Teratothyasides (Hansvietsia) vanilla, 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 : 63-64

Teratothyasides (Hansvietsia) vanilla sp. nov.

Fig. 29 a–d

Type series: Holotype ♀, MNHN Ac 1466, MD 040, 21.08.2001 Ranomena (Fianarantsoa), spring at right margin of the stream (MD 035) NW from the 1.07 km-railway-tunnel, 950 m, in liquid. Paratypes: Same site and date (1/2/1) slide mounted, Ac 1409-1412; (0/17/0) in liquid, Ac 1467; MD 043, 21.08.2001 Ranomena (Fianarantsoa), spring area of the stream NW from the 1.07 km-railway-tunnel (right affluent of MD 034), 1100 m, (0/1/1) slide mounted, Ac 1413; MD 234, Ranomena (Fianarantsoa), spring area of the stream NW from the 1.07 km-railwaytunnel (same site: MD 043, right affluent of MD 034), 1017 m, S 21°29’45.9’’, E 047°24’07.5’’, 26.04.2011, (0/3/1) slide mounted, Ac 1414-1417.

Diagnosis: Genital field ( Fig. 29 c ) relatively large (L ♂ 200, ♀ 200–230), with about 20 (15–37) pairs of rather large acetabula (diameter Ac-1, ♂ 38, ♀ 33–40), most of them close to their neighbours. Mouth parts ( Fig. 29 a–b) comparatively large (gnathosoma L 230–250, chelicera total L 490–540, palp total L 428–458), palp segments strongly elongated (L/H P-2, 1.8–2.0, P-3, 1.7–2.0; P-4, 5.4–6.1).

Description: Membranous integument with densely arranged, long papillae. Sclerite plates lattice-like, with a high number of often +/- angular pores (10–12 along an imaginary transect crossing dorsocentral plates see Fig. 29 d–e). Genital field ( Fig. 29 c ) with 15–37 pairs of acetabula, often asymmetric in number right/left, at lateral genital plate margin arranged in a triple line; Ac-1 separated by a distinct gap from the remaining, posteriormost Ac slightly enlarged. Each genital plate with about 30 (14-27 medial, 7-20 posterior) setae. Leg claws proximoventrally with a pointed, tooth-like projection. Gnathosoma and appendages as described for T. ravenala , but palp segments distinctly more slender ( Fig. 29 b ).

Measurements: Male: Idiosoma L/W 1430/1050; coxal field 760/850; Cx-I+II 440/320; Cx-III+IV 550/440; genital field L/W 200/250, Ac n right/left 15/16, L Ac-1 38, posterior Ac 30; genital skeleton L/W 75/23; gnathosoma L 230; chelicera basal segment proximal/total L 230/340, total L 490, ratio basal segment/claw 0.88, L/H 6.13. Palp total L 428; L, L/H ratio, relative L [% total L] palp segments: P-1, 70, 1.75, 16; P-2, 75, 1.88, 18; P-3, 78, 1.94, 18; P-4, 163, 5.4, 38; P-5, 43, 2.83, 10; L ratio P-2/-3, 0.97; P-2/-4, 0.46; P-3/-4, 0.48. Legs not measured.

Females: Idiosoma L/W 1420–1800/1000–1450; coxal field 660–830, Cx-I+II 360–470/225–360; Cx-III+IV 300–600/280–470; genital field L/W 200–230/230–280; Ac n right/left 8 [! misshapen]-37/21–33, L Ac-1 33–40, posterior Ac 25–35; gnathosoma L 2380–250; chelicera total L 500–540, basal segment/claw 0.86–0.96, L/H 5,4– 7,5; Palp total L 435–458; L, L/H ratio, relative L [% total L] palp segments: P-1, 68–75, 1.56–2.14, 15–16; P-2, 73–81, 1.81–2.03, 17–18; P-3, 73–80, 1.76–2.00, 16–18; P-4, 168–178, 5.38–6.09, 38–40; P-5, 45–50, 3.00–3.64, 10–11. L ratio P-2/-3, 0.94–1.12; P-2/–4, 0.43–0.46; P-3/-4, 0.41–0.46. Leg segments L/H, L/H ratio: I-L-2, 110– 125, 1.63–1.92; I-L-3, 120–135, 1.78–1.93; I-L-4, 175–195, 2.69–2.88; I-L-5, 195–215, 3.57–3.91; I-L-6, 170–190, 2.92–3.14; claw L 45–50. II-L-2, 140–150, 1.93–2.07; II-L-3, 140–158, 2.07–2.25; I-L-4, 245–263, 3.77–4.16; II-L-5, 240–265, 4.08–4.61; II-L-6, 195–225, 3.00–3.55; claw L 50–53. III-L-2, 110–125, 1.64–1.92; III-L-3, 130– 140, 2.08–2.17; III-L-4, 225–235, 3.75–4.23; III-L-5, 225–240, 4.09–4.84; III-L-6, 195–220, 3.25–3.87; claw L 50–60. IV-L-2, 150–170, 2.07–2.36; IV-L-3, 175–190, 2.50–2.71; IV-L-4, 305–325, 4.77–4.88; IV-L-5, 260–300, 4.52–5.45; IV-L-6, 235–250, 3.62–4.26; claw L 58–63. Total L segments 2–6: I-L, 785–840; II-L, 985–1048; III-L, 905–950; IV-L, 1145–1210.

Derivatio nominis: The climbing plant Vanilla ( Orchidaceae ), of great importance in Madagascan agriculture. The name is a noun in apposition.

Remarks: In comparison with the previously described species of the subgenus, the same differences are found in T. vanilla as discussed above for T. ravenala . In addition to generally smaller measurements of idiosoma and mouthparts (as given in the diagnosis, see above), the latter (in parentheses) differs from T. vanilla in stouter palp segments (L/H P-2 <1.7, P-3 <1.8; P-4 <4.8), a lower number of acetabula in females (9–17 pairs) and the pointed proximoventral extension of leg claws. A further difference is found in comparatively longer legs (only females measured in T. vanilla , Σ L segments 2–6, T. ravenala in parentheses): I-L 785–840 (613–725); II-L 985–1048 (718–923); III-L 905–950 (660–785); IV-L 1145–1210 (860–1113), with more slender segments IV-L-3, L/H 2.5– 2.7 (2.2–2.4), and IV-L-4, L/H 4.8–4.9 (4.1–4.8). Differences in comparison to T. scutulatus from the Comoros are discussed above, under T. ravenala .

Habitat: Weakly seeping helocrenic springs.

Distribution: Madagascar, endemic. Only found in a restricted area around 1000 m a.s.l., in the central part of the eastern rainforest belt.

Figures

FIGURE 29. Family Teratothyadidae, Teratothyasides vanilla (MD 040). a.–c. female; a. chelicera; b. palp; c. genital field; d.–e. male; d. venter; e. dorsum.