On the morphology and classification of larval water mites (Hydrachnidia, Acari) from springs in Luxembourg Author Martin, Peter text Zootaxa 2006 1138 1 44 journal article 10.5281/zenodo.172007 bd92c31d-534c-4bb2-a395-fb69e7ab01a9 1175­5326 172007 Sperchontidae Thor, 1900 Diagnosis: Dorsal plate mostly large, in unengorged specimens covering more than half the length of the idiosoma, Dp bearing 4 pairs of setae; lateral eyes on each side borne on a common eye plate; coxal plates I to III separate, plate III often larger than the others; plates I­III with 3 or 4 pairs of coxal setae (seta C3 on CX­II present or absent); chelicerae small, basal segments separated from each other; chela dentate; palpal segment 4 and 5 short, P5 thumb­like; some setae on palpal segments very large; legs I to III fivesegmented and each with three heavy claws; fusion line of former basifemur and telofemur present on legs I to III; leg segments 5 broad distally; eupathidium present on distal leg segment of legs I, II and III; solenidia on leg segments 3 to 5 of legs I and II very thin and placed at the distal end of the segment. Remarks: The available descriptions of larval Sperchontidae do not allow genera diagnoses within the family. The formerly proposed differences between the genera Sperchonopsis and Sperchon (see Prasad & Cook 1972 ; Smith 1982 ) relating to characters of the chetotaxy and patterns of the Dp is no longer valid after the description of Sperchonopsis verrucosa ( Protz, 1896 ) by Martin (2000) . For details, see the discussion therein.