Lithobius (Monotarsobius) songi Pei, Ma, Shi, Wu & Zhou 2011

Body 5.9–6.9 mm long; cephalic plate 0.6–0.7 mm long, 0.6–0.7 mm wide. Colour: tergites and basal articles pale brown; transition to yellow brownish from the seventh or eighth articles onwards, the terminal article yellow brown; tergites pale chestnut; pleural region pale gray; SS pale orange; distal part of forcipules brown, the remaining part of forcipules, forcipular coxosternite and SS 14 and 15 pale yellow-brownish; all legs pale yellow-brownish, tarsi of all legs yellow-brown. Antennae composed of 19+19–21+21 articles (Fig. 1), most often 19+19; basal article almost as long as wide, second one markedly longer than wide, succeeding articles gradually shortening; terminal article typically longer than wide, up to 2.3–2.9 times longer than wide. Antennal setation: abundant setae on antennal surface, but fewer setae on outer side and ventral and dorsal side in basal articles, gradual increase in density of setae to about fourth or fifth article, then more or less constant. Cephalic plate smooth, convex, as long as broad, covered with sparse tiny setae; anterior part of the cephalic capsule with shallow median sulcus; pigment concentrated as close netlike veins, few short to long setae scattered along the marginal ridge; lateral marginal ridge continuous; posterior margin straight, without widening in middle part (Fig. 1). Six–seven ocelli on each side of cephalic plate (Fig. 2), more often 6, arranged in 2 irregular rows; the terminal one larger, the ocelli near the dorsal slightly larger, the ocelli near the ventral slightly smaller; overhanging the lateral margin of the cephalic plate; ocelli gently bulging, translucent, usually darkly pigmented. Tömösváry’s organ moderately small (Fig. 2–To), nearly rounded, situated ventrad to anterolateral margin of cephalic pleurite, slightly smaller than the adjoining ocelli. Coxosternite (Fig. 3) approximately trapezoidal, anterior margin moderately narrow with 2+2 comparatively sharp coxosternal teeth, median diastema relatively deep, V-shaped (Fig. 3); coxosternal shoulder lacking; porodonts lying posterolateral to the lateral tooth, comparely long and slender, without a bulge at the base. Moderately short to long setae sparsely scattered over the dental margin, comparatively long and thick near the dental margin. All tergites moderately smooth, without wrinkles, backside slightly hunched, tiny setae scattered very sparsely over the surface; T 1 generally subrectangular, anteriorly broadened; T 1 slightly narrower than T 3 and the cephalic plate, the latter slightlywider than T3; lateral marginations of all tergites continuous, setae scattered sparsely along the lateral borders, more setae on anterior angles of tergites; posterior margin of TT 1, 3, 5, 7, 8, 10, 12 and 14 slightly concave; all tergites without posterior triangular projections (Fig. 1). All sternites posterolaterally narrower than anterolaterally, generally trapeziform, moderately smooth, 2–4 moderately setae on anterior part of each sternite, 2–3 longer setae on posterior part of each sternite. Legs strong, tarsus 1–2 articulation fused on legs 1–13, well-defined on legs 14 and 15; claw moderately long and curved ventrad in all legs; accessory spur on both anterior and posterior side of claw of legs 1–14, anterior accessory spur moderately long and thicker, forming a moderately large angle with the claw; posterior accessory spur short and slender, forming a comparatively small angle with the claw; no accessory claws on leg 15; short to moderately long setae scattered over the surface of legs 1–13, tarsi generally more setose, few setae on legs 14–15; legs 14 and 15markedly thickened, the male more thicken than the female, tarsus 1 about 4.0–5.3 times longer than wide, tarsus 2 about 67%–81% length of tarsus on legs 15. Legs’ plectrotaxy: as in Table 1. Coxal pores arranged in a row, ovate to round, moderately small, 1222. Pore-field set in a slightly shallow groove, 8 short to moderately long setae scattered sparsely over the margin of shallow groove. Female S 15 posterolaterally narrower than anterolaterally, generally trapeziform, straight posteromedially; short to long setae scattered very sparsely over its surface and lateral margins. The sternite of genital segment usually well sclerotised, wider than long, posterior border moderately deeply concave between condyles of gonopods, except for a small, median approximately rhombic bulge, distally lightly sclerotised; short to moderately long setae evenly scattered over the surface of genital sternite except for middle and anterior parts. Female gonopods: basal article moderately broad, bearing 8 moderately long setae, arranged in 3 irregular rows, and 2+2 small coniform spurs; inner spur slightly smaller and more anterior than the outer (Fig. 4); second article with 6 moderately long setae, arranged in 2 irregular rows; usually 3–4 moderately long setae on the surface of third article; terminal claw tridentate (Fig. 5), dorsal and ventral tooth about same in size. Male S 15 posterolaterally narrower than anterolaterally, generally trapeziform, straight posteromedially; short to long setae scattered very sparsely over its surface and lateral margins. The sternite of genital segment usually well sclerotised, wider than long; comparatively long setae about evenly scattered on the ventral surface, slightly fewer near S15. Posterior margin of the sternite of the genital segment quite deeply concave between gonopods, no bulge medially; gonopods short and small, only a small hemispherical bulge, with 1–2 long setae on surface, terminal slightly sclerotised (Fig. 6).

Known only fromthe Hebei Province (Hengshui and Zhangjiakou Cities), NE China. Legs’ plectrotaxy ofLithobius (Monotarsobius) songisp. n. Letters in brackets indicate variable spines.legsventraldorsalCtPFTCtPFT1pampapa2pammpapap3–9ammapap10ammpap11(m)ammppp12mpamamppp13(m)mp(a)m(p)mmppp14mmpmmmp15mmpmmmp