Gamasides Chiliens (Arachnides): II. Revision de la famille Ichthyostomatogasteridae Sellnick, 1953 ( = Uropodellidae Camin, 1955)

Abstract

The mites studied here come mainly from soils of the northern half of Chile, which seems to be, nowadays, the only territory in the world where the family lchthyostomatogasteridae shows a rather large systematic diversification, frequency and abundance. The sampling of the microarthropods from the Chilean soils has been carried out quantitatively. Among the two genera, the first one (Asternolaelaps) is an omnivorous grinder, the second (Uropodella) probably consumes fluid food, as do the other contemporary gamasid mites. The Ichthyostomatogasteridae are epicrioid *tocospermal gamasids. The comparative morphological study of the members of this family and of several *podospermal gamasid mites has, on the one hand, led to some unclassical conceptions regarding this matter, and, on the other hand, to a terminological adjustment (see also the "Index terminologique"). Presumably the family lchthyostomatogasteridae is a gamasid lineage gondwanian in origin; its phyletic diversification could have taken place in the Palaeantarctic continent. It is deemed to be relictual even in the country where it originates from, and the only consistent settlement which remains of the family could be the Chilean representatives. Outside this country, several representatives of the genus Asternolaelaps survive as palaeoendemic relicts in Australia, Argentina and Europe, and Uropodella has been found in Brazil, Argentina, Paraguay and United States. The first part analyses the world distribution of the members of the family Ichthyostomatogasteridae, delineates the geographical areas and the ecological trends of the Chilean species and provides the collecting and census of the sampling of Chilean soils. The second part gives an improved definition of the family, of the genera Asternolaelaps and Uropodella, and of the new subgenus Parasternolaelaps. The systematic structure of the family is discussed; several tables illustrate the proposed classification and allow the identification of the ten known species. Finally, in the "Catalogue des Especes", six species are newly described; three of them belong to the genus Asternolaelaps and the three others to the genus Uropodella.