Sperm ultrastructure and spermiogenesis of the dipluran Japygidae (Japyx solifugus, Metajapyx braueri and Occasjapyx japonicus) and Campodeidae (Campodea sp.) were studied with the aim of looking for potential characters for the reconstruction of the phylogenetic relationships of basal hexapods. Both Japygidae and Campodeidae share a common sperm axonemal model 9+9+2, provided with nine accessory microtubules. These microtubules, however, after their formation lose the usual position around the 9+2 and migrate between the two mitochondria. In Japygidae, four of these microtubules are very short and were observed beneath the nucleus after negative staining and serial sections. Accessory microtubules have 13 protofilaments in their tubular wall. Diplura have a sperm morphology which is very different from that of the remaining Entognatha (Protura+Collembola). On the basis of the present results, the presence of accessory microtubules suggests that Diplura are the sister-group of the Insecta s.s.. Moreover, Japygidae and Campodeidae differ with regards to the relative position of the sperm components, the former having the axoneme starting from beneath the nucleus (above which sits the short acrosome), while the latter having a long apical acrosome and a nucleus running parallel with the proximal part of the axoneme. The present study also allowed to redescribe the male genital system of Japyx.

Dallai, R., Mercati, D., Carapelli, A., Nardi, F., Machida, R., Sekiya, K., et al. (2011). Sperm accessory microtubules suggest the placement of Diplura as the sister-group of Insecta s.s. ARTHROPOD STRUCTURE & DEVELOPMENT, 40, 77-92 [10.1016/j.asd.2010.08.001].

Sperm accessory microtubules suggest the placement of Diplura as the sister-group of Insecta s.s.

DALLAI, ROMANO;MERCATI, DAVID;CARAPELLI, ANTONIO;NARDI, FRANCESCO;FRATI, FRANCESCO
2011-01-01

Abstract

Sperm ultrastructure and spermiogenesis of the dipluran Japygidae (Japyx solifugus, Metajapyx braueri and Occasjapyx japonicus) and Campodeidae (Campodea sp.) were studied with the aim of looking for potential characters for the reconstruction of the phylogenetic relationships of basal hexapods. Both Japygidae and Campodeidae share a common sperm axonemal model 9+9+2, provided with nine accessory microtubules. These microtubules, however, after their formation lose the usual position around the 9+2 and migrate between the two mitochondria. In Japygidae, four of these microtubules are very short and were observed beneath the nucleus after negative staining and serial sections. Accessory microtubules have 13 protofilaments in their tubular wall. Diplura have a sperm morphology which is very different from that of the remaining Entognatha (Protura+Collembola). On the basis of the present results, the presence of accessory microtubules suggests that Diplura are the sister-group of the Insecta s.s.. Moreover, Japygidae and Campodeidae differ with regards to the relative position of the sperm components, the former having the axoneme starting from beneath the nucleus (above which sits the short acrosome), while the latter having a long apical acrosome and a nucleus running parallel with the proximal part of the axoneme. The present study also allowed to redescribe the male genital system of Japyx.
2011
Dallai, R., Mercati, D., Carapelli, A., Nardi, F., Machida, R., Sekiya, K., et al. (2011). Sperm accessory microtubules suggest the placement of Diplura as the sister-group of Insecta s.s. ARTHROPOD STRUCTURE & DEVELOPMENT, 40, 77-92 [10.1016/j.asd.2010.08.001].
File in questo prodotto:
File Dimensione Formato  
dallai et al 2011.pdf

non disponibili

Tipologia: Post-print
Licenza: NON PUBBLICO - Accesso privato/ristretto
Dimensione 7.92 MB
Formato Adobe PDF
7.92 MB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11365/33441
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo