The aim of the present study was to investigate the sequence of shell bone formation in the embryos of the Pleurodira, Podocnemis unifilis. Their bones and cartilage were collected and cleared before staining. The shell was also examined by obtaining a series of histological slices. All the bony elements of the plastron have independent ossification centers, which subsequently join together and retain two fontanelles until the period of hatching. This turtle has a mesoplastra, which is characteristic of the Podocnemididae. The carapace begins to form concurrently with the ossification of the ribs at the beginning of stage 20. All the plates, except the suprapygal, initiate ossification during the embryonic period. The main purpose of the histological investigation was to highlight the relationship between the formation of the carapace and ribs with that of the neural plates. The costal and neural plates were found not to independent ossification centers, but to be closely related to components of the endoskeleton, originating as expansions of the perichondral collar of the ribs
The mouse, chicken, African clawed frog, and zebrafish are considered ¨model organisms¨ due to their extensive embryological and genetic characterization. However, they are far from representative of known diversity, impairing phylogenetic analyses of developmental patterns. Since squamates have historically received limited attention in developmental studies, we here describe the developmental sequence for Tropidurus torquatus, and provide the first post-ovipositional developmental series for the lizard family Tropiduridae. Fifteen developmental stages are described based on morphological traits such as the eye and accessory visual structures, pharyngeal arches, fusion of facial primordia, limb development, pigmentation, and scales. Organogenesis is already in progression at oviposition (Stage 28), with embryos continuing to develop at the incubation temperature of 30°C ± 1°C, and hatching after 75 ± 5 days, at Stage 42. Comparisons with other lizards show a conserved embryonic sequence, however developmental timing differences were found in features such as the pharyngeal arches, endolymphatic sacs, pigmentation and scales. The development of the phallic and cranial lip of the cloaca anlages are compared with that of other lizards. The order of T. torquatus fore- and hindlimb formation differs from that most commonly observed in lizards. The abundance and close association of this species with urban environments, as well as the ease of capturing and managing females, makes T. torquatus an attractive source of developmental data for future experimental and ontogenetic studies. Anat Rec, 300:277-290, 2017. © 2016 Wiley Periodicals, Inc.
The objective of the present study was to analyze chondrogenesis and the ossification pattern of the limbs of Melanosuchus niger in order to contribute with possible discussions on homology and the fusion pattern of autopodial elements and phylogeny. In the Reserva Extrativista do Lago Cuniã, Rondônia, Brazil, six nests were marked and two eggs removed from each nest at 24-hour intervals until hatching. Embryos were cleared using KOH; bone tissue was stained with alizarin red S and cartilage with Alcian blue. Routine staining with HE was also performed. In the pectoral girdle, the scapula showed ossification centers before the coracoid process. In the pelvic girdle, the ilium and the ischium were condensed as a single cartilage, although ossification took place through two separate centers, forming distinct elements in the adult. The pubis developed from an independent cartilaginous center with free end, which reflects its function in breathing. In the initial stages, the stylopodium and the zeugopodium developed from the condensation of a Y-shaped cartilage in the limbs, and differentiation of the primary axis and digital arch were observed. The greatest changes were observed in the mesopodia. In their evolution, Crocodylia underwent a vast reduction in the number of autopodial elements as a consequence of fusions and ossification of some elements. This study shows that the chondrogenesis and ossification sequences are dissociated. Moreover, the differences between M. niger and other species show clear variation in the patterns for these events in Alligatoridae.
ABTRACT.To gain an understanding of the detailed anatomical aspects of Mazama gouazoubira (brocket deer), this paper describes the relationships between its spinal cord and the vertebral canal, adding information with a clinical and surgical approach. Three specimens of M. gouazoubira were prepared following the methods normally used in anatomy. The epaxial muscles and vertebral arches were removed to expose the spinal cord and the spinal nerve roots. The dimensions of the medullary segments were measured using a pachymeter with 0.05 mm precision. The spinal cord is cylindroidal, dorsoventrally flattened, with an average craniosacral length of 656.27 mm, and has two dilatations corresponding to the cervical and lumbar intumescences. The cervical, thoracic, lumbar and sacrocaudal segments showed an average length of 175.07, 226.03, 123.47 and 43.63 mm, with indices of 28.02, 35.34, 19.68 and 6.93%, respectively. The medullary cone, whose average length is 46.27 mm, begins between L2 and L3 and ends between S1 and S2, with a mean index of 7.53%. The overall average distance between the nerve roots of the cervical, thoracic and lumbosacral segments was 2.23, 2.06 and 1.98 cm, respectively.Key words: brocket deer, neural system, skeletopy, spinal cord.RESUMO. Anatomia topográfica da medula espinal e relações vértebro-medulares em Mazama gouazoubira Fisher, 1814 (Artiodactyla; Cervidae). Propondo conhecer os aspectos anatômicos pormenorizados de Mazama gouazoubira (veado catingueiro), o presente trabalho descreve as relações entre sua medula espinal e o canal vertebral, adicionando informações com enfoque clínico-cirúrgico. Utilizaram-se três espécimes de M. gouazoubira que foram preparados seguindo métodos usuais em anatomia. Retirou-se a musculatura epiaxial e os arcos vertebrais para a exposição da medula espinal e raízes dos nervos espinais. As dimensões dos segmentos medulares foram obtidas utilizando um paquímetro de precisão 0,05 mm. A medula espinal possui a forma cilindróide, aplanada dorsoventralmente, com comprimento crânio-sacral médio de 656,27 mm, possui duas dilatações correspondentes às intumescências cervical e lombar. Os segmentos cervical, torácico, lombar e sacro-caudal apresentam 175,07; 226,03; 123,47 e 43,63 mm de comprimento médio, com índices de 28,02; 35,34; 19,68 e 6,93% respectivamente. O cone medular de comprimento médio 46,27 mm inicia-se entre L2 e L3 e termina em S1 e S2, com índice médio de 7,53%. A média geral obtida para a distância entre as raízes dos nervos dos segmentos cervical, torácico e lombossacral foi de 2,23; 2,06 e 1,98 cm, respectivamente.Palavras-chave: medula espinal, veado catingueiro, esqueletopia, sistema neural.
Descriptive anatomy applied to the kinesiology and basic biomechanics of the pectoral girdle, stylopodium and zeugopodium muscles of broad snouted caiman
Among the Brazilian crocodilian, Caiman crocodilus crocodilus is widely distributed, given its adaptation to diverse habitats and their generalist diet. Information about the reproductive and ethological character of this species is abundant, whereas morphological data are still scarce. This study aimed to identify and report the muscles and their origin and the insertion into the pectoral and forelimb of C. crocodilus crocodilus. We used two male specimens, adults, belonging to the collection of the UFG -Jataí. We performed usual procedures for dissection and further individualization, withdrawal of members, and observation of muscle origins and insertions. The musculature of C. crocodilus crocodilus generally conservative is similar to C. latirostris and A. mississippiensis. The muscles of the pectoral girdle showed little variation among crocodilians. In the forelimb, the triceps muscle has five distinct heads and biceps has only one. The extensor and flexor surface of the hand showed similar topography to A. mississippiensis. We described some differences in the origin and insertion of certain muscles, as well as the classification and topography of some flexor and extensor muscles in the forearm segment. The distal segments showed more variations, which probably reflects the variety of locomotor habits among crocodilians. Keywords: Common caiman; crocodilians; myology; muscle; reptiles. ResumoDentre os crocodilianos brasileiros, Caiman crocodilus crocodilus apresenta ampla distribuição, haja vista sua adaptação a habitats diversificados e sua dieta generalista. Informações de caráter etológico e reprodutivo acerca desta espécie são abundantes, enquanto dados morfológicos são ainda escassos. Objetivou-se identificar e relatar os músculos e suas origens e inserções nos segmentos da cintura e membro torácico de C. crocodilus crocodilus. No estudo, foram utilizados dois exemplares machos, adultos, pertencentes ao acervo da UFG -Jataí. Para isto utilizaram-se métodos usuais em dissecação e posteriormente os músculos foram individualizados, descritos e sua origem e inserção determinadas. A musculatura de C. crocodilus crocodilus é conservativa, sendo similar a C. latirostris e A. mississippiensis. Os músculos da cintura peitoral apresentaram uma pequena variação dentre os
In order to determine the normal stages of formation in the sequence of ossification of the cranium of Podocnemis expansa in its various stages of development, embryos were collected starting on the 18 th day of natural incubation and were subjected to bone diaphanization and staining. In the neurocranium, the basisphenoid and basioccipital bones present ossification centers in stage 19, the supraoccipital and opisthotic in stage 20, the exoccipital in stage 21, and lastly the prooptic in stage 24. Dermatocranium: the squamosal, pterygoid and maxilla are the first elements to begin the ossification process, which occurs in stage 16. However, ossification centers begin to appear in stage 17 in most of these bone elements, i.e., the frontal, jugal, postorbital, parietal, premaxilla and prefrontal, followed by the palatine and quadratojugal in stage 19 and lastly by the vomer in stage 25. The quadrate bone of the splanchnocranium ossifies in stage 23. The mandible and hyoid apparatus, the dentary, coronoid and supra-angular, show ossification centers in stage 16 and the branchial horn I in stage 17. The sequence and synchronization of ossification in P. expansa show similarities as well as differences when compared with other species of Testudines. RESUMO. Ontogenia dos ossos do crânio em tartaruga-da-amazôniaPodocnemis expansa Schweigger, 1812 (Testudines, Podocnemididae). Com o propósito de estabelecer etapas normais de formação da sequência de ossificação do crânio em Podocnemis expansa, nos diferentes estágios de desenvolvimento, coletaram-se embriões a partir do 18º dia de incubação natural, os quais foram submetidos à técnica de diafanização e coloração dos ossos. No neurocrânio, no estágio 19, o basisfenoide e o basioccipital apresentam centro de ossificação; no estágio 20, o supraoccipital e o opistótico; no estágio 21, o exoccipital; somente no estágio 24, o proótico. Dermatocrânio: o esquamosal, o pterigoide e a maxila são os primeiros elementos a iniciar o processo de ossificação, que ocorre no estágio 16. Mas a maioria desses elementos ósseos apresenta centros de ossificação no estágio 17, são eles: frontal, jugal, pós-orbital, parietal, pré-maxila, pré-frontal, seguido do palatino e quadradojugal no estágio 19 e, por último, o vômer no estágio 25. O osso quadrado do esplancnocrânio, no estágio 23. Ossificação da mandíbula e aparelho hioide: tanto o dentário, coronoide e o supra-angular apresentam centros de ossificação no estágio 16; o corpo branquial I, no estágio 17. A sequência e a sincronização da ossificação em P. expansa exibem similaridades, bem como diferenças, quando comparada com outras espécies de Testudines. Palavras-chave: répteis, Podocnemididae, alizarina, ossificação.
RESUMO.-O objetivo foi realizar a descrição anatômica do esqueleto de Melanosuchus niger, com o intuito de contribuir com informações evolutivas sobre a espécie. Utilizaram-se três espécimes adultos de M. niger, com comprimento médio de 2,40m, provenientes da coleção biológica do Lapas-UFU. Na cintura peitoral, a escápula é maior do que o coracóide. Já nos elementos da cintura pelvina, o púbis não participa da formação do acetábulo, o contato com o ilío, ocorre por ligamentos, e sua articulação com o ísquio, permite movimentos dorso-ventrais. The objective was an anatomical description of the skeleton of Melanosuchus niger, in order to contribute with evolutionary information about the species. Three adult specimens of M. niger with an average length of 2.40m were used, originating from the biologic collection of Lapas-UFU. In the forelimb, the scapula is bigger than the coracoid. Regarding the hindlimbs, the pubic does not participate in the formation of the acetabulum; the contact with the ilium is made by ligaments, and its articulation with the rump allows dorsal-ventral movements. Regarding the forelimbs, the humerus is a stylopodium element, and the ulna and radius a zeugopodium element. The carpus exibits the ulnar-radial+intermedium fusion, fusion of the distal carpals 3+4+5, and the pisiform. It has five metacarpals, numbered lateromedially as metacarpal 1, 2, 3, 4, and 5. The phalangeal formula is 2:3:4:3:2. Regarding the pelvic limbs, the stylopodium is formed by the femur, and the zeugopodium by tibia and fibula. In tarsus has four bones: fusion of the intermedium+centrale, fibulare, distal tarsal 3, and distal tarsal 4. It has four long metatarsals I, II, III and IV, with metatarsal II and III being relatively longer than the others. Metatarsal V is a very small bone; the feet have the phalangeal formula 2:3:4:4. At the skull, the nasal opening is only the palatine bones, vomer, pterygoid, premaxilla and maxilla forming the bone structure of the secondary palate; the parietal bone is the only element on the cranial roof. In the pos-axial skeleton ist distinct pairs of ribs which articulate with the cervical, dorsal, lumbar, sacral and caudal vertebrae. The gastralia consists of seven rows of fine bone located between the pubic bone and caudal part of the sternum.
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