. Bonner zoologische Monographien. Zoology. PANESAR, EVOLUTION IN WATER MITES Limnesiidae, especially Neomamersa, Memmecia and Neotorrenticola as apomorph. The plesiomorphic condition is expressed in Nilo- tonia species, with their acetabula lying free in the gonopore without enlarged basal sclerites. Fusion of enlarged basal-sclerites to a common strip situated on each side of the gonopore below the movable flap is an apomorphic character state found for example in Dartia hoettgeri. In Shivatonia this strip is raised and adpressed to the medial border of the genital flap, while in Neomamersa
. Bonner zoologische Monographien. Zoology. PANESAR, EVOLUTION IN WATER MITES Limnesiidae, especially Neomamersa, Memmecia and Neotorrenticola as apomorph. The plesiomorphic condition is expressed in Nilo- tonia species, with their acetabula lying free in the gonopore without enlarged basal sclerites. Fusion of enlarged basal-sclerites to a common strip situated on each side of the gonopore below the movable flap is an apomorphic character state found for example in Dartia hoettgeri. In Shivatonia this strip is raised and adpressed to the medial border of the genital flap, while in Neomamersa conjuncta it is fused to the medial bor- der of the genital flap, with the setae still arising from the "old" medial border of the flap (now lateral to the fused basal sclerites of the acetabula). Bharatonia shows a situation where the basal sclerite of the third acetabulum is already fused to the posterior end of the genital flap, while the two ante- rior pairs are still situated well medial and "inside" the flaps. If the anterior acetabula pairs developed en- larged basal sclerites, adpressed to the medial border of the genital flap, the situation found in Shivatonia is reached. If in addition the acetabula proliferated, a situation is reached exactly as it is found in Neo- torrenticola (Neotorrenticolinae, Limnesiidae). The gradual changes in the organization of the genital region go along with several other character states in adult and nymphal morphology connecting Bharatoniinae closely to other subfamilies of the Lim- nesiidae (, the short genital sclerite found in Bha- ratonia and Shivatonia is similar to the one depicted for Neomamersa but clearly different from the ones described for Nilotonia, Bandakia and Limnesia). A revision of the early derived subfamilies of the Lim- nesiidae would be the next step to decide if the trans- formation series in the organization of the genital field can be related to other synapomorphic character states in a p
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