Morphology of spermatozoa and sperm packages in the European Belisarius xambeui

There are few modern studies on the rarest scorpion in Europe, Belisarius xambeui. This troglophylous scorpion is only reported from the southeastern Pyrenees in France and in Cataluña in Spain, and is placed in Chactidae by some authors and Troglotayosicidae by others. Vignoli, Klann & Michalik, 2008 has done a study of the morphology of the spermatozoa and sperm packages of Belisarius, and the results are linked to systematics and phylogeny. Here is the abstract from the article:

Studies on the sperm morphology in scorpions are rare, but the existing investigations already revealed a remarkable interfamiliar diversity. The present study reports for the first time on the spermatozoa and sperm packages of a representative of the family Troglotayosicidae, the troglophylous species Belisarius xambeui. The spermatozoa are characterized by (1) a thread-like nucleus, which is slightly bent anteriorly; (2) an asymmetrical cap-like acrosomal vacuole, which encloses the anterior tip of the nucleus; an acrosomal filament is absent; (3) an axoneme with a 9 + 0 microtubular pattern; (4) a midpiece consisting of elongated mitochondria coiling around the axoneme; the number can vary between 3 and 6 (mostly 4). At the end of spermiogenesis, the spermatozoa aggregate in order to form oval-shaped sperm packages in which all sperm cells show the same orientation. A single package consists of approximately 150 sperms. A secretion sheath is always absent. The present results might provide new characters for further systematic studies and their phylogenetic implications are briefly discussed.

Reference:
Vignoli V, Klann AE, Michalik P. Spermatozoa and sperm packages of the European troglophylous scorpion Belisarius xambeui Simon, 1879 (Troglotayosicidae, Scorpiones). Tissue Cell. 2008;40:411-6. [Subscription required for fulltext]

Family Chactidae