Sperchon (Sperchon) smiti, Tuzovskij, 2021

Tuzovskij, Petr V., 2021, Two new water mite species of the Sperchon tridentatus-group from Asia (Acari Hydrachnidia, Sperchontidae), Zootaxa 4970 (1), pp. 143-150 : 147-150

Sperchon (Sperchon) smiti sp. n.

( Figs 10–21 )

Material examined. Holotype male, slide 9939, Asia , Kazakhstan, Turkestan Province , Tolebiyskiy District , Aksu- Zhabagly Nature Reserve, Boldyrbek stream, 42°19’36.4”N 70°22’17.8”E, 1230 m, depth 40 cm, bottom: large stones. 16.08.2019, leg. V. Stolbov.

Diagnosis. Muscle attachment scleritesnot developed, integument with wrinkled lineation, genital acetabula well developed, ac.2 larger than ac.1 and ac.3, capitulum with short rostrum; P-2 ventrodistal projections moderately long and bearing two fine setae, near base of projection there is short, thick seta; P-3 ventral margin convex, P-4 longer than P-3, excretory pore sclerotized, leg claws with three clawlets.

Description. Male. Idiosoma colour yellow. Idiosoma oval and somewhat flattened. Muscle attachment sclerites not developed. Integument ( Fig. 10 ) with wrinkled lineation. Setae Fch ( Fig. 11 ) short, thick, other idiosomal setae thin ( Figs 12–13 ). Trichobotria Fp situated on small sclerites, and trichobothria Oi on relatively large sclerites ( Fig. 13 ).

Anterior coxal groups ( Fig. 14 ) close to each other but not fused, with straight posteromedial margins, apodemes slightly developed. Sclerites bearing setae Hv situated near posterolateral angles of coxae II. Posterior coxal groups widely separated, glandularia Pe open at anteromedian angle of coxae III. Genital field situated between posterior coxal groups, with three pairs of unequal acetabula, ac.2 larger than ac.1 and ac.3 ( Fig. 15 ). Gonopore shorter than genital flaps.Anterior and posterior genital sclerites small and subequal in shape and size. Each genital flap with about 28–30 median and three fine lateral setae. Pregenital sclerite very small, postgenital sclerite relatively large and unsclerotized. Excretory pore surrounded by sclerotized ring ( Fig. 16 ).

Capitulum with a short rostrum, ventral margin of capitular base convex, lateral surface with several lineations ( Fig. 17 ). Both pairs of hypostomal setae subequal in length. Chelicera basal segment large, chela crescent-shaped ( Fig. 18 ).

Pedipalp rather slender ( Fig. 19 ): P-1 short and without setae; P-2 large, with six thick subequal dorsal setae, ventrodistal projections long and bearing two fine distal and thick proximal seta which shorter than projection; P-3ventral margin convex, with three thick dorsoproximal setae and one or two thin dorsodistal setae; P-4 slender and longer than P-3, with several rather long dorsodistal and ventrodistal fine setae, ventral margin with two small tubercles bearing short subequal peg-like setae.

Legs slender, especially posterior pair, III–IV-Leg-3–5 with rather numerous long dorsal plumose dorsal setae ( Fig. 20 ). Leg claws with three unequal pointed clawlets, dorsal clawlet a little longer than median and ventral clawlets, lamella slightly developed with strong concave ventral margin ( Fig. 21 ).

Measurement (n=1). Idiosoma L 810; capitulum L 150, rostrum L 25; genital flap L 160, genital acetabula (ac.1–ac.3) L: 50, 62, 45; cheliceral segments: base L 160, chela L 50; pedipalp segments (P-1–5) L: 32, 95, 112, 150, 37; legs segments L: I-Leg-1–6: 60, 75, 100, 160, 175, 160; II-Leg-1–6: 60, 75, 110, 185, 200, 185; III-Leg- 1–6: 60, 75, 125, 225, 235, 210; IV-Leg-1–6: 125, 135, 150, 275, 250, 225.

Female: Unknown.

R emarks. The present species is similar to S. tridentatus in the structure of the integument. Differences between the two species are found in the following characters (character states of S. tridentatus given in parentheses, data from Sokolow 1940): P-2 distoventral projecting with two fine distal setae and short, thick seta, Fig. 19 ) (with three fine setae, thick seta near projection absent, Fig. 22 ), P-3 ventral margin convex (straight), P-4 longer than P- 3 (P-4 shorter than P-3), genital acetabula large and located close to each other (comparatively small and distinctly separated), capitulum with short rostrum, Fig. 17 (long and a little shorter than capitular base), claw lamella ventral margin strong concave, Fig. 21 (lamella ventral margin straight, Fig. 23 ).

Etymology. Named after Dr Harry Smit ( The Netherlands).

Habitat. Running waters.

Distribution. Asia, Kazakhstan: Turkestan Province.

Figures

FIGURES 10–18. Sperchon (Sperchon) smiti sp. n., male: 10, fragment of integument; 11, seta Fch; 12, idiocomal seta associated with glandularia; 13, trichobothria Oi; 14, coxal plates, left side; 15, genital field; 16, excretory pore; 17, capitulum, lateral view; 18, chelicera. Scale bars: 10–13, 16 = 50 μm, 14–15, 17–18 = 100 μm.

FIGURES 19–21. Sperchon (Sperchon) smiti sp. n., male: 19, pedipalp; 20, IV-Leg-3–6; 21, leg claw. Scale bar: 1, 2, 3–5, 6 = 50 μm, 7, 8 = 20 μm

FIGURES 22–26. Sperchon, adults: S. tridentatus: 22, pedipalp; 23, leg claw (after Sokolow 1940); S. minor: 24, idiosoma, dorsal view; 25, idiosoma, ventral view; 26, pedipalp (after Tuzovsky 2003).