Fine structure of developing and mature spermatozoa in Tubiluchus (priapulida, tubiluchidae)

Axonemal structure and insect phylogeny

“…The presence of an external set of tubules is a peculiarity shared by few animal groups. Nevertheless, while we can exclude that the priapulid Tubiluchus (Alberti & Storch, 1983) and the annelid Questa (Jamieson, 1983) have accessory tubules homologous to those of Insects, it is still debatable whether we can consider the presence of the 9 accessory tubules in onychophorans and insects as a synapomorphy.…”

4. Priapulida

“…This anterior nuclear region is surrounded by the acrosome, which has two arms that wind in a corkscrew manner around each other in the anterior part and then around the anterior part of the nucleus (Alberti & Storch 1983, Ferraguti & Garbelli 2006. Alberti & Storch (1983) also mention accessory microtubules for Tubiluchus sp., but the number is unknown. Five mitochondria are reported for Tubiluchus sp.…”

“…Important broad studies including histological sections were made by Ehlers (1862), Apel (1885) and Scharff (1885). Ultrastructural investigations are, besides data on Priapulus caudatus and Halicryptus spinulosus, available for Tubiluchus species (Alberti & Storch 1983, 1986, Storch & Alberti 1985a,b, Storch et al 1985, Ferraguti & Garbelli 2006 and for Meiopriapulus fijiensis (Storch et al 1989a,b). Ultrastructural investigations were summarized by Storch (1991), Adrianov & Malakhov (1996a) and Lemburg (1999).…”

“…The round-headed spermatozoon of Priapulus caudatus (Afzelius & Ferraguti 1978), Halicryptus spinulosus (Adrianov et al 1992) and Meiopriapulus fijiensis (Storch et al 1989a & Ferraguti 1978) and Tubiluchus philippinensis (B; after Alberti & Storch 1983). ac = acrosome, ace = accessory centriole, ci = cilium, mi = mitochondria, nu = nucleus.…”

“…4.1.10 B) have an elongate anterior part and a cilium. (Alberti & Storch 1983) and three for T. troglodytes (Ferraguti & Garbelli 2006). This anterior nuclear region is surrounded by the acrosome, which has two arms that wind in a corkscrew manner around each other in the anterior part and then around the anterior part of the nucleus (Alberti & Storch 1983, Ferraguti & Garbelli 2006.…”