Diptacus suichangensis, Tan & Lv & Ruan & Zhao, 2021

Tan, Meng-Chao, Lv, An-Kang, Ruan, Hong-Yan & Zhao, Ping, 2021, Two new Diptacus and one new Trimeroptes species (Acari: Diptilomiopidae) from China, Zootaxa 5067 (2), pp. 224-236 : 225-228

Diptacus suichangensis sp. nov.

( Figs. 1–2 )

Description. Female (n=14): Body fusiform, light yellow, 242 (205–251), 80 (72–82) wide, 55 (50–55) thick. Gnathosoma 43 (40–43), projecting downwards, pedipalp coxal setae ep 3 (2–3), dorsal pedipalp genual setae d 14 (14–15), unbranched; subapical pedipalp tarsal setae v 3 (2–3); cheliceral stylets 55 (53–55). Prodorsal shield 47 (40–47), including frontal lobe, 58 (55–60) wide; frontal lobe 15 (15–17) over gnathosomal base, slightly emarginate anteriorly; median line complete and reaching rear margin of the shield, admedian lines complete and sinuose, median and admedian lines joined by transverse lines, forming four cells in the middle of shield, submedian present on about posterior half of the shield between scapular tubercles and posterior rear of the shield; scapular tubercles placed ahead rear shield margin, 28 (26–29) apart, scapular setae sc 13 (13–15), directed upward. Coxisternal plates with several short lines and distinct dashes; prosternal apodeme 9 (8–11), anterolateral setae on coxisterna І 1b 19 (18–21), 16 (15–18) apart; proximal setae on coxisterna І 1a 29 (27–32), 8 (7–8) apart; proximal setae on coxisterna ІІ 2a 46 (44–48), 32 (30–32) apart. Coxigenital semiannuli 15 (13–15), microtuberculated. Legs: Six segments, lacking setae on both femora. Leg І 55 (54–57), trochanter 3 (3–4), femur 16 (15–16), basiventral femoral setae bv absent; genu 7 (7–8), antaxial genual setae l'' 38 (36–41); tibia 19 (19–20), paraxial tibial setae l′ located at 1/2 from dorsal base, 12 (11–12); tarsus 10 (10–11), paraxial fastigial tarsal setae ft' 25 (25–27), antaxial fastigial tarsal setae ft'' 26 (26–28), paraxial unguinal tarsal setae u' 5 (4–5); tarsal empodium em, divided, 6 (6–7), 5-rayed*, tarsal solenidion ω 7 (6–7), knobbed. Leg ІІ 49 (48–51), trochanter 3*, femur 15 (15–16), setae bv absent; genu 7 (6–7), setae l'' 16 (14–16); tibia 15 (15–17); tarsus 9 (9–10), tarsal setae ft' 7 (6–7), tarsal setae ft'' 26 (26–28), tarsal setae u' 5 (4–5); tarsal empodium em, divided, 6 (6–7), 5-rayed*, tarsal solenidion ω 7 (7–8), knobbed. Opisthosoma: dorsal opisthosoma with central dorsal ridge and subdorsal ridges, all the ridges ending at rear; dorsal annuli 70 (68–70), smooth; ventral annuli 115 (112–116), with round microtubercles on rear annular margins except posterior 11 (11–12) annuli with elongated and linear microtubercles; setae c2 28 (25–28), 70 (68–71) apart, on ventral annulus 26 (23–26); setae d 62 (60–67), 50 (48–51) apart, on ventral annulus 52 (49–52); setae e 26 (24–26), 27 (25–28) apart, on ventral annulus 80 (76–80); setae f 49 (46–49), 31 (30–33) apart, on 12 th ventral annulus from the rear; setae h1 1*, setae h2 121 (115–123), 12 (12–13) apart. Female genitalia 20 (18–21), 30 (29–30) wide; coverflap with 13 (12–14) longitudinal striae; proximal setae on coxisterna ІІІ (3a) 13 (12–13), 22 (20–23) apart.

Male (n=3): Smaller than females and generally similar to them. Body fusiform, light yellowish, 158–163, 58–64 wide. Gnathosoma 40–42, setae ep 2–3, setae d 13–14; setae v 2–3; cheliceral stylets 50–51. Prodorsal shield 37–40, including frontal lobe, 48–50 wide; frontal lobe 13–15; scapular tubercles placed ahead rear shield margin, 24–26 apart, setae sc 8–10, directed upward. Coxisternal plates, setae 1b 15–16, 14–15 apart; setae 1a 17–18, 7–8 apart; setae 2a 37–45, 20–23 apart. Coxigenital semiannuli 15–17, microtuberculated. Leg І 48–50, trochanter 3*, femur 15*, setae bv absent; genu 5–6, setae l'' 35–37; tibia 17*, setae l′ located at 1/2 from dorsal base, 10–11; tarsus 8–9, tarsal setae ft' 24–26, tarsal setae ft'' 24–25, tarsal setae u' 4*; tarsal empodium em, divided, 6*, 5-rayed*, tarsal solenidion ω 6–7, knobbed. Leg ІІ 42–44, trochanter 3*, femur 15*, setae bv absent; genu 5*, setae l'' 12–13; tibia 12–13; tarsus 7–8, tarsal setae ft' 5–6, tarsal setae ft'' 24–25, tarsal setae u' 4*; tarsal empodium em, divided, 6*, 5- rayed*, tarsal solenidion ω 6–7, knobbed. Opisthosoma: dorsal opisthosoma with central dorsal ridge and subdorsal ridges; dorsal annuli 68–70; ventral annuli 104–108; setae c2 21–23, 48–52 apart, on ventral annulus 21*; setae d 62–64, 31–34 apart, on ventral annulus 41–43; setae e 23–24, 18–20 apart, on ventral annulus 61–65; setae f 42–45, 22–25 apart, on 12 th ventral annulus from the rear; setae h1 2*, setae h2 105–107. Male genitalia: 23–25 wide; setae 3a 11–12, 15–16 apart.

Type material. Holotype: female (slide number EDD3-2.1), Jiulongshan National Nature Reserve, Suichang County, Lishui City, Zhejiang Province, P. R. China, 28°19′21″N, 118°49′15″E, elevation 650m, 27 Sept. 2019, from Aralia chinensis L. ( Araliaceae ), collected by Mengchao Tan. Paratypes: 13 females and 3 males (slide number EDD3-2.2~2.17), with the same data as holotype.

Relation to host. The mite found to be vagrant on the undersurfaces of leaves of their associated host causing no visible damage.

Etymology. The specific name suichangensis refers to the “Suichang County”, the locality where the holotype was collected. The gender is male.

Differential diagnosis. Diptacus hederiphagus Nuzzaci, 1975 and the new species are the only two Diptacus species that have been reported on plants of the family Araliaceae . The new species differs from D. hederiphagus in the prodorsal shield pattern (complete median line in D. suichangensis sp. nov. versus incomplete median line in D. hederiphagus ), length of scapular setae sc (13–15 in D. suichangensis sp. nov. versus 2 in D. hederiphagus ), and number of dorsal semiannuli and ventral semiannuli (68–70, 112– 116 in D. suichangensis sp. nov. versus 55, 80 in D. hederiphagus ). In addition, D. suichangensis sp. nov. appears to be morphologically close to Diptacus chizhouensis Wang, Xue & Hong, 2009 [found on Rubus corchorifolius Linn. f. (family Rosaceae ) from Anhui, China]. They share similar characters such as coxisternal plates with fine dashes, empodium rays number (5), coverflap with striae, dorsal annuli smooth. However, these two species can be differentiated by the number of the dorsal annuli (68–70 in D. suichangensis sp. nov. versus 44–47 in D. chizhouensis ), the number of the ventral annuli (112–116 in D. suichangensis sp. nov. versus 68–73 in D. chizhouensis ), the length of the setae f (46–49 in D. suichangensis sp. nov. versus 28–31 in D. chizhouensis ), the median line on prodorsal shield (complete median line in D. suichangensis sp. nov. versus incomplete median line in D. chizhouensis ).

The new species is also close to Diptacus elegantulum Rajput, Han, Xue & Hong, 2014 [collected from Acer elegantulum Fang & Chiu (Sapindaceae) ] in prodorsal shield design (admedian lines complete, median and admedian lines joined by transverse lines, forming cells in the middle of shield), coxisternal plates I (with short lines and granules), and coverflap design (with longitudinal ridges). The two species differ in the following features: prodorsal shield with complete median line in D. suichangensis sp. nov. versus incomplete (versus broken median line in D. elegantulum ); scapular tubercles ahead of the rear shield margin in D. suichangensis sp. nov (versus near rear shield margin in D. elegantulum ); tarsal empodium 5-rayed in D. suichangensis sp. nov. (versus 3-rayed in D. elegantulum ); dorsal opisthosoma with smooth annuli in D. suichangensis sp. nov. (versus microtuberculated annuli in D. elegantulum ).

Figures

FIGURE 1. Line drawings of Diptacus suichangensis sp. nov.: AD. Prodorsal shield; AL. Lateral view of anterior body region; CGF. Coxigenital region of female; em. Empodium; GM. Genital region of male; IG. Internal genitalia of female; LO. Lateral view of annuli; L1. Leg I; L2. Leg II; PD. Dorsal view of posterior opisthosoma; PM. Lateral view of posterior opisthosoma. Scale bar: 5 μm for em; 10 μm for IG, GM; 15 μm for CGF, LO; 20 μm for PD, PM; 22 μm for AD, L1, L2; 25 μm for AL.

FIGURE 2. Images of Diptacus suichangensis sp. nov.: (A) Prodorsal shield, female; (B) Coxigenital region of female; (C) Dorsal view of posterior opisthosoma; (D) Genital region of male; (E) Ventral view of posterior opisthosoma. Scale bar: 15 μm for C, D, E; 20 μm for A, B.