Decapauropus biclavulus Dong & Qian

Qian, Changyuan, Dong, Yan, Bernard, Ernest C. & Sun, Hongying, 2015, Records of Pauropoda (Pauropodidae, Brachypauropodidae, Eurypauropodidae, Sphaeropauropodidae) from China, with a key to the species and descriptions of three new species of Decapauropus, Zootaxa 4006 (3), pp. 521-539 : 526-528

Decapauropus biclavulus Dong & Qian sp. n.

Fig. 2

Type material. Holotype: ad.9 (female), Laoshan Mountain, Jiangsu Province, 15 August 2010, leg. Dong et al. loc. LS20100815. Paratypes: ad.9 (female), Laoshan Mountain, Jiangsu Province, 17 January 2011, leg. Qian et al. loc. LS20110117

Etymology. From the Latin bi- = two, and clavula = claviform (referring to the shape of the appendages of the anal plate).

Description. Holotype length 0.80 mm, paratypes length 1.30 mm and 1.50 mm. Dorsal head (Fig. 2A) setae thin, tapering, of medium length to fairly long, densely annulate. Relative lengths of setae: 1st row: a 1 = 10, a 2 = 7(8); 2nd row: a 1 = 8, a 2 = 6 (7), a 3 = 7 (8); 3rd row: a 1 = 9 (8), a 2 = 7 6); 4th row: a 1 = 6 (6), a 2 = 6 (7), a 3 = 9 (8), a 4 = 8 (9). Ratio a 1/ a 1‒ a 1 in 1st row 3.5, in 2nd row 1.4 (1.6), in 3rd row 0.6 (0.53), in 4th row 3.0 (3.0). Length of temporal organs much longer than shortest interdistance. Head cuticle glabrous.

Antennal (Fig. 2B) segment 4 with four cylindrical, annulate setae. Relative lengths of setae: p = 100, p ’ = 69 (67), p ” = 47 (45), r = 35 (32). Tergal seta p 1.9 (2.0) times as long as tergal branch t. The latter slender, cylindrical, as long as greatest diameter and 0.7(0.8) times as long as sterna branch s which is 1.3 (1.5) times as long as greatest diameter; seta q 1.5 (1.4) times as long as sterna branch s. Relative lengths of flagella (base segment included) and base segments alone: F 1 = 100, bs 1 = 8 (10), F 2 = 32 (35), bs 2 = 9 (8), F 3 = 78 (80), bs 3 = 7.6 (9). F 1 6.3 (7.0) times longer than t. F 2 and F 3 1.6 (1.5) and 4.0 (3.6) times as long as s, respectively. Globulus g 1.3 (1.5) times as long as greatest diameter; width of g 0.86 (0.9) times of greatest diameter of t.

FIGURE 2. Decapauropus biclavulus sp. n., holotype. A) Head, median and right part, tergal view. B) Right antenna, tergal view. C) Collum segment, median and left part, sterna view. D) Tarsus of 9th pair of legs. E) Bothriotrix T 3. F) Bothriotrix T 5. G) Seta on trochanter of 9th pair of legs. H) Pygidium, tergal view.

Setae of collum segment (Fig. 2C) clavate, striate, and appearing simple. Sublateral setae 2.1 times as long as submedian setae; sternite process triangular, with incision. 4+4 setae on tergite I, 6+6 on II‒IV, 6+4 on V, 4+2 on VI.

Relative lengths of bothriotricha: T 1=100, T 2=110(109), T 3 (Fig. 2E) = 120(118), T 4 = 126(124), T 5 (Fig. 2F) = 140 (145). All with simple straight axes and short oblique pubescence.

Coxa and trochanter of leg 9 with furcate setae (Fig. 2G), branches subcylindrical, blunt. Tarsus of leg 9 (Fig. 2D) short, somewhat tapering, 2.8 times as long as greatest diameter; setae of similar appearance, thin, cylindrical, striate, their length 0.2× length of tarsus.

Posterior margin of pygidial tergum (Fig. 2H) evenly rounded. Relative lengths of setae: a 1=100, a 2=150, a 3=308, st =50. All setae but st pointed, and almost glabrous; st subcylindrical, straight and glabrous; Distance a 1‒ a 1 0.96 times length of a 1; distance a 1‒ a 2 3.7 times as long as a 2– a 3; distance st–st 2.4 times as long as st and st–st 0.52 times length of distance a 1‒ a 1. Pygidial sternum: posterior margin of sternum evenly rounded. Relative lengths of setae (a 1 = 100): b 1 = 87.5, b 2 = 354. All setae tapering, almost glabrous. Distance b 1‒ b 1 1.8× length of b 1; distance b 1‒ b 2 0.16× length of b 2.

Anal plate semicircular, glabrous, 1.4 times wider than long, posterior margin with two short, claviform, glabrous and parallel appendages, length almost 0.5× length of plate.

Diagnosis. The new species is similar to Allopauropus (D.) virgininsularis Scheller, 1989 from U.S. Virgin Islands. The species are similar especially in the structure of the antennae and pygidium, but they can be distinguished by the following characters: number of setae on fourth antennal segment ( D. biclavulus sp. n. with four cylindrical, annulate setae, A. (D.) virgininsularis with six thin, cylindrical, densely annulate, blunt setae); shape and orientation of st (long, subcylindrical, parallel in D. biclavula sp. n., short, cylindrical, converging in A. (D.) virgininsularis ); and the appearance of the anal plate (anal plate semicircular, appendages glabrous, parallel in D. biclavula sp. n.; anal plate narrowest anteriorly, with rounded posterolateral corners, appendages striate, parallel in A. (D.) virgininsularis ).