Wandesia pelipoda, Gerecke, 2020

Gerecke, Reinhard, 2020, The early derivative water mites (Acari: Hydrachnidia, superfamilies Eylaoidea, Hydrachnoidea and Hydryphantoidea) of Madagascar, Zootaxa 4727 (1), pp. 1-77 : 39-40

Wandesia (s. s.) pelipoda sp. nov.

Fig. 21

Type series: Holotype ♂, MNHN Ac 1349, MD 066, 08.09.2001 Andohahela ( Tulear ), Fenoevo , small stream crossing RIP 118 at N margin of forest (left affluent of MD 064), 400 m, interstitial dig, slide mounted .

Diagnosis: Male (female unknown): Cx-I with prominent lateral edges, Cx-IV with very short posterior apodeme ( Fig. 21 a ). Leg claws simple, with a very fine dorsal clawlet. I-L-6 club-shaped inflated, ventrally bowed, with a dense cover of fine, hair-like setae, two short distoventral peg setae and an arrow-head-shaped seta on posterior distal margin ( Fig. 21 d ). IV-L-5–6 with a dense cover of fine ventral setae ( Fig. 21 e ). Genital field ( Fig. 21 a ) with three Ac on very short stalks; genital flaps reduced to two pairs of small sclerites, one with one seta between Ac-1 and -2, the other with two setae between Ac-2 and -3. Male genital skeleton with short arms and rather long proximal chamber (about half the length of the organ–see Fig. 21 b ). Palp stout, with very short P-3 ( Fig. 21 c ).

Description: Male: Integument completely smooth, very thin; sclerotized parts with a fine, regular porosity. No eye pigment developed; in the area of the lateral eyes paired dots of thickened integument probably interpretable as remnants of eye lenses. Anterior coxal plates with straight medial margin; Cx-I with prominent lateral edges, Cx-II with equally rounded lateral margins. Cx-III with strongly projecting anterior margin, Cx-IV subtriangular in shape, posteriorly ending in a knob-shaped projection. Cx-I+II retracted into a collar-like structure formed by the membranous interspace between Cx-II and -III. Under increased pressure, Cx-I+II are extruded and the distance between anterior and posterior coxal plates increases to more than the length of Cx-I+II (probably a characteristic of all species of the genus). Legs with rather simple claws having a very fine dorsal clawlet. As compared with other species of the genus, I-L-2/3 relatively slender (L/H ratio 1.76 resp. 2.17), but I-L-6 relatively stout (2.5). I-L- 2 in the centre of ventral surface with a pair of fine setae (one very fine, in L corresponding to segment H, the other slightly stronger and longer, about ventral segment L); I-L-2–4 with two strong distal setae each, I-L-3–5 with strongly diverging dorsal and ventral margins, all in the proximal half of dorsal surface with a long, fine seta surrounded by three to four fine hair-like setae and accompanied or by a stout, peg-like seta (on I-L-3), or by a further long and fine seta (on I-L-4–5). I-L-6 inflated and covered by numerous fine setae on all sides, but particular dense distoventrally. Slightly set off from distoventral edge two short and stout peg setae, a further one, arrow-head-shaped, on the posterior distal margin flanking the claws. IV-L with rather long and slender segments, IV-L-2–5 with several strong setae, on IV- L-2 and -5 restricted to distal margin, on IV-L-3–4 also on the ventral surface; ventral margins of IV-L-5–6 with a characteristic cover of fine, short, hair-like setae. II-L in general shape and setation very similar to I-L, and III-L to IV-L (except for the absence of fine ventral setae on III-L-5–6).

Genital field mostly membranous, bearing three pairs of round, cupuliform Ac inserted on very short, collar-like stalks. Genital flaps nearly completely reduced–as remnants, two pairs of small, weakly sclerotized platelets in the interspaces Ac-1/2 (with one seta) and Ac-2/3 (with two setae). Ejaculatory complex rather slender, with short anterior and posterior arms and a relatively large proximal chamber proximal horns not observed but could be present as poorly developed structures (observations made with the organ in situ).

Gnathosoma in ventral view posteriorly strongly narrowed, posterior margin rounded; rostrum little developed, mouth opening flanked by a pair of bluntly pointed anteriorly-directed projections. Chelicerae not dissected. Palps short and stout, P-2 strongly curved, with straight ventral and equally convex dorsal margin; P-3 very short (L/H ca. 0.6), ventrally straight, dorsally weakly convex; P-4 ventral margin proximally straight, distally slightly convex, dorsal margin equally convex.

Measurements: Idiosoma L/W 1400/350; Cx-I+II L/W 130/60; Cx-III+IV L/W 120/70. Genital field L 110; diameter Ac-1–3, 20-21-23; ejaculatory complex L/W 135/55. Gnathosoma L/W 145/90; palp total L 196; L/H, L/H-ratio, relative L [% total L] palp segments: P-1, 20/31, 0.64, 10; P-2, 58/33, 1.77, 29; P-3, 25/40, 0.63, 13; P- 4, 70/23, 3.11, 36; P-5, 24/10, 2.38, 12. Leg segments L/H, L/H ratio: I-L-1, 45/45, 1.0; I-L-2, 55/31, 1.76; I-L-3, 65/30, 2.17; I-L-4, 63/35, 1.79; I-L-5, 76/35, 2.18; I-L-6, 100/40, 2.50. II- and III-L not measured; IV-L-4, 75/25, 3.00; IV-L-5, 100/25, 4.00; IV-L-6, 108/25, 4.3.

Derivatio nominis: pelos (Greek: πέλος), hair, and podos (gen., Greek: πους, ποδός), foot.

Remarks: Wandesia pelipoda differs from all known species of the genus in the combination of: (1) Ac on short, but in tangential view well recognizable stalks; (2) I-L-6 inflated, with dense cover of hair-like setae; (3) IV-L-5–6 rather slender, ventrally with densely-arranged hair-like setae; (4) palp with strongly shortened P-3. It is probably closely related to the species described below (see there).

Habitat: Low order forest stream, interstitial.

Distribution: Madagascar, endemic, only known from the type locality.

Figures

FIGURE 21. Family Hydryphantidae, Wandesiinae, genus Wandesia, W. pelipoda (MD 066); a. anterior venter, partial view (Cx-I+II and gnathosoma partially sunk into a membranous integument fold); b. ejaculatory complex; c. palp. d. I-L, claw; e. IV-L-4–6, claw.