Teratothyas (Ascoteratothyas) reducta, 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 : 57-59

Teratothyas (Ascoteratothyas) reducta sp. nov.

Fig. 27 c –f

Type series: Holotype ♀, MNHN Ac 1388, MD 072, 10.09.2001 Andohahela (Tulear), Isaka, stream crossing RIP 118 at km 34.5, 540 m, slide mounted. Paratypes: MD 063a, 07.09.2001 Andohahela (Tulear), Isaka, stream exp. W 1 km N from the village, 250 m, riffle, (0/2/0) in liquid, Ac 1453; MD 064, 08.09.2001 Andohahela (Tulear), Fenoevo, stream at N margin of forest (milky turbid waters), 330 m, (2/1/0) in liquid, Ac 1454; MD 065, 08.09.2001 Andohahela ( Tulear ), Fenoevo, right affluent of the turbid water stream (MD 064) at N margin of forest (clear water), 330 m, (2/0/0) in liquid, Ac 1455; MD 074a, 11.09.2001 Andohahela ( Tulear ), Isaka, stream crossing RIP 118 at km 32, 360 m, riffle, (0/4/0) slide mounted, Ac 1389-1390; MD 154b, 17.11.2001 Joffreville (M. d’Ambre, Antsiranana), R de Manques in Reserve Fontenay, 550 m, roots, (2/1/0) slide mounted, Ac 1391-1392; MD 162a, 20.11.2001 same stream, 730 m, riffle, (0/1/0) slide mounted, Ac 1393; MD 163a, 20.11.2001 same stream, 580 m, riffle, (1/1/1) slide mounted, Ac 1394; MD 165a, 21.11.2001 Joffreville (M. d’Ambre, Antsiranana), R Antomboka downstr. large cascade, 850 m, riffle, (3/2/0) in liquid, Ac 1456; MD 170a, 29.11.2001 Tampoketsan Ankazobe (Antananarivo), R Andranofeno Sud at bridge R.N.4, km 130, 1450 m, riffle, (1/0/0) slide mounted, Ac 1395 .

Diagnosis: Membranous integument areas papillate ( Fig. 27 e). Small in dimensions (e.g., idiosoma L/W ♂♂ <830/520, ♀♀ <950/650, genital field L ♂♂ <160, ♀♀ <180. Genital field ( Fig. 27 f) with acetabula absolutely and relatively short (L Ac-1, 30–53, 23–32 % genital field L, Ac-2, 40–63, 27–38 %). Palp ( Fig. 27 d) short and stout (total L, P-4 L ♂♂, 226 [260], 78 [85]; ♀♀, 216–253, 75–88), maximum H P- 4 in central part.

Description: Membranous parts of integument with densely-arranged papillae ( Fig. 27 e). Dorsal and ventral sclerite plates with rather few, large pores (about 10 per transect–see Fig. 27 f). Genital field with relatively small acetabula (Ac-1 distinctly shorter than posterior medial plate margin, its posterior end far anterior to level of anterior edge of Ac-2). Genital flaps together forming a subtriangular structure, anterolaterally with a porose secondary sclerite, anteromedially forming a narrow bay embracing the longish Ac-1. Dorsolateral and posteroventral sclerite plates, as well as secondary sclerite fringes of coxae forming a pattern of strong stellate trabeculae. Leg claws with a very poorly developed, obtuse angled ventral blade.

Gnathosoma ( Fig. 27 c) slender, ventral margin in proximal part straight, on the level of palp insertion smoothly convex, distal part concave. Chelicera L/H 7.8–9.4. Palp ( Fig. 27 d) stout, P-4 maximum H basally or in distal half, ventral margin here smoothly convex, proximally slightly concave.

Measurements: Male: Idiosoma L/W 560–825/360–520; coxal field L/W 380–470/390–450; Cx-I+II L/W 210– 260/150–162; Cx-III+IV L/W 180–340/180–240; genital field L/W 125–150/125–157; maximum diameter Ac-1, 30–45, Ac-2, 40–45 Ac-3, 40, ejaculatory complex L 130–140; gnathosoma L 250–275; chelicera total L 310–339, L/H 7.8–9.4; basal segment/claw 1.19–1.38. Palp total L 226; L, L/H ratio, relative L [% total L] palp segments: P- 1, 34, 1.17, 15; P-2, 49, 1.58, 22; P-3, 31, 1.00, 14; P-4, 78, 3.00, 35; P-5, 34, 2.27, 15; L ratio P-2/-3, 1.58, P-2/-4, 0.63, P-3/-4, 0.40. Leg segments L/H, L/H ratio: I-L-2, 33–75, 1.56–1.67; I-L-3, 70–73, 1.61–1.65; I-L-4, 110, 2.44; I-L-5, 113, 2.50; I-L-6, 125, 2.94; claw L 38. II-L-2, 75, 1.58-1.88; II-L-3, 75, 1.67; II-L-4, 138–143, 3.00–3.44; II-L-5, 135–140, 2.95–3.00; II-L-6, 140–143, 3.11–3.35; claw L 38–40. III-L-2, 60–70, 1.56–1.60; III-L-3, 60–68, 1.50–1.60; III-L-4, 105–118, 2.61–2.63; III-L-5, 110–115, 3.14–3.29; III-L-6, 115–125, 3.13–3.29–3.18; claw L 40. IV-L-2, 75–80, 1.76–1.78; IV-L-3, 85–95, 2.00–2.11; IV-L-4, 160–175, 3.89–4.27; IV-L-5, 145–155, 3.87–3.88; IV-L-6, 140–145, 3.50–3.63; claw L 43–53. Total L segments 2–6: I-L, 480; II-L, 563–575; III-L, 450–495; IV-L, 610–645.

Females: Idiosoma L/W 840–930/560–630; coxal field L/W 460–520/465–550; Cx-I+II L/W 265–305/275– 200; Cx-III+IV L/W 260–370/260–270; genital field L/W 150–175/160–170; maximum diameter Ac-1, 35–53, Ac-2, 48–63, Ac-3, 38–48; gnathosoma L 270–337; chelicera total L 370, basal segment/claw 1.18, L/H 9.25; Palp total L 216–253; L, L/H ratio, relative L [% total L] palp segments: P-1, 30–40, 0.97–1.14, 13–16; P-2, 48–58, 1.58–1.74, 22–23; P-3, 29–30, 0.92–1.00, 12–13; P-4, 75–88, 2.79-3.04, 35; P-5, 33-38, 2.73-2.89, 15-16; L ratio P-2/-3, 1.65-1.92, P-2/-4, 0.63-0.67, P-3/-4, 0.34-0.38. Leg segments L/H, L/H ratio: I-L-2, 80-90, 1.33-1.80; I-L-3, 73-85, 1.45–1.62; I-L-4, 120–150, 2.30–3.00; I-L-5, 105–130, 2.33–2.89; I-L-6, 135–150, 2.84–3.16; claw L 40–43. II-L-2, 90–105, 1.73–1.83; II-L-3, 85–100, 1.71–1.82; II-L-4, 150–190, 3.16–3.45; II-L-5, 145–195, 3.20–4.11; II- L-6, 143–170, 3.05–3.56; claw L 40–50. III-L-2, 65–88, 1.53–1.75; III-L-3, 73–90, 1.71–1.89; III-L-4, 120–168, 2.82–3.72; III-L-5, 135–165, 3.38–4.13; III-L-6, 148–160, 3.33–3.56; claw L 43–48. IV-L-2, 80–115, 1.68–2.09; IV-L-3, 95–120, 1.95–2.29; IV-L-4, 175–230, 3.68–4.60; IV-L-5, 150–218, 3.53–4.72; IV-L-6, 145–195, 3.05–3.95; claw L 40–50. Total L segments 2–6: I-L, 560–570; II-L, 613–760; III-L, 578–668; IV-L, 645–878.

Remarks: Teratothyas reducta differs from the other two species of the subgenus in smaller dimensions and in acetabula reduced in size (% genital field L, the other species in parentheses): Ac-1, 24–30 (32–44), Ac-2, 27–38 (41–55)–the posteromedial genital flap margin is distinctly longer than Ac-1, the level of the posterior margin of Ac-1 lies distinctly anterior to the anterior margin of Ac-2.

Derivatio nominis: reductus (Latin), reduced–the species, in particular its Ac-1, is reduced size.

Habitat: Low order streams.

Distribution: Madagascar, endemic. Probably the whole island (found in three areas far away from each other–in the centre, the extreme north and extreme south).