# The second species of Testudacarus and one new record of Torrenticola for the Chinese fauna (Acari, Hydrachnidia, Torrenticolidae)

Xin-Yao Gu, Hai-Tao Li, Dao-Chao Jin, Jian-Jun Guo

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Xin-Yao Gu, Hai-Tao Li, Dao-Chao Jin, Jian-Jun Guo. The second species of Testudacarus and one new record of Torrenticola for the Chinese fauna (Acari, Hydrachnidia, Torrenticolidae). Acarologia, 2023, 64 (1), pp.18-31. 10.24349/a3di-wcie. hal-04416680

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# The second species of *Testudacarus* and one new record of *Torrenticola* for the Chinese fauna (Acari, Hydrachnidia, Torrenticolidae)

Xin-yao Gu IDª, Hai-tao Li IDᵇ, Dao-chao Jin IDᵇ, Jian-jun Guo IDᵇ

## Original research

### ABSTRACT

Two water mites species of Torrenticolidae are reported from China. *Testudacarus sinensis* Gu & Guo sp. nov. is described as the second species of Testudacarinae in Chinese fauna and the 22nd species of the subfamily. Moreover, the first record from China is given for *Torrenticola rangareddyi* Pešić & Smit, 2019. In addition to an updated key for all species of Torrenticolidae recorded from China, the dorsal plate arrangements of torrenticolid mites are reviewed to provide further references and data for the taxonomy of Chinese Torrenticolidae.

**Keywords** water mites; Torrenticolidae; taxonomy; China

**Zoobank** http://zoobank.org/FEB3DBE2-4578-4EBC-909A-0CF49F106D52

### Introduction

According to the latest classification system, Torrenticolidae is divided into two subfamilies, seven genera and 12 subgenera (Simt 2020). According to statistics from the European Watermite Research (http://www.watermite.org/) and the latest published paper, 618 species belong to this family (Gu *et al.* 2023). However, there are only 22 known species (including the new species reported in this contribution) in the Testudacarinae Walter, 1928, mainly distributed in North America, with a few species occurring in Asia (O'Neill *et al.* 2016). From China, only one species, *Testudacarus binodipalpis* Guo & Jin, 2005, was reported in 2005 (Guo & Jin 2005).

In this paper, one new species of Testudacarinae from China, *Testudacarus sinensis* Gu & Guo sp. nov., is described. Furthermore, one new record for the Chinese fauna is given, i.e. *Torrenticola rangareddyi* Pešić & Smit, 2019, which was previously reported from Thailand (Pešić & Smit 2019). In addition, an updated key of Chinese torrenticolid mites is provided.

### Material and methods

All the material was collected, preserved, cleaned, and mounted following Jin & Gu (Jin 1997; Gu *et al.* 2023). Measurements are according to Goldschmidt (2007) and are given in µm. Morphological terminology follows Jin (1997) and Fisher *et al.* (2015). All the specimens examined are deposited at the Institute of Entomology, Guizhou University, Guizhou, P. R. China.

Received 01 July 2023
Accepted 30 November 2023
Published 14 December 2023

Corresponding author
Jian-jun Guo ID: jjguo@gzu.edu.cn

Academic editor
Auger, Philippe

https://doi.org/10.24349/a3di-wcie

ISSN 0044-586X (print)
ISSN 2107-7207 (electronic)

<figure><img src="image_7.png" /></figure>

Gu X. *et al.*

Licensed under
Creative Commons CC-BY 4.0

OPEN ACCESS

<footnote>ªCollege of Animal Sciences, Guizhou University, Guiyang 550025, P. R. China.</footnote>

<footnote>ᵇInstitute of Entomology, Guizhou University, Guizhou Provincial Key Laboratory for Plant Pest Management of the Mountainous Region, the Scientific Observing and Experimental Station of Crop Pest in Guiyang, Ministry of Agriculture, P. R. China, Guiyang 550025, P. R. China.</footnote>
The following abbreviations are used (Jin 1997; Gu et al. 2022): aL = apical length; Ap = anal pore; bs = basal segment of chelicera; Cx-I–Cx-IV = coxae I–IV; dL = dorsal length; Gf = Genital field; I-L-1–6, etc. = first leg's segment 1–6, etc.; L = length; mL = medial length; P-1–5 = palp segment 1–5; vL = ventral length; W = width. The chaetotaxy and nomenclature of glandularia used follows Jin (1997); A₂ = postantennal glandularia; D₁–D₄ = dorsoglandularia 1–4; C₂, C₄ = coxoglandularia 2, 4; L₁–L₄ = lateroglandularia 1–4; O₂ = postocularia; V₁–V₄ = ventroglandularia 1–4.

Abbreviations of dorsal plate arrangements according to Wiles (1997) are updated: 3+14+1 = three anterior platelets (one frontal and two shoulder platelets), one dorsal plate and 14 platelets (surrounded the dorsal plate); 4+1= four anterior platelets (two frontal and two shoulder platelets) and one single large dorsal plate; 2+2p+1 = two frontal platelets, and the shoulder platelets partially fused to the dorsal plate; 2+1 = two frontal platelets and a single large dorsal plate, the shoulder platelets are fused to the large dorsal plate; 1+2 = the frontal and shoulder platelets of each side are fused to each other but are separated from the large dorsal plate. 0+1 = two frontal and two shoulder platelets are fused to the large dorsal plate. (Figure 1).

# Taxonomy

## Torrenticolidae Piersig, 1902

## Testudacarinae Cook, 1974

## Testudacarus Walter, 1928

### Testudacarus sinensis Gu & Guo sp. nov.

Zoobank: E39E392A-71B8-444B-B67B-E7D4835402C3

(Figures 2–5)

## Material examined

Holotype male, No. GZ-TO-20160722, Fodingshan, Guizhou Province, China (27°20′14″N, 108°03′08″E, 930 m a.s.l.), collected by Xinyao Gu, 11 Jul. 2016. Paratypes, 5 males and 8 females, same collection data as for holotype, No. GZ-TO-20160723 – GZ-TO-20160735; 3 males and 2 females, Doupengshan, Guizhou province (26°07′55″N, 107°18′54″E, 1000 m a.s.l.), No. GZ-TO-20160901 – GZ-TO-20160905, collected by Xinyao Gu and Zhuhui Ding, 30 Sept. 2016; 4 females and 5 males, Anzhihe, Sichuan province (30°47′43″N, 103°12′36″E, 1690 m a.s.l.), No. SC-TO-20160705 – SC-TO-20160713, 29 Jul. 2016, collected by Zhuhui Ding; 1 male and 4 females, Xiaoxi National Nature Reserve, Hunan Province (28°45′21″N, 110°18′36″E, 690 m a.s.l.), 19 Aug. 2016, collected by Xinyao Gu and Zhuhui Ding, No. HN-TO-20160801 – HN-TO-20160805.

## Diagnosis

Dorsal plate arrangement 3+14+1, median anterior platelet trapezoid, shoulder platelets oblong; dorsal apodeme long and blunt, ventral apodeme pointed and curved to dorsum in gnathosoma; P-4 without ventral seta.

## Description

**Male** — (n = 15) – Idiosoma L 726 (611–726), W 463 (400–463), L/W ratio 1.6 (1.5–1.6). Dorsal plate arrangement 3+14+1; dorsal plate surrounded by seven pairs of small platelets, L 532 (461–535), W 372 (306–372), L/W ratio 1.4 (1.4–1.5); median anterior platelet trapezoid L 132 (129–153), W 74 (74–82), L/W ratio 1.8 (1.7–1.9); shoulder platelets oblong, L 185 (155–185), W 70 (70–90), L/W ratio 2.6 (2.0–2.6) (Figure 2A). Gnathosomal bay U-shaped, depth 147 (126–147); Cx-I L 256 (228–256), mL 110 (102–113); Cx-II + III L 111 (106–111),
<figure><img src="image_8.png" /></figure>

**Figure 1** Abbreviations of dorsal plate arrangements: A – *Testudacarus sinensis* Gu & Guo sp. nov. (3+14+1); B – *Torrenticola spinextension* Gu & Guo, 2020 (4+1); C – *Torrenticola acrisarostrum* Gu & Guo, 2020 (2+2p+1); D – *Torrenticola* sp. (2+1); E – *Monattractides trilaminatus* Gu, Jin & Guo, 2020 (1+2); F – *Monattractides jinni* Gu & Guo, 2019 (0+1). A–D, Scale bars = 200 µm; E, F Scale bars = 300 µm.

$C_4$ posterior to the trailing edge of Cx-IV. $V_1$ on the same line with Ap, $V_2$ posterior to Ap, $V_4$ at the line of primary sclerotization (Figure 2B). Gf oblong, L 170 (122–170), W 125 (104–151), L/W ratio 1.4 (1.1–1.4). Distance between Gf and Ap 68 (58–72). Gnathosoma: dL 95 (95–99), vL 156 (143–156), dorsal apodeme long and blunt, ventral apodeme pointed and curved to dorsum; chelicera bs L 141 (134–142), and curved to the abdomen, claw L 19 (17–19) (Figure 2E). Palp (Figure 2D): P-1 short and with one dorsal seta; P-2 with three dorsal setae, one ventral seta; P-3 with two dorsal setae and one ventral seta; P-4 with one long and one shot dorsal setae; dL of palp: P-1, 22 (16–22); P-2, 50 (45–57); P-3, 39 (36–40); P-4, 50 (34–52); P-5, 14 (14–17). dL of leg segments: I-L-1-6: 43 (43–72), 75 (42–75), 60 (60–64), 86 (68–88), 86 (76–88), 81 (72–81); II-L-1-6: 64 (43–64), 67 (60–92), 60 (60–65), 93 (77–93), 95 (80–108), 111 (90–111); III-L-1-6: 53 (50–58), 88 (76–88), 64 (52–71), 110 (104–112), 121 (104–121), 141 (121–141); IV-L-1-6: 85 (83–97), 92 (85–92), 115 (101–115), 150 (120–150), 159 (148–159), 161 (125–161).

**Female** — (n=18) – Idiosoma features same as in male except: Ap away from the line of primary sclerotization, at the same level with $V_1$ and $V_2$; Gf pentagonal (Figure 4B). Idiosoma
<figure><img src="image_9.png" /><figcaption>**Figure 2** *Testudacarus sinensis* Gu & Guo sp. nov., Male: A – Dorsal view; B – Ventral view; C – Ejaculatory complex; D – Palp; E – Gnathosoma and chelicera. Scale bars = 100 µm.</figcaption></figure>

L 756 (637–756), W 501 (452–507), L/W ratio 1.5 (1.4–1.5); dorsal shield L 626 (563–626), W 471 (380–471), L/W ratio 1.3 (1.3–1.5); dorsal plate L 500 (468–500), median anterior platelets L 133 (122–139), W 89 (89–90), L/W ratio 1.5 (1.4–1.5); shoulder platelets L 193 (182–193), W 77 (77–88), L/W ratio 2.5 (2.2–2.5); gnathosomal bay 190 (137–190); Cx-I L 296 (233–296), mL 101 (92–108), Cx-II+III mL 43 (43–54); Gf L 160 (132–160), W 133 (123–171), L/W ratio 1.2 (0.9–1.2); distance between Gf and Ap 193 (193–199). Gnathosoma: vL 149 (149–161), dL 147 (96–147); chelicera bs L 145 (145–147), claw L 31 (19–31). dL of palp: P-1, 27 (25–27);
<figure><img src="image_10.png" /><figcaption>**Figure 3** *Testudacarus sinensis* Gu & Guo sp. nov., Male: A – Leg-I; B – Leg-II; C – Leg-III; D – Leg-IV-1-4; E – Leg-IV-5, 6. Scale bars = 100 µm.</figcaption></figure>

P-2, 54 (45–54); P-3, 42 (38–42); P-4, 48 (41–48); P-5, 20 (12–20). dL of leg segments: I-L-1-6: 38 (38–60), 85 (52–85), 68 (59–68), 93 (83–93), 97 (87–97), 96 (86–96); II-L-1-6: 40 (40–64), 70 (70–92), 66 (44–66), 114 (87–114), 121 (88–121), 137 (88–137); III-L-1-6: 46 (46–66), 97 (62–97), 75 (66–75), 114 (96–114), 127 (113–127), 125 (125–128); IV-L-1-6: 98 (89–104), 127 (90–127), 122 (102–122), 156 (137–156), 168 (152–168), 156 (143–156).

## Habitat

Streams, with large stones, turbulent.

## Remarks

Due to the length of idiosoma (600–900 µm), median anterior platelets wide and prismatic, this species differs from most species of *Testudacarus* in O’Neill *et al.* (2016). However, it is similar to *Testudacarus tripeltatus* Walter, 1928 and *Testudacarus okadai* Imamura, 1976 due to the short median suture of Cx-II+III (Pešić & Smit 2007). Compared to *T. tripeltatus*, differences are found in: (1) P-2 ventrodistal setae pinnate in *T. tripeltatus*, but smooth in Chinese specimens; (2) Tips of Cx-I with one distinct protrusion in *T. tripeltatus*, but absent in Chinese specimens; (3) Ap located after *V*₁ before *V*₂ in *T. tripeltatus*, but on the same line
<figure><img src="image_11.png" /><figcaption>**Figure 4** *Figure 4. Testudacarus sinensis* Gu & Guo sp. nov., Female: A – Dorsal view; B – Ventral view. Scale bars = 100 µm.</figcaption></figure>

with *V*₁ in Chinese specimens. Meanwhile, *T. okadai* has one pair of small and narrow shoulder platelets, but shoulder platelets are broad and large in the new species.

We also compared the new species with *Testudacarus binodipalpis* Guo & Jin, 2005 (Guo & Jin 2005), which was the first species of *Testudacarus* reported from China. Distinct differences between this new species and *T. binodipalpis* are: (1) P-4 with two ventral extensions in *T. binodipalpis*, but without ventral extensions in the new species; (2) P-3 and P-4 eachwith one pinnate ventral seta in *T. binodipalpis*, but ventral seta smooth in the new species; (3) the tips of Cx-I with one triangular protrusion in *T. binodipalpis*, but without protrusion in the new species.

**Etymology**

The new species is named after China. The specific name "*sinensis*" is from Latin roots "*sino*-", which means China.

**Distribution**

China (Guizhou, Hunan, Sichuan).
<figure><img src="image_12.png" /></figure>

**Figure 5** *Testudacarus sinensis* Gu & Guo sp. nov. Female: A – Palp; B – Gnathosoma and chelicera; C – Leg-I; D – Leg-II; E – Leg-III; F – Leg-IV-1–3; G – Leg-IV-4–6. Scale bars = 100 µm.

**Torrenticolinae Piersig, 1902**

**Torrenticola Piersig, 1896**

**Torrenticola rangareddyi Pešić & Smit, 2019**

(Figures 6–7)

*Torrenticola turkestanica* Pešić & Smit, 2009: 50.

*Torrenticola rangareddyi* Pešić & Smit, 2019: 1872.

**Material examined**

Two males, No. FJ-TO-20180814, FJ-TO-20180815, Wuyishan National Nature Reserve, Fujian Province (27°45′24″N, 117°41′20″E, 710 m a.s.l.), collected by Xinyao Gu, 6 Aug. 2018; 2 males, No. GX-TO-20190901, GX-TO-20190902, Dayaoshan National Nature Reserve, Guangxi Province (24°08′41″N, 110°14′21″E, 1000 m a.s.l.), collected by Min Ao and Haitao Li, 4 Sept. 2019.
## Description

**Male** — (n = 4) – Idiosoma elliptical, L 612 (612–641), W 394 (390–410), L/W ratio 1.55 (1.55–1.57). Dorsal plate arrangement 4+1 (Figure 6A), dorsal shield L 497 (497–537), W 349 (349–374), L/W ratio 1.42 (1.42–1.43); dorsal plate L 471 (471–502); frontal platelets L 115 (113–118), W 40 (39–44), L/W ratio 2.9 (2.7–2.9); shoulder platelets L 146 (142–155), W 43 (43–46), L/W ratio 3.4 (3.3–3.5). Gnathosomal bay U-shaped, deep 109 (104–119); Cx-I L 210 (210–241), mL 101 (101–122), Cx-II+III mL 104 (76–104); Gf L 143 (134–143), W 105 (103–108), L/W ratio 1.4 (1.3–1.4); C₄ at the same level as the 5th pair of acetabula (Figure 6B); distance between Gf and Ap 96 (96–112). Gnathosoma: dorsal apodeme short and blunt, ventral apodeme long and blunt, rostrum rude; gnathosoma dL 196 (192–198), vL 268 (263–274); chelicera bs L 270 (266–275), claw L 48 (48–55) (Figure 6D); P-1 short, with one dorsal seta; P-2 wide, with three dorsal setae, and one ventral seta on a serrated rectangular extension; P-3 with two dorsal setae and one long ventral seta on serrated ventral extension; P-4 with two dorsal setae, one long and three short ventral setae on the two ventral extensions (Figure 6C). L of palp: P-1, 30 (30–42); P-2, 80 (80–85); P-3, 55 (48–56); P-4, 80 (72–81); P-5, 13 (13–17). L of leg segments: I-L-1-6: 31 (31–38), 56 (56–82), 65 (59–65), 70 (70–78), 80 (80–88), 82 (80–84); II-L-1-6: 35 (35–45), 57 (57–73), 62 (62–70), 76 (76–97), 87 (87–118), 102 (102–131); III-L-1-6: 35 (35–42), 77 (67–77), 66 (56–66), 91 (78–93), 109 (93–109), 121 (113–125); IV-L-1-6: 88 (88–106), 90 (90–100), 95 (93–99), 118 (118–146), 130 (130–152), 136 (136–148). Ejaculatory complex L 185 (185–194), AL 131 (131–143).

**Female** Unknown.

## Habitat

Stream, with many big stones at the bottom; the water is clear and rapid.

## Remarks

Due to the characteristics of palp: P-2 and P-3 with one subrectangular ventrodistal projection respectively, the ventral margin of P-2 convex, the P-2 with one ventral seta exceeding the distal end of the ventrodistal projection, the Chinese specimens match the description of *Torrenticola rangareddyi* Pešić & Smit, 2019 (Pešić & Smit 2009, 2019). The only difference between the Chinese specimens and *T. rangareddyi* is P-4 with a stubby dorsodistal seta, which is absent in the Chinese specimens. Therefore, we considered that the difference is they belong to different geographical populations.

In addition, we noted that *T. rangareddyi* and *Torrenticola wonchoeli* Pešić & Smit, 2019 had been provisionally assigned to *Torrenticola turkestanica* (Sokolow, 1926) by Pešić & Smit (2009, 2013, 2019). Therefore, we also compared the Chinese specimens with *T. turkestanica* and *T. wonchoeli*. Differences between them are given in Table 1 (Pešić & Smit 2007, 2009, 2013, 2019; Pešić et al. 2022). Although those species can be distinguished from morphological characteristics, we also agree with the view of Pešić, Smit and Gurung that should be tested with the application of molecular techniques"(Pešić & Smit 2019; Pešić et al. 2022).

<table><caption>**Table 1** Differences in diagnostic characters between Chinese specimens and *Torrenticola wonchoeli* Pešić & Smit, 2019, *Torrenticola turkestanica* (Sokolow, 1926) and *Torrenticola rangareddyi* Pešić & Smit, 2019</caption><thead><tr><th></th><th>Chinese specimens</th><th><i>T. wonchoeli</i></th><th><i>T. turkestanica</i></th><th><i>T. rangareddyi</i></th></tr></thead><tbody><tr><td>Ventral seta on P-2</td><td>Short<fnref n="1" /></td><td>Long<fnref n="2" /></td><td>Long</td><td>Short</td></tr><tr><td>P-4 with a stubby dorsodistal seta</td><td>Yes</td><td>No</td><td>No</td><td>No</td></tr><tr><td>Colour of dorsal shield</td><td>yellow brown</td><td>tawny</td><td>dark orange (India) or yellow-brown (Bhutan)</td><td>yellow brown</td></tr><tr><td>Idiosoma</td><td>Elongated-oval (dorsal shield L/W ratio 1.4)</td><td>Elongated (dorsal shield L/W ratio 1.5–1.6)</td><td>Oval (dorsal shield L/W ratio 1.3)</td><td>Elongated-oval (dorsal shield L/W ratio 1.3–1.4)</td></tr></tbody></table>

<footnote n="1">1 = ventral seta to the anterior margin of P-2;</footnote>

<footnote n="2">2 = ventral seta exceeding to the anterior margin of P-2, nearly 2 times</footnote>
Distribution

Thailand (Pešić & Smit 2009; Pešić *et al.* 2013); New for the fauna of China.

Key to the known species of the family Torrenticolidae in China

Updated from Gu *et al.* 2019, Gu & Guo 2019

<table><tr><td>1. Three pairs of acetabula</td><td>(Subfamily Testudacrinae) – 2</td></tr><tr><td>— Six pairs of acetabula</td><td>(Subfamily Torrenticolinae) – 3</td></tr></table>

<table><tr><td>2. The tips of Cx-I with one triangular protrusion, P-4 with two ventral extensions, P-3 and P-4 each with one pinnate ventral seta</td><td><i>Testudacarus binodipalpis</i> Gu & Jin, 2005</td></tr><tr><td>— Tips of Cx-I without any protrusions, P-4 without ventral extensions, P-3 and P-4 each with one smooth ventral seta</td><td><i>Testudacarus sinensis</i> Gu & Guo sp. nov.</td></tr></table>

<table><tr><td>3. P-4 short, not more than twice as long as W, P-5 with broad, blunt terminal setae</td><td>(Genus <i>Neoatractides</i>) – 4</td></tr><tr><td>— P-4 long, more than twice as long as W</td><td>5</td></tr></table>

<table><tr><td>4. Length of frontal platelet about 2/3 of shoulder platelet, the tip of Cx-I with seven slender setae</td><td><i>Neoatractides proclusteroseta</i> Gu & Guo, 2018</td></tr><tr><td>— Length of frontal platelet about 3/2 of shoulder platelet, the tip of Cx-I with only one slender seta</td><td><i>Neoatractides malayensis</i> (Wiles, 1991)</td></tr></table>

<table><tr><td>5. Gnathosomal dorsal apodeme short, P-2 and P-3 with distinct ventral prolongations or hyaline extensions</td><td>(Genus <i>Torrenticola</i>) – 6</td></tr><tr><td>— Gnathosomal dorsal apodeme long, P-2 and P-3 without projections on ventral margin</td><td>(Genus <i>Monatractides</i>) – 44</td></tr></table>

<table><tr><td>6. Rostrum curved; most of P-2 and P-3 without distinct ventral prolongations, P-2 and P-4 thin and long, P-2 longer than or equal to P-4</td><td>(Subgenus <i>Megapalpis</i>) – 7</td></tr><tr><td>— Rostrum straight, P-2 and P-3 with distinct ventral prolongations or hyaline extensions, P-2 and P-4 short, P-2 shorter than P-4</td><td>(Subgenus <i>Torrenticola</i>) – 9</td></tr></table>

<table><tr><td>7. P-4 with distinct ventral extensions</td><td>8</td></tr><tr><td>— P-4 without any ventral extensions</td><td><i>Torrenticola yii</i> Gu & Guo, 2022</td></tr></table>

<table><tr><td>8. Gnathosomal bay V-shaped</td><td><i>Torrenticola aduncrostrum</i> Gu, Jin & Guo, 2020</td></tr><tr><td>— Gnathosomal bay U-shaped</td><td><i>Torrenticola distans</i> K.O. Viets, 1981</td></tr></table>

<table><tr><td>9. Dorsal plate arrangements: 4+1</td><td>10</td></tr><tr><td>— Dorsal plate arrangements: 2+1 or 2+2p+1</td><td>36</td></tr></table>

<table><tr><td>10. Rostrum short (<1/2 of gnathosoma dL)</td><td>11</td></tr><tr><td>— Rostrum long (≥1/2 of gnathosoma dL)</td><td>20</td></tr></table>

<table><tr><td>11. Palp relatively slender and long</td><td>12</td></tr><tr><td>— Palp robust and compact</td><td>19</td></tr></table>

<table><tr><td>12. Ventral extensions of P-3 with some teeth</td><td>13</td></tr><tr><td>— Ventral extensions of P-3 smooth</td><td>14</td></tr></table>

<table><tr><td>13. P-2 with a distinct and irregular serrated terminal margin</td><td><i>Torrenticola multiserrater</i> Gu & Guo, 2023</td></tr></table>
27. The concavity between the ventral prolongations of P-4 small..................28
— The concavity between the ventral prolongations of P-4 large and distinct, with four setae on the ventral prolongations, idiosoma oblate ........ Torrenticola fodingensis Gu & Guo, 2018

28. Ap anterior to V₂..................................................29
— Ap on the line with V₂ or posterior to V₂....................................30

29. P-2 shorter than 1/3 palp L, idiosomal frontal margin with a convex outline....................
.................................................................... Torrenticola nipponica (Enami, 1940)
— P-2 longer than 1/3 palp L, ventral margin convex, ventrodistal protrusion bluntly pointed and slightly curved towards distal, gnathosoma elongated, chelicera long and straight ............
.................................................................... Torrenticola tenuichelicera Gu & Guo, 2018

30. Ap on the line with V₂, shoulder platelets close to the sides of idiosoma..................31
— Ap posterior to V₂, shoulder platelets offset to the inside, away from the sides of idiosoma....................
.................................................................... Torrenticola hainanensis Gu & Guo, 2019

31. Gnathosomal bay V-shaped.................... Torrenticola planusirostrum Gu, Jin & Guo, 2020
— Gnathosomal bay U-shaped ....................................................32

32. Dorsal apodeme of gnathosoma almost absent, rostrum extremely slender, and curved slightly to the venter .................................... Torrenticola yunnanensis Gu, Jin & Guo, 2020
— Dorsal apodeme of gnathosoma distinct, rostrum straight .................................33

33. Gnathosoma dorsal apodeme absent ............ Torrenticola rectrostrum Gu, Jin & Guo, 2020
— Gnathosoma dorsal apodeme distinct ....................................................34

34. Cx-I more elongated, tips rounded .................... Torrenticola semicolor K.O. Viets, 1977
— Cx-I wider nearly triangular, tips pointed ....................................................35

35. Body without color pattern.................................... Torrenticola tetrapora (Viets, 1935)
— The posterior half of the dorsal plate reddish, dorsal plate with a reddish-purple coloration, hour-glassshaped with pale “shoulder-patches” ....................................................
.................................................................... Torrenticola lushanensis Gu, Jin & Guo, 2020

36. Dorsal plate arrangements: 2+2p+1 ....................................................37
— Dorsal plate arrangements: 2+1, P-3 distal margin with denticles, P-4 stocky ............
.................................... Torrenticola taiwanicus Pešić, Semenchenko, Chatterjee, Yam, Chan, 2011

37. Posterior suture line of Cx-IV indistinct ....................................................41
— Posterior suture line of Cx-IV distinct ....................................................38

38. P-4 with three ventral extensions ............ Torrenticola triextensio Gu, Jia, Jin & Guo, 2020
— P-4 with two ventral extensions ....................................................39

39. Cx-I-III exceeding the anterior margin of idiosoma....................................
.................................................................... Torrenticola wuyiensis Gu & Guo, 2020
— Only Cx-I and Cx-II exceeding the anterior margin of idiosoma ............................40

40. Gnathosoma rostrum thick .................... Torrenticola neoungeri Pešić, Asadi & Smit, 2019
— Gnathosoma rostrum thin .................... Torrenticola suptilisrostrum Gu & Guo, 2020
54. P-2 and P-3 ventral setae pinnate.................. *Monattractides setivalvata* (Cook, 1967)
— P-2 and P-3 ventral setae smooth.................. *Monattractides sichuanensis* Gu & Guo, 2020

55. The tip of Cx-I with a long elongated cuticular extension .................................................... *Monattractides hamatapodemus* Gu & Guo, 2019
— The tip of Cx-I with a short and small cuticular extension .................................................... *Monattractides macrocorpis* Gu & Guo, 2019

56. Gnathosomal bay V-shaped..................................................57
— Gnathosomal bay U-shaped, frontal margin of idiosoma distinctly concave, P-2 almost as long as P-4.................................................... *Monattractides stadleri* (Walter, 1924)

57. Gnathosomal ventral apodeme shorter than dorsal apodeme, and with a blunt end, P-4 longer than P-2.................................................... *Monattractides oxystomus* (K. Viets, 1935)
— Gnathosomal ventral apodeme equal in length to the dorsal apodeme, P-4 shorter than P-2 . .................................................... *Monattractides serratifera* Jin, 1997

## Notes

Two North American species, *Torrenticola semicolor* Viets, 1977 and *Torrenticola alargada* Goldschmidt, 2007, were reported as a new recorded species from China by Zhang *et al.* (2011). Will North American species be distributed in China, which is far apart? To further clarify this point, we have conducted careful identification again, and the Chinese specimens are still very similar in morphological characteristics to the two North American species, and even the length-to-width ratio of each part is consistent. Maybe, it belongs to different faunal regions. We agreed with other scholars, that those species should be tested by other methods (such as DNA barcoding), but it is currently difficult to confirm due to the lack of fresh specimens. Neither having sufficient evidence to draw up a species or establish a species is not a good decision. We still believe that they are the same species until there is new evidence to prove that they are not the same species.

## Acknowledgments

We are grateful to Zhuhui Ding (Guizhou University, P. R. China), Min Ao (Guizhou University, P. R. China) for collections of specimens.

## Funding

This research was supported by the National Natural Science Foundation of China No.32260125; Guizhou Provincial Science and Technology Projects (Qiankehe Pingtai Rencai-GCC [2022]029-1); the Talent Introduction Research Project of Guizhou University (Gui Da Ren Ji He Zi [2022]32).

## ORCID

Xin-yao Gu https://orcid.org/0000-0002-3535-631X

Hai-tao Li https://orcid.org/0009-0002-4639-7843

Dao-chao Jin https://orcid.org/0000-0003-2727-5621

Jian-jun Guo https://orcid.org/0000-0002-0523-6704
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