Torrenticola multiserrater Gu & Guo sp. nov. (Figures 1–4)

Type Materials. Holotype male: No. CQ-TO-2022081101, China, Chongqing, Wuxi County, Yintiaoling National Nature Reserve, Linkouzi (31°28′35′′N, 109°53′18′′E, 1250 m a.s.l.), collected by Yuhao Zhang, 11-VIII-2022 . Paratypes: 1/3/0, No. CQ-TO-2022081102 –CQ-TO-2022081105, same data as holotype.

Diagnosis. Dorsal plate arrangement: 4+1; P-2 with five dorsal setae, a jagged serrated extension on ventrum, and one ventral seta at the base of ventral extension; P-3 with an obvious serrated terminal-margin, one serrated ventral extension, and three dorsal and one ventral setae.

Description. Male (n = 2): Idiosoma elliptical, L 733 (730), W 442 (432), L/W ratio 1.66 (1.69). Dorsal plate arrangement: 4+1 (Fig. 1A); dorsal shied L 598 (576), W 392 (385), dorsal plate L 532 (519), frontal platelets L 150 (122), W 60 (65), shoulder platelets L 180 (177), W 70 (70). Infracapitular bay V-shaped, L 121 (117); Cx-I L 246 (235), mL 126 (120), Cx-II+III mL 117 (127); genital field elliptical, L 138 (129), W 101 (97); C 4 at the same level as the 4 th pair of acetabula; V 1 anterior to V 2, V 2 almost at the same level of Ap (Fig. 1B). Gnathosoma: dL 218 (225), vL 299 (305); rostrum long and dorsal apodeme short and blunt, ventral apodeme long and blunt; chelicera bs L 302 (301), claw L 43 (44) (Fig. 1D). Palp (Fig. 1C): P-1 short, with one dorsodistal seta; P-2 with five dorsal setae, and one ventral seta at the base of a jagged serrated extension; P-3 with an obvious serrated terminal-margin, one serrated ventral extension, and three dorsal and one ventral setae; P-4 with one thin dorsal seta and three ventral setae on two ventral extensions. L of palp segments: P-1, 31 (28); P-2, 78 (79); P-3, 52 (55); P-4, 115 (101); P-5, 14 (13). Legs (Fig. 2): L of leg segments: I-L-1–6: 30 (29), 54 (59), 62 (63), 71 (73), 85 (92), 86 (93); II-L-1–6: 28 (30), 70 (78), 54 (59), 69 (74), 78 (80), 67 (86); III-L-1–6: 34 (37), 82 (81), 57 (58), 79 (82), 92 (99), 92 (100); IV-L-1–6: 88 (91), 97 (94), 88 (98), 110 (120), 121 (128), 110 (114). Ejaculatory complex (Fig. 1E), L 158 (148), aL 105 (-).

Female (n = 3). Body features same as the male except genital field pentagonal (Fig. 3B). Idiosoma L 753 (725–753), W 464 (449–464), L/W ratio 1.6 (1.61–1.62). Dorsal shield L 607 (600–607), W 399 (399–409), L/W ratio 1.5 (1.48–1.52); dorsal plate L 543 (534–543), frontal platelets L 134 (134–148), W 53 (53–61), L/W ratio 2.5 (2.4–2.5). Infracapitular bay depth 132 (124–132); Cx-I L 258 (254–258), mL 123 (123–129), Cx-II + III mL 97 (97–103). Genital field L 156 (156–157), W 138 (138–140), L/W ratio 1.11 (1.11–1.13); distance between genital field and Ap 175 (164–175). Gnathosoma vL 323 (297–323), dL 231 (231–268), chelicera bs L 315 (315–335), claw L 45 (40–45). L of palp: P-1, 30 (30–32); P-2, 83 (81–83); P-3, 53 (53–58); P-4, 93 (88–93); P-5, 14 (13–14). L of leg segments: I-L-1–6: 32 (32–34), 76 (76–81), 62 (62–65), 76 (76–79), 86 (87–96), 87 (87–97); II-L-1–6: 31 (31–34), 76 (75–76), 59 (59–60), 69 (69–72), 80 (80–85), 84 (84–85); III-L-1–6: 35 (32–35), 86 (67–86), 59 (59–61), 87 (84–87), 98 (94–98), 88 (88–94); IV-L-1–6: 90 (90–97), 101 (97–101), 96 (96–101), 120 (117–120), 129 (123–129), 104 (104–116).

Habitat. Streamlet, about 0.3–0.5 m in depth, with many small stones at the bottom.

Remarks. Plap with serrated ventral extensions was also found in a small number of torrenticolid mites, such as T. dentifera Wiles, 1991 (Gu et al. 2020b), T. dentipalpis Jin, 1997 (Jin 1997), T. alargada Goldschmidt, 2007 (Goldschmidt 2007) and T. turkestanica (Sokolow, 1926) (Pešić & Smit 2009) . However, the aforementioned torrenticolid mites only have a regular (rod-shaped or rectangular) ventral extension on P-2. T. multiserrater Gu & Guo sp. nov., can be distinguished from other members of the genus by P-2 with a jagged serrated extension on ventrum, which like a flower cluster or coral, and one ventral seta at the base of ventral extension; P-3 with an obvious serrated terminal-margin, one serrated ventral extension, and three dorsal setae and one ventral seta (Figs. 1C, 3C).

Etymology. The specific name, multiserrater, is a combination from the Latin words: “ multi- ” and “ serrated ”, referring to this species having multiple serrated extensions, forming a jagged serrated extension on ventrum (Figs. 1C, 3C); used as a noun in apposition.

Distribution. Known only on the type locality (Wuxi, Chongqing of China).