Lucélia Gonçalves Vieira

SEQUENCE OF METATARSAL AND PHALANGEAL BONE FORMATION IN EMBRYOS OF PODOCNEMIS EXPANSA SCHWEIGGER, 1812 (TESTUDINES, PODOCNEMIDIDAE)

Abstract The present study analyses the sequence of metatarsal and phalangeal bone formation in Podocnemis expansa. The ontogenetic sequence studied comprises 24 embryos collected at 5-days intervals in various stages of prenatal development, starting from the 18th day of natural incubation. Biometric measurements were taken and the embryos were cleared and stained with alizarine for bone visualization, followed by the Davis and Gore method. Each pe has five metatarsals (M) and 14 phalanges, two on the fifth finger and three on each of the other fingers, with a phalangeal formula of 3:3:3:3:2. Retention of the stain in metatarsals occurs in the following order: M III > M II = M IV > M V > M I. In stage 20, it is evident that the ossification center progresses in the direction of the epiphyses in all metatarsals. The sequence of stain retention in distal phalanges (DP) occurs in the following order: DP V > DP IV > DP III > DP II > DP I. In the medial phalanges (MP), the stain retention sequence is MP III > MP IV > MP II > MP I. Lastly, the proximal phalanges (PP) retain staining in the following sequence: PP V > PP I > PP II > PP III > PP IV. Differences and similarities in synchronization of ossification in Podocnemis expansa and comparable species are evident. The lack of a common osteogenetic pattern among all chelonians is due to variations in the initial site of bone formation and sequence of ossification.

Ontogeny of the Appendicular Skeleton in Melanosuchus niger (Crocodylia: Alligatoridae)

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.

Ontogeny of the Postcranial Axial Skeleton of Melanosuchus niger (Crocodylia, Alligatoridae)

This study proposes the description of the development of the postcranial axial skeleton, including vertebrae, gastralium, ribs, sternum, and interclavicle, in Melanosuchus niger. Six nests were marked and two eggs removed from each nest at 24‐hr intervals until hatching. For posthatching evaluation, 30 hatchlings were kept in captivity and one exemplar was euthanized at three‐day intervals. Samples were diaphanized using potassium hydroxide (KOH), alizarin red S, and Alcian blue. A routinely generally used method was applied for histological evaluation. It was difficult to define in which vertebrae the development of cartilaginous centers began, but it was possible to observe that this condensation advanced in the craniocaudal direction. The condensation started in the vertebral arches and was visibly stronger in the cervical and dorsal regions, advancing to the lumbar, sacral and, last, to the caudal region. The atlas showed a highly different morphology compared with the other cervical vertebrae, with a short intercenter, two neural arches, and a proatlas. The ossification process began in the body of cervical vertebrae III to VIII and alizarin retention decreased in the last vertebrae, indicating a craniocaudal direction in bone development, similar to cartilage formation. In the histological sections of gastralium and interclavicles of M. niger at several development stages, it was possible to observe that these elements showed intramembranous development. Anat Rec, 301:607–623, 2018.

Morphology, development and heterochrony of the carapace of Giant Amazon River Turtle Podocnemis expansa (Testudines, Podocnemidae)

With aim to report the ontogeny of the osseous elements of the carapace in Peurodiras, 62 embryos and 43 nestlings of Podocnemis expansa were collected and submitted to the clearing and staining technique of bones and cartilages and study of serial histological slices. The carapace has mixed osseous structure of endo and exoskeleton, formed by 8 pairs of costal bones associated with ribs, 7 neural bones associated with neural arches, 11 pairs of peripheral bones, 1 nuchal, 1 pygal and 1 suprapygal. This structure begins its formation in the beginning of stage 16 with the ossification of the periosteal collar of the ribs. With exception of the peripheral bones, the other ones begin their ossification during the embrionary period. In histologic investigation it was found that the costal bones and neural bones have a close relation to the endoskeleton components, originating themselves as intramembranous expansions of the periosteal collar of the ribs and neural arches, respectively. The condensation of the mesenchyme adjacent to the periosteal collar induces the formation of spikes that grow in trabeculae permeated by fibroblasts below the dermis. The nuchal bone also ossifies in an intramembranous way, but does not show direct relation to the endoskeleton. Such information confirms those related to the other Pleurodira, mainly with Podocnemis unifilis, sometimes with conspicuous variations in the chronology of the ossification events. The formation of dermal plates in the carapace of Pleurodira and Criptodira follow the same pattern.

Effects of Exposure to Methyl Parathion on Egg Hatchability and Eggshell Chemical Composition in Podocnemis expansa (Testudines, Podocnemididae)

Eggshell evaluation may serve as an indicator of the effect of substances released in the environment, which may change eggshell shape, size, structure, and/or chemical composition. Additionally, exposure may interfere with hatching rates in contaminated eggs. The objective of this study was to better understand how exposure to the insecticide methyl parathion interferes with chemical changes in eggshells of Podocnemis expansa throughout their artificial incubation, as well as with egg hatchability. A total of 343 P. expansa eggs were collected in a natural reproduction area for the species. These eggs were transferred to and artificially incubated in the Wild Animal Teaching and Research Laboratory at Universidade Federal de Uberlândia. On the first day of artificial incubation, 0, 35, 350, and 3500 ppb of methyl parathion were incorporated to the substrate. Eggs were collected every three days for chemical analysis of eggshells. Hatchability was evaluated as the number of hatchlings in each treatment, for the eggs that were not used in the chemical analysis. Students T-test was used for data on eggshell chemical composition, and the Binomial Test for Two Proportions was used in the hatchability analysis, at a 5% significance level. It was observed that the incorporation of methyl parathion to the substrate on the first day of artificial incubation of P. expansa eggs reduced the levels of total fat in the shells throughout their incubation, besides reducing egg hatchability.

Estudo da vascularização arterial do baço em javalis (Sus scrofa scrofa, linnaeus - 1758)

Related searches to wild animals are growing more each day, yielding important information related to anatomy, physiology and behavior, essential for the survival of the animals. The spleen is an organ with multiple functions being responsible for the formation of blood cells, blood filtration and immune response. Although there are many studies on this organ segmentation in wild animals, there is not much information about this vascularization in Sus scrofa scrofa. The aim of this study was to describe the arteries distribution of the in the spleens of wild boars. To conduct the work we used 20 organs of animals from breeding. The carotid artery was isolated and injected with Neoprene Latex solution. The animals were fixed and spleens were dissected exposing the branches from the splenic artery. Analyzing the results we found similarities spleens characteristics of pigs, carnivores (dogs and cats) and opossums. However there were differences in the branches of the lienais arteries between the gender of the specie.

Anatomical Behavior of the Celiacomesenteric Artery of Pirarucu Arapaima gigas Cuvier, 1817 (Osteoglossiforme, Arapaimidae)

El pirarucu, pez de la familia Arapaimidae, es una de las especies mas importantes y emblematicas de la ictiofauna amazonica. Para estudiar las caracteristicas anatomicas de su sistema circulatorio, fueron utilizados 10 ejemplares de Arapaima gigas, con un longitud total media de 74 cm, provenientes de lagos del rio Araguaia, Sao Miguel do Araguaia, Goias, Brasil. A los peces se les abrio la cavidad celomatica donde se identifico y canalizo la arteria aorta dorsal, injectandose una solucion coloreada de latex sintetico. La fijacion del material se realizo con inyecciones de formol al 10%. La arteria celiacomesenterica es responsable de la irrigacion del tubo digestivo y tiene origen en las 2a, 3a y 4a arterias branquiales eferentes izquierdas. El estomago esta irrigado por la arteria celiaca y por una rama gastrica de la arteria cecal ventral. El intestino recibe ramas arteriales procedentes de la arteria celiacomesenterica y de las arterias mesentericas craneal y caudal; los ciegos dorsal y ventral estan irrigados por las arterias cecales dorsal y ventral, respectivamente