Ultrastructural Study of Spermatogenesis in Gamasid Mites (Acari, Gamasida)
作者:
W. Witaliński,
R. Dallai,
期刊:
Acta Zoologica
(WILEY Available online 1991)
卷期:
Volume 72,
issue 1
页码: 49-54
ISSN:0001-7272
年代: 1991
DOI:10.1111/j.1463-6395.1991.tb00315.x
出版商: Blackwell Publishing Ltd
数据来源: WILEY
摘要:
AbstractStructural alterations accompanying the development of germ cells in representatives of two families of gamasid mites: Pergamasidae (Pergumasus barbarus. P. truatellus) and Parasitidae (Porrhostaspis lunulata) were examined by scanning electron microscopy. Spermatogenesis occurs in cysts containing two (P. lunuluta) or four spermatogonia (P. barbarusandP. truatellus) prior to meiosis. later arranged in a tetrahedral pattern. Meiosis produces 8 and 16 spermatids per cyst, respectively. Spermatids are located radially and elongate synchronously. Dimples appear at their acrosomal ends, soon replaced by peg‐like structures surrounded by superficial ridges. The number of ridges which correspond to longitudinal ribbons can vary between and within species as well as between spermatids occupying one cyst. Our observations suggest some unknown mechanism which allows the spermatozoa to enter vasa deferentia in a unidirectional orientatio
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