Acta Parasitologica, Vol. 50, No. 2, 2005, 132-144 Jordi Miquel(1)*, Zdzislaw Swiderski(2,3), Daniel Mlocicki(2), Catarina Eira(1)
and Bernard Marchand(4) - Ultrastructure of spermatogenesis of the anoplocephalid
cestode Gallegoides arfaai (Mobedi et Ghadirian, 1977)
Tenora et Mas-Coma, 1978
(1)Laboratori de Parasitologia, Departament de Microbiologia i Parasitologia Sanitaries, Facultat de Farmacia, Universitat de Barcelona,
Av. Joan XXIII s/n, E-08028 Barcelona, Spain; (2)W. Stefanski Institute of Parasitology, Polish Academy of Sciences, 51/55 Twarda Street,
00-818 Warsaw, Poland; (3)Department of General Biology and Parasitology, Warsaw Medical University, 5 Chalubinskiego Street,
02-004 Warsaw, Poland; (4)Laboratoire Parasites et Ecosystemes Mediterraneens, Faculte des Sciences et Techniques,
Universite de Corse, F-20250 Corte, France
*Corresponding author: jordimiquel@ub.edu
ABSTRACT
Spermatogenesis in Gallegoides arfaai is similar to that described for other cestode species. Six incomplete synchronic cytokineses
occur: four mitotic and two meiotic cell divisions. The primary spermatogonium divides forming two secondary spermatogonia.
All further divisions occur simultaneously, resulting in a rosette of four tertiary, then eight quaternary spermatogonia
and sixteen primary spermatocytes. The first meiotic division forms thirty-two secondary spermatocytes and after the second
meiotic division sixty-four spermatids are formed. Spermiogenesis begins with the formation of a differentiation zone in
the form of a conical projection of cytoplasm delimited by a ring of arching membranes. Within this area there are two centrioles,
a centriolar adjunct and vestigial striated rootlets. During spermiogenesis, only one of the centrioles develops an axoneme
that grows directly into the cytoplasmic extension. The other centriole remains oriented in a cytoplasmic bud and posteriorly
aborts. The nucleus elongates and moves into the cytoplasmic extension. Granular material present in each sperm originates
from electron-dense material present in the periphery of the spermatid. In the final stage of spermiogenesis two crest-like bodies
appear at the base of the spermatid. Finally, the ring of arching membranes constricts and the young spermatozoon detaches
from the residual cytoplasm. In order to increase homogeneity in the designation of the non-typical striated rootlets previously
described, in this study we propose to group them under the common designation of "vestigial striated rootlets" and its
importance is discussed according to previous findings of related structures in other cyclophyllideans.
KEY WORDS: Ultrastructure, spermatogenesis, Cestoda, Anoplocephalidae, Gallegoides arfaai