Rutripalpidae Sokolow, 1934

Gerecke, Reinhard & Tuzovskij, Petr, 2001, The water mite Rutripalpus limicola Sokolow, 1934: new data on morphology and biology, and considerations on the systematic position of the monotypic family Rutripalpidae (Acari, Hydrachnidia), Journal of Natural History 35 (6), pp. 931-944 : 933-934

Rutripalpidae Sokolow, 1934

Diagnosis

Male. Integument of idiosoma soft, arrangement of glandularia and setae in agreement with the ground plan of Lebertioidea and Hygrobatoidea sensu Cook (1974) (idiosoma dorsal view ®gure 1, ventral view ®gure 2, chaetom formula: 2- 2-4-4-6-4-4-4-2-4-0, ®ve pairs of slit organs); lateral eyes with two lenses in a small eye capsule; glandularia with thick setae inserted above gland openings on small sclerites, subcutaneous portion of glands as large vesicles; neither a frontal eye, nor a frontal sclerite; ®ve pairs of dorsocentralia always well sclerotised, about six pairs of dorsolateralia sclerotised to diOEerent degree, sometimes only visible as small muscle attachment dots; coxal plates in paired anterior and posterior groups, Cxgl- 1 in the integument between Cx-2 and Cx-3, Cxgl- 2 in the integument posterior to Cx-4; accessory Cxgl in indentations near medial angles of Cx-4; legs (®gures 3±8) stout, with rosettes of strong distal setae on segments 3±5, claws I±III with ventral blade, claws IV stronger, but lacking ventral appendages; genital organ (®gures 12±14) consisting of an elongate, penis-like curved tube formed by the fused genital plates; the tip of this tube in erect position directed anteriorly, in recovered position ventroposteriorly, with the`penis’ tube embedded in a pit of the membranous integument; as can be observed in ®xed specimens, protrusion of this organ is induced by increased haemolymph pressure, accompanied by expansion of the normally folded integument posterior to the genital ®eld; the anterior part of this organ bearing a paired group of long, posteriorly directed setae; the distal part of the genital tube with three pairs of acetabula; the acetabula-bearing area of the organ ¯anked by a lateral collar diverging posteriorly and forming a pair of tips on the level of the acetabula 3; this collar, its surroundings and the caudal margin of the acetabular area bearing numerous spine-like short setae; between the acetabula, no longish gonopore visible, but a posteriorly directed tube originating medially from acetabula 3, probably made up from the fused gonopore lips, the whole genital organ protrusible like a penis due to a snap mechanism; genital skeleton (®gure 15) small, brachia proximalia and proximal horns reduced; excretory pore with a small semicircular anterior sclerite, one pair of large ventrolateral sclerites ¯anking the genital area; gnathosomal base short and stocky, chelicera (like ®gure 21) with dorsal projection near the proximal base of the basal segment and a short, hooklike claw; pedipalp (®gures 9, 10) without ventral projections, P-2 strongly thickened, P-4 very short, P-5 ¯attened and enlarged, in dorsal view with a lateral indentation, with four strong, nail-like claws arranged in two groups.

Female. As given for male; dorsocentral sclerites smaller and dorsolateralia never sclerotized (®gure 16); genital ®eld with a pair of ¯aps ¯anking three pairs of acetabula and the posterior half of the gonopore (®gures 17, 18) praegential plate prominent, pent- or hexangular; mouth parts as in males, but P-4 more slender and longish, P-5 without lateral indentation (®gures 19, 20).

Deutonymph. Similar to adult, but smaller in size and with lower numbers of pedipalp and leg setae and V2 (Pi) lacking glandularia; dorsalia lightly sclerotized, accessory glandularia not completely embedded in sclerotization of medial angles of Cx-4; genital ®eld with two pairs of acetabula embraced by halfmoon-shaped ¯aps (®gure 22); pedipalp with P-4 slender as described for females (®gure 23).

Larva. Idiosoma (®gures 25, 26) chaetom formula: 2-2-2-4-4-4-4-4-2-4-4, ®ve pairs of slit organs; dorsal plate bearing four pairs of setae (Lp1,2; Mp1,2); all setae Hu, Mh, Lh, slit organs, and lateral eye lenses (on two separate platelets, ®gure 27) arranged in the dorsal furrow; coxal plates clearly delineated by complete suture lines, urstigma round, anteriorly covered by hemispheric cap (®gure 28); Cx-3 with two pairs of setae (C4 anteriorly, V1 posteromedially), V2 separate in the ventroposterior membranous integument; excretory platelet trapezoidal, bearing two pairs of setae (®gure 29), membranous integument surrounding excretory plate bearing V3 (shifted to the dorsal region) and V4 setae; numbers and typology of leg setae (®gures 30±33): I-L-1±5: 1, 7, 6 (s,e), 11 (2s), 17(s, a,2e); II-L1±5: 1, 7, 6(s,e), 11(2s), 16 (s,a,e); III-L-1±5: 1, 6, 5(s), 10(s), 13; chelicera: ®gure 24; pedipalp (®gure 35) setae number and typology: P-1 ±5: 0, 1, 2, 3, 7 (s); P-4 bifurcate.