. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Figure I. The pouch on the hack of a Gastrotheca riobambae female, a. When the female is not incubating embryos, the pouch has an inverted V-shaped opening with smooth borders, b. When the female is ready to ovulate or is incubating embryos, the pouch closes with the borders touching except at the posterior end. (From del Pino, 1983.) chamber. Embryos, in turn, develop disk-shaped gills, the bell gills (Noble. 1927), that envelop the growing embryo in a vascularized gill sac. Fertilization. Fertilization in G. riobambae, G.
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Figure I. The pouch on the hack of a Gastrotheca riobambae female, a. When the female is not incubating embryos, the pouch has an inverted V-shaped opening with smooth borders, b. When the female is ready to ovulate or is incubating embryos, the pouch closes with the borders touching except at the posterior end. (From del Pino, 1983.) chamber. Embryos, in turn, develop disk-shaped gills, the bell gills (Noble. 1927), that envelop the growing embryo in a vascularized gill sac. Fertilization. Fertilization in G. riobambae, G. p/iim- bea, and F. pygmaeus is external, but it does not occur in water as in most frogs. Eggs are fertilized during the journey from the female's cloaca to the pouch, as already discussed. Since the requirements for in vitro fertilization are unknown, we depend on normal mating of frogs to obtain fertilized eggs. When testis of G. riobambae are macerated in full strength MBS, sperm cells show little motility, but remain alive. Saline solutions of low ionic strength (like 10% MBS) do not trigger sperm motility. Such media, in fact, result in rapid swelling and bursting of sperm. Xenopus laevis sperm, in contrast, swim actively in solutions of low ionic strength before dying (Wolf and Hedrick, 1971). The ex- perience of mixing both gametes for in vitro fertilization has, so far, been unsuccessful. The length of time needed for the process and the possible requirement of pouch secretions to activate sperm are factors that need to be considered for an in vitro fertilization method. Culture of embryos. Embryos of G. riobambae can be removed from the pouch without affecting the mother or the development of other embryos in the pouch. Embryos are removed with a wide probe or a blunt pair of forceps. With frequent removal of embryos and handling of the frog, some embryos die and desiccate in the pouch. Dead embryos do not affect the development of the brood. Gentle handling of the fro
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
