Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 4 of 4
Full-Text Articles in Life Sciences
The Biology Of Xenopus By R. C. Tinsley And H. C. Kobel, Rafael O. De Sá
The Biology Of Xenopus By R. C. Tinsley And H. C. Kobel, Rafael O. De Sá
Biology Faculty Publications
The Biology of Xenopus presents a summary of current knowledge about a single genus resulting from a symposium held at the Zoological Society of London in September 1992. This approach to summarizing available information has also been taken for other taxa, such as Atelopus (Lotters, 1996). However, the task of compiling data for Xenopus is enormous relative to any other amphibian group, because Xenopus laevis has become a model system for molecular and development research (Cannatella and de Sa, 1993). Unfortunately, most of our knowledge of Xenopus is biased toward this single species. There are about 20 recognized species of …
Chondrocranial Morphology Of Leptodactylus Larvae (Leptodactylidae: Leptodactylinae): Its Utility In Phylogenetic Reconstruction, Peter M. Larson, Rafael O. De Sá
Chondrocranial Morphology Of Leptodactylus Larvae (Leptodactylidae: Leptodactylinae): Its Utility In Phylogenetic Reconstruction, Peter M. Larson, Rafael O. De Sá
Biology Faculty Publications
Chondrocranial morphology of leptodactylid frogs is scarcely known and has not been completely described for any species of Leptodactylus. We describe the diversity of chondrocranial morphology in the genus Leptodactylus based on the analysis of 22 species, representing the four species groups: the fuscus Group, ocellatus Group, melanonotus Group, and pentadactylus Group. Furthermore, 26 characters are identified and used in a phylogenetic analysis. The phylogenetic analysis using Physalaemus, Crossodactylus, and Hylodes as outgroups suggests two monophyletic clades within Leptodactylus: the melanonotus-ocellatus clade and the pentadactylusfuscus clade. However, it does not support the monophyly of the species groups as currently recognized …
Seedling Development In Species Of Chamaesyce (Euphorbiaceae) With Erect Growth Habits, W. John Hayden, Olga Troyanskaya
Seedling Development In Species Of Chamaesyce (Euphorbiaceae) With Erect Growth Habits, W. John Hayden, Olga Troyanskaya
Biology Faculty Publications
Seedling development is described for Chamaesyce hirta, C. hypericifolia, and C. mesembrianthemifolia as discerned by light microscopy and scanning electron microscopy. Although these species ultimately develop erect to ascending growth habits, epicotyl development is limited to the production of a single pair ofleaves located immediately superjacent to and decussate with the cotyledons. The shoot system develops from one or more buds located in the axils of the cotyledons. In all respects, seedling ontogeny is very similar to that of previously studied prostrate species of Chamaesyce. Evidence from seedling ontogeny thus contradicts a hypothesis concerning homologies of plant …
Chondrocranial Anatomy And Skeletogenesis In Dendrobates Auratus, Rafael O. De Sá, Shannon Hill
Chondrocranial Anatomy And Skeletogenesis In Dendrobates Auratus, Rafael O. De Sá, Shannon Hill
Biology Faculty Publications
The larval chondrocranium and visceral skeleton of Dendrobates auratus ls described and compared with those of other dendrobatids. Four characters, i.e. lack of fusion between orbital cartilages and otic capsules, wide processus muscularis palatoquadrati, lack of processus pseudopterygoideus, and lack of processus anterolateralis hyalis, represent derived conditions for Dendrobates within Dendrobatidae. Cranial and postcranial ossification sequences are reported for D. auratus and Epipedobates tricolor. Skeletogenesis is earlier in E. tricolor, but the overall pattern of ossification is similar in the two species.