Hygrobates (Lurchibates), 2011

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 : 21-25

Key to all so far known species of Hygrobates (Lurchibates)

1 P-5 without basal cone; P-2, P-3 ventro-distally without denticles ( Fig. 58 ); male genital field compact, round ( Fig. 59 )............................................................................................ ancistrophorus 1* P-5 with basal cone; P-2 and/or P-3 ventro-distally with few to many denticles; male genital field broad-oval, dumbbell or apple-shaped......................................................................................... 2

2 Palp, especially P-4 very short, compact (palp total L 300; P-4 L 96, L/H 2.1); basal cone at P-5 rounded ( Fig. 60 ); chelicera with short basal segment (basal L/claw L 1.1) ( Fig. 61 ); anterior coxal group very broad, compact (Cx-I/II L/ W 0.60) ( Fig. 62 )............................................................................. salamandrarum (only female)

2* Palp longer (palp total L 376–658), P-4 longer, more slender (P-4 L 118–230, L/H 2.3–3.3); basal cone at P-5 cone-shaped to pointed; basal segment of chelicera relatively longer (basal L/claw L 1.2–1.6); anterior coxal group broad to slender (Cx-I/II L/ W 0.62 –0.81)....................................................................................... 3

3 Anterior coxae very slender, Cx-I basally very narrow (Cx-I L/basal W 3.0) ( Fig. 63 ); palp slender, especially P-3 (L/H 1.8) ( Fig. 64 )........................................ fragmentarius sp. nov. (only known in one fragmented specimen)

3* anterior coxae more compact, Cx-I basally relatively broad (Cx-I L/basal W 1.5 –2.8), in most species clearly broader; palp compact to slender, P-3 shorter (L/H 0.9–1.4)............................................................... 4

4 palp, especially P-4 rather compact (P-4 L/H 2.3–2.7, relative L 0.30–0.33)....................................... 5

4* palp, especially P-4 rather slender (P-4 L/H 2.8–3.3, relative L 0.34–0.39)........................................ 7

5 male genital field dumbbell-shaped, rounded ( Fig. 65 ); both sexes P-5 basal cone large pointed; large claws similar in size ( Fig. 66 ); cheliceral claw relatively straight (curve 22–24°) ( Fig. 67 )...................................... robustipalpis

5* male genital field apple-shaped ( Fig. 70 , 71); both sexes P-5 basal cone large, blunt; large distal claws of slightly different size, small one slender ( Fig. 68 ); cheliceral claw curved (angle 30–31°), distally very broad ( Fig. 69 )....................... 6

6 male genital field broad apple-shaped (L/ W 0.67 –0.75); Cx-I basally flat rounded, relatively broad (Cx-I L/basal W 1.63 –1.78), Cx-I+II broader (L/ W 0.67 –0.75) ( Fig. 70 )........................................................ macrochela

6* male genital field narrow apple-shaped (L/ W 0.77); Cx-I basally curved rounded, relatively narrow (Cx-I L/basal W 1.90), Cx- I+II narrow (L/ W 0.81) (Fig. 71)....................................................... malosimilis (only male)

The following group of species is clearly separated in the shape of the male genital field, the females are very similar. However in one species the male is unknown.

7 IV-leg-3 proximo-dorsally bearing a group of heavy, short, thick setae (2–4 in females, 4–6 in males) ( Fig. 72 ); male genital field relatively broad triangular, posterior margin straight (L/ W 0.50 –0.53) ( Fig. 73 ); palp mid-sized ( Fig. 74 ); chelicera relatively straight (curve 20°) ( Fig. 75 )................................................................ forcipifer

7* IV-leg-3 proximo-dorsally without a group of heavy setae; male genital field compact triangular ( Fig. 76 ), posterior margin straight (L/ W 0.55 –0.63) or dumbbell-shaped or broad wing-like with many setae (Figs. 80, 84); palp mid-sized to large ( Figs. 78 , 82, 86, 89); chelicera straight to curved (curve 19–26°) ( Figs. 79 , 83, 87, 90)................................... 8

8 female genital plates flanking 2/3 of genital opening ( Figs. 77 , 81); palp small in both sexes (total L 423–553), P- 4 in females shorter (L 162–188), P-2 ventro-distally always without denticles ( Figs. 78 , 82); male genital field triangular or dumbbellshaped ( Figs. 76 , 80).................................................................................. 9

8* female genital plates flanking at least 3/4 of genital opening ( Figs. 85 , 88 ); both sexes palp large (total L 530–658), P- 4 in females longer (L 204–230), P-2 ventro-distally mostly with very few denticles ( Figs. 86 , 89 ); male genital field (only known in one of the following species) broad wing-like, bearing many setae ( Fig. 84 )................................... 10

9 male genital field triangular rounded, posterior margin straight ( Fig.76 ); both sexes coxal field smaller (Cx-I+II L/W male 254– 306/372–420, female 300–348/426–504, Cx-I basal W male 127, female 150–169, Cx-III+IV L/W male 252–268/222–252, female 282–307/234–258) ( Figs. 76, 77 ); chelicera ( Fig. 79 ) and palps ( Fig. 78 ) relatively small (chelicera L male 330–384, female 402–426, palp total L male 423–456, female 461–500)............................................. aloisii

9* male genital field dumbbell-shaped, broad-oval (Fig. 80); both sexes coxal field larger (Cx-I+II L/W male 294–310/439–462, female 408/589, Cx I basal W male 150–160, female 211, Cx-III+IV L/W male 283–288/270, female 356/320) (Figs. 80, 81); chelicera (Fig. 83) and palps (Fig. 82) larger (chelicera L male 394–408, female 456, palp L 486– 493 males, 550 females)............................................................................................. intermedius

Figures

FIGURE 70. Hygrobates (Lurchibates) macrochela, male, idiosoma. FIGURE 71. Hygrobates (Lurchibates) malosimilis, male, idiosoma.

FIGURES 58, 59. Hygrobates (Lurchibates) ancistrophorus, male; Fig. 58. palp; Fig. 59. idiosoma.

FIGURES 60–62. Hygrobates (Lurchibates) salamandrarum, female, Fig. 60. palp. Fig. 61. chelicera. Fig. 62. idiosoma.

FIGURES 63, 64. Hygrobates (Lurchibates) fragmentarius, Fig. 63. gnathosoma and right anterior coxae. Fig. 64. palp.

FIGURES 65–67. Hygrobates (Lurchibates) robustipalpis, male, Fig. 65. idiosoma; Fig. 66. palp; Fig. 67. chelicera.

FIGURES 68, 69. Hygrobates (Lurchibates) macrochela, male, FIG. 68. palp; FIG. 69. chelicera.

FIGURES 72–75. Hygrobates (Lurchibates) forcipifer, male, Fig. 72. IV-leg-3; Fig. 73. idiosoma; Fig. 74. palp; Fig. 75. chelicera.

FIGURES 76–79. Hygrobates (Lurchibates) aloisii, Fig. 76. male, idiosoma; Fig. 77. female, idiosoma; Fig. 78. female, palp; Fig. 79. female, chelicera.

FIGURES 84–87. Hygrobates (Lurchibates) pilosus, Fig. 84. male, idiosoma; Fig. 85. female, idiosoma; Fig. 86. male, palp; Fig. 87. male, chelicera.

FIGURES Fig. 88–90. Hygrobates (Lurchibates) incognitus, female, FIG. 88. idiosoma; Fig. 89. palp; Fig. 90. chelicera.