Pretarsal structures of camel-spiders: new characters for the systematics of Solifugae
Anja Elisabeth Klann, Gerd Alberti
Zoologisches Institut & Museum, Ernst-Moritz-Arndt-Universität Greifswald
Solifuges, also called camel-spiders, live mainly in tropical and subtropical regions preferably in arid ecosystems. The current classification recognizes 12 families, 140 genera and 1075 species. The most comprehensive taxonomic treatment of the order Solifugae was done by Roewer but this has been constructively criticized by various authors due to his reliance on considerably variable characters such as spine-like leg setae on which Roewer based much of his taxon delineation. Pretarsal structures of the walking legs have neither been studied in detail from the point of functional morphology nor been taken into account in current classifications of Solifugae. In the present study, representatives of the families Ammotrechidae, Daesiidae, Eremobatidae, Galeodidae, Gylippidae, Karschiidae and Solpugidae were studied by means of scanning electron microscopy. There is a relatively high variation of the morphology of the arolia between the different families. They can be either relatively simple cushion-like or bipartite or even consist of different lobe-like structures. E.g., in the genera Galeodes and Paragaleodes (Galeodidae) the structure of the arolia is cushion-like and quite uniform with only slight differences, whereas within the family e.g., Daesiidae the arolia exhibit very distinct shapes. Although tarsal structures may also be highly adapted to ecological conditions, the putative systematic and phylogenetic value is discussed.