Dasongius liupanensis, Bu, 2021

Bu, Yun, 2021, Two new species of the genus Dasongius (Myriapoda, Pauropoda, Pauropodidae) from China, Zootaxa 4908 (2), pp. 239-250 : 240-244

Dasongius liupanensis new species

Figures 1‒21 , Table 1.

Material examined: Holotype, female adult with 9 pairs of legs (slide no. NX-LPS-PA2009001) ( SNHM), Ningxia, Guyuan City, Jingyuan County, Liupan Mountain , Longtan forest farm, soil samples in a broad-leaf forest, 35°37’40’’N 106°33’25’’E, elev. 2000 m, 11-VII-2009, colls. C.W. Huang & W. J. Chen . Paratypes, 1 female adult with 9 pairs of legs (slide no. NX-LPS-PA2009002), same data as holotype ; 2 female adults with 9 pairs of legs (slide nos. SX-LS-PA2013019, SX-LS-PA2013020), Shanxi, Jincheng City, Qinshui County, Zhongcun Town , Zhangma village , soil samples in a broad-leaf forest, 35°59’15’’N 111°57’20’’E, elev. 550 m, 8-VII-2013, colls. Y. Bu & Y. Gao ; 1 female adult with 9 pairs of legs (slide no. SC-PA2017001 ), Sichuan, Aba Tibetan and Qiang Autonomous Prefecture , Jinchuan County, soil samples from broad-leaf forest, 31°11’35’’N 101°58’20’’E, elev. 2020 m, 24-VIII-2017, coll. C.W. Huang. Non-type material, 1 juvenile with 8 pairs of legs (slide no. NX-LPS-PA2009003), 1 juvenile with 5 pairs of legs (slide no. NX-LPS-PA2009004), same data as holotype .

Diagnosis. Dasongius liupanensis sp. n. is characterized by the cylindrical, non-furcate setae on the collum segment; long seta p on tergal branch and long q on sternal branch of antenna; 6+6 setae on tergite II; leg 9 with furcate setae on coxa and non-furcate setae on trochanter; tergum of pygidium with long and glabrous seta a 1, a 2, and clavate setae st; anal plate pubescent, medially separated into two processes posteriorly, and with 2 long, cylindrical appendages. Dasongius liupanensis sp. n. can be easily distinguished from the other three known species of the genus by the shape of the anal plate. It also differs from D. rugosus and D. bicruris in the shape of the tergum of pygidium, length of setae on antennal segment 4, shape of setae of collum segment, and the shape of the setae on coxa and trochanter of leg 9 ( Table 1).

Description. Adult body length (0.8–) 0. 95 mm (n = 5); white to pale yellow and with pygidium light brown in alcohol ( Fig. 10 ).

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Head ( Figs. 1 , 11 ). Dorsal head setae short to moderately long, annulate, clavate; lateral ones slender. Relative lengths of setae, 1 st row: a 1 = 10, a 2 = 13 (–14); 2 nd row: a 1 = 10, a 2 = (25–) 26, a 3 = 14 (–18); 3 rd row: a 1 = 10, a 2 = (10–) 12; 4 th row: a 1 = 10 (–12), a 2 = (20–) 22, a 3 = 26 (–28), a 3 = 24 (–25); lateral group setae l 1 =21 (–22), l 2 = 22 (–23) l 3 = 24 (–25); the ratio a 1 / a 1 – a 1 in 1 st row 0.9 (–1.0), 2 nd row 0.4 (–0.5), 3 rd row 0.6 (–0.7), and 4 th row 1.3 (–1.4). Temporal organs oval in dorsal view, their length 0.7 (–0.8) of their shortest distance apart. Head cuticle glabrous. Antennae ( Figs. 2–4 , 15 ). Chaetotaxy of segments 1–4: 2/2/3/4. Antennal segment 4 with four cylindrical, annulate setae; relative lengths of setae: p = 100, p ’ = (57–) 66, p ’’ = 43 (–49), r = 46(–51); tergal seta p 1.5 (–1.9) times as long as tergal branch t. The latter cylindrical, (3.0–) 4.2 times as long as its greatest diameter and (1.4–) 1.6 times as long as sternal branch s, which itself is 1.8 (–2.3) times as long as its greatest diameter. Seta q cylindrical, annulate, (1.3–) 1.5 times as long as s. Relative lengths of flagella (base segments included) and base segments: F 1 = 100, bs 1 = 9 (–11); F 2 = 38 (–45), bs 2 = (6–)7; F 3 =81 (–87), bs 3 = 9 (–11). F 1 4.2 (–4.7) times as long as t, F 2 and F 3 (2.2–) 2.5 and 3.5 (–4.3) times as long as s respectively. Distal calyces small, hemispherical; flagella axes cylindrical below calyx. Globulus g 1.5 (–1.6) times as long as wide; with 10 bracts, capsule spherical; width of g 0.4 of the greatest diameter of t. Antennae glabrous. Trunk. Setae on collum cylindrical, annulate. Sublateral setae length (25–) 27 μm, 2.2 (–2.5) times as long as submedian setae ( Fig. 12 ); sternite process triangular, pointed; appendages narrowing distally and with flat caps ( Fig. 12 ). Setae on tergites thin, cylindrical; 4 + 4 setae on tergite I ( Fig. 13 ), 6 + 6 on II–IV ( Fig. 14 ), 6 + 4 on V ( Fig. 19 ), 4 + 2 on VI ( Fig. 20 ); shortest one 10 μm and longest one 34 μm on I–V; posterior setae on VI extremely long ( Fig. 20 ), straight, 58 (–80) μm, their mutual distance 20 (–22) μm. Tergites I–V glabrous, VI with dense pubescence on posterior part. Bothriotricha. Relative lengths: T 1 = 100 (–116), T 2 = (107–) 113 (–123), T 3 = (107–) 113 (–126), T 4 = (134–) 140 (–150), T 5 = (193–) 210 (–228). T 1 – T 4 with simple, straight axes and dense pubescence ( Figs. 8 , 19 ). T 5 with thicker axis; pubescence sparse and long in proximal part, dense and short in distal part ( Fig. 9 ). Legs. Setae on coxa and trochanter of legs 1–8 subcylindrical, short, and annulate ( Fig. 16 ). Setae on coxa of leg 9 furcate with subcylindrical, annulate, blunt branches, length (15–) 16 μm, on trochanter of leg 9 cylindrical, slender, annulate, length 17 (–20) μm ( Fig. 17 ). Tarsus of leg 9 long, 50 (–53) μm, tapering, 4.2 (–4.4) times as long as its greatest diameter ( Figs. 5 , 18 ). Proximal seta long, 25 (–30) μm, tapering, striate; distal seta (10–) 11 μm, cylindrical, annulate; their lengths 0.5 (–0.6) and 0.2 of the tarsal length, respectively. Tarsus of leg 1–8 each with only 1 distal, annulate seta, (7–) 8 μm. All leg tarsi with three claws, one of them with a round, pubescent flap. Cuticle of tarsus pubescent. Pygidium. Tergum ( Figs. 7 , 20 ). Surface highly modified as engraved, honeycombed, pentagonal and tetragonal cellae. Anterior margin projected forward in the middle, posterior margin with two weak indentions in the middle. Lengths of setae: a 1 = (30–) 35 μm, a 2 = (43–) 45 μm, a 3 = 55 (–60) μm, st = (12–) 15 μm. All setae tapering, pointed, a 1 and a 2 glabrous and long, a3 pubescent ( Fig. 7 ); st clavate and curved inward ( Fig. 6 ); Distance a 1 – a 1 (0.5–) 0.6 of length of a 1; distance a 1 – a 2 (2.5–) 3.3 times as long as a 2 – a 3; distance st–st 1.1 (–1.2) times as long as st and 0.7 (–0.9) of distance a 1 – a 1. Sternum ( Figs. 6 , 21 ) pubescent, posterior margin with weak indentation between between b 1. Lengths of setae: b 1 = 35 (–37) μm, b 2 = 32 (–40). Seta b 1 cylindrical, blunt, annulate, b 2 tapering and pubescent. Distance b 1 – b 1 0.9 of length of b 1; distance b 1 – b 2 0.5 (–0.6) of length of b 2. Anal plate ( Figs. 6 , 21 ) densely pubescent, (2.1–) 2.2 times as long as broad, posterior half of plate divided into 2 tapering processes, each of them with 1 pubescent, cylindrical appendage inserted basally and protruding backwards, 0.5 (–0.6) of length of plate.

Etymology. The species is named after the type locality, Liupan Mountain.

Distribution. China (Ningxia, Shanxi, Sichuan).

Figures

FIGURES 1–6. Dasongius liupanensis sp. n. 1, head, right part, dorsal view; 2, left antennal segments I–IV, tergal view; 3, sternal branch of antennal segment IV; 4, tergal branch of antennal segment IV; 5, tarsus of leg 9; 6, sternum of pygidium. Scale bars: 20 μm.

FIGURES 7–9. Dasongius liupanensis sp. n. 7, tergum of pygidium; 8, T 3; 9, T. Scale bars: 20 μm.

FIGURES 10–21. Dasongius liupanensis sp. n. 10, habitus; 11, head, dorsal view; 12, collum segment, sternal view; 13, tergite I; 14, tergite II; 15, left antenna, tergal view; 16, coxa and trochanter of leg 1; 17, coxa and trochanter of leg 9; 18, tarsus of leg 9; 19, tergite V, right part; 20, tergum of pygidium; 21, sternum of pygidium. Scale bars: 100 μm (10); 20 μm (11–21).