Tetranychus hirsutus, Zeity & Srinivasa & Gowda, 2016

Zeity, Mahran, Srinivasa, N. & Gowda, C. Chinnamade, 2016, New species, new records and re-description of spider mites (Acari: Tetranychidae) from India, Zootaxa 4085 (3) : -

Tetranychus hirsutus sp. nov. Zeity & Srinivasa

( Figs. 12–32 )

General diagnosis. Female with 4 tactile setae proximad to proximal duplex setae of tarsus I; peritreme hooked distally; dorsal striae forming diamond pattern between setae e1 and f1; empodium on tarsus I without mediodorsal spur; pre-genital striae longitudinal, broken; dorsal lobes with hair-like processes. Male with: aedeagal knob asymmetrical, a small acute ventrally-directed posterior projection and a larger rounded anterior projection, dorsal margin of knob rounded; empodium with spurs on ambulacra I and II, empodium II with proximoventral hairs. Based on Flechtmann & Knihinicki (2002) this species can be grouped in the 9th group along with Tetranychus kanzawai .

Description. Male: Holotype: Idiosomal length 397 µm (including gnathosoma), range 371–385µm (three paratypes). Dorsal striae lacking lobes. Terminal sensillum (spinneret) of palpus (5.7–6.4µm) thrice as long as broad and dorsal sensillum (3.4–3.7) fusiform, shorter than terminal. Peritreme hooked distally. Measurements of dorsal setae: v2 54 (53–57), sc1 108(102–106), sc2 75(70–78), c1 90(88–95), c2 97(94–97), c3 85(80–88), d1 96(92–98), d2 94(94–96), e1 85(80–87), e2 87(84–86), f1 60(55–62), f2 45(42–48), h1 26(23–26); distance between dorsal setae for only one dorsally mounted paratype: v 2 - h1 240–250, v2-v2 54, sc1-sc1 70, sc2-sc2 170, c1-c1 61, c2-c2 132, c3-c3 214, d1-d1 73, d2-d2 140, e1- e1 31, e2-e2 110, f1-f1 40, f2-f2 50, h1-h1 24.

Aedeagus. With long shaft, narrowing gradually and bent dorsad with relatively shorter neck bearing a knob. Dorsal margin of knob convex. Anterior projection of knob rounded and posterior projection acute and curved downwards. Aedeagus measurements of holotype: a-7.66–7.80, b-12.3–12.81, c-5.33–5.70, d-33.9–34.80, knob width 2.95–3.59 ( Fig. 18 ).

Legs. Empodia with proximoventral hairs fused into ventral spur on tarsus I; empodium II similar to empodia III and IV, with proximoventral hairs but proximoventral hairs much thicker in empodium II. Number of tactile setae and solenidia (in parentheses) on legs I–IV:

I 2 – 1 – 10– 5– 9 + (4) – 13 + (3) + 2 duplexes

II 2 – 1 – 6 – 5 – 7 – 13 + (1) + 1 duplex

III 1 – 1 – 4 – 4 – 6 – 9 + (1)

IV 1 – 1 – 4 – 4 – 7 – 10 + (1)

Tarsus I with 4 tactile setae and 2 solenidia proximad to proximal duplex setae. Tarsus II with 3 tactile setae and 1 solenidion proximad to duplex setae.

Female. Idiosomal length 548–571µm (including gnathosoma), width 344–392 µm (n=4).

Gnathosoma. Terminal sensillum (spinneret) almost twice as long as broad (length 6.3–6.95µm). Dorsal sensillum fusiform and shorter than terminal (5.2–5.57µm). Peritreme hooked distally.

Dorsum. Dorsal setae slightly barbed, longer than the distance between their longitudinal bases. Measurements of dorsal setae: v2 62 –73, sc1 164–175, sc2 114–115, c1 147–150, c2 134–137, c3 122–125, d1 135–155, d2 132– 145, e1 128–134, e2 137–140, f1 112–120, f2 96–110, h1 40–45, distance between dorsal setae v2 -h1 388–395, v2- v2 66 –73, sc1-sc1 92–95, sc2-sc2 264–273, c1-c1 73–84, c2-c2 181–193, c3-c3 355–380, d1-d1 88–96, d2-d2 229– 242, e1- e1 53–61, e2-e2 192–196, f1-f1 62–52, f2-f2 108–116, h1-h1 35–36. Striae between e1-e1 and f1-f1 longitudinal, forming a diamond-shape. Dorsal lobes with broad bases and extended as hair like processes.

Venter. Genital flap with arched, transverse striae. Pre-genital striae broken, with medial area of dense broken lines. Ventral striae without lobes medioventrally. Measurements of ventral setae, 1a 39–44, 1b 54–57, 1c 62–65, 2b 55–58, 2c 80–82, 3a 44–46, 3b 58–60, 4a 55–58, 4b 54–59, ag 55–60, g1 34–37, g2 33–39, ps 1 22–23, ps 2 22– 27.

Legs. Number of tactile setae and solenidia (in parenthesis) on legs I–IV:

I 2 − 1 − 10 − 5 − 9 + (1) – 13 + (1) + 2 duplexes

II 2 − 1 – 6 – 5 – 7 − 13 + (1) + 1 duplex

III 1 − 1 − 4 − 4 – 6 – 9 + (1)

IV 1 − 1 − 4 − 4 – 7 – 10 + (1)

Tarsus I with 4 tactile setae and 1 solenidion proximad to proximal duplex setae. Tarsus II with 3 tactile setae and 1 solenidion proximad to duplex setae. Empodial spurs absent.

Etymology. The specific epithet is derived from an adjective in Latin " hirsutus " meaning " hairy ", and refers to the hair like projections or processes on the dorsal striae of the female.

Type material. Holotype one male, from G. sylvestre , University of Agricultural Sciences, Bangalore, south India (N13o04 ' 35''; E77o34 ' 46''; elevation 934 m), January 2015, coll. Mahran Zeity. Paratypes, 17 males and 10 females, data same as for holotype ( AINP 1738).

Remarks. The aedeagus of this new species is similar to Tetranychus kanzawai Kishida in having a broad and rounded dorsal margin with slight angulation. The aedeagus differs slightly in having the posterior projection extended and curved distally, whereas this projection is straight in T. kanzawai . Females also differ from T. kanzawai in having broken pregenital striae, whereas they are entire in T. kanzawai . Furthermore, the new species is distinctive from all described species under Tetranychus in having dorsal striae with lobes extended like hairs. Carbonnelle and Hance (2004) found that the shape of dorsal lobes was highly variable in the T. urticae species complex, thus showing it has limited diagnostic power. However, the dorsal lobes of T. hirsutus are so unique that we believe they can be used to distinguish this species from others. The extension of these dorsal lobes increases the total surface area and might play a significant role in temperature and body water regulation, as Jeppson et al. (1975) and Mollet and Sevacherian (1984) have opined. More investigation is required to ascertain the functional significance of these lobes.

Biological observations. The new species inhabits the undersurface of leaves of Gymnema sylvestre . The body size of females is relatively large, while that of males is smaller. Both sexes are red in color but females are darker. Females lay orange colored eggs under silken webbing and freshly emerged adult females are ash colored, which develop into dark red females on maturity.

Figures

FIGURES 12 – 18. Tetranychus hirsutus sp. nov. (12) Dorsal lobes of female; (13) Peritreme; (14) Palp tarsus of female; (15) Palp tarsus of male; (16) Dorsal striae of female between e 1 and f 1; (17) Genital area of female; (18) Male aedeagus.

FIGURES 19 – 22. Tetranychus hirsutus sp. nov. (19) Tibia and tarsus I of female; (20) Tibia and tarsus II of female; (21) Tibia and tarsus I of male; (22) Tibia and tarsus II of male.

FIGURES 23 – 32. Tetranychus hirsutus sp. nov. (23 – 26) Empodium I – IV of female; (27 – 30) Empodium I – IV of male; (31 & 32) SEM images of dorsal lobes of female.