Unionicola ypsilophora (Bonz), a water mite new to the Iberian Peninsula By Antonio G,-Valdecasas, Cristian R. Altaba & Anna Travesset i Vilagines Madrid Barcelona Abstract There are 14 species of water mites parasitizing in freshwater mussels or sponges known in Europa so far of tlie genus Unionicola. With a detection of U. ypsilophora (Bonz) out of Anodonta cygnea in the lake of Banyoles the number of reported Unionicola-species increased up to 6 for the Iberian Peninsula. Knowledge of water mite fauna of the Iberian Peninsula after Viets (1930) and Lundblad (1956) landmarks, has increased at a great paucity (see a Balance of previous works in G.-Valdecasas 1981). Despite other european provinces (Illies 1978), the Iberian Peninsula is poorly known regarding its water mite fauna, and search in new habitats will produce a different view of what is presently know. Although there is a long tradition of malacological studies in the Iberizan Peninsula, there has not been any mention of water mites parasitizing mussels. In this paper we record the presence of Unioni-cola ypsilophora (Bonz, 1783) from the mussei Anodonta (s. s.) cygnea (Linnaeus, 1758). Five adult females were found in a specimen of A. cygnea living in the calcareous lime bottom, 0.5 m. , of the lake of Banyoles (Miracle 1975). The animals fit the description of Viets (1936, pag. 289) and the drawings of Mitchell and Pitchford (1953). Fig 1 shows the genital area and the palp of one specimen. A female had two eggs. "Water mites of the genus Unionicola are known to be parasites of freshwater mussels or sponges. Fourteen species of this genus has been found in Europe and only five to the I. P. Until date U. inusi-tata Koenike was the only species known to grow up in mussels and found freeswimming in this area (Viets 1930). Previous records of U. ypsilophora points to a highly specific parasitisms. Mitchell and Pitchford {1951)) coWectionoi 21)% Anodonta specimens rendered a unique parasitism of L''. ypsilophora toA. cy-gnea. It was not found in any other Anodonta species. Davids (1973) had found a similar, although not such an extreme Situation. He mentions that U. ypsilophora could be "rarely found" in A. anatina. Notwithstanding, many authors (see Haas 1969) think that both are the same species. In arecent study, one of US (C. R. A.) has not found any difference for maintaining the distinction between both species. Abb. 1: Unionicola ypsilophora 5 -A. Genital area. B. Palp. 73
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