Please use this identifier to cite or link to this item:
|Type:||Artigo de periódico|
|Title:||The Ultrastructure Of The Spermatozoa Of The Worm Lizard Amphisbaena Alba (squamata, Amphisbaenidae) And The Phylogenetic Relationships Of Amphisbaenians|
|Abstract:||We describe the ultrastructure of epididymal spermatozoa of Amphisbaena alba and make comparisons with spermatozoa of other squamates. The mature spermatozoon of A. alba is filiform and characterized by the following features: the acrosome is depressed in transverse section; the perforatorial base plate is absent; the perforatorial tip is pointed; the perforatorium is single; the epinuclear lucent zone is well developed; the midpiece is moderately long; the mitochondria are columnar, forming regular circlets interrupted by dense bodies in transverse section; the dense bodies are solid, arranged in regular rings and linear series; the nuclear shoulders are rounded; the nucleus is elongate; the endonuclear canal is absent; fibers 3 and 8 are enlarged; multilaminar membranes are absent; and the fibrous sheath is in the midpiece. A phylogenetic analysis of squamates using spermatozoon-ultrastructure characters resulted in 2415 equally parsimonious, largely unresolved trees. The use of a constraint tree derived from gross anatomical characters suggested that the Amphisbaenia is the sister-group of the Autarchoglossa. We conclude that to improve the resolution of phylogenetic hypotheses derived from spermatozoon-ultrastructure characters, the number of characters ought to be increased and more investigations are necessary to ascertain the degree of intrafamilial variability.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.