Hygrobates intermedius, Goldschmidt & Nishikawa & Hiruta & Shimano, 2020

Goldschmidt, Tom, Nishikawa, Kanto, Hiruta, Shimpei F. & Shimano, Satoshi, 2020, Description of three new water mite species of Hygrobates Koch, 1837 (Lurchibates Goldschmidt & Fu, 2011) (Acari, Hydrachnidia, Hygrobatidae), parasitic in newts of the genera Paramesotriton and Pachytriton (Amphibia, Caudata, Salamandridae) from China, Zootaxa 4768 (1), pp. 25-42 : 27-31

Hygrobates intermedius sp. nov. Goldschmidt, Nishikawa & Shimano

Material examined: Holotype male, slide mounted in glycerine jelly, preparation no. CIB INV 0001, parasitic on Paramesotriton qixilingensis ( Amphibia, Caudata , Salamandridae ): newt was collected in China, Jiangxi Province, Yongxin County, Shenyuan Station; N 26° 46’ 25.2’’, E 114° 10’ 53.7’’, 375m a.s.l. on March 26th 2014, preserved in 70% Ethanol; mite was attached to the fore- or hindlimb of the newt ( CIB 140328).

Paratypes: one female CIB INV 0002 from fore- or hindlimb of the newt ( CIB 140328), one male CIB INV 0003 from mouth cavity, limbs, or lateral body of the newt ( CIB 140327, 29–31, or 33)—newts data are the same as holotype’s host.

Distribution: All three specimens of H. intermedius sp. nov. have been recorded on Paramesotriton qixilingensis . The type locality of the newt (Qixiling Nature Reserve, Mount Shenyuan, Yongxin County, Jiangxi, China) is the only known collecting site for both, the newt and the mite.

Derivatio nominis: intermedius (lat.)—located between, intermediate; named for the fact that most characters of the new species are somehow intermediate between all other species of Lurchibates .

Diagnosis: Characters of the subgenus Lurchibates ; anterior coxal group relatively narrow posteriorly (compared to most other species of the subgenus), posterior coxal group triangular; male genital field rounded dumbbell-shaped, regularly surrounded by many setae; female genital plates crescent-shaped, relatively short (flanking only posterior 2/3 of genital opening); palp relatively long and slender, P-3 ventrally with dense field of denticles, P-4 long, straight, proximo-ventral extension of P-5 blunt, cone-shaped; cheliceral claw relatively straight, long and slender.

Description, Male (n = 2): Idiosoma rounded-oval, L/W ratio 1.34 (1.25), L/W 900 (900)/672 (720); fused anterior coxae of both sides slightly elongate (Cx-I + II L/W 294 (310)/462 (439)), medio-posterior margin straight to slightly convex, laterally extended by secondary sclerotization (swallow-tail shaped, lateral tips reaching under medial margin of Cx-III/IV), Cx-I basal W 160 (150); gnathosoma broad, posteriorly only slightly 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 288 (283)/270 (270), laterally closely approached to anterior plates (Cx- II postero-laterally overlapping antero-lateral corners of Cx-III), medially clearly diverging from anterior coxae, nearly regularly triangular in shape, small, rounded medial edges formed by Cx-IV only, Cx-IV short and broad, nearly triangular, posterior margin straight to slightly convex, medially pointing towards anterior, lateral margin straight to convex ( Fig. 1 ); genital field dumbbell-shaped (Ac-1 and Ac-3 anteriorly and especially posteriorly extending beyond pre- and postgenitale), outline broad-oval (anteriorly and laterally rounded, posteriorly straight), pregenitale nose-shaped, anteriorly extended, genital opening relatively small, elongated egg-shaped, genital field L/W 198 (204)/ 348 (384); Ac-1 elongated oval, Ac-2 irregularly oval, Ac-3 elongated triangular, anteriorly pointed (L/W Ac-1, 104 (100)/54 (51), Ac-2, 118 (107)/51 (54), Ac-3, 113 (116)/77 (64)), 25–28 setae on each side of plate, arranged at the margins of the genital plate ( Fig. 1 ); excretory pore slit-shaped; genital skeleton L/W 223 (252)/183 (181), compact (L/W ratio 1.22 (1.39)), shape typical for the subgenus, brachia distalia long, strong, laterally strongly 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, 252 (248)/54 (48), I-leg-6, 216 (199)/48 (50); II-leg-5, 264 (277)/54 (54), II-leg-6, 228 (240)/48 (49); III-leg-5, 294 (259)/56 (53), III-leg-6, 252 (222)/52 (48); IV-leg-3, 180 (175)/68 (66), IV-leg-5, 300 (306)/49 (54), IV-leg-6, 282 (270)/43 (48); chelicerae very strong, with a relatively short, high basal segment and long basal groove; cheliceral claws very large, slender, sharply pointed, dorsal margin in the distal third with strong serration that continues proximally in a lateral serration, medially and laterally striated ( Figs. 7, 8 ); palps strong ( Figs. 9, 10 ), ventral margin of P-2 slightly concave, antero-ventral margin rounded, without denticles, P-3 ventrally straight with a field of pointed denticles in the distal half, occasionally the distal two thirds, P-4 relatively long and straight, distally slightly curved, with a pair of ventral setae in the distal third; P-5 with a well developed, blunt cone-shaped ventro-proximal projection, dorsodistally P-5 bears one compact, denticle-like distal claw and ventro-distally a pair of similar large, strong, pointed, slightly curved claws; mouthpart measurements: chelicera total L 408 (394), maximum H 102 (96), L/H ratio 4.0 (4.1), basal segment L 259 (244), claw L 198 (190), basal segment/claw ratio 1.3 (1.3); curvation of cheliceral claw 21° (20°), palp total L 486 (493), L/H P-1, 47 (45)/63 (68), P-2, 129 (134)/81 (80), P-3, 94 (94)/75 (75), P-4, 169 (173)/56 (56), P-5, 47 (47)/45 (47).

Description, Female (n = 1): Idiosoma similar to male, much larger, L/W 1824/1464, and more rounded (L/W ratio 1.25); unpaired anterior coxal group slightly more compact, basally broader than in males (Cx-I + II L/W 408/589), basal width Cx-I 211; medio- and latero-posterior margin extended by secondary sclerotization, Cx-I latero-posteriorly with apodemes similar to those in males, however more hook-shaped; gnathosoma broadly fused with the posterior part of the first coxae, lateral margins straight, nearly parallel, coxal groups further separated than in males, medially heavily diverging ( Fig. 11 ); paired posterior coxal groups well distanced from each other and from the anterior coxal group, L/W 356/320, roughly triangular in shape with medial edges only slightly diverging from longitudinal axis, postero-medial corner less pointed, medial margin formed by Cx-IV and Cx-III ( Fig. 11 ); genital field far distant from coxae, rather small, with strongly sclerotized pre- and postgenitale, genital plates well distant from each other, separated by soft integument, slightly kidney-shaped, anteriorly rounded, flanking posterior 2/3 of genital opening, total genital field L/W 312/420; acetabula irregularly-oval (L/W Ac-1, 83/54, Ac- 2, 109/54, Ac-3, 101/58); 20/22 setae arranged mainly at the anterior, posterior and lateral margins of the genital plates, two, respectively three, setae anterior to genital plates ( Fig. 11 ); legs similar to males, slightly more slender ( Figs. 12–15 ); measurements of distal leg segments: L/H I-leg-5, 276/54, I-leg-6, 276/54; II-leg-5, 294/54, II-leg-6, 257/54; III-leg-5, 324/60, III-leg-6, 282/53; IV-leg-3, 228/85, IV-leg-5, 354/60, IV-leg-6, 312/48; anterior margin of the gnathosoma by far more projecting than in males, anterior half completely separated from Cx-I ( Fig. 11 ); chelicerae similar to males, slightly more compact ( Figs. 16, 17 ); palps similar to males ( Figs. 18, 19 ); mouthpart measurements: chelicera total L 456, maximum H 126, L/H ratio 3.6, basal segment L 282, claw L 221, basal segment/claw ratio 1.3; cheliceral claw curve 21°; palp total L 550, L/H P-1, 54/78, P-2, 150/94, P-3, 110/85, P-4, 188/62, P-5, 47/49.

Figures

FIGURE 11 Hygrobates intermedius sp. nov., paratype female, ventral view of idiosoma; scale bar = 100 μm.

FIGURES 1–2. Hygrobates intermedius sp. nov., holotype male, Fig. 1. ventral view of idiosoma, Fig. 2. genital skeleton in anterior view; scale bar = 100 μm.

FIGURES 3–10. Hygrobates intermedius sp. nov., holotype male, Fig. 3. I-leg, left, Fig. 4. II-leg, left, Fig. 5. III-leg, left, Fig. 6. IV-leg, left, 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; scale bar = 100 μm.

FIGURES 12–19. Hygrobates intermedius sp. nov., paratype female, Fig. 12. I-leg, right, Fig. 13. II-leg, right, Fig. 14. III-leg, right, Fig. 15. IV-leg, right, Fig. 16. left chelicera in lateral view, Fig. 17. right chelicera in medial view, Fig. 18. left palp in lateral view, Fig. 19. right palp in medial view; scale bar = 100 μm.