Description of female and larva of the water mite Tiphys yaroslavlensis Tuzovskij, 2011 (Acari: Hydrachnidia, Pionidae)

The water mite Tiphys yaroslavlensis Tuzovskij, 2011 was described and known only from the male. The aim of the paper is to describe of female and larva of this water mite. The material was collected by the author in the Yaroslavl Province of Russia. To obtain larvae, water mite was maintained in laboratory (room temperature, natural day-night conditions). Idiosomal setae are named according to Tuzovskij (1987): Fch – frontales chelicerarum, Fp – frontales pedipalporum, Vi – verticales internae, Ve – verticales externae, Oi – occipitales internae, Oe – occipitales externae, Hi – humerales internae, He – humerales externae, Hv – humerales ventralia, Sci – scapulares internae, Sce – scapulares externae, Li – lumbales internae, Le – lumbales externae, Si – sacrales internae, Se – sacrales externae, Ci – caudales internae, Pi – praeanales internae, Pe – praeanales externae, Ai – anales internae, Ae – anales externae. Furthermore, the following abbreviations are used: P–1–5, pedipalp (trochanter, femur,

Diagnosis. Female: Medial margin of coxal plate IV slightly longer than medial margin of coxal plate III; sclerites, bearing setae Hv, fused with posteromedial margin of coxa II; genital plates more or less triangular with 3 acetabula and 9 short and fine setae each, all genital setae situated on each side of genital plate, gonopore and genital plates equal in length, anterior genital sclerite wider than posterior one; P-3 with 3 unequal setae, base of long lateral seta situated proximally to middle of segment; P-4 with relatively short distolateral spine (4.0-5.0 times shorter than tarsus), both ventral setae situated distally to middle of segment; larva: Dorsal shield elongate (ratio length/width 1.54-1.70), covering almost all dorsum in unengorged larva and bearing 3 pairs of setae, Vi situated on soft integument; setae Oe longest, Hi longer and thinner than He; coxal setae C1 and C4 subequal and longer than C2-C4, base of setae C4 on coxal plate III situated closely to medial end of suture line between coxal plates II and III; tmas scar present; setae Se much longer than setae Si; dorsal shield and coxal plates I-III punctuated; excretory pore plate anterior portion wider than posterior one, anal setae subequal and situated near anterior margin of excretory pore plate; formula of heavy setae on leg segments as follows: I-Leg 1-5: 0, 1, 1, 1, 0; II-Leg 1-5: 0, 1, 2, 4, 0; III-Leg 1-6: 0, 1, 2, 4, 0.

Description
Female. Colour red. Idiosoma oval, integument soft and finely striated. Dorsum with two pairs unequal anterior platelets, anteromedial platelets comparatively large and elongate (L/W ratio 2.9-3.0), anterolateral platelets small transverse (Fig. 1). The number and position of idiosomal setae typical for the genus Tiphys. All dorsal setae thin and approximately equal in length, but setae Fch (Fig. 2) longer and thicker than others idiosomal setae associated with glandularia ( Fig. 3) and trichobothria (Fig. 4). Anterior coxal plates with short apodemes (Fig. 5). Sclerites bearing setae Hv fused with posterior margins coxal plates II. Suture line between coxal plates III and IV complete. Medial margin of coxal plate IV slightly longer than medial margin of coxal plate III. Posterior margins of coxal plate IV forming right or obtuse angle, apodemes slightly developed. Acetabular plates and gonopore equal in length, with three subequal genital acetabula and 9 genital setae on each plate (Fig. 6). Excretory pore surrounded by slightly sclerotized ring and with small anterior sclerite (Fig. 7). Chelicera ( Fig. 8) with large basal segment and short crescent claw. Surface of basal segments punctuated.  Pedipalp stout (Fig. 9): P-1 short, with single short dorsodistal seta; P-2 large, with straight ventral margin and bearing six dorsal setae; P-3 with three unequal setae, base of long lateral seta located proximally middle of segment; P-4 rather slender, both ventral setae located on small conical unequal tubercles distally middle of segment, dorsodistal spine short (4-5 times shorter than P-5) and pointed; P-5 with proximal solenidion, five thin setae and four short, thick distal spines.
Coxal plates (Fig. 14) moderately large and elongate, first pair of plates with short apodemes directed laterally, plates II-III with a rudimentary apodeme on each side. Setae C1 and C4 subequal and slightly longer than C2 and C3. Setae Ci very long thickened, located on small tubercles. Setae Se much longer than Si, Pe slightly longer than Pi. Excretory pore plate (Figs 15-16) more or less triangular (L/W ratio 0.83 -0.90), its anterior portion wider than posterior one, anterior margin convex; setae Ai and Ae subequal and forming nearly true transverse row; bases of Ai close to each other, located anteriorly to excretory pore; distance between setae Ae-Ae almost three times longer than distance between Ai-Ai. Surface of all coxal plates punctuated.  Capitulum (Fig. 17) with wide base and relatively narrow rostrum, anterior hypostomal setae much longer than posterior ones. Basal segments of chelicerae (Fig. 18) fused to each other medially, longer than wide, expanded proximally and tapering distally; cheliceral claws small pointed.
Remaks. The water mite Tiphys yaroslavlensis is similar to T. torris (Müller, 1776). However, the following clear differences can be found in the morphology of female and larva of T. yaroslavlensis (character states of female and larva of T. torris are given in parenthesis after Tuzovskij 2011, respectively): female: all genital setae situated on acetabular plates, Fig. 6 (2-3 genital setae situated on soft cuticle between anterior genital sclerite and anterior ends of genital plates on each side); P-3 lateral seta situated proximally to middle of segment, Fig. 9 ( P-3 lateral seta situated distally to middle of segment); P-4 with short dorsodistal spine, 4-5 times shorter than P-5 (P-4 with rather long distolateral spine, 2.0-2.5 times shorter than tarsus); larva: dorsal shield bearing three pairs of setae, Fig. 13 (four pairs of setae); coxal setae C1 and C4 subequal, Fig. 14 (C4 much longer than C1), dorsal shield and coxal plates I-III punctuated (with cell-shaped reticulations); number of heavy setae on II/III-Leg-4: four (number of heavy setae on II/III-Leg-4: three).
The female was collected near locus typicus, distance about 1 km. The female and the male are characterised by identical colouring (colour red) and the structure of the pedipalps.