# Studies on the subgenus Lemienia Koenike, 1910 new to China (Acari, Hydrachnidia, Neumania)

Zhu-Hui Ding, Tian-Ci Yi, Jian-Jun Guo, Dao-Chao Jin

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Zhu-Hui Ding, Tian-Ci Yi, Jian-Jun Guo, Dao-Chao Jin. Studies on the subgenus Lemienia Koenike, 1910 new to China (Acari, Hydrachnidia, Neumania). Acarologia, 2025, 65 (2), pp.313-330. 10.24349/9qsv-3aua. hal-05059123

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# Studies on the subgenus *Lemienia* Koenike, 1910 new to China (Acari, *Hydrachnidia*, *Neumania*)

Zhu-Hui Ding<sup>D a</sup>, Tian-Ci Yi<sup>D b</sup>, Jian-Jun Guo<sup>D b</sup>, Dao-Chao Jin<sup>D b</sup>

## Original research

### ABSTRACT

New data on five species of water mites of the subgenus *Lemienia* Koenike, 1910, from the People's Republic of China are provided. These include two new species: *Neumania (Lemienia) quadroa sp. nov.* and *Neumania (Lemienia) flectata sp. nov.*, two new combinations: *Neumania (Lemienia) heterotaxis* Jin, 1997 **comb. nov.** and *Neumania (Lemienia) megaspina* Jin, 1997 **comb. nov.** and one new record: *Neumania (Lemienia) diversa* Savatenalinton & Smit, 2017.

**Keywords** Unionicolidae; taxonomy; new species; new records; new combinations

**Zoobank** http://zoobank.org/8E58FEED-EA12-446E-8084-5BCF700A5551

## Introduction

The genus *Neumania* has worldwide distribution. Currently, 12 subgenera are recognized globally (Smit 2020). Although *Neumania* is a large genus, only 30 species across three subgenera have been documented in China to date: the nominal subgenus, *Soarella* Koenike, 1907 and *Egeoglandula* Ding *et al.*, 2023.

The *Lemienia* subgenus, a prominent subgenus within *Neumania*, ranges from the initial description of *Neumania multipora* (Daday 1900) to the recent report of *Neumania australica* Smit, 2021 from Australia. It encompasses 18 species distributed across the Afrotropical, Australian, and Oriental regions. The primary distinguishing features of this subgenus are the potential fusion of the genital field with Cx-IV and the modification of leg IV in males (Cook 1974; Smit 2020), yet this characteristic poses a challenge for identifying females. Upon examining all *Neumania* specimens in China, we observe that bisexual $V_4$ typically resides at the lateral lower position of genital field. As a result, this feature is included as a key identifying feature for this subgenus, leading to the identification of two new species, one newly recorded species, and the revision of two others, thereby filling a previous gap in the Chinese *Neumania* water mite fauna.

## Material and methods

A dip net with a diameter of 40–60 cm and a fine mesh size of 250 µm is used to collect samples by sweeping back and forth in either still water (preferably near aquatic plants) or flowing water. Subsequently, two stacked sieves (a 4 mm sieve on top and a 250 µm sieve below) are used to remove debris and impurities from the collected material. Finally, water mites are collected using a 2-mL dropper and a white tray before being transferred into 2.5-mL centrifuge tubes. The specimens are prepared for study using the methods of Jin (1997) and Gu *et al.* (2018).

Received 03 December 2023

Accepted 24 March 2025

Published 14 April 2025

Corresponding author

Dao-Chao Jin<sup>D</sup>: dcjin@gzu.edu.cn

Academic editor

Mąkol, Joanna

https://doi.org/10.24349/9qsv-3aua

ISSN 0044-586X (print)

ISSN 2107-7207 (electronic)

<figure><img src="image_2.png" /></figure>

Ding Z.-H. *et al.*

Licensed under

Creative Commons CC-BY 4.0

<footnote><sup>a</sup> Key Laboratory of Characteristic and Efficient Agricultural Plant Protection Informatization in Central Guizhou, College of Agriculture, Anshun University, Anshun, P. R. China.</footnote>

<footnote><sup>b</sup> Institute of Entomology, Guizhou Provincial Key Laboratory for Agricultural Pest Management of the Mountainous Region, Guizhou University, Guiyang 550025, P. R. China.</footnote>
All holotypes and paratypes are deposited in the Institute of Entomology, Guizhou University, Guiyang, P. R. China (GUGC) (Zhang 2018). The method and terms used follow Ding *et al.* (2019), ratios are calculated after Valdecasas (2022). The following abbreviations are used: asl = above sea level, *A*<sub>1</sub> = preantennal glandularia, *A*<sub>2</sub> = postantennal glandularia, ACG = anterior coxal group (Cx-I + Cx-II), Cx-I–IV = coxae I–IV, *D*<sub>1</sub>–*D*<sub>4</sub> = dorsoglandularia 1–4, *C*<sub>1</sub>–*C*<sub>4</sub> = coxoglandularia 1–4, H = altitude, I-L-1–6 = first–sixth segment of the first leg, *L*<sub>1</sub>–*L*<sub>4</sub> = lateroglandularia 1–4, L = length, LA = length between anterior end of Cx-I and posterior end of posterior apodeme of ACG, LP = length between anterior margin of Cx-III and posterior end of posterior apodeme of Cx-IV, *O*<sub>1</sub> = preocularia, *O*<sub>2</sub> = postocularia, P-1–P-5 = first–fifth segment of palp, PCG = posterior coxal group (Cx-III + Cx-IV), *V*<sub>1</sub>–*V*<sub>4</sub> = ventroglandularia 1–4, W = width. All measurements are given in *µm*, measurements of palp and leg segments are of the dorsal margins. Numbers are given as male/female/deutonymph or adult/deutonymph.

## Taxonomy

**Class Arachnida Lamarck, 1801**

**Order Trombidiformes Reuter, 1909**

**Suborder Prostigmata Kramer, 1877**

**Family Unionicolidae Oudemans, 1909**

**Subfamily Pionatacinae K. Viets, 1916**

**Genus Neumania Lebert, 1879**

**Subgenus Lemienia Koenike, 1910**

**Diagnosis** — Integument smooth, idiosoma soft, without dorsal and ventral shields, but sometimes male well-sclerotized, all glandularia normal. Female with single pair of genital plates, pregenital and postgenital sclerites all away from the genital plates, male genital field fused with Cx-IV occasionally. *V*<sub>4</sub> usually located on the lower side of the genital field, sometimes fused with the male genital field. Palp typically five-segmented. Leg IV sexually dimorphic, IV-L-5 sometimes with concavity, and IV-L-6 always curved and arched in male.

**Habitat** — Slow flowing water, standing waters.

**Distribution** — The Afrotropical, Palaearctic, Australian and Oriental regions.

**Remarks** — This subgenus was discovered in China for the first time, distributed across Shandong, Anhui, Hainan, and other regions, spanning the Palearctic and Oriental regions. The subgenus *Lemienia* is characterized solely by the bowed IV-leg-6 in males. Additionally, the arrangement of setae along the ventral margin of this segment is unique within the subgenus (Smit 2020). However, distinguishing females is particularly challenging, especially with the nominate subgenus *Neumania*, which appears very similar. We observed that the key difference lies in the positioning of the glandularia *V*<sub>4</sub>: in the subgenus *Lemienia*, these glandularia are primarily located on the lower side of the genital field, whereas in the subgenus *Neumania*, they are positioned upper side of the genital field.

**Neumania (Lemienia) heterotaxis Jin, 1997 comb. nov.**

(Figure 1)

*Neumania (Neumania) heterotaxis* Jin, 1997: 122

**Diagnosis** — Idiosoma soft, dorsum with a pair of small dorsalia, suture line between Cx-III/IV incomplete, female genital field with 13 pairs of acetabula, *V*<sub>4</sub> located posterolateral to the genital field. P-3 with two asymmetric dorsal setae, P-4 with two well-separated ventral setae and a distal peg-like seta. Ventral apodeme of gnathosoma slightly longer than dorsal apodeme.
<figure><img src="image_3.png" /><figcaption>**Figure 1** *Neumania (Lemienia) heterotaxis* (Female A-F): A-I-L-1-6; B-II-L-1-6; C-III-L-1-6; D-IV-L-1-6; E-Palp; F-Genital field; Scale bars = 100 µm.</figcaption></figure>

**Material examined** — Holotype: ♀; 34-1, Wanding County, Yunnan Province, China; 24°5'4"N, 98°4'16"E, 836 m a.s.l.; 31 May 1992; Dao-Chao Jin leg.; GUGC.

**Description** — female: Integument smooth and soft, dorsum with a pair of round dorsalia, *L*₄ inflated. Coxal plates in four groups, surface lightly reticulated, interspace between Cx-II and Cx-III wider, posterior apodemes of ACG extending to half of Cx-IV, posterior projection of Cx-IV somewhat straight and blurry. Genital field with 13 pairs of acetabula, length of gonopore longer than genital plates (Figure 1F), *V*₄ inflated located posterolateral to the genital
field, excretory pore located terminally.

Palp typically five-segmented, P-1 without seta, P-2 with three dorsal setae, P-3 with a dorsodistal seta much longer than the mediolateral one, P-4 with two small setal tubercles each bearing one seta and a peg like seta inserting on its well-developed base, with a distolateral long fine seta, P-5 claws distinctly trigeminal (Figure 1E). Ventral apodeme of gnathosoma slightly longer than dorsal apodeme. Chelicera with a well-developed claw. II-L-4, -5 ventrodistally each with a swimming setae. III-L-3, -4, -5 distally with one, five, three swimming setae, respectively. IV-L-3, -4, -5 with three, five, three swimming setae, respectively. IV-L-6 ventrally with two serrate setae (Figure 1 A–D).

**Measurements** — Female (n = 1): Idiosoma L 748, W 600 (L/W ratio 1.47); genital plates L 117, W 93 (L/W ratio 1.26). LA 383; LP 235; medial distance between Cx-IV 113. Gnathosoma L 134. Chelicera L 139. Lengths of the palp segments (P-1–5): 24, 100, 52, 96, 35. Lengths of I-L-1–6: 77, 125, 145, 222, 211, 170. Lengths of II-L-1–6: 80, 117, 147, 230, 225, 173. Lengths of III-L-1–6: 79, 98, 108, 181, 200, 193. Lengths of IV-L-1–6: 87, 118, 159, 218, 236, 212.

Male: Unknown.

**Remarks** — *Neumania heterotaxis* was originally described by Jin (1997). Examination of the type specimens from Jin's collection revealed that *V*₄ is positioned posterolateral to the genital field, and *V*₂ is not enlarged—distinctive features of the subgenus *Lemienia*. Furthermore, the distribution of swimming setae on leg IV matches perfectly with those of *Lemienia*, confirming that this species belongs to this subgenus.

**Distribution** — China (Yunnan Province), rice fields.

**Neumania (Lemienia) megaspina Jin, 1997 comb. nov.**

(Figure 2)

*Neumania* (*Neumania*) megaspina Jin, 1997: 124

**Diagnosis** — Idiosoma soft, dorsum with two pairs of small dorsalia, suture line between Cx-III/IV complete, female genital field with 19–21 pairs of acetabula, *V*₄ located posterolateral to the genital field. P-3 distally with two asymmetric dorsal setae, P-4 with two well-separated ventral setae and a triangular sclerotized extension extending to half of P-5. Ventral apodeme of gnathosoma much longer than dorsal apodeme.

**Material examined** — Holotype: ♀; 47-2, Huaxi District, Guiyang City, Guizhou Province, China; 26°27′39″N, 106°41′3″E, 1102 m a.s.l.; 25 Apr. 1991; Dao-Chao Jin leg.; GUGC.

**Description** — Female: Integument smooth and soft, dorsum with two pairs of oval dorsalia, *L*₄ inflated. Coxal plates in four groups, surface lightly reticulated, interspace between Cx-II and Cx-III wider, posterior apodemes of ACG extending to one-third of Cx-IV, posterior projection of Cx-IV somewhat hook-like. Genital field with 19–21 pairs of acetabula, length of gonopore longer than genital plates (Figure 2E), *V*₄ inflated located posterolateral to the genital field.

Palp five-segmented, P-1 with one dorsal seta, P-2 with three dorsal setae, the proximal twos slightly longer, P-4 with two well-separated small setal tubercles each bearing one seta and a peg like seta inserting on its base, distally with a triangular sclerotized extension extending to half of P-5 (Figure 2F). Ventral apodeme of gnathosoma much longer than dorsal apodeme, the surface of ventral apodeme wide and curved upwards, with a small protrusion at the base, the dorsal apodeme slender and upswept. II-L-4, -5 ventrodistally each with a swimming setae. III-L-3, -4, -5 distally with one, five, three swimming setae, respectively. IV-L-3, -4, -5 with two, five, three swimming setae, respectively. IV-L-6 ventrally with one serrate seta (Figure 2A–D).

**Measurements** — Female (n = 1): Idiosoma L 791, W 670 (L/W ratio 1.47); genital plates L 137, W 98 (L/W ratio 1.40); gonopore L 197. LA 365; LP 261; medial distance between Cx-IV 52. Gnathosoma L 153. Chelicera L 153. Lengths of the palp segments (P-1–5): 29, 104, 48, 113, 47. Lengths of I-L-1–6: 75, 109, 121, 181, 186, 179. Lengths of II-L-1–6 (II-L-2–6):
<figure><img src="image_4.png" /><figcaption>**Figure 2** *Neumania (Lemienia) megaspina* (Female A–F): A – I-L-1–6; B – II-L-2–6; C – III-L-2–6; D – IV-L-1–6; E – Palp; F – Genital field; Scale bars = 100 µm.</figcaption></figure>

110, 114, 187, 197, 169. Lengths of III-L-1-6: 63, 87, 92, 148, 176,163. Lengths of IV-L-1-6: 101, 108, 130, 194, 219, 196.

Male: Unknown.

**Remarks** — This species, described by Jin (1997), was initially classified under the
subgenus *Neumania*. Although only female specimens were collected, the position of *V*₄ posterolateral to the genital field and normal *V*₂ clearly indicate its placement in the subgenus *Lemienia*. Certain characteristics of this species resemble those of *N. quadroa* sp. nov., which is found in Shandong and Anhui provinces. However, *N. quadroa* differs in that its P-4 extends from the dorsal side, whereas in this species, it extends from the ventral side. Additionally, *N. quadroa* has a greater number of acetabula.

**Distribution** — China (Guizhou Province), stream.

**Neumania (Lemienia) diversa Savatenalinton & Smit, 2017, new to China**

(Figures 3–5)

**Diagnosis** — Idiosoma soft, densely with fine setae, dorsum with two pairs of small oval dorsalia. The tubercle at the subterminal of the P-4 ventral surface larger than the middle one. 12–22 pairs acetabula mostly or entirely attached to the ventral integument, male pregenital sclerite U-shaped, IV-L-5, 6 slightly deformed in male.

**Material examined** — 1♂, 1♀; Diaoluo Mountain National Nature Reserve, China; 18°42'73"N, 109°50'26"E, 578 m a.s.l.; 30 Jan. 2018; Zhu-Hui Ding and Xin-Yao Gu leg.; GUGC.

**Description** — Male: Idiosoma soft, covered with fine setae, dorsum with two pairs of quite blurry dorsalia, *D*₃ without glandular sclerites, excretory pore terminally located, with a well-developed tubercle (Figure 3A). Coxal plates in four groups, interspace between Cx-II and Cx-III narrow, suture line between Cx-III/IV complete, posterior apodemes of ACG extending to three-fourths of Cx-IV, posterior projection of Cx-IV long and straight (Figure 3B). Genital field wider than long, with 12–22 pairs of acetabula, few acetabula situated on small genital palates, the rest on the soft venter; genital field with 11–12 pairs of genital setae, excretory pore V-shaped, located subterminally (Figure 4F).

Palp typically five-segmented. P-1 with one dorsal seta, P-2 with three dorsal setae, P-4 with two ventral setae situated on tubercles, and the subterminal one larger than the middle one, along with one peg-like seta inserted at its well-developed base. (Figure 4A). Ventral apodeme of gnathosoma slightly longer than dorsal apodeme, the apex of the ventral projection curves upward to form a right angle (Figure 4C). Chelicera with a well-developed claw (Figure 4E). II-L-4, 5 ventrodistally with one short swimming seta each (Figure 5B). III-L-3, -4, -5 distally with one, ten, two swimming setae, respectively (Figure 5C). IV-L-3, -4, -5 distally with five, ten, six swimming setae, respectively, and IV-L-5 tapers gradually. IV-L-6 light curving, ventrally with four serrate setae (Figure 5D).

**Measurements** — Male (n = 1): Idiosoma L 673, W 531 (L/W ratio 1.27); genital plates L 157, W 244 (L/W ratio 0.64). LA 455; LP 291; medial distance between Cx-IV 18. Gnathosoma L 111. Chelicera L 189. Ejaculatory complex L: 123. Lengths of the palp segments (P-1–5): 37, 129, 72, 126, 49. Lengths of I-L-1–6: 101, 161, 187, 291, 365, 256. Lengths of II-L-1–6: 100, 159, 194, 320, 373, 279. Lengths of III-L-1–6: 101, 133, 161, 259, 300, 273. Lengths of IV-L-1–6: 145, 150, 223, 300, 369, 287.

Female: Interspace between Cx-II and Cx-III wide, the mid-edge spacing of Cx-IV broad, and the posterior projection of Cx-IV bends outward, resembling the shape of the Arabic numeral “3” (Figure 3D). Genital field with 10–11 pairs of free genital setae and 26–28 pairs of acetabula (Figure 4G). IV-L-3, -4, -5 distally with five, ten, five long swimming setae, respectively (Figure 5E).

**Measurements** — Female (n = 1): Idiosoma L 1301, W 969 (L/W ratio 1.34); genital plates L 192, W 108 (L/W ratio 1.78); gonopore L 263. LA 562; LP 380; medial distance between Cx-IV 90. Gnathosoma L 130. Chelicera L 198. Lengths of the palp segments (P-1–5): 43, 138, 71, 128, 55. Lengths of I-L-1–6: 115, 177, 229, 345, 376, 239. Lengths of II-L-1–6 (II-L-2–6): 111, 170, 211, 352, 370, 249. Lengths of III-L-1–6: 103, 135, 173, 300, 340, 290. Lengths of IV-L-1–6: 135, 174, 252, 333, 384, 336.

**Remarks** — This species was first described by Savatenalinton and Smit (2017) in Thailand. The Thai specimens lack small dorsal plates, possibly because the plates are too indistinct; and
<figure><img src="image_5.png" /><figcaption>**Figure 3** *Neumania (Lemienia) diversa* (Male A, B; Female C, D): A, C – Idiosoma, dorsal view; B, D – Idiosoma, ventral view; Scale bars = 100 µm.</figcaption></figure>
<figure><img src="image_6.png" /><figcaption>**Figure 4** *Neumania (Lemienia) diversa* (Male A, C–F; Female B, G): A, B – Palp; C – Gnathosoma; D – Ejaculatory Complex; E – Chelicera; F, G – Genital field; Scale bars = 100 µm.</figcaption></figure>
<figure><img src="image_7.png" /><figcaption>**Figure 5** *Neumania (Lemienia) diversa* (Male A–D; Female E): A – I-L-1–6; B – II-L-1–6; C – III-L-1–6; D – IV-L-1–6; E – IV-L-5, 6; Scale bars = 100 µm.</figcaption></figure>

the other features are nearly identical. While the curvature of IV-L-6 in males is not particularly pronounced, the arrangement of ventral setae on the anterior part of IV-L-6 conforms to the typical features of the subgenus *Lemienia*.

**Distribution** — China (Hainan Province); Thailand, pond.

**Neumania (Lemienia) quadroa Ding & Jin sp. nov.**

Zoobank: AD05FA7F-74A7-46DD-9B5E-979EF27FAA81
(Figures 6–8)

**Diagnosis** — Male idiosoma moderate sclerotization, with a dorsal plate. Female with weak sclerotization. Genital field with 8–15 pairs of acetabula. P-4 distally with one dagger-shaped sclerotized extension. IV-L-6 of male curved.

**Etymology** — The specific name is from Latin word: “quadro-” means quadrate, the name of this new species is derived from the quadrate idiosoma of the male.

**Material examined** — Holotype: ♂; Kunyushan National Nature Reserve, Shandong Province, China; 37°17′49″N, 121°45′58″E, 84 m a.s.l.; 20 Jul. 2017; Xin-Yao Gu and Zhu-Hui Ding leg.; GUGC. Paratypes: 1♂, 5♀♀; the same data as the holotype; GUGC. 2♂♂, 2♀♀; Mount Huangshan Town, Mount Huangshan City, Anhui Province; 30°9′25″N, 118°8′0″E, 768 m a.s.l.; 21 Jun. 2002; Tian-Ci Yi leg.; GUGC.

**Description** — Male: Idiosoma moderately sclerotized, dorsum with two pairs of dorsalia, a complete dorsal plate located beneath the boundary of the anterior dorsalia, surface lightly reticulated (Figure 6A), Cx-II and Cx-III almost connected, suture line between Cx-III/IV partly incomplete, posterior apodemes of ACG extending to one-fourth of Cx-IV, posterior projection of Cx-IV somewhat hook-shaped. Cx-IV connected in medial line (Figure 6B). Genital field located terminally, anterior margin connected with posterior margin of Cx-IV, each with 8–12 acetabula. *V*<sub>4</sub>, *V*<sub>1</sub> and excretory pore all incorporated into genital field (Figure 7E).

Palp five-segmented. P-1 distally with one dorsal seta, P-4 features two small ventral projections, located close to each other, each bearing a single seta, along with one ventrodistal peg-like seta situated on a tubercle, lateromedially with a cluster of fine bristles, distally with a dagger-shaped sclerotized extension that extends beyond P-5 (Figure 7A). Gnathosoma pincer-shaped (Figure 7C). Chelicera with a well-developed claw (Figure 7D). II-L-4, 5 ventrodistally each with one swimming seta, respectively (Figure 8B). III-L-3, -4, -5 distally with one, four, three swimming setae, respectively (Figure 8C). IV-L-3, -4, -5 distally with two, five, three swimming setae, respectively. IV-L-5 with three blunt setae and with a distinct concavity near the subterminal region. IV-L-6 curved, with a peg-like projection at the bend, which bears a single seta, IV-L-6 shorter than IV-L-5. (Figure 8D).

**Measurements** — Male (n = 4): Idiosoma L 396–404, W 293–308 (L/W ratio 1.31–1.35) ; genital field L 66–74, W 194–195 (L/W ratio 0.34–0.38). LA 245–250; LP 175–196; medial distance between Cx-IV 0–1. Chelicera L 97–107. Gnathosoma L 89–113. Lengths of the palp segments (P-1-5): 21–25, 81–83, 20–25, 64–66, 42–44. Lengths of I-L-1-6: 52–56, 80–81, 84–89, 132–139, 148–150, 152–155. Lengths of II-L-1-6: 55–58, 77–81, 85–91, 138–141, 158–164, 159–161. Lengths of III-L-1-6: 56–58, 84–68, 65–66, 103–106, 123–125, 115–117. Lengths of IV-L-1-6: 80–90, 83–85, 95–100, 139–145, 150–160, 99–101.

Female: Significant differences exist compared to male. Idiosoma elliptical, with weak sclerotization (Figure 6C), interspace between Cx-II and Cx-III wide, the mid-edge spacing of Cx-IV broad, posterior apodemes of ACG extending to one-third of Cx-IV (Figure 6D). Genital field with a pair of genital plates, each with 12–15 acetabula (Figure 7E). P-4 lacks a cluster of fine bristles, and distal sclerotized extension reaches halfway along P-5 (Figure 7B). Both IV-L-5 and IV-L-6 appear normal, with IV-L-6 being approximately equal in length to IV-L-5 (Figure 8F).

**Measurements** — Female (n = 7): Idiosoma L 598–606, W 478–494 (L/W ratio 1.22–1.25); genital field L 86–90, W 65–76 (L/W ratio 1.18–1.32). Gonopore L 130–136. LA 329–347; LP 217–223; medial distance between Cx-IV 32–38. Chelicera L 120–127. Gnathosoma L 84–87. Lengths of the palp segments (P-1-5): 25–30, 86–99, 36–41, 82–89, 44–50. Lengths of I-L-1-6: 53–60, 90–102, 98–103, 158–163, 166–169, 159–161. Lengths of II-L-1-6: 64–67, 94–100, 107–114, 160–180, 178–188, 162–169. Lengths of III-L-1-6: 63–70, 80–82, 79–83, 136–138, 153–159, 153–168. Lengths of IV-L-1-6: 80–92, 97–102, 115–120, 166–170, 192–205, 185–189.

**Remarks** — The dorsal plate of this new species, delineated by the anterior dorsalia, is an exceptionally rare feature within the genus *Neumania*. This unique feature sets the species apart from others in the subgenus *Lemienia*. Additionally, the dagger-shaped sclerotized
<figure><img src="image_8.png" /><figcaption>**Figure 6** *Neumania (Lemienia) quadroa* sp. nov. (Male A, B; Female C, D): A, C – Idiosoma, dorsal view; B, D – Idiosoma, ventral view; Scale bars = 100 µm.</figcaption></figure>
<figure><img src="image_9.png" /><figcaption>**Figure 7** *Neumania (Lemienia) quadroa* sp. nov. (Male A, C-E; Female B, F): A, B – Palp; C – Gnathosoma; D – Chelicera; E, F – Genital field; Scale bars = 100 µm.</figcaption></figure>

extension at the extremity of P-4, which extends to or even overlaps P-5, is another uncommon characteristic. To date, the sclerotized extension structure of P-4 has only been observed in *N. megaspina*. However, in *N. megaspina*, the extension is directed from below, whereas in this species, it extends from above.

**Distribution** — China (Shandong and Anhui Province), pond.
<figure><img src="image_10.png" /><figcaption>**Figure 8** *Neumania (Lemienia) quadroa* sp. nov. (Male A–D; Female E, F): A – I-L-1–6; B – II-L-1–6; C – III-L-1–6; D – IV-L-1–6; E – I-L-5; F – IV-L-5, 6; Scale bars = 100 µm.</figcaption></figure>

**Neumania (Lemienia) flectata** Ding & Jin sp. nov.

Zoobank: 8A4A5A99-AB42-4F71-B50D-D1B8B27ED02A

(Figures 9–11)

**Diagnosis** — Idiosoma weakly sclerotized. P-4 bears two thin setae ventrally, positioned on its tubercles. Suture line between Cx-III/IV complete, male genital field contains 8–9 pairs of acetabula, along with *V*₁, *V*₃, *V*₄, *C*₄, excretory pore and posterior margins of Cx-IV. IV-L-5 without swimming seta in males.
<figure><img src="image_11.png" /><figcaption>**Figure 9** *Neumania (Lemienia) flectata* sp. nov. (Male A, B; Female C, D): A, C – Idiosoma, dorsal view; B, D – Idiosoma, ventral view; Scale bars = 100 µm.</figcaption></figure>
**Etymology** — The specific name is from Latin word: “flect-” means bend, the name of this new species is derived from IV-L-6 curved in males.

**Material examined** — Holotype: ♂; Diaoluo Mountain National Nature Reserve, Hainan Province, China; 18°42'73"N, 109°50'26"E, 578 m a.s.l.; 30 Jan. 2018; Zhu-Hui Ding and Xin-Yao Gu leg.; GUGC. Paratypes: 3♂♂, 4♀♀; the same data as the holotype; GUGC.

**Description** — Male: Idiosoma weakly sclerotized, dorsum with two pairs of irregular dorsalia (Figure 9A). Coxal plates in four groups, surface lightly reticulated, interspace between Cx-II and Cx-III narrow, suture line between Cx-III/IV complete, posterior apodemes of ACG extending to half of Cx-IV, posterior projection of Cx-IV forming the shape of a mountain mound (Figure 9B). Genital plates wider than long, with 8–9 pairs of acetabula, along with *V*₁, *V*₃, *V*₄, *C*₄, excretory pore and posterior margins of Cx-IV (Figure 10E).

Palp five-segmented. P-1 slender, mediodorsal with one seta, P-4 with two ventral projections, each bearing one seta, and one ventrodistal peg-like seta on a tubercle, the claws of P-5 distinctly trifurcated (Figure 10A). Ventral apodeme of gnathosoma almost as long as dorsal apodeme (Figure 10C). Chelicera with a well-developed claw (Figure 10D). I-L-4, -5 ventrodistally each with one short swimming seta (Figure 11A). II-L-5 ventrodistally with one swimming seta (Figure 11B). III-L-3, -4, -5 distally with one, three, three swimming setae, respectively (Figure 11C). IV-L-3, -4, -5 distally with three, five, zero swimming setae, respectively. IV-L-5 subterminal part has no depression but significantly narrowed, IV-L-6 curved and much shorter than IV-L-5 (Figure 11D).

**Measurements** — Male (n = 4): Idiosoma L 436–450, W 378–405 (L/W ratio 1.11–1.15); genital field L 93–107, W 156–171 (L/W ratio 0.59–0.63). LA 287–290; LP 202–210; medial distance between Cx-IV 0–4. Chelicera L 99–109. Gnathosoma L 73–80. Lengths of the palp segments (P-1-5): 23–24, 75–77, 41–43, 73–77, 29–32. Lengths of I-L-1-6: 57–60, 91–94, 103–107, 138–145, 170–174, 168–177. Lengths of II-L-1-6: 62–64, 84–86, 112–115, 151–155, 179–186, 147–150. Lengths of III-L-1-6: 58–63, 69–70, 89–91, 114–116, 147–148, 132–135. Lengths of IV-L-1-6: 62–65, 88–91, 107–112, 145–147, 197–202, 138–140.

**Female:** Significant differences exist compared to male (Figure 9C), interspace between Cx-II and Cx-III wide, the mid-edge spacing of Cx-IV broad, posterior apodemes of ACG extending to one-fourth of Cx-IV, posterior projection of Cx-IV hook-like (Figure 9D). Genital field contains 8–10 pairs of acetabula and 7 pairs of genital setae, five of which located on the genital plate, while two outside the plate (Figure 10F). P-3 and P-4 both without lateral fine seta (Figure 10B). IV-L-3, -4, -5 distally with three, five, three swimming setae, respectively. Both IV-L-5 and IV-L-6 appear normal, IV-L-6 with two ventral setae (Figure 11E).

**Measurements** — Female (n = 4): Idiosoma L 706–740, W 582–633 (L/W ratio 1.16–1.21); genital field L 78–83, W 69–71 (L/W ratio 1.13–1.16); gonopore L 136–160. LA 378–395; LP 258–265; medial distance between Cx-IV 41–54. Chelicera L 130–140. Gnathosoma L 90–99. Lengths of the palp segments (P-1-5): 27–28, 94–103, 52–54, 96–98, 36–38. Lengths of I-L-1-6: 71–74, 102–121, 141–143, 190–195, 205–206, 188–189. Lengths of II-L-1-6: 76–81, 109–118, 124–127, 174–197, 214–216, 188–190. Lengths of III-L-1-6: 72–77, 82–87, 99–101, 149–158, 199–201, 171–204. Lengths of IV-L-1-6: 79–84, 104–112, 130–132, 182–184, 235–236, 204–213.

**Remarks** — The male genital field of the new species is located terminally. Its anterior margin connects to the center of the posterior margin of Cx-IV, while its posterior margin is fused with the excretory pore and bilateral *V*₁. The enlarged *V*₄ is fused with the genital plate through its lateral wing. The *C*₄ healing from the anterior margin, and *V*₃ connects to the anterior edge of the plate through a corridor-shaped, secondary-sclerotized edge. It is evident that the above features are rare in the entire species of the subgenus *Lemienia*, thus they can serve as distinguishing features. Although *Neumania* (*Lemienia*) *maharashtris* Cook, 1967 also exhibits a similar structure, the following features can clearly distinguish it from the new species: male IV-L-5 of this species bears swimming setae, the suture line between Cx-III/IV is incomplete, and the dorsal seta on P-1 is absent.

**Distribution** — China (Hainan Province), marsh.
<figure><img src="image_12.png" /><figcaption>**Figure 10** *Neumania (Lemienia) flectata* sp. nov. (Male A, C-E; Female B, F): A, B - Palp; C - Gnathosoma; D - Chelicera; E, F - Genital field; Scale bars = 100 µm.</figcaption></figure>

**Acknowledgments**

The authors are grateful to Hai-Tao Li, Xin-Yao Gu for collecting specimens, this research was supported by Guizhou natural science research projects (Qianjiaoji [2022]052) and Anshun
<figure><img src="image_13.png" /><figcaption>**Figure 11** *Neumania (Lemienia) flectata* sp. nov. (Male A–D; Female E): A – I-L-1-6; B – II-L-1-6; C – III-L-1-6; D – III-L-1-5, 6; E – IV-L-3-6; Scale bars = 100 µm.</figcaption></figure>

University doctoral fund project (asxybsjj202213).

ORCID

Zhu-Hui Ding ID https://orcid.org/0009-0006-2732-1535

Tian-Ci Yi ID https://orcid.org/0000-0002-9953-3709
Jian-Jun Guo ID https://orcid.org/0000-0002-0523-6704

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

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