Monatractides hamatapodemus Gu & Guo, 2019

Gu, Xinyao, Jin, Daochao, Yi, Tianci & Guo, Jianjun, 2019, Contributions to the knowledge of Torrenticolid water mites (Acari: Hydrachnidia) in Doupengshan, China, Zootaxa 4695 (2), pp. 101-121 : 113-116

Monatractides hamatapodemus Gu & Guo , sp. nov.

( Figs. 10–13 )

Material examined. Holotype male, No. GZ-TO-20161027, Doupengshan , Guizhou Province, China (26°23’1”N, 107°22’28”E, 1090 m a.s.l.), stream, collected by Xinyao Gu, 3. X.2016 . Paratypes, 1/1/0, No. GZ-TO-20161028– GZ-TO-20161029, same data as holotype; paratype, 0/1/0, No. GZ-TO-20161030; Doupengshan , Guizhou Prov- ince, China (26°22’50”N, 107°22’41”E, 1093 m a.s.l.), stream, collected by Xinyao Gu, 4. X.2016 .

Diagnosis. Infracapitular bay narrow and deep, U-shaped; the tip of Cx-I sharp and with an elongated cuticular extension; the line of primary sclerotization anterior to others’ regular locations; infracapitular rostrum short, apodemes curved to each other, curve and hamate.

Description. Male (n = 2): Idiosoma roundish, L/W ratio 1.3 (1.2). Dorsal plate (4+1), frontal platelets L/W ratio 1.3 (1.7), shoulder platelets L/W ratio 2.3 (2.1) ( Fig. 10A ). Infracapitular bay narrow and deep, U-shaped; the tip of Cx-I sharp, with an elongated cuticular extension ( Fig. 10C ); Gf elongated and rhombic, L/W ratio 1.4 (1.2), genital flaps with 18 setae at the margins; E 4 at the same level as the 4 th pair of acetabula; the line of primary sclerotization anterior to others’ regular locations (distance between the line of primary sclerotization and the line of L 4 about a half of the distance observed in other species); Ap clearly posterior to the line of primary sclerotization and anterior to V 2, at the same line with V 1. P-1 short, with a short seta; P-2 with three dorsal setae, and a ventral seta; P-3 with two dorsal and one ventral setae; P-4 with three dorsal setae, three ventral setae ( Fig. 10F ). Infracapitular rostrum short, apodemes curved to each other, curve and hamate ( Fig. 10E ).

Measurements. Idiosoma L 1224 (1040), W 933 (867). Dorsal shield L 983 (890), W 847 (805), dorsal plate L 928 (820), frontal platelets L 190 (177), W 114 (103), shoulder platelets L 270 (253), W 117 (120). Infracapitular bay L 237 (210); Cx-1 L 397 (327), mL 160 (117), Cx-II +III mL 93 (93); Gf L 270 (208), W 187 (173), distance between Gf and Ap 223 (201). Gnathosoma vL 237 (241), dL 285 (283), chelicera bs L 238 (231), claw L 42 (55). Ejaculatory complex ( Fig. 10C ), L 272 (264), aL 202 (196). L of palp: P-1, 31 (32); P-2, 93 (95); P-3, 68 (62); P-4, 83 (73); P-5, 27 (30). L of leg segments: I-L-1–6: 149 (148), 133 (125), 169 (150), 163 (146), 138 (130); II-L-1–6: 97 (93), 165 (143), 111 (107), 183 (163), 215 (197), 182 (163); III-L-1–6: 73 (69), 175 (157), 141 (125), 209 (196), 248 (226), 232 (201); IV-L-1–6: 161 (150), 189 (194), 192 (187), 252 (243), 275 (265), 226 (218).

Female (n = 2): Body features same as the male except: E 4 at the same level as the 5 th pair of acetabula; Gf pentagonal wider, L/W ratio 1.2 (1.2); Ap slightly posterior to V 1.

Measurements. Idiosoma L 1186 (1190), W 923 (1000). Dorsal shield L 1033 (1060), W 820 (843), dorsal plate L 965 (973), frontal platelets L 183 (190), W 106 (128), shoulder platelets L 268 (274), W 120 (146). Infracapitular bay L 190 (253); Cx-1 L 346 (380), mL 126 (156), Cx-II +III mL 73 (73); Gf L 265 (280), W 218 (233), distance between Gf and Ap 236 (255). Gnathosoma vL 241 (245), dL 270 (290), chelicera bs L 230 (238), claw L 51 (53). L of palp: P-1, 30 (33); P-2, 92 (95); P-3, 62 (64); P-4, 75 (81); P-5, 33 (34). L of leg segments: I-L-1–6: 81 (94), 136 (141), 125 (132), 150 (163), 146 (152), 124 (130); II-L-1–6: 87 (93), 143 (149), 106 (114), 163 (174), 196 (200), 163 (180); III-L-1–6: 67 (68), 155 (163), 133 (140), 202 (207), 230 (246), 210 (211); IV-L-1–6: 154 (156), 190 (194), 192 (202), 250 (257), 263 (276), 227 (254).

Habitat. Stream about 10 meters wide, between two mountains with mayflies and leeches as associated fauna; stream about 6 meters wide and 30 centimeters depth, with mayflies, leeches and caddisfly larvae as associated fauna.

Remarks. The present species is similar to Monatractides circuloides (Halík, 1930) ( Pešić & Smit 2009b, 2010; Pešić et al. 2011). Both species have a narrow and deep infracapitular bay; a short infracapitular rostrum. The new species differs from M. circuloides in: (1) M. circuloides with three pairs of knob-shaped protrusions at the margin of the infracapitular bay, but without them in M. hamatapodemus ; (2) M. circuloides dorsal apodeme blunted, curved to dorsum, but in M. hamatapodemus dorsal apodeme hamate, curved to abdomen; (3) Cx-II + III mL of M. circuloides longer than M. hamatapodemus .

Etymology. Named after the characters of the shape of infracapitular apodemes, dorsal and ventral apodemes curved to each other, hamate. From the latin “hamatus” which means shaped like a hook; here we use hamat- a prefix that means curved, and “apodem-” means apodeme.

Distribution. China (Doupengshan).

Figures

FIGURE 10. Monatractides hamatapodemus Gu & Guo, sp. nov., male: A = dorsal view; B = ventral view; C = an elongated circular extension on the tip of Cx-I; D = ejaculatory complex; E = infracapitulum and chelicera; F = palp. Scale bars = 100 μm.

FIGURE 11. Monatractides hamatapodemus Gu & Guo, sp. nov., male:A = Leg-I; B = Leg-II; C = Leg-III; D = Leg-IV. Scale bars = 100 μm.

FIGURE 12. Monatractides hamatapodemus Gu & Guo, sp. nov., female: A = dorsal view; B = ventral view. Scale bars = 100 μm.

FIGURE 13. Monatractides hamatapodemus Gu & Guo, sp. nov., female:A = Leg-I; B = Leg-II; C = Leg-III; D = Leg-IV; E = infracapitulum and chelicera; F = palp. Scale bars = 100 μm.