Three New Eriophyid Mite Species from China (Acari: Eriophyidae)

Simple Summary

The Eriophyidae is the largest family in the Eriophyoidea, consisting of over 3790 extant species. Eriophyid mites have a patchy distribution worldwide and are concentrated in the temperate regions. In this study, we describe and illustrate three new eriophyid mites from the temperate region of China—Scolotosus ehretus sp. nov., Neotegonotus ulmchangus sp. nov., and Leipothrix ventricosis sp. nov. All three new species are vagrant on the lower leaf surface, causing no apparent symptoms to the host plant.

Abstract

Eriophyid mites (Eriophyidae) are strictly phytophagous and are concentrated in Europe, Eastern Asia, Southeast Asia, Western and Eastern North America, Southern India, and New Zealand. South and southwest China are hot spots for eriophyid mite species diversity and endemism. In this study, we describe two new species, Scolotosus ehretus sp. nov. on Ehretia acuminata (Boraginaceae) and Neotegonotus ulmchangus sp. nov. on Ulmus changii (Ulmaceae), from south and southwest China (the Oriental Region), and one new eriophyid mite, Leipothrix ventricosis sp. nov. on Hosta ventricosa (Asparagaceae), from northeast China (the Palearctic Region). All three new eriophyid mite species are distributed in the temperate region of China. We further provided mitochondrial gene (cox1, 12S rRNA) and nuclear gene (18S rRNA, 28S rRNA) sequences for three new species.

1. Introduction

Eriophyoid mites are strictly phytophagous [1]. Over 80% of eriophyoid mite species are monophagous [2,3]. Host plants supposedly played key roles in their diversification [4,5]. The Eriophyoidea include three families—Phytoptidae (ca. 160 species), Eriophyidae (ca. 3790 species), and Diptilomiopidae (ca. 450 species) [1,6]. The Eriophyidae can be differentiated from the other two families by having a gnathosoma relatively small and projecting obliquely downwards (a gnathosoma large and abruptly curved near the base in the Diptilomiopidae) and a prodorsal shield without setae vi and ve (a prodorsal shield has setae vi and ve in the Phytoptidae) [1]. Although eriophyoid mites have a worldwide distribution, the richness centers differ among the three families—the Eriophyidae are concentrated in Europe, Eastern Asia, Southeast Asia, Western and Eastern North America, Southern India, and New Zealand [4]. South and southwest China are hot spots for eriophyid mite species diversity and endemism [4].

Field surveys of eriophyoid mites have been conducted in China since 1980 [7]. To date, more than 1200 eriophyoid mites have been described in China [8]. Based on a DNA barcoding dataset, the Chinese fauna of eriophyoid mites was inferred, including over 2300 species [3]. To understand the species diversity of eriophyoid mites in China, Xiao-Feng Xue and colleagues have been conducting a long-term field survey since 2002. In this study, we describe and illustrate two new eriophyid mite species (Scolotosus ehretus sp. nov. and Neotegonotus ulmchangus sp. nov.) from south and southwest China (the Oriental Region) and one new eriophyid mite species (Leipothrix ventricosis sp. nov.) from northeast China (the Palearctic Region). All three new eriophyid mite species are distributed in the temperate region of China. We further provided mitochondrial and nuclear gene sequences for three new species.

2. Materials and Methods

2.1. Taxa Sampling and Morphological Identification

Samples were collected in the field using a hand lens (30×) in China. Mite samples were stored in 96% ethanol at −20 ℃ prior to DNA extraction. Mite specimens were also slide-mounted using Keifer’s Booster and modified Berlese medium [9], but without adding additional fibers, as was suggested by de Lillo et al. [10]. The morphological terminology used herein follows Lindquist [11] and Amrine et al. [1], the internal female genitalia nomenclature follows Chetverikov [12], and the generic classification is made according to Amrine et al. [1] in combination with descriptions of all the published genera after 2003. Specimens were measured following de Lillo et al. [10]. They were examined with the aid of a Zeiss A2 (Carl Zeiss, Gottingen, Germany) research microscope with phase contrast, and semi-schematic drawings were made. Microphotographs were taken with a Zeiss A2 (microphoto camera AxioCam MRc) research microscope with phase contrast or differential interference using 10× eyepieces at 100× oil magnification, connected to a computer using Axiovision (Rel. 4.8) image analysis software. For each species, the holotype female measurements precede the corresponding range for paratypes (given in parentheses). For males, only ranges are given. If no variation was observed among measurements, it will be indicated with an “*”. All measurements are in micrometers (μm) and represent lengths when not otherwise specified. The holotypes and paratypes are deposited in the Arthropod/Mite Collection of the Department of Entomology, Nanjing Agricultural University (NJAU), Jiangsu Province, China [13].

2.2. DNA Extraction and Sequencing

Eriophyid mites have limited distinguishable morphological characters, leading to many species complexes [3,14]. To provide more information besides morphological characteristics, we sequenced fragments of two mitochondrial (cox1, 12S rRNA) and two nuclear (18S rRNA, 28S rRNA) genes for three new species (i.e., Leipothrix ventricosis sp. nov., Scolotosus ehretus sp. nov., Neotegonotus ulmchangus sp. nov.) using published PCR primer pairs for each fragment [14]. Genomic DNA was extracted using a DNeasy Blood and Tissue Kit (Qiagen) following a modified protocol [15]. PCR reaction, purification, and sequencing followed Liu et al. [14].

3. Results

Taxonomy

Family Eriophyidae Nalepa

Subfamily Phyllocoptinae Nalepa

Tribe Phyllocoptini Nalepa

Genus Leipothrix Keifer

Leipothrix ventricosis sp. nov.

(Figure 1 and Figure 2)

Description. Female (n = 8): Body fusiform, 229 (229–246), 81 (81–85) wide, and 70 (69–70) thick; light yellow in color. Gnathosoma 20 (17–20), projecting obliquely downwards, cheliceral stylets 18 (18–20), pedipalp coxal seta (ep) 2 (2–3), dorsal pedipalp genual setae (d) divided (Figure 1G and Figure 2F), the longer branch 17 (17–20), the shorter branch 3 (2–3), and palp tarsal ventral setae (v) absent. Prodorsal shield 61 (58–61), including the frontal lobe, 81 (81–85) wide, frontal lobe broad; median and admedian lines absent, submedian lines incomplete on the posterior 2/3. Scapular tubercles ahead of the rear shield margin, setae sc 5 (4–5), 19 (19–21) apart, projecting centrad. Coxigenital region with 10 * semiannuli between coxal plates and genitalia, smooth; coxal plates with dashes and short lines, anterolateral setae on coxisternum І (1b) 9 (8–10), 18 (18–19) apart; proximal setae on coxisternum І (1a) 16 (11–16), 11 (11–12) apart; proximal setae on coxisternum ІІ (2a) 23 (20–23), 32 (32–34) apart. Prosternal apodeme present, 10 (10–11). Leg І 29 (29–30), femur 10 *, basiventral femoral setae (bv) absent; genu 5 *, antaxial genual setae (l’’) 30 (29–30); tibia 7 (7–8), paraxial tibial setae (l’) 4 *, located at basal 1/3; tarsus 5*, paraxial fastigial tarsal setae ft’ 18 (16–18), antaxial fastigial tarsal setae ft’’ 22 (20–22), setae u’ 4 (4–5); tarsal empodium (em) 6 (5–6), simple, 4-rayed, tarsal solenidion (ω) 6 *, knobbed. Leg ІІ 28 (28–29), femur 10 (9–10), basiventral femoral setae (bv) absent; genu 5 *, antaxial genual setae (l’’) 11 (8–11); tibia 6 *; tarsus 5 (5–6), paraxial fastigial tarsal setae ft’ 3 *, antaxial fastigial tarsal setae ft’’ 21 (18–21), setae u’ 3 (3–4); tarsal empodium (em) 6 (5–6), simple, 4-rayed, tarsal solenidion (ω) 6 (5–6), knobbed. Opisthosoma dorsally with 42 (42–43) semiannuli, with elliptical microtubercles at the lateral side (Figure 1B,D), with three ridges, the middorsal ridge smooth and ending in a furrow; ventrally with 73 (71–75) semiannuli, with round microtubercles, except the posterior 15–17 semiannuli with elliptical to linear microtubercles. Setae c2 11 (11–14), on ventral semiannulus 10 (10–12), 58 (58–62) apart; setae d 15 (13–15), on ventral semiannulus 29 (28–29), 35 (35–37) apart; setae e 10 (10–11), on ventral semiannulus 52 (50–52), 17 (17–20) apart; setae f 26 (24–26), 25 (25–26) apart, on the 6th ventral semiannulus from the rear; setae h1 4 (3–4), setae h2 48 (46–48). Female genitalia 20 (20–21), 26 (25–26) wide, coverflap with granules and short lines, setae 3a 11 (9–11), 15 (15–17) apart. Internal genitalia: spermathecae ovoid, oriented posterolaterad; spermathecal tubes relatively short as long as 1/4 of spermathecal length; transverse genital apodeme trapezoidal.

Male: Not found.

Type material. Holotype, female (slide number NJAUH92.1; marked Holotype), found on Hosta ventricosa Stearn (Asparagaceae), Heilongjiang Forest Botanical Garden, Harbin city, Heilongjiang province, China, 45°62′87″N, 127°21′79″E, elevation 151 m, 27 July 2018, coll. Liang-Fei Yao and Yue Yin, deposited as a slide-mounted specimen in the Arthropod/Mite Collection of the Department of Entomology, NJAU. Paratypes, seven females on seven slides (slide number NJAU H92.2–NJAU H92.8; marked paratypes), from Hosta ventricosa Stearn (Asparagaceae), same details as the holotype, deposited as slide-mounted specimens in the Arthropod/Mite Collection of the Department of Entomology, NJAU.

GenBank accession numbers. MZ279892 (18S rRNA); MZ288929, MZ326514 (28S rRNA); MZ255319 (12S rRNA).

Relation to the host plant. Vagrant on the lower leaf surface. No apparent symptom of the host plant was observed.

Etymology. The specific designation ventricosis is derived from the species name of the host plant, ventricosa, changing postfix -a to -is; feminine in gender.

Differential diagnosis. The new species is morphologically similar to Leipothrix juniperensis Xue and Yin, 2020 [16], by the presence of divided dorsal pedipalp genual setae (d), dorsal opisthosoma with three ridges, and coxal plates with granules and short lines, but can be differentiated by admedian lines absent from the prodorsal shield (admedian lines present in L. juniperensis), female genital coverflap with granules and short lines (female genital coverflap with 6 to 8 ribs in L. juniperensis).

Tribe Tegonotini Bagdasarian

Genus Scolotosus Flechtmann and Keifer

Scolotosus ehretus sp. nov.

(Figure 3 and Figure 4)

Description. Female (n = 10): Body fusiform, 167 (150–167), 58 (58–64) wide, and 40 (36–40) thick; light yellow in color. Gnathosoma 17 (17–18), projecting obliquely downwards, cheliceral stylets 14 (14–15), pedipalp coxal seta (ep) 3 (3–4), dorsal pedipalp genual setae (d) 6 (6–7), palp tarsal ventral setae (v) absent. Prodorsal shield 64 (58–64), including the frontal lobe, is 58 (58–63) wide, with the frontal lobe 5 (5–6) being broad (Figure 3A,D and Figure 4A,B,D); median and submedian lines are absent, admedian lines are concave at the anterior 1/4, forming a vase-shape; many pits are present on the prodorsal shield (Figure 3D and Figure 4A,B). Scapular tubercles ahead of rear shield margin, 5 (4–5), setae sc 7 (7–8), 44 (44–45) apart, projecting lateral. Coxigenital region with 4 * smooth semiannuli between coxal plates and genitalia; coxal plates smooth, anterolateral setae on coxisternum І (1b) 6 (6–7), 12 (10–12) apart; proximal setae on coxisternum І (1a) 16 (13–16), 7 (7–8) apart; proximal setae on coxisternum ІІ (2a) 24 (20–24), 18 (18–22) apart. Prosternal apodeme is absent. Leg І 29 (29–31), femur 10 (9–10), basiventral femoral setae (bv) 7 (7–8); genu 5 (4–5), antaxial genual setae (l’’) 17 (17–18); tibia 6 (5–6), paraxial tibial setae (l’) 4 (3–4), located at basal 1/3; tarsus 6 (5–6), paraxial fastigial tarsal setae ft’ 13 (13–16), antaxial fastigial tarsal setae ft’’ 18 (16–18), setae u’ 2 (2–3); tarsal empodium (em) 5 (5–6), simple, 4-rayed, tarsal solenidion (ω) 5 (5–6), knobbed. Leg ІІ 25 (25–26), femur 9 (9–10), basiventral femoral setae (bv) 5 (5–6); genu 4 (4–5), antaxial genual setae (l’’) 5 (4–5); tibia 5 *; tarsus 5 (4–5), paraxial fastigial tarsal setae ft’ 5 (4–5), antaxial fastigial tarsal setae ft’’ 17 (17–18), setae u’ 3 (3–4); tarsal empodium (em) 5 *, simple, 4-rayed, tarsal solenidion (ω) 5 *, knobbed. Opisthosoma dorsally with 28 (28–29) semiannuli, smooth, with three ridges, middorsal ridge as long as subdorsal ridges extended on the whole dorsal opisthosoma; and ventrally with 50 (47–50) semiannuli, with elliptical to linear microtubercles. Setae c2 8 (8–9), on ventral semiannulus 7 *, 45 (43–45) apart; setae d 35 (35–40), on ventral semiannulus 16 (16–17), 30 (30–31) apart; setae e 6 (6–8), on ventral semiannulus 29 (28–29), 13 (12–13) apart; setae f 16 (15–16), 16 (16–18) apart, on the 5th ventral semiannulus from rear; setae h1 4 *, setae h2 61 (61–63). Female genitalia 14 (14–15), 22 (22–23) wide, coverflap with 10 longitudinal striae, setae 3a 13 (13–15), 15 (15–16) apart. Internal genitalia: spermathecae ovoid, oriented posterolaterad; spermathecal tubes relatively short, as long as 1/5 of spermathecal length; transverse genital apodeme trapezoidal.

Male (n = 2): Body fusiform, 136–145, 49–53 wide; light yellow in color. Gnathosoma 16–17, projecting obliquely downwards, cheliceral stylets 10 *, pedipalp coxal seta (ep) 2 *, dorsal pedipalp genual setae (d) 5 *, palp tarsal ventral setae (v) absent. Prodorsal shield 53–57, including the frontal lobe, is 49–53 wide. Scapular tubercles ahead of the rear shield margin, setae sc 5–6, 43–45 apart, projecting lateral. Coxigenital region with 4 smooth semiannuli between coxal plates and genitalia, coxal plates smooth, anterolateral setae on coxisternum І (1b) 7 *, 14 * apart; proximal setae on coxisternum І (1a) 15–16, 7–9 apart; proximal setae on coxisternum ІІ (2a) 20 *, 21–22 apart. Prosternal apodeme is absent. Leg І 25–26, femur 9 *, basiventral femoral setae (bv) 5 *; genu 4 *, antaxial genual setae (l’’) 15–19; tibia 5 *, paraxial tibial setae (l’) 3 *, located at basal 1/3; tarsus 5 *, paraxial fastigial tarsal setae ft’ 10 *, antaxial fastigial tarsal setae ft’’ 16 *, setae u’ 3 *; tarsal empodium (em) 5 *, simple, 4-rayed, tarsal solenidion (ω) 5 *, knobbed. Leg ІІ 24–26, femur 8 *, basiventral femoral setae (bv) 5 *; genu 4 *, antaxial genual setae (l’’) 5–6; tibia 5 *; tarsus 5 *, paraxial fastigial tarsal setae ft’ 5–6, antaxial fastigial tarsal setae ft’’ 16–17, setae u’ 3 *; tarsal empodium (em) 5 *, simple, 4-rayed, tarsal solenidion (ω) 5 *, knobbed. Opisthosoma dorsally with 27 * semiannuli, smooth; ventrally with 49–50 semiannuli, with elliptical to linear microtubercles. Setae c2 10–11, on ventral semiannulus 7 *, 44–45 apart; setae d 30–32, on ventral semiannulus 16 *, 30 * apart; setae e 6 *, on ventral semiannulus 29 *, 14–15 apart; setae f 14 *, 15 * apart, on the 5th ventral semiannulus from the rear; setae h1 3 *, setae h2 56–58. Male genitalia are 10 *, 17 * wide, and setae 3a 10–11, 15 * apart.

Type material. Holotype, female (slide number NJAUGX54.1; marked Holotype), found on Ehretia acuminata R. Brown (Boraginaceae), Guilin city, Guangxi Zhuang Autonomous Region, China, 25°26′89″N, 110°31′21″E, elevation 164 m, 29 August 2017, coll. Liang-Fei Yao and Yue Yin, deposited as a slide-mounted specimen in the Arthropod/Mite Collection of the Department of Entomology, NJAU. Paratypes, nine females on nine slides and two males on two slides (slide number NJAU GX54.2–NJAU GX54.12; marked paratypes), from Ehretia acuminata R. Br. (Boraginaceae), same details as the holotype, were deposited as slide-mounted specimens in the Arthropod/Mite Collection of the Department of Entomology, NJAU.

GenBank accession numbers. MZ279974 (18S rRNA); MZ289015, MZ326597 (28S rRNA); MZ274841 (cox1); MZ255373 (12S rRNA).

Relation to the host plant. Vagrant on the lower leaf surface. No apparent symptom to the host plant was observed.

Etymology. The specific designation ehretus is derived from the generic name of the host plant, Ehretia, changing the postfix -ia to -us, which is masculine in gender.

Differential diagnosis. Only two Scolotosus species were reported worldwide (

Table 1. Gross comparison of some important traits among Scolotosus ehretus sp. nov., S. centrolobii Flechtmann and Keifer, 2010, and S. hartfordi Flechtmann and de Queiroz, 2010.

Characters	S. ehretus sp. nov.	S. centrolobii	S. hartfordi
Dorsal semiannuli number	28–29	26	26
Ventral semiannuli number	47–50	26	26–30
Number of semiannuli between coxal plates and genital coverflap	4	4	4
Number of empodium I rays	4	5	5
Setae sc length	7–8	9	8–10
Setae c2 length	8–9	12	7–10
Setae d length	35–40	38	24–37
Setae e length	6–8	9	6–9
Setae f length	15–16	9	16–18
Setae h1 length	4	3	3
Setae 3a length	13–15	10	6–11

). The new species is morphologically similar to Scolotosus centrolobii, Flechtmann and Keifer, 2010 [17], with the presence of many pits on the prodorsal shield and scapular tubercles located laterally, but can be differentiated by smooth coxal plates (coxal plates with short lines in S. centrolobii) and smooth dorsal annuli (dorsal annuli with granules in S. centrolobii). The new species is also similar to Scolotosus hartfordi Flechtmann and de Queiroz, 2010 [17], by the presence of many pits on the prodorsal shield, smooth coxal plates, and scapular tubercles located laterally, but can be differentiated by a female genital coverflap with ridges (smooth coverflap in S. hartfordi), and an empodium 4-rayed (empodium 5-rayed in S. hartfordi).

Genus Neotegonotus Newkirk and Keifer

Neotegonotus ulmchangus sp. nov.

(Figure 5 and Figure 6)

Description. Female (n = 8, dorsal view): Body fusiform, 179 (166–179), 67 (67–68) wide; light yellow in color. Gnathosoma 18 (16–18), projecting obliquely downwards, cheliceral stylets 15 (15–16), pedipalp coxal seta (ep) 3 (2–3), dorsal pedipalp genual setae (d) 6 (6–7), palp tarsal ventral setae (v) absent. Prodorsal shield 50 (50–51), including the frontal lobe, is 68 (67–70) wide, the frontal lobe 5 (5–6) is broad (Figure 5A and Figure 6B); the median line is absent, the admedian and submedian lines are incomplete, they are parallel at the posterior 2/3; many pits are present on the prodorsal shield (Figure 5A and Figure 6B). Scapular tubercles on the rear shield margin, setae sc 10 (9–10), 44 (42–44) apart, projecting the posterior. Coxigenital region with 13–14 smooth semiannuli between coxal plates and genitalia; coxal plates with short lines, anterolateral setae on coxisternum І (1b) 9 (8–9), 13 (13–14) apart; proximal setae on coxisternum І (1a) 14 (14–15), 9 (9–10) apart; proximal setae on coxisternum ІІ (2a) 30 (27–30), 24 (24–27) apart. Prosternal apodeme is present, 9 (9–10). Leg І 29 (29–31), femur 10 (9–10), basiventral femoral setae (bv) 10 (9–10); genu 5 (4–5), antaxial genual setae (l’’) 20 (19–20); tibia 6 (5–6), paraxial tibial setae (l’) 5 (4–5), located at basal 1/3; tarsus 6 (5–6), paraxial fastigial tarsal setae ft’ 18 (18–19), antaxial fastigial tarsal setae ft’’ 20 *, setae u’ 3 (3–4); tarsal empodium (em) 5 (5–6), simple, 4-rayed, tarsal solenidion (ω) 5 (5–6), knobbed. Leg ІІ 25 (25–26), femur 9 *, basiventral femoral setae (bv) 10 (8–10); genu 5 (4–5), antaxial genual setae (l’’) 4 (4–5); tibia 5 *; tarsus 5 (5–6), paraxial fastigial tarsal setae ft’ 5 (4–5), antaxial fastigial tarsal setae ft’’ 21 (17–21), setae u’ 3 (3–4); tarsal empodium (em) 5 *, simple, 4-rayed, tarsal solenidion (ω) 5 *, knobbed. Opisthosoma dorsally with 16 (16–17) semiannuli, smooth, the first dorsal annuli broad, projecting posterior (Figure 5A and Figure 6A,B); with three ridges, the middorsal ridge as long as the subdorsal ridges; ventrally with 56 (53–56) semiannuli, with elliptical to linear microtubercles. Setae c2 18 (17–19), on ventral semiannulus 11 (10–11), 55 (55–60) apart; setae d 35 (35–39), on ventral semiannulus 19 (18–19), 33 (33–36) apart; setae e 11 (8–11), on ventral semiannulus 34 (32–34), 14 (14–16) apart; setae f 20 (18–20), 18 (16–18) apart, on the 5th ventral semiannulus from rear; setae h1 2 *, setae h2 55 (54–58). Female genitalia 15 (14–15), 20 (20–21) wide, coverflap with 13–14 longitudinal striae, setae 3a 15 (12–15), 17 (17–18) apart. Internal genitalia: spermathecae ovoid, oriented posterolaterad; spermathecal tubes relatively short, as long as 1/3 of spermathecal length; transverse genital apodeme trapezoidal.

Male (n = 3, dorsal view): Body fusiform, 140–145, 51–52 wide; light yellow in color. Gnathosoma 15–16, projecting obliquely downwards, cheliceral stylets 13 *, pedipalp coxal seta (ep) 2 *, dorsal pedipalp genual setae (d) 6 *, palp tarsal ventral setae (v) absent. Prodorsal shield 45–46, including the frontal lobe, is 51–53 wide. Scapular tubercles on the rear shield margin, setae sc 10–11, 35–36 apart, projecting posterior. Coxigenital region with 13 smooth semiannuli between coxal plates and genitalia, coxal plates with short lines, anterolateral setae on coxisternum І (1b) 8 *, 13 * apart; proximal setae on coxisternum І (1a) 15–16, 9–10 apart; proximal setae on coxisternum ІІ (2a) 24–27, 20–21 apart. Prosternal apodeme is present, 9 (9–10). Leg І 25–26, femur 9 *, basiventral femoral setae (bv) 9–10; genu 4 *, antaxial genual setae (l’’) 18–19; tibia 5 *, paraxial tibial setae (l’) 4 *, located at basal 1/3; tarsus 5 *, paraxial fastigial tarsal setae ft’ 17 *, antaxial fastigial tarsal setae ft’’ 20 *, setae u’ 3 *; tarsal empodium (em) 5–6, simple, 4-rayed, tarsal solenidion (ω) 5 *, knobbed. Leg ІІ 24–26, femur 9 *, basiventral femoral setae (bv) 8 *; genu 4 *, antaxial genual setae (l’’) 5–6; tibia 5 *; tarsus 5 *, paraxial fastigial tarsal setae ft’ 5–6, antaxial fastigial tarsal setae ft’’ 17–18, setae u’ 3 *; tarsal empodium (em) 5 *, simple, 4-rayed, tarsal solenidion (ω) 5 *, knobbed. Opisthosoma dorsally with 17 * semiannuli, smooth; ventrally with 49–50 semiannuli, with elliptical to linear microtubercles. Setae c2 17–18, on ventral semiannulus 10 *, 45–46 apart; setae d 30–32, on ventral semiannulus 18 *, 35 * apart; setae e 8 *, on ventral semiannulus 27 *, 14–15 apart; setae f 15–16, 15 * apart, on the 5th ventral semiannulus from the rear; setae h1 2 *, setae h2 57–60. Male genitalia 11 *, 16 * wide, setae 3a 10–11, 15 * apart.

Type material. Holotype, female (slide number NJAUFJ27.1; marked Holotype), found on Ulmus changii W.C. Cheng (Ulmaceae), Wuyi mountain, Fujian province, China, 27°40′28″N, 118°2′37″E, elevation 251 m, 21 August 2017, coll. Liang-Fei Yao and Yue Yin, deposited as a slide-mounted specimen in the Arthropod/Mite Collection of the Department of Entomology, NJAU. Paratypes, seven females on seven slides and three males on three slides (slide number NJAUFJ27.2–NJAUFJ27.11; marked paratypes), from Ulmus changii W.C. Cheng (Ulmaceae), with the same details as the holotype, deposited as slide-mounted specimens in the Arthropod/Mite Collection of the Department of Entomology, NJAU.

GenBank accession numbers. MZ279799 (18S rRNA); MZ288836, MZ326418 (28S rRNA); MZ255260 (12S rRNA).

Relation to the host plant. Vagrant on the lower leaf surface. No apparent symptom of the host plant was observed.

Etymology. The specific designation ulmchangus is derived from the combination of the host plant name, Ulmus changii, by sdeleting -us from the genus name and changing the postfix -ii to -us in the species name; masculine in gender.

Differential diagnosis. Six Neotegonotus species were described worldwide (

Table 2. List of Neotegonotus species.

Species	Hosts	Distribution	Relation to Host
N. alopebaccae Meyer, 1990 [18]	Diospyros mespiliformis Hochstetter ex A. P. de Candolle (Ebenaceae)	South Africa	Vagrant
N. fastigatus (Nalepa 1892) [19]	Acer campestre Linnaeus (Sapindaceae)	Palearctic [20,21], USA [22], India [23]	Erineum or vagrant
N. indicus Mondal and Chakrabarti, 1982 [24]	Ficus benghalensis Linnaeus (Moraceae)	India	Apical shoots brownish and stunted
N. pengensis Meyer, 1990 [18]	Ficus capreifolia Delile (Moraceae)	South Africa	Vagrant
N. shangsiensis Wei, 2003 [25]	Acronychia pedunculata (Linnaeus) Miquel (Rutaceae)	China	Vagrant
N. sycamori Abou–Awad, 1984 [26,27]	Ficus sycomorus Linnaeus (Moraceae)	Egypt, South Africa [18]	Vagrant
N. ulmchangussp. nov.	Ulmus changii W.C. Cheng (Ulmaceae)	China	Vagrant

). The new species is morphologically similar to N. pengensis, Meyer, 1990 [18], by the presence of many pits on prodorsal shield, coxal plates with short lines, and female genital coverflap with many longitudinal striae, but can be differentiated by dorsal annuli smooth (dorsal annuli with microtubercles in N. pengensis), admedian and submedian lines incomplete (admedian lines complete, submedian lines absent in N. pengensis), and empodium 4-rayed (empodium 5-rayed in N. pengensis).

Key to species of Neotegonotus

• Dorsal annuli smooth……….…….…………….………...……………….……………..2

-

Dorsal annuli with microtubercles……………………….………………..……………3

2.

Coxal area smooth, empodium 5-rayed….…N. indicus Mondal and Chakrabarti, 1982

-

Coxal area with short lines, empodium 4-rayed………....….…N. ulmchangus sp. nov.

3.

Coxal area smooth……………………………………………. N. shangsiensis Wei, 2003

-

Coxal area with granules or short lines........................................................................…4

4.

Female genital coverflap with two rows of striae…...N. sycamori Abou–Awad, 1984

-

Female genital coverflap with one row of striae………………………………………5

5.

Setae h1 present, empodium 5-rayed………………………………………………..…6

-

Setae h1 absent, empodium 4-rayed…………………....…. N. alopebaccae Meyer, 1990

6.

Prodorsal shield with lined granules, admedian lines complete, submedian lines absent.……………………………………………….……………N. pengensis Meyer, 1990

-

Prodorsal shield without lined granules, submedian lines complete, admedian lines absent……………………………………………………………N. fastigatus (Nalepa 1892)

4. Discussion

In this study, we described and illustrated three new eriophyoid mite species from three genera (Leipothrix, Scolotosus, and Neotegonotus) in China. All three new species belong to the subfamily Phyllocoptinae (Eriophyidae), based on the distinct morphological characters—body shape fusiform; gnathosoma relatively small, projecting obliquely downwards; with legs having the typical segmentation; dorsal annuli broader than the ventral annuli (Amrine et al., 2003) [1]. However, the monophyly of Phyllocoptinae was rejected by molecular studies [5,28,29] as well as the non-monophyly of two genera, Leipothrix and Neotegonotus [5]. It should be noted that the phylogenetic position of L. ventricosis sp. nov. (named Leipothrix sp. H92 in Figure 2 of reference [5]) was inferred to be nested with three Paraepitrimerus species [5]. L. ventricosis sp. nov. is morphologically similar to species in the genus Paraepitrimerus [30] by exhibiting femur setae absent, an opisthosoma with three ridges, and scapular setae and tubercles ahead of the rear shield margin, but can be differentiated distinctly by dorsal pedipalp genual setae (d) divided, which is a generic character of Leipothrix [1]. Two Neotegonotus species, N. ulmchangus sp. nov. (named Neotegonotus sp. FJ27 in Figure 2 of reference [5]), and N. shangsiensis, failed to be grouped in the analysis of reference [5]. By contrast, N. ulmchangus sp. nov. was inferred to be closer to species in the genera Aculus, Abacarus, and Shevtchenkella [5]. S. ehretus sp. nov. (named Scolotosus sp. GX54 in Figure 2 of reference [5]) was nested within species from genera Tegolophus and Aculus [5]. Therefore, it is likely that their generic characteristics should be reconsidered in future studies. All three new species are distributed in the temperate region of China. The species diversity and endemism of eriophyid mites peak in temperate regions [4]. The south and southwest mountains of China are hot spots for eriophyid mite species diversity and endemism [4], reflecting potential “museums” and “cradles”. Given the over 1200 eriophyoid mite species described in China [8] and suspected 2300 species for the eriophyoid mite fauna of China [3], more field surveys should be conducted, especially in the mountains of southwest China, to unveil the species diversity of eriophyoid mites.

The Leipothrix is among the most species-rich genera in the Eriophyidae, including more than 50 named species (personal data of X.-F.X.). Eighteen Leipothrix species have been reported in China. Most of them (13/18) were distributed in the temperate region, while the remaining species were distributed in the tropical region. S. ehretus sp. nov. is one of three Scolotosus species reported in the temperate region of China. The other two Scolotosus species, S. centrolobii Flechtmann and Keifer, 2010, and S. hartfordi Flechtmann and de Queiroz, 2010, were distributed in the temperate region of Brazil [17]. The genus Neotegonotus holds seven species (including N. ulmchangus sp. nov., Table 2), of which N. fastigatus and N. sycamori have a cosmopolitan distribution [18,20,21,22,23,26,27]. All species in three genera (Leipothrix, Scolotosus, and Neotegonotus) have high (100%) host plant specificity; no alternative host plants were reported for each eriophyoid mite species.

Eriophyid mites have simplified morphological characteristics (e.g., only two pairs of legs, reduced setae on the opisthosoma and legs, ringed opisthosoma) when compared with other mite species [1]. Two fossil species dating back to the Triassic are morphologically similar to extant species [31]. It is likely that the eriophyoid mites were in morphological stasis during long-term evolution, leading to a potential species complex [3,14,32]. COI barcodes were recently explored in eriophyoid mite delimitation, enabling the discrimination of 99% of eriophyoid mite species [3]. Besides morphological characteristics, we provide a COI barcode for Scolotosus ehretus sp. nov. However, we failed to sequence the COI barcode for the other two species. We further provided mitochondrial (12S rRNA) and nuclear gene (18S rRNA, 28S rRNA) sequences for Leipothrix ventricosis sp. nov., Scolotosus ehretus sp. nov., Neotegonotus ulmchangus sp. nov. We suggested a combination of molecular sequences and morphological characters in the description of new eriophyoid mite species.