Ultrastructure of spermatozoa in Orthalicidae Mol

Authors: María Gabriela Cuezzo

Publish Date: 2011/06/17

Volume: 130, Issue: 3, Pages: 147-

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Abstract

Sperm morphology of orthalicid gastropods Clessinia pagoda Spixia tucumanensis Plagiodontes daedaleus Odontostominae and Drymaeus hygrohylaeus D poecilus Bostryx stelzneri Bulimulinae are examined and described for the first time using transmission electron microscopy Spermatozoa show the general characteristic of Pulmonata an acrosomal vesicle sperm nucleus helical mitochondrial derivative forming a continuous sheath with paracrystalline material and coarse fibers associated with axonemal doublets Features in the acrosomal complex and shape of the nucleus distinguish orthalicid sperms from other stylommatophoran The acrosomal pedestal is traversed by fine striations in all species examined except in S tucumanensis The structure and thickness of the perinuclear sheath with a single or double layer of electrondense material ensheathing the nuclear apex is characteristic of the group The presence of a subnuclear ring in Drymaeus Bostryx and Clessinia species is also reported A data matrix of eleven species per 34 characters 16 sperm plus 18 anatomical and shell characters from orthalicids plus other stylommatophoran and systellommatophoran representative species was constructed Three cladistic analyses spermbased anatomicalbased and a combined sperm + anatomicalbased were performed to test the phylogenetic potential of sperm ultrastructure in orthalicid systematics and understand how sperm characters affect the topology and resolution of the obtained trees Stylommatophora resulted in a monophyletic clade in the spermbased and in the combinedcharacter analysis Orthalicidae is monophyletic only in the combinedcharacter cladogram Within Orthalicidae Odontostominae is recovered as a monophyletic clade in all analyses while Bulimulinae is paraphyletic in all trees except in the combined phylogeny The present study and cladistic analyses performed support the hypothesis that characters on sperm ultrastructure are informative for stylommatophoran systematic and phylogenetic approaches providing synapomorphies at familiar subfamiliar and generic levelStaff of the Laboratory of Electron Microscopy of Northwestern Argentina LAMENOA is greatly acknowledged for the support given to the present study JM Healy is thanked for kindly providing information and special literature that made this study possible A Gandolfo Nixon Cornell University USA and S Toranzo are thanked for reviewing English language The author is grateful to the editor Th Bartolomaeus and anonymous reviewers for their detailed review and suggestions Permission for collecting specimens was provided by the Argentinean National Park Service Agency to which the author’s gratitude is extended The author is a researcher of CONICET Consejo Nacional de Investigaciones Científicas y Técnicas Argentina support from which is greatly acknowledged Funding to develop this research was provided by PIP 6048 CONICET and PICT 528 ANPCyT

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