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Full-Text Articles in Ecology and Evolutionary Biology
The Timing And Pattern Of Myogenesis In Hymenochirus Boettgeri, Matthew T. Smetanick, Rafael O. De Sá
The Timing And Pattern Of Myogenesis In Hymenochirus Boettgeri, Matthew T. Smetanick, Rafael O. De Sá
Biology Faculty Publications
Differences in the relative timing of homologous developmental events among closely related species, known as heterochronies, may provide valuable clues in understanding evolutionary relationships (McKinney, 1988; McNamara, 1995). Examining the timing of myogenic events is a relatively easy and effective method for finding heterochronic events. For example, whether muscle proteins and myofibrils appear before or after multinucleation can be determined through histological techniques (Kielbowna, 1981). Simple observations of live specimens can pinpoint functional landmarks such as first twitch (spontaneous or due to external stimuli) and first heartbeat.
Development Of The Suprarostral Plate Of Pipoid Frogs, Rafael O. De Sá, Charles C. Swart
Development Of The Suprarostral Plate Of Pipoid Frogs, Rafael O. De Sá, Charles C. Swart
Biology Faculty Publications
The rostral region of nonpipoid tadpoles has two sets of cartilages, the cornua trabeculae and the suprarostral cartilages, whereas the rostral region in pipoid larvae is occupied by a single and continuous cartilage, the suprarostral plate. The homology of this region in pipoid and nonpipoids tadpoles has been controversial. We examined the early formation and development of the suprarostral plate using serially cross-sectioned specimens of Rhinophrynus, Xenopus, and Hymenochirus. We conclude that the cartilaginous structures present in the rostral area of pipoid and nonpipoid larvae are homologous. Furthermore, we found two different developmental patterns among pipoid larvae. The chondrocranium …