Atractides (Tympanomegapus) tergumus Zhang & Guo 2023
Creators: name: Zhang, Yu-Hao
name: Li, Hai-Tao
name: Hu, Zhan-Yu
name: Guo, Jian-Jun
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Trombidiformes
Hygrobatidae
Atractides
Atractides tergumus

description: Atractides (Tympanomegapus) tergumus Zhang & Guo, 2023
Figs 22–25
Diagnosis
O 2 slightly anterior to D 1. Genital field with three pairs of acetabula forming triangle, V 1 separated from V 2, excretory pore smooth and slightly posterior to level of V 1 and V 2. P-4 ventral margin straight and divided by two ventral hairs in sectors 3:2:3, sword seta near distoventral hair, P-5 without lateral cheeks. I-L-5 thickens from base to end, S-1 and S-2 both with blunt tips and similar in shape; I-L-6 slightly straight and end little thicker than base.
Material examined
P.R. CHINA • 1 ♂, 2 ♀♀; Hainan Province, Lingshui Li Autonomous County, Diaoluo Mountain National Forest Park; 18.6683° N, 109.9227° E; 84 m a.s.l.; 13 Apr. 2023; Hai-Tao Li, Yu-Lin Zheng and Yu-Hao Zhang leg.; main river (Diaoluo River) 40–50 cm deep, with sand and rotten leaves on bottom, plants around, shore with helophytes (Fig. 25B); slide nos. HN-HY-2023041301 to 2023041303; GUGC.
Description
Female (n = 2)
Idiosoma oval, O 1 posterior to A 1, O 2 slightly anterior to D 1 and on platelets; all slit organs visible, So 1 near A 2, So 2 at same level of D 1, So 3 at same level of D 2, So 4 located in front of L 4, So 5 behind of D 4 and out (Figs 22A, 24A). ACG fused and with suture line, apodemes of ACG strong and horn-like, and interspace between two apodemes; PCG separated, and suture line of Cx-III and Cv-IV nearly straight, C 4 near suture line between Cx-III and Cv-IV. Genital field with three pairs of acetabula forming triangle, V 1 separated from V 2, V 3 close to PCG, V 4 at same level of pregenital sclerite, V 3 and V 4 forming trapezoid, excretory pore smooth and slightly posterior to level of V 1 and V 2 (Figs 22B, 24B).
Palp five-segmented; P-1 elongated, P-2 and P-3 ventral margins more or less straight; P-4 with numerous dorsal hairs, ventral margin straight and divided by two ventral hairs in sectors 3:2:3, sword seta near to distoventral hair, P-5 without lateral cheeks (Fig. 22C). I-L-5 thickens from base to end, S-1 and S-2 both with blunt tips and similar in shape; I-L-6 slightly straight and end little thicker than base (Fig. 23).
MEASUREMENTS (measurements of other specimens in parentheses). Idiosoma L 730 (746), W 578 (538); coxal field L 384 (366), Cx-III W 408 (410), ACG IL 271 (269), mL 126 (139), W 293 (280); gnathosoma bay L 177 (158); gonopore L 95 (107), pregenital sclerite L 97 (101), postgenital sclerite L 49 (56); Ac1–3 L 30 (33), 36 (34), 29 (34); chelicera L 365 (357), cheliceral claw L 99 (98), basal segment L 291 (283); gnathosoma L 271 (251); palp dL: P-1 71 (60), P-2 69 (70), P-3 73 (64), P-4 107 (100), P-5 33 (32); leg segments: I-L-1 dL 58 (57), I-L-2 dL 84 (74), I-L-3 dL 100 (93), I-L-4 dL 141 (129), I-L-5 dL 132 (122), HB 37 (35), I-L-6 dL 108 (100), HB 23 (22), S-1 L 39 (37), W 4 (4), S-2 L 41 (39), W 5 (4); dL: II-L-1 64 (58), II-L-2 72 (72), II-L-3 91 (83), II-L-4 117 (104), II-L-5 126 (114), II-L-6 117 (109); dL: III-L-1 62 (61), III-L-2 95 (81), III-L-3 92 (89), III-L-4 125 (114), III-L-5 143 (139), III-L-6 140 (135); dL: IV-L-1 137 (125), IV-L-2 106 (97), IV-L-3 149 (143), IV-L-4 177 (171), IV-L-5 192 (186), IV-L-6 167 (168).
Distribution
China (Hainan Province).
Remarks
In this study, we collected one male and two females from Diaoluo Mountain National Forest Park, Lingshui Li Autonomous County, Hainan Province, and found that the male matches the description of the male of A. (T.) tergumus. Moreover, the collection site is very close to the site where A. (T.) tergumus was collected. We believe the females we collected belong to A. (T.) tergumus, and this is the first description to the female of the species.
description: Published as part of Zhang, Yu-Hao, Li, Hai-Tao, Hu, Zhan-Yu & Guo, Jian-Jun, 2025, Two new species in the genus Atractides Koch, 1837 (Acari: Hydrachnidiae: Hygrobatidae), with the first descriptions of the female of two species from China, pp. 47-76 in European Journal of Taxonomy 976 on pages 69-72, DOI: 10.5852/ejt.2025.976.2775, http://zenodo.org/record/14771799