A fresh look at Dinodasys mirabilis (Gastrotricha, Macrodasyida), with focus on the reproductive apparatus and sperm ultrastructure
Articolo
Data di Pubblicazione:
2012
Citazione:
A fresh look at Dinodasys mirabilis (Gastrotricha, Macrodasyida), with focus on the reproductive apparatus and sperm ultrastructure / M.A. Todaro, L. Guidi, M. Ferraguti, M. Balsamo. - In: ZOOMORPHOLOGY. - ISSN 0720-213X. - 131:2(2012), pp. 115-125. [10.1007/s00435-012-0147-2]
Abstract:
Adults of Dinodasys mirabilis were studied for the Wrst time. The specimens, collected from the west coast
of Sweden, were investigated alive and with electron microscopy. Sexually mature specimens attain a total
length of 450–490 m; the adhesive apparatus is made up of anterior, lateral, ventrolateral, dorsal and posterior tubes; and one pair of “cirrata” type tubes is also present. The reproductive apparatus is hermaphroditic, paired testes
extend rearward from the pharyngeo-intestinal junction to 3/4 of the trunk, and sperm ducts bend anteriorly at U52 and join together into a common, mid-ventral pore at U33. Two ovaries lie along the sides of the caudal intestine, extending anteriorly from U68. Frontal organ present on the
right side of the body centered a U70; caudal organ was absent; a gland organ surrounding the terminal intestine
may be present, but its homology with other organs in a similar position is uncertain. The spermatozoon is a Wliform cell, formed by a long acrosome, a spring-like nucleus and
a Xagellum. The acrosome is divided into two regions: the anterior-most is thin and corkscrew-shaped, and the posterior one is rectilinear; both regions are delimited by a continuous
external layer of thick, dense material, which in longitudinal section appears obliquely striated and surrounds
a long pile of stout, electron-dense cylinders; the nucleus contains condensed chromatin and is coiled around
an elongate mitochondrion; the Xagellum possesses a 9 £ 2 + 2 axoneme devoid of striated cylinder. Within
Macrodasyida, U-bend sperm ducts and the peculiar ultrastructure
of the acrosome are characteristics shared by other Turbanellidae studied so far, providing a foundation for the
current systematization of Dinodasys.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Gastrotrich ; Turbanellidae ; Marine
meiofauna ; Reproductive system ; Spermatozoon ;
Ultrastructure
Elenco autori:
M.A. Todaro, L. Guidi, M. Ferraguti, M. Balsamo
Link alla scheda completa: