Platymamersopsis K. Viets, 1914

Goldschmidt, Tom, 2008, Taxonomical, ecological and zoogeographical studies on anisitsiellid water mites (Acari: Hydrachnidia: Anisitsiellidae Koenike, 1910) from Madagascar, Zootaxa 1954 (1), pp. 1-120 : 88

Platymamersopsis K. Viets, 1914

Diagnosis (varied after Cook 1974): Complete ventral and dorsal shield; dorsal shield with central area separated by a ridge (clear in the rostral part, more or less clear in the caudal part), peripherally bearing post-ocular setae, Dgl-3 to -6 and Lgl-4; narrow dorsal furrow with five pairs of lyrifissures (caudal pair can be fused with ventral shield); lateral eyes as well as Lgl-1 to -3 fused with ventral shield; Cx-IV rectangular with lateral ridge, medially separated by genital field, insertions of leg-IV lateral to genital field; Cxgl-2 between Cx-II and -III or at posterior margin of Cx-II, Cxgl-4 on Cx-III (in most species near anterior margin; three pairs of genital acetabula; male sex probably without genital skeleton; capitulum blunt, compact (typical subgenus) or with keel-like rostrum (Madagascaran subgenus); palps compact, ”mamersopsid-type”, in a Madagascaran subgenus with long and slender P5; legs usually compact, in some species with long setae, without swimming hairs; claws on leg-I to -III with comb-like ventral clawlets (Asian and some Madagascaran species) or with simple dorsal and ventral clawlets (African and some Madagascaran species); leg-IV without claws, bearing two distal setae of variable size.

Remarks: Unfortunately, previous descriptions of Platymamersopsis spp. contained little information on the shape of the legs. The species from Madagascar, described in the following, show large variation in the chaetotaxy as well as the proportions of the distal leg segments. Therefore further descriptions of new species of this genus should also include leg shape and chaetotaxy. Until now, no genital skeleton was found in the males of the genus, the male sex being mainly characterised by a smaller, more rounded genital field. However, especially in the species only known in one sex, the assignation is often uncertain.

Mamersella (Neomamersella) tototaensis Cook, 1966 , collected in a stream in Liberia (West-Africa), was transferred to the genus Platymamersopsis by Panesar (2004). In view of the following character states, this species should be retained in Mamersella (see above, characters of Platymamersopsis in parenthesis): Large dorsal plate without peripheral ridge leaving a wide dorsal furrow (dorsal plate with clear ridge covering nearly the complete dorsum); five pairs of glandularia — Dgl as well as Lgl — in dorsal furrow (all glandularia fused with dorsal or ventral shield); suture between Cx-III and -IV incomplete, Cx-IV meet medially anteriorly to genital field (suture between Cx-III and -IV complete, Cx-IV completely separated by genital field); Cx-III without glandularia (Cx-III bearing Cxgl-4); P4 elongated, club-shaped, P5 with long and slen- der claws (P4 compact, P5 compact or elongated, with short, stout claws).