Comparative morphological analysis of spemr packages from selected species of the family Bothriuridae (Scorpiones)

VRECH, D., C. I. MATTONI & A. V. PERETTI

San Pedro, San Pablo, Brasil

Conferencia; 17th International Congress of Arachnology; 2007

International Society of Arachnology

Some arachníds possess spermatozoa grouped in different forms. Scorpions have spermatozoa connected by a secretion. Sperm packages are widely distributed in the order, but absent in the fami1y Buthidae. The morphology of the sperm packages is quite variable, apparently carrying valuable phylogenetic informatíon. The main objective of this work is to conduct a morphological analysis and comparison of the different sperm packages of selected species of Bothriuridae. Male specimens from at least two species of the following genera were studied: Brachistostemus, Timogenes, Urophonius, Cercophonius, Vachonia, Orobotltriurus, and Bothriurus. In Bothriurus, we increased the taxon sampling to observe differences inside a genus. Specimens of luridae and Euscorpiidae were used as out-group comparison. Microscope slide preparations with the content of the vesicle from the paraxial organ were made and observed in the light microscope. Pictures were taken with a digital camera and analyzed with a computer programo Oetailed extemal structure was observed in some species through scanning electro-microscope. We distinguished three regions in the packages, Head, Body and Tail. Parameters taken to compare were: Total Length, Head Thick, Body-head Angle, Total Area, and Head Length. Measures were statistically analyzed and compared within and among genera. These analyses showed little change in general sperm package morphology within genus and species, but much more differences among genera. Brachistostemus showed round forehead with short body. Timogenes possesses folded packages, equivalent to that of some Bothriurus members in size. The same folded morphology was observed in Vachonia. Urophonius has hooked-head packages with a particular corrugation in the body part. Cercophonius showed packages with a round thick head, and short bodies with a well defined tail. Orobothriurus has very thin packages with short heads. Botitriurus's packages were long with heads that showed very little differences in general shape between species. Some anomalies were observed, such as the presence of packages that seemed to carry less sperm that the regular ones. Sperm packages may result in an interesting tool for taxonomic research, as another source of characters to gather mayor taxa such as genus or families. The potentíal roles that some traits of sperm packages (e.g. shape and size) could have in scenarios of sperm competition are discussed.