Unusual spermatozoa and reproductive modalities of Xenodasys eknomios (Gastrotricha: Xenodasyidae)
Articolo
Data di Pubblicazione:
2009
Citazione:
Unusual spermatozoa and reproductive modalities of Xenodasys eknomios (Gastrotricha: Xenodasyidae) / L. Guidi, M. Ferraguti, M.A. Todaro, L. Pierboni, M. Balsamo. - In: THE ITALIAN JOURNAL OF ZOOLOGY. - ISSN 1125-0003. - 76:2(2009), pp. 165-172.
Abstract:
The rare macrodasyidan Xenodasys eknomios is the first member of the genus to be found in the Mediterranean Sea and the
fourth species known worldwide. As Xenodasys has proved to be at the base of the Macrodasyida clade, we provide new data
on the reproductive system and spermatozoa to try and shed light on the ground pattern of gastrotrich reproduction. The
hermaphroditic system of X. eknomios consists of two testes with ventrolateral pores and two caudal ovaries. A sac-like
frontal organ, generally containing a spermatophore, is enveloped by a basal lamina and attached to the body wall by
muscular fibres, appearing as a permanent structure. The spermatophore contains mature, filiform, spermatozoa, each
composed of acrosome, spiralized nucleus, connecting piece and flagellum. The complex acrosome is the predominant
element and forms the axis of the sperm. Most of the acrosome, is surrounded by two helixes, the external one is the nucleus
and the internal one is a crystalline-like ribbon structure. The peculiar acrosome–nucleus complex, and the long connecting
piece appear as autapomorphies. The structural plans of the reproductive system and the spermatozoa support the current
systematization of Xenodasyidae and provide evidence for a possible sperm transfer modality in these species.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Xenodasys ; Gastrotricha ; Macrodasyida ; reproductive system ; spermatozoa ; ultrastructure ; fertilization
modalities
Elenco autori:
L. Guidi, M. Ferraguti, M.A. Todaro, L. Pierboni, M. Balsamo
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