Diptacus pyracanthae, 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 : 229-232

Diptacus pyracanthae sp. nov.

( Figs. 3–4 )

Description. Female (n=12): Body fusiform, light yellow, 232 (196–236), 93 (91–95) wide, 81 (77–82) thick. Gnathosoma 39 (37–41), projecting downwards, setae ep 3 (2–3), setae d 15 (14–15); setae v 3 (2–3); cheliceral stylets 65 (65–68). Prodorsal shield 39 (37–40), including frontal lobe, 60 (58–62) wide; frontal lobe 8 (5–8) over gnathosomal base; median line incomplete, with an interruption on about half of shield, admedian lines complete, connected with submedian lines by transverse lines, forming 7 cells in anterior part, a big V-shaped lines in the middle side, near rear shield margin; scapular tubercles placed ahead rear shield margin, 24 (23–24) apart, setae sc 4 (3–4), directed upward. Coxisternal plates with several short lines and distinct dashes; setae 1b 15 (15–16), 16 (15–16) apart; setae 1a 16 (15–16), 13 (13–15) apart; setae 2a 67 (63–67), 37 (32–37) apart. Coxigenital semiannuli 12 (12–14), microtuberculated. Legs: Six segments, lacking setae on both femora. Leg І 47 (45–48), trochanter 4 (3–4), femur 15 (14–15), setae bv absent; genu 5*, setae l'' 44 (43–46); tibia 14 (14–15), setae l′ located at 1/2 from dorsal base, 9 (9–10); tarsus 9 (9–10), tarsal setae ft' 27 (25–27), tarsal setae ft'' 25 (25–26), tarsal setae u' 5 (5–6); tarsal empodium em, divided, 8 (7–8), 5-rayed*, tarsal solenidion ω 9 (8–9), knobbed. Leg ІІ 42 (39–43), trochanter 3 (3–4), femur 15 (14–15), setae bv absent; genu 5 (4–5), setae l'' 10 (9–12); tibia 10 (9–10); tarsus 9 (8–9), tarsal setae ft' 5 (4–5), tarsal setae ft'' 24 (24–27), tarsal setae u' 5 (5–6); tarsal empodium em, divided, 7 (7–8), 5-rayed*, tarsal solenidion ω 8 (8–9), knobbed. Opisthosoma: dorsal opisthosoma with median dorsal ridge; dorsal annuli 48 (48–51), anterior 6 (6–7) annuli with elongated and linear microtubercles, posterior 16 (16–18) annuli with round microtubercles, and others smooth; ventral annuli 90 (88–91), with elliptic microtubercles except posterior 14 (14– 15) annuli with elongated and linear microtubercles; setae c2 45 (43–45), 70 (70–74) apart, on ventral annulus 25 (23–26); setae d 67 (61–70), 52 (50–54) apart, on ventral annulus 40 (39–40); setae e 55 (52–60), 30 (28–30) apart, on ventral annulus 56 (56–58); setae f 40 (40–41), 29 (28–30) apart, on 10 th ventral annulus from the rear; setae h1 1 (1–2), setae h2 85 (81–92). Female genitalia: 20 (19–21), 31 (30–31) wide; coverflap smooth; setae 3a 11 (10–13), 22 (22–23) apart.

Male (n=2): Smaller than females and generally similar to them. Body fusiform, light yellow, 176–184, 83–85 wide. Gnathosoma 35–37, setae ep 3*, setae d 11–12; setae v 3–4; cheliceral stylets 55–57. Prodorsal shield 30–32, including frontal lobe, 56–57 wide; frontal lobe 13–14; scapular tubercles placed ahead rear shield margin, 20–21 apart, setae sc 3–4. Coxisternal plates, setae 1b 12–13, 15 apart; setae 1a 13–14, 12–13 apart; setae 2a 38–40, 33–35 apart. Coxigenital semiannuli 9–10, microtuberculated. Leg І 39–41, trochanter 3*, femur 12*, setae bv absent; genu 5*, setae l'' 35–38; tibia 11–12, setae l′ located at 1/2 from dorsal base, 10; tarsus 8–9, tarsal setae ft' 10–11, tarsal setae ft'' 21–23, tarsal setae u' 5–6; tarsal empodium em, divided, 6–7, 5-rayed*, tarsal solenidion ω 7–8, knobbed. Leg ІІ 38–41, trochanter 3*, femur 13–14, setae bv absent; genu 5*, setae l'' 9–10; tibia 10*; tarsus 8–9, tarsal setae ft' 4–5, tarsal setae ft'' 10–13, tarsal setae u' 5*; tarsal empodium em, divided, 7, 5-rayed*, tarsal solenidion ω 7–8, knobbed. Opisthosoma: dorsal opisthosoma with central dorsal ridge and subdorsal ridges; dorsal annuli 49–50, ventral annuli 74–76; setae c2 25–27, 70–72 apart, on ventral annulus 15–17; setae d 58–62, 43–45 apart, on ventral annulus 29–30; setae e 44–47, 25–26 apart, on ventral annulus 45–47; setae f 38–40, 26–27 apart, on 10 th ventral annulus from the rear; setae h1 1*, setae h2 47–53. Male genitalia: 23–24 wide; setae 3a 10–11, 18–19 apart.

Type material. Holotype: female (slide number EDD3-1.1), Nanchang University, Nanchang City, Jiangxi Province, P. R. China, 28°39′12″N, 115°47′32″E, elevation 30m, 28 June 2019, from Pyracantha fortuneana (Maxim.) Li (Rosaceae) (synonym: Photinia crenatoserrata Hance , Photinia fortuneana Maxim. , Pyracantha crenulata var. yunnanensis M.Vilm. ex Mottet , Pyracantha gibbsii var. yunnanensis Osborn , Pyracantha yunnanensis (M.Vilm. ex Mottet) Chitt. ), collected by Mengchao Tan and Guoquan Wang. Paratypes: 11 females and 2 males (slide number EDD3-1.2~1.14), with the same data as holotype.

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

Etymology. The specific epithet originates from the generic name of the type host plant, Pyracantha , in the genitive case.

Differential diagnosis. The new species herein described was compared with about 18 Diptacus species known from plants of the family Rosaceae and the highest similarity was observed with D. shangzhous Xie, 2013 . The two species have the same number of the empodial rays (5-rayed), coxisternal plates with several short lines and distinct dashes, incomplete median line of prodorsal shield and similar scapular setae sc length and paraxial tibial setae l' length. However, D. pyracanthae sp. nov. can be differentiated by the sculpture of female genitalia coverflap (entirely smooth in D. pyracanthae sp. nov. versus basal granules and distal smooth in D. shangzhous ), microtubercles on dorsal semiannuli (anterior 6–7 annuli with elongated and linear microtubercles, posterior 16–18 annuli with round microtubercles, and others smooth in D. pyracanthae sp. nov. versus all annuli with elongated and linear microtubercles in D. shangzhous ), the number of dorsal annuli (48–51 in D. pyracanthae sp. nov. versus 57–61 in D. shangzhous ). Diptacus pyracanthae sp. nov. also appears to be very close to Diptacus mercuriasis Song, Xue & Hong, 2007 infesting leaves of Mercurialis leiocarpa Sieb. et Zucc. (Euphorbiaceae) in Gansu Province (P. R. of China). They have similar sculpture of prodorsal shield and coxal plates I, scapular setae sc and setae h1 length. Nevertheless, the new species is distinguishable from D. mercuriasis in having the coxal plates I merged, coxal plates II with fine granules, dorsal annuli smooth beside anterior 6–7 and posterior 16–18 annuli, empodium 5-rayed. In D. Mercuriasis , coxal plates I separated, coxal plates II smooth, all dorsal annuli with elongated microtubercles, empodium 6-rayed.

Figures

FIGURE 3. Line drawings of Diptacus pyracanthae sp. nov.: AL. Lateral view of anterior body region; CGF. Coxigenital region of female; D. Dorsal view 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; PM. Lateral view of posterior opisthosoma. Scale bar: 5 μm for em; 15 μm for CGF, IG, LO, L1, L2; 20 μm for GM; 25 μm for AL; 30 μm for PM; 40 μm for D.

FIGURE 4. Images of Diptacus pyracanthae sp. nov.: (A) Prodorsal shield, female; (B) Coxigenital region of female; (C) Dorsal view of posterior opisthosoma; (D) Genital region of male; (E) Legs. Scale bar: 15 μm for B, D, E; 35 μm for A, C.