The ultrastructure of the spermatozoon of the oligochaetoid polychaete Questa sp. (Questidae, Annelida) and its phylogenetic significance

Jamieson B.G.M. (1983) The ultrastructure of the spermatozoon of the oligochaetoid polychaete Questa sp. (Questidae, Annelida) and its phylogenetic significance. Journal of Ultrasructure Research, 84 3: 238-251. doi:10.1016/S0022-5320(83)80004-5


Author Jamieson B.G.M.
Title The ultrastructure of the spermatozoon of the oligochaetoid polychaete Questa sp. (Questidae, Annelida) and its phylogenetic significance
Journal name Journal of Ultrasructure Research   Check publisher's open access policy
ISSN 0022-5320
Publication date 1983-01-01
Sub-type Article (original research)
DOI 10.1016/S0022-5320(83)80004-5
Volume 84
Issue 3
Start page 238
End page 251
Total pages 14
Subject 1312 Molecular Biology
2702 Anatomy
Abstract Questids are clitellate annelids with oligochaetoid features but spermatozoal ultrastructure confirms that they are not oligochaetes. The very elongate acrosome vesicle and contained tubular perforatorium, somewhat exceeding 5 μm, are followed by a highly condensed elongate nucleus. Between acrosome and nucleus a subacrosomal and a narrow nuclear plate intervene. Behind the nucleus a complex centriolar apparatus with evidence of two centrioles, of which the distal has triplets and accessory microtubules, gives rise to a long glycogen-containing flagellum. At least 12 μm of the axoneme, constituting the midpiece, is invested by two mitochondrial derivatives, each with a narrow crescentic transverse profile, posteriorly limited by an annulus. The axoneme is of the 9 + 2 type but in the mitochondiral region as many as 27 accessory peripheral microtubules, in 9 triads, encircle it. Elongation of the primary vesicle and of the mitochondrial derivatives, and presence of an extensive axial rod, are seen in sperm of protodrilid archiannelids with which, as with dinophilids, questids have somatic similarities indicative of a relationship closer than with other annelids. The accessory flagellar microtubules, unique in the Annelida, may prove a distinctive autapomorphy of the Questidae. Questids are retained in the Polychaeta pending clarification of polychaete-archiannelid relationships and the new name Euclitellata is proposed for the former class Clitellata.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import - Archived
 
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Created: Tue, 05 Jul 2016, 11:28:36 EST by System User