The tail of Ascaphus : a historical resume and new histological-anatomical details

[摘要] ENGLISH ABSTRACT: The pelvic girdles of the two anuran genera Ascaphus and Leiopelmaof the family Ascaphidae are very similar. Attached to them by cartilage(or connective tissue in some Ascaphus specimens) is a cartilaginous, inLeiopelmu somewhat ossified, epibubis. In Ascaphu8, as in Xenopus, the epipubisoriginates from two Anlages, and its muscles are also paired in the Ascaphidae,while in Xenopus only one is present, although this also appears to originate(rom two muscles. The cloaca extends behind the pelvic girdle in both sexesin Al:lcaphus, and it is supported by two rods consisting of strong connectivetissue (Faserknochen?). These rods are attached to the ventral surface ofthe pelvic girdle, in the female closely, in the male by means of tendons.Between the rods and the epipubis a broad tendinous band extends, which isthick in the male; in the latter the mm. compressores cloacae have theirorigins posteriorly on the rods, while in the female the rods are completelyimbedded in these muscles posteriorly. In the female particularly there aretransverse muscle fibres which are not striped although probably derived fromthe mm. compressorcs cloacae. Behind the pelvic girdle there is cavernoustissue in both layers of the tunica muscularis, and ventrally it covers the mm.eompressores cloacae. The circular and longitudinal muscle layers areposte riorly separated by gliding planes. The cloaca is supplied by branchesof the a. mcsenterica posterior and the au. pudendae anteriores, and is drainedby the vv. pudendae and a small medial v. eaudalis. The cloaca is innervateddorsally by the plexus ischio·coccygeus and ventrally by a branch of the n.ischiadicus (the n. pudendus). The cloaca of the male serves as a copulatoryorgan. There is internal fertilization.

[发布机构] Stellenbosch University