Diptacus acutifolius, Xie & Chen & Han, 2021

Xie, Manchao, Chen, Zhenning & Han, Fuzhong, 2021, Three new species of eriophyoid mites from Maixiu National Forest Park, Qinghai Province, China (Acari: Eriophyoidea), Zoological Systematics 46 (3), pp. 200-207 : 205-207

Diptacus acutifolius sp. nov. ( Figs 17–21 )

Diagnosis. The new species is similar to D. shangzouensis Xie, 2013 with 5-rayed tarsal empodium and host plants (from the family Rosaceae ) and fauna (the northwestern China), but can be differentiated from the latter by shield design with incomplete networks (shield design with complete networks in D. shangzouensis ), and dorsal annuli smooth (dorsal annuli sculptured with lines in D. shangzouensis ). Besides this, the species is also characterized by: Body fusiform, yellowish-brown in color; gnathosoma large and projecting straight down, prodorsal shield with anterior shield lobe present; shield design with median line strong and incomplete networks on frontal edge; scapular tubercles ahead of rear shield margin, scapular setae projecting up and and centrad; coxisternal plates with granules, prosternal apodeme absent; legs with tarsal empodium divided, 5-rayed, tarsal solenidion with large knob; opisthosoma dorsally with 45–53 semi-annuli, smooth; and ventrally with 84–89 semi-annuli, with rounded microtubercles except caudal 12–15 ventral semi-annli with elongated microtubercles; setae h1 present; female genitalia coverflap almost smooth besides one line.

Description. Female (n = 10). Body fusiform, 215 (190–248), 115 (107–115) wide, 110 (95–113) thick; yellowish-brown in color. Gnathosoma 56 (56–60), projecting straight down; pedipalp coxal setae (ep) 5 (5), dorsal pedipalp genual setae (d) 13(13–15). Prodorsal shield 41 (40–41), 82 (82–90) wide, frontal lobe feeble. Shield design with median line strong and incomplete networks on frontal edge. Scapular tubercles ahead of rear shield margin, 27 (25–27) apart; scapular setae (sc) 6 (5–7), projecting up and centrad. Coxigenital region with 11(11–13) semi-annuli between coxae and genitalia. Coxal plates I and II with few granules, anterolateral setae on coxisternum I (1b) 18 (18–20), 14 (14–15) apart; proximal setae on coxisternum I (1a) 50 (45–55), 13 (13–14) apart; proximal setae on coxisternum II (2a) 60 (55–60), 35(35–37) apart; prosternal apodeme absent. Leg I 58 (52–61), trochanter 5 (5), femur 17 (17–18), basiventral femoral setae (bv) absent; genu 8 (5–8), antaxial genual setae (l'') 45 (45–50); tibia 18 (16–18), paraxial tibial setae (l')12 (10–12), located at 1/2 from dorsal base; tarsus 10 (9–12), paraxial, fastigial, tarsal setae (ft') 30 (30–33), antaxial, fastigial, tarsal setae (ft'') 30 (30–33); tarsal empodium (em) 5 (5–6), divided, 5-rayed; tarsal solenidion (ω) 6 (6–7), knobbed. Leg II 54 (49–57), trochanter 5 (5), femur 17 (17–18), basiventral femoral setae (bv) absent; genu 8 (5–8), antaxial genual setae (l'') 15 (12–15); tibia 14 (13–14); tarsus 10 (9–12), paraxial, fastigial, tarsal setae (ft') 10 (8–12), antaxial, fastigial, tarsal setae (ft'') 30 (30–33); tarsal empodium (em) 5 (5–6), divided, 5-rayed; tarsal solenidion (ω) 6 (6–7), knobbed. Opisthosoma dorsally with 48 (45–53) semi-annuli, smooth; ventrally with 84 (84–89) semi-annuli, with few round microtubercles except caudal 12–15 ventral semi-annli with elongated microtubercles; setae c2 60 (55–60) on ventral semi-annulus 18–19, 67 (67–85) apart; setae d 70 (70–80) on ventral semi-annulus 32–33, 50 (50–57) apart; setae e 60 (60–65) on ventral semi-annulus 51–52, 25(24–25) apart; setae f 55 (50–60) on 13-14 ventral semi-annulus from rear, 37 (37–40) apart. Setae h1 1, 10 (9–10) apart; setae h2 90 (80–100), 14 (13–14) apart. Female genitalia 25 (22–25), 33 (30–33) wide, coverflap almost smooth besides one line, setae 3a 12 (12– 15), 17 (17–18) apart.

Male. Unknown.

Type material. Holotype ♀, from Cotoneaster acutifolius Turcz. (Rosaceae) , Maixiu National Forest Park, Zeku Couty, Huangnan Tibetan Autonomous Prefecture, Qinghai, China, 35°12´56"N, 101°50´20"E, elev. 3080 m, 15 August 2019, coll. Manchao Xie. Paratypes. 9♀, same data as holotype.

Relation to host. The mites are vagrant on the undersurfaces of leaves, with no visible symptoms observed.

Etymology. The specific designation acutifolius is derived from the specific name of the host plant.

Remarks. The genus Diptacus ( Diptilomiopidae , Diptilomiopinae ) was erected by Keifer in 1951. About 43 species are arranged in the genus in the world ( Amrine et al., 2003), of which 41 species are distributed in China ( Hong et al., 2010), and 2 species are in Qinghai ( Li et al., 2012), namely D. berberinus Li, Xue & Hong, 2012 and D. mengdaensis Li, Xue & Hong, 2012 .

This is the second species of eriophyid mite collected from the leaves of Cotoneaster acutifolius Turcz. , the first one is Rhyncaphytoptus acutifoliae Song, Xue & Hong, 2009 .

Acknowledgements This work is supported by Biodiversity Background Survey in Maixiu National Forest Park, Huangnan Tibetan Autonomous Prefecture, Qinghai Province, China. We thank greatly anonymous reviewers for valuable comments on the manuscript.

Figures

Figures 17–21. Diptacus acutifolius sp. nov., female. 17. Lateral mite. 18. Dorsal mite. 19. Lateral opisthosoma (enlarged). 20. Empodium (enlarged). 21. Coxal-genital region. Scale bars: 17–18, 21=20μm.