Asexual repooduction in Glossobalanus crozieri (Ptychoderidae,Enteropneusta, Hemichordata) |
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Authors: | J A Petersen A S F Ditadi |
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Institution: | (1) Institute of Biosciences, Institute of Marine Biology, University of São Paulo, São Paulo, Brazil;(2) Present address: Friday Harbor Laboratories, 98250 Friday Harbor, Washington, USA;(3) Department of Physiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil |
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Abstract: | Several aspects of asexual reproduction in Glossobalanus crozieri (a species first found in Bermuda, but occurring also on the coast of Brazil) have been observed. The results are compared with those by earlier authors on other species of Enteropneusta. A revision of asexual reproduction in the Enteropneusta (Hemichordata) is made. Developmental rates and regeneration were studied in branchiogenital individuals, hepatic individuals and regenerands. The habitat where these forms are found is described. Possible meaning of gonad maturation and sexual reproduction in relation to asexual reproduction in different species is discussed. The need for further studies on the variation of forms which reproduce both sexually and asexually is emphasized, with a view to taxonomic problems, based both upon the proportions of the different body regions and on the number of branchial pores. The present findings indicate that, when compared to the results reported for other species, asexual reproduction in all ptychoderids (Balanoglossus, Glossobalanus and Ptychodera) follows the same general pattern. The phenomenon of asexual reproduction in this group is also confirmed to be worldwide. |
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