) allowed a detailed description of its anatomy. Among the novel anatomical data presented here, we provide the first tridimensional complete reconstruction of a rhynchosaurid palate. This structure is extremely complex in comparison to the plesiomorphic archosauromorph condition, and more data on other rhynchosaurid palates are needed to shed light on the sequence of character states acquisition that resulted in this peculiar anatomy. The presence of a pair of septomaxillae in H. sanjuanensis is the first report of these bones in a rhynchosaurid, and this new information allowed to identify septomaxillae also in the hyperodapedontines Teyumbaita sulcognathus and Hyperodapedon mariensis. The better understanding of the skull anatomy of the holotype of H. sanjuanensis is a first step towards an improved knowledge of the morphology and taxonomy of the South American rhynchosaurs.


Assuntos
Dinossauros , Animais , Argentina , Dinossauros/anatomia & histologia , Fósseis , Osteologia , Filogenia , Crânio/anatomia & histologia
14.
Anat Rec (Hoboken) ; 305(7): 1739-1786, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-34652885

RESUMO

Amblyrhynchus cristatus, the marine iguana, is unique among the ~7,000 species of living limbed lizards as it has successfully evolved adaptations that allow it to live in both terrestrial and marine environments. This species is endemic to the Galápagos Archipelago and has evolved a specialized feeding behavior, consuming primarily the algae that grow on the rocky seafloor. The intriguing questions arising around the evolution of the marine iguana concerns the use of exaptations of terrestrial features for aquatic and specifically marine adaptations. However, the lack of fundamental information about its anatomy currently prevents us from understanding how it became adapted to such a peculiar lifestyle in comparison to all other iguanids. The goal of this study is to provide the first ever description of the skull, mandible, and hyoid of Amblyrhynchus. We examined several specimens of marine iguana, including skeletal, wet, and ct-scanned material, and individuals at different ontogenetic stages. We also analyzed specimens of all other modern iguanid genera (Conolophus, Iguana, Ctenosaura, Cyclura, Dipsosaurus, Brachylophus, Sauromalus) in order to make comparisons between Amblyrhynchus and its closest relatives. We were able to identify several autapomorphic features that distinguish the marine iguana from all other iguanids. These unique morphologies are mostly associated with the modified configuration of the snout (nasal chamber), increased muscle attachments in the temporal-postorbital region of the skull, and dentition. Since Amblyrhynchus is the only nonophidian squamate currently able to exploit the ocean at least for some vital functions (i.e., feeding), we used comparisons to fossil marine lizards (e.g., mosasaurids) to discuss some of these unique traits. The new cranial features described for Amblyrhynchus may represent a source of novel morphological characters for use in future phylogenetic analyses of iguanian (or squamate) relationships, which will then serve as the foundation for the exploration of evolutionary patterns and processes that led to the development of such unique adaptations.


Assuntos
Osso Hioide , Iguanas , Mandíbula , Crânio , Animais , Humanos , Osso Hioide/anatomia & histologia , Iguanas/fisiologia , Lagartos/fisiologia , Mandíbula/anatomia & histologia , Osteologia , Filogenia , Crânio/anatomia & histologia
15.
J Fish Biol ; 100(1): 161-174, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34698382

RESUMO

This study resolves a significant impediment to the taxonomy of the Neotropical endemic hematophagous candirus by providing the first high-resolution, CT-based osteological descriptions of type and nontype specimens of Paracanthopoma parva, type species of the genus. We also describe the distinctive new species Paravandellia alleynei based on specimens that were previously misidentified as Parac. parva in the only taxonomic study of that species since its 1935 description. Paracanthopoma parva is distinguished from all nominal congeners by its parietosupraoccipital and caudal skeleton morphology and by various meristics, including numbers of teeth on median premaxilla, vertebrae, and procurrent and principal caudal-fin rays. Paravandellia alleynei differs from both nominal congeners (Paravandellia oxyptera and Paravandellia phaneronema) by the unique morphology of its maxilla, mesethmoid and opercular apparatus, relative position of the pelvic- and anal-fin origins, orientation of the opercular odontodes, and various meristics, including numbers of vertebrae, median premaxillary teeth, medial teeth on premaxilla, branchiostegal rays, opercular and interopercular odontodes, distal claw-like premaxillary teeth, dorsal-fin rays and dentary teeth. This is the first species of Paravandellia recognized from Guyana and the Essequibo River basin. It is currently known only from two type specimens from the lower Essequibo River basin and 43 nontype specimens from the upper Branco River basin. By providing the first skeletal observations for type specimens of the type species Parac. parva and for topotypic specimens of all three nominal species of Paravandellia, we clarify and confirm the diagnosis of Parac. parva and establish a robust foundation for ongoing taxonomic revisions of these two small-sized and species-poor, yet trans-continentally distributed genera, both of which contain considerable unrecognized diversity.


Assuntos
Peixes-Gato , Dente , Animais , Osteologia , Rios , Coluna Vertebral
17.
Zootaxa ; 5068(2): 211-239, 2021 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-34810712

RESUMO

The genus Gastrotheca (Anura: Hemiphractidae) is a group of marsupial frogs particularly diverse in Andean regions. Several taxonomic studies of this genus have been conducted in the humid cloud forestsor Yungasof the Andean eastern slopes of central Bolivia (departments of Cochabamba and Santa Cruz). Yet, the distinction among three species that occur sympatrically in these forests, G. lauzuricae (proposed as a junior synonym of G. coeruleomaculatus in 2015), G. piperata, and G. splendens, remains unclear since the morphological characters that purportedly support their differentiation are variable and partly shared among them. We have carried out external morphological studies, including multivariate morphometric analyses, to assess how they support the taxonomic status of these three species. We also evaluated characters of the cranial osteology of a sample of six individuals using micro CT-scanning. Principal component and linear discriminant analyses resulted in a great overlap among the putative species. Cranial osteological comparisons did not reveal highly significant differences among them, but suggested that different degrees of hyperossification could be related to the developmental state of individuals. Our results indicate that most morphological and osteological reported differences between the three species likely represent intraspecific variation. Thus, we propose that the three nominal species belong to a single biological entity, for which the name Gastrotheca splendens (Schmidt, 1857) has priority. We also restrict the name Gastrotheca coeruleomaculatus (Werner, 1899) to externally similar congeneric populations from the Yungas forests of department of La Paz, but highlighting the need of a detailed evaluation of their taxonomic identity.


Assuntos
Anuros , Marsupiais , Animais , Bolívia , Florestas , Osteologia , Filogenia
18.
Zootaxa ; 5023(4): 509-536, 2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34810950

RESUMO

Taiwan is one of the richest in the world in terms of eel fauna. In this study, we examined the osteological and morphological characteristics of eels under order Anguilliformes. Furthermore, we focused on the neurocranium of total of 30 Anguilliformes fishes under family Congridae (10), Muraenesocidae (1), Muraenidae (7), Nemichthyidae (1), Nettastomatidae (2), Ophichthidae (5), Synaphobranchidae (4), which are caught in Taiwanese waters. This paper shows the results of a comparative study on osteological characters of the neurocranium including the ratio of seven length characters using its NCL (neurocranium length), NCW (neurocranium width), OBL (orbit length), MFW (maximum frontal width), NCDB (neurocranium depth at basisphenoid), PEVW (premaxilla-ethmovomer width) and mPOBL (mid pre-orbital length), and 20 morphological diagnostic characters for 30 eel species. Results shows that species under family Nemichthyidae and Nettastomatidae have the highest values on the ratio of NCL/MFW, NCL/NCDB, and NCW/mPOBD. In morphological characters, it shows that species of the same family mostly share similar formation of the PEV plate and frontal structure. The usage of the length measurements and morphological diagnostic characters of neurocranium allowed for a more in depth understanding of how similar or different these eels can be. The neurocranial description and morphological characters may prove valuable for identification purposes and might be necessary tool for further studies on the status of order Anguilliformes.


Assuntos
Enguias , Crânio , Animais , Osteologia , Taiwan
19.
Anat Rec (Hoboken) ; 304(10): 2110-2117, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34473414

RESUMO

Scolecophidian snakes have long posed challenges for scholars interested in elucidating their anatomy. The importance, and relative paucity, of high-quality anatomical data pertaining to scolecophidians was brought into sharp focus in the late 20th century as part of a controversy over the phylogeny and ecological origin of snakes. The basal position of scolecophidians in the phylogeny of snakes makes their anatomy, behavior, ecology, and evolution especially important for such considerations. The depauperate fossil record for the group meant that advances in understanding their evolutionary history were necessarily tied to biogeographic distributions and anatomical interpretations of extant taxa. Osteological data, especially data pertaining to the skull and mandible, assumed a dominant role in shaping historical and modern perspectives of the evolution of scolecophidians. Traditional approaches to the exploration of the anatomy of these snakes relied heavily upon serial-sectioned specimens and cleared-and-stained specimens. The application of X-ray computed tomography (CT) to the study of scolecophidians revolutionized our understanding of the osteology of the group, and now, via diffusible iodine-based contrast-enhanced computed tomography (diceCT), is yielding data sets on internal soft anatomical features as well. CT data sets replicate many aspects of traditional anatomical preparations, are readily shared with a global community of scholars, and now are available for unique holotype and other rare specimens. The increasing prevalence and relevance of CT data sets is a strong incentive for the establishment and maintenance of permanent repositories for digital data.


Assuntos
Fósseis , Osteologia , Serpentes , Animais , Raios X
20.
BMC Ecol Evol ; 21(1): 184, 2021 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-34587907

RESUMO

BACKGROUND: Alligator lizards (Gerrhonotinae) are a well-known group of extant North American lizard. Although many fossils were previously referred to Gerrhonotinae, most of those fossils are isolated and fragmentary cranial elements that could not be placed in a precise phylogenetic context, and only a handful of known fossils are articulated skulls. The fossil record has provided limited information on the biogeography and phylogeny of Gerrhonotinae. RESULTS: We redescribe a nearly complete articulated fossil skull from the Pliocene sediments of the Anza-Borrego Desert in southern California, and refer the specimen to the alligator lizard genus Elgaria. The fossil is a representative of a newly described species, Elgaria peludoverde. We created a morphological matrix to assess the phylogeny of alligator lizards and facilitate identifications of fossil gerrhonotines. The matrix contains a considerably expanded taxonomic sample relative to previous morphological studies of gerrhonotines, and we sampled two specimens for many species to partially account for intraspecific variation. Specimen-based phylogenetic analyses of our dataset using Bayesian inference and parsimony inferred that Elgaria peludoverde is part of crown Elgaria. The new species is potentially related to the extant species Elgaria kingii and Elgaria paucicarinata, but that relationship was not strongly supported, probably because of extensive variation among Elgaria. We explored several alternative biogeographic scenarios implied by the geographic and temporal occurrence of the new species and its potential phylogenetic placements. CONCLUSIONS: Elgaria peludoverde is the first described extinct species of Elgaria and provides new information on the biogeographic history and diversification of Elgaria. Our research expands the understanding of phylogenetic relationships and biogeography of alligator lizards and strengthens the foundation of future investigations. The osteological data and phylogenetic matrix that we provided will be critical for future efforts to place fossil gerrhonotines. Despite limited intraspecific sampled sizes, we encountered substantial variation among gerrhonotines, demonstrating the value of exploring patterns of variation for morphological phylogenetics and for the phylogenetic placement of fossils. Future osteological investigations on the species we examined and on species we did not examine will continue to augment our knowledge of patterns of variation in alligator lizards and aid in phylogenetics and fossil placement.


Assuntos
Jacarés e Crocodilos , Lagartos , Jacarés e Crocodilos/genética , Animais , Teorema de Bayes , Lagartos/genética , Osteologia , Filogenia , Crânio/anatomia & histologia
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