Hygrobates (Lurchibates) macrochela, Goldschmidt & Nishikawa & Hiruta & Pfingstl & Jiang & Shimano, 2021

Goldschmidt, Tom, Nishikawa, Kanto, Hiruta, Shimpei F., Pfingstl, Tobias, Jiang, Jian-Ping & Shimano, Satoshi, 2021, Systematics, distribution and morphology of the newt parasitic water mites of the subgenus Lurchibates Goldschmidt & Fu, 2011 (Acari, Hydrachnidia Hygrobatidae, Hygrobates Koch, 1837), including the description of four new species and a key to all so far known species, Zootaxa 4985 (1), pp. 1-36 : 3-7

Hygrobates (Lurchibates) macrochela sp. nov. Goldschmidt, Nishikawa & Shimano

Material examined: Holotype male, slide mounted in glycerine jelly, preparation no. CIB INV 0017, parasitic on Pachytriton inexpectatus ( Amphibia, Caudata , Salamandridae ); newt was collected in China, Guangxi Zhuang Autonomous Region, Jinxiu Yao Autonomous County, Dayaoshan 24°08’1’’ N, 110°11’5.9’’ E, 1140 m a.s.l. on October 10 th 2008, preserved in 70% ethanol; mite was attached to the fingers of the newt ( CIB GX20081028).

Paratypes (as well parasitic on Pachytriton inexpectatus ): Two males ( CIB INV 0019 , 0020 ) from fingers and toes of the same newt ( CIB GX20081028 ), two females ( CIB INV 0018 ) from left hindlimb of the newt ( CIB 200712004 ) collected in China, Guangxi Zhuang Autonomous Region, Ziyuan, Maoershan 25°54’44.3’’ N, 110°27’55.8’’ E, 1651 m a.s.l. on December 12 th 2007 and ( CIB INV 0021 ) from fore- or hindlimb of the newt ( CIB GX20081003 ) collected at same locality as holotype on October 9 th 2008 .

Distribution: All specimens of H. (L.) macrochela sp. nov. were recorded on Pachytriton inexpectatus from China, Guangxi Zhuang Autonomous Region, China. The new species is at maximum limited to the same distribution as its host, which is so far known from Eastern Guizhou, southwestern and southern Hunan, extreme northwestern Guangdong, and northern and eastern Guangxi, China ( Fig. 54 ).

Derivatio nominis: macrochela ; a combination of the words macro, derived from μακρός (makrós) (Greek = large) and chela, χηλή (Greek = claw); named for the fact that the cheliceral claws of the new species are the most massive within the species of Lurchibates .

Diagnosis: Anterior coxal group basally broad (compared to most other species of the subgenus), posterior coxal group medially rounded, therefore irregular triangular; male genital field broad apple-shaped, surrounded by rather few setae; female genital plates crescent-shaped, about same length as genital opening (slightly shifted to posterior); palp relatively compact, P-3 ventrally with rather large field of denticles, covering distal half of segment, P-4 relatively short, curved, proximo-ventral extension of P-5 blunt, cone-shaped, large distal claws slightly different in size, small one slender; cheliceral claw curved, characteristically extended in distal half.

Description, Male (n = 3): Idiosoma rounded-oval, L/W ratio 1.33 (1.19–1.24), L/W 864 (624–756)/648 (504–636); fused anterior coxae of both sides slightly elongate (Cx-I + II L/W 276 (256–264)/378 (372–382), ratio 0.73 (0.67–0.71)), medio-posterior margin convex, postero-laterally extended by secondary sclerotization (lateral tips small, not reaching medial margin of Cx-III/IV), Cx-I basal broad, W 155 (157–162), Cx-I L/basal W 1.78 (1.62–1.63); gnathosoma broad, posteriorly clearly converging, widely fused with the posterior part of the first coxae, anterior margin of gnathosoma curved ( Fig. 1 ); posterior coxal groups (Cx-III + IV of one side) L/W 216 (229–233)/204 (168–199), laterally closely approached to anterior plates (Cx-II postero-laterally overlapping antero-lateral corners of Cx-III), medially clearly diverging from anterior coxae, medial edges rounded, pointing towards anterior, formed by Cx-IV only, antero-medial and posterior margin irregular curved, Cx-III antero-laterally extended, lateral margin straight, Cx-IV compact, lateral margin convex ( Fig. 1 ); genital field broad apple-shaped (genital plates and pre- and postgenitale seamless fused), anterior with small indentations between fused acetabular plates and pregenitale, posterior with deep, broad rhombic indentation (Ac-2 and Ac-3 posteriorly far extending beyond postgenitale), genital opening elongated-oval, margins nearly straight, genital field L/W 174 (170–180)/246 (240–256); acetabula irregular oval-drop-shaped (Ac-3 kidney-shaped), L/W Ac-1 70 (64–73)/34 (37–40), Ac-2 86 (83–89)/33 (31–34), Ac-3 92 (72–80)/42 (39–42), 17 (19–22) setae (of different size) on each side of plate, irregularly arranged at the margins of the genital plate ( Fig. 1 ); excretory pore slit-shaped; genital skeleton L/W (200–207)/(143–153), compact (L/W ratio (1.35–1.39), shape typical for the subgenus, brachia distalia strong, slightly curved, brachia proximalia strong, distally broadened, parallel to longitudinal axis ( Fig. 2 ); all legs slender, bearing many heavy setae ( Figs. 3–6 ); measurements (L/H) of distal leg segments: I-leg-5 186 (198)/42 (42), I-leg-6 176 (174)/40 (40); II-leg-5 204 (211–220)/42 (44–46), II-leg-6 188 (190–192)/41 (42); III-leg-5 222 (234–240)/47 (44–48), III-leg-6 204 (210–214)/42 (36–44); IV-leg-3 152 (162–172)/65 (54–58), IV-leg-5 229 (244–246)/48 (42– 48), IV-leg-6 216 (222–224)/42 (41–42); chelicerae very strong, with a compact basal segment and short basal groove; cheliceral claws very heavy, strongly curved, sharply pointed, dorsal margin in the distal half extended, with strong serration, medially and laterally striated ( Figs. 7, 8 ); palps strong, rather compact ( Figs. 9, 10 ), dorsal margin of P-2 regularly curved, ventrally without denticles, P-3 ventrally straight with a small field of pointed denticles in the distal half, P-4 relatively short and curved, with a pair of ventral setae in the distal third, distal margin curved; P- 5 with a well developed, blunt cone-shaped ventro-distal projection, dorso-distally P-5 bearing one small, relatively slender distal claw and distally a pair of clearly different, large, strong, pointed, slightly curved claws (medial claws clearly more slender than lateral ones); mouthpart measurements: Chelicera total L 372 (378), H 108 (113–114), L/ H ratio 3.44 (3.35), basal segment L 255 (261), claw L 162 (174–176), basal segment/claw ratio 1.6 (1.5); curvation of cheliceral claw 30° (30°); palp total L 381 (411–414), L/H P-1 35 (33–35)/61 (66–67), P-2 116 (132)/92 (92–94), P-3 71 (78–80)/74 (79–81), P-4 119 (125–127)/49 (52–56), P-5 40 (42)/38 (39–40).

Description, Female (n = 2): Idiosoma similar to male, larger, L/W 882–960/600–672, less rounded (L/W ratio 1.43–1.47); unpaired anterior coxal group slightly more compact, basally broader than in males (Cx-I + II L/W 312–342/444–456, ratio 0.70–0.75), basal width Cx-I 197–202; medio- and latero-posterior margin extended by secondary sclerotization, lateral apodemes slightly larger than in males, more hook-shaped; gnathosoma broadly fused with the posterior part of the first coxae, lateral margins straight, posterior converging, anterior margin slightly convex, nearly straight; coxal groups slightly further separated than in males, laterally not overlapping ( Fig. 11 ); posterior coxal groups similar to males, L/W 258–276/216–222, roughly triangular in shape, medial margin formed by Cx-IV ( Fig. 11 ); genital field with strongly sclerotized pre- and postgenitale, genital plates well distant from each other, separated by soft integument, crescent- to kidney-shaped, anteriorly and posteriorly rounded, about as long as genital opening, however slightly shifted to posterior, total genital field L/W 204–206/306–312, individual genital plate L/W 162–169/73; Ac-1 irregularly-oval, L/W 64–66/36–39, Ac-2 elongated-oval, L/W 83–89/36–42, Ac-3 irregularly triangular, apically pointed, L/W 66–70/57–66); 18–21 setae arranged mainly at the anterior and posterior margins of the genital plates ( Fig. 11 ); egg diameter 150, number of eggs five to 53 (four ovigerous females are not part of the type series); legs similar to males, slightly more slender ( Figs. 12–15 ); measurements of distal leg segments: L/H I-leg-5 228–235/44–52, I-leg-6 180–198/32–42; II-leg-5 246–252/48–52, II-leg-6 196–210/42–43; III-leg-5 264–281/50–55, III-leg-6 228–240/42–44; IV-leg-3 186–187/62–66, IV-leg-5 274–294/42–48, IV-leg-6 246–252/42–42; chelicerae of similar shape as in males, slightly larger ( Figs. 16, 17 ); palps similar to males, slightly less compact ( Figs. 18, 19 ); mouthpart measurements: Chelicera total L 468–511, H 138–144, L/H ratio 3.4–3.6, basal segment L 315–355, claw L 212–244, basal segment/claw ratio 1.5; cheliceral claw curve 30–31°; palp total L 472–501, L/H P-1 40–42/80–82, P-2 155–165/106–115, P-3 78–89/89–96, P-4 146–157/59–66, P-5 49–52/47.

Figures

Figure 11. Hygrobates (Lurchibates) macrochela sp. nov., paratype female, ventral view of idiosoma; scale bar = 100 µm.

FIGURE 54. Map of East Asia showing the distribution of the host newts of the genera Laotriton, Pachytriton and Paramesotriton.

FIGURES 1, 2. Hygrobates (Lurchibates) macrochela sp. nov., holotype male, Fig. 1. ventral view of idiosoma; Fig. 2. genital skeleton in anterior view; scale bars = 100 µm.

FIGURES 3–10. Hygrobates (Lurchibates) macrochela sp. nov., holotype male, Fig. 3. I-leg, right; Fig. 4. II-leg, right; Fig. 5. III-leg, right; Fig. 6. IV-leg, right; Fig. 7. left chelicera in medial view; Fig. 8. right chelicera in lateral view; Fig. 9. left palp in medial view; Fig. 10. right palp in lateral view (P-1 missing); scale bar = 100 µm.

FIGURES 12–19. Hygrobates (Lurchibates) macrochela sp. nov., paratype female, Fig. 12. I-leg, right; Fig. 13. II-leg, right; Fig. 14. III-leg, right; Fig. 15. IV-leg (terminal segment separated), right; Fig. 16. left chelicera in lateral view; Fig. 17. right chelicera in medial view (slightly broken); Fig. 18. left palp in lateral view; Fig. 19. right palp in medial view; scale bar = 100 µm.