Banca de DEFESA: MARIANNA ISABELLA ROSA RODRIGUES DE OLIVEIRA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : MARIANNA ISABELLA ROSA RODRIGUES DE OLIVEIRA
DATE: 25/02/2022
TIME: 08:00
LOCAL: Universidade Federal da Bahia
TITLE:

Structural and heterochronic variation during Physalaemus initial ontogeny (Amphibia, Anura, Leptodactylidae)

KEY WORDS:

Ontogeny, Heterochrony, Physalaemus

PAGES: 164
BIG AREA: Ciências Biológicas
AREA: Zoologia
SUBÁREA: Taxonomia dos Grupos Recentes
SUMMARY:

The idea that early ontogenies are similar and that definitive characters appear only in late stages has long influenced the developmental biology. However, many studies carried out since the beginning of the 20th century have demonstrated a great diversity in these early stages. In the case of anurans, the comparison of embryonic ontogeny has revealed a scenario as diverse as in the late stages. In addition to structural diversity, a diversity in development times has suggested the importance of heterochrony in the history of the group. Here we study the initial ontogeny of 15 species of Physalaemus with the general objective of describing and comparing the initial ontogeny with an emphasis on external morphology, evaluating patterns of spatial and temporal variation. Our specific goals were to describe embryos of species of the P. signifer group with emphasis on transitory and larval characteristics; comparing shape-size relationships to interpret patterns of allometric change; explore heterochronic variations in developmental sequences; to study the evolution of body and tail shape ontogeny considering temporal changes. Embryonic structures were described, compared and series of events constructed. Allometric analysis was performed using geometric morphometry with multivariate statistics. The shape ontogenies were mapped onto a well-supported phylogenetic hypothesis using PASOS that infers ancestral ontogenies and compares the shapes considering developmental time. Our findings indicate variations in the morphology of embryonic structures, in the shape, size and developmental time of Physalaemus. The embryonic morphology of P. camacan and P. signifer is similar to that of most species of the genus, with some differences in relation to the P. cuvieri clade. Some morphological characteristics as well as the developmental sequence may be correlated with the tendency towards terrestriality of most species of the P. signifer clade and with ecomorphological aspects. Physalaemus embryos follow the allometric pattern already found for other exotrophic species, where ontogenetic shape change is correlated with size increase. Embryos of the P. signifer clade and the P. gracilis group are among the largest, slightly peramorphic and with rapid development. On the other hand, P. cicada embryos are the smallest, with very rapid development and more peramorphic shapes. Paedomorphosis associated with P. biligonigerus and P. henselii groups is respectively correlated with fast vs. slow development times. The trajectories in the P. cuvieri group are quite diverse, mainly in size and development time. Sequences of developmental events are generally conserved in the genus, with the main difference in oral disc ontogeny of Pleurodema. Some patterns can be explained by differences in the environments where these embryos develop, but others can be related to developmental constrictions not associated with ecological aspects. Interpreting ontogenetic changes in a phylogenetic context from ancestor-descendant comparisons is important because interspecific comparisons do not always indicate evolutionary changes. Our results indicate that paedomorphosis and peramorphosis conditions depend on which xii characters are considered (e.g., oral disc, gillls, body shape, etc.) and changes related to size and time are widely variable. Here we reinforce the idea that organisms are clearly a mosaic of features with their own ontogenetic trajectories and subject to disparate evolutionary changes.

BANKING MEMBERS:
Presidente - 011.276.017-17 - LUIZ NORBERTO WEBER - UFRJ
Externa à Instituição - VANESSA KRUTH VERDADE
Externa à Instituição - CLARISSA COIMBRA CANEDO
Externa à Instituição - ANA MARIA PAULINO TELLES DE CARVALHO E SILVA
Externa à Instituição - DENISE DE CERQUEIRA ROSSA-FERES