Lithobius (Sinuispineus) sinuispineus, sinuispineus, 2020

Chang, Xiaodong, Pei, Sujian, Zhu, Chunying & Ma, Huiqin, 2020, An unusual new centipede subgenus Lithobius (Sinuispineus), with two new species from China (Lithobiomorpha, Lithobiidae), ZooKeys 980, pp. 43-55 : 43

Lithobius (Sinuispineus) sinuispineus sp. nov. Figs 1 , 2A-L

Diagnosis.

Antennae 20-25 articles; ocelli usually nine on each side, in three irregular rows; posterior two ocelli comparatively large; Tömösváry’s organ larger than adjacent ocelli. Commonly 2+2 coxosternal teeth; porodonts lying posterolateral to lateral-most tooth. Coxal pore formula 3-5 in one row. Tarsal articulation ill-defined on legs 1-13, well-defined on legs 14 and 15. Female gonopods with 2+2 moderately small, coniform spurs; male gonopods short and small. Legs 15 are considerably modified in males: posterior spurs on dorsal side of femur of male legs 15 curving backward near base.

Material examined.

Holotype: ♂ (LS01-1) (Fig. 1A ); body 11.56 mm long; cephalic plate 1.09 mm long, 1.24 mm wide. South East China, Huanggangshan, Wuyishan National Nature Reserve, Wuyishan County, Nanping City, Fujian Province, 27°52.025'S, 117°51.030'E, 544 m, 15 August 2010, leg. F. Zhang, H. Ma. Paratypes: 1♀, 1♂ (LS01-1), same locality and date as holotype.

Other material examined.

2 ♂♂ (LS01-2), South East China, Yulinting, Wuyishan National Nature Reserve, Wuyishan County, Nanping City, Fujian Province, 27°40.917'S, 117°56.030'E, 462 m, 8 August 2010, leg. F. Zhang, H. Ma.

Description.

Body 11.6-15.2 mm long; cephalic plate 1.1-1.3 mm long, 1.2-1.4 mm wide.

Colour: antennae pale brown to pale greyish yellow from base to end; tergites pale brown, pleural region pale lavender, and sternites pale greyish yellow; basal parts of forcipules, forcipular coxosternite, and SS14 and 15 darker; coxa, trochanter, prefemur, femur, and tibia of all legs pale lavender; tarsus 1 pale brown; tarsus 2 pale yellow-brown in all legs.

Antennae: 25 articles in female, 20 articles in male (Fig. 1A ). Length of first antennal article approximately equal to width of base; length of remaining articles longer than wide. Second article thicker and longer than other articles: from second article, each article gradually shortened, and distalmost articles still considerably longer than wide, 3.8-4.3 times as long as wide. Abundant setae on antennal surface, less so on basal articles; density of setae to approximately fourth article gradually increasing, then more or less constant.

Cephalic plate smooth, convex, slightly wider than long; tiny setae emerging from pores scattered very sparsely over the whole surface; frontal marginal ridge with shallow anterior median furrow; short to long setae scattered along the marginal ridge of the cephalic plate; lateral marginal ridge discontinuous, posterior margin continuous, wider than lateral marginal ridge (Fig. 1A ).

Nine, oval to rounded ocelli on each side, from small to large, arranged in three irregular rows; posterior two ocelli comparatively large. Ventral ocelli slightly smaller than the dorsal, domed, translucent, and usually darkly pigmented (Fig. 1B ).

Tömösváry’s organ (Fig. 1B -To) near ocelli, at anterolateral margin of cephalic plate; moderately larger than adjoining ocelli; surrounding sclerotised area not obvious.

Coxosternite subtrapezoidal (Fig. 1C ); anterior margin narrow; lateral margins slightly longer than medial margins. Median diastema moderately deep, narrowly V-shaped; anterior margin with 2+2 acute triangular teeth. Porodonts thicker, lying posteriolaterally to lateral-most tooth (Fig. 1C ). Long, scattered setae on ventral side of coxosternite; longer setae near dental margin.

All tergites smooth, without wrinkles, tiny setae emerging from pores scattered sparsely over entire surface; near margin with few long setae. T1 narrower postero-laterally than antero-laterally, generally trapezoidal; T1 and T3 narrower than cephalic plate; T3 wider than T1; T8 widest. Lateral marginal ridges of all tergites continuous. Posterior margin of TT1 and 6 straight; TT 3, 5, 8, 10, 12, 14 slightly concave. Posterior angles of tergites rounded, without triangular projections. Miniscule setae scattered sparsely over the surface; one thick and long setae on both anterior angles of each tergite.

Posterior side of sternites narrower than anterior, generally trapezoidal, smooth. Setae emerging from sparsely scattered pores on the surface and lateral margin, very few long setae scattered sparsely among them. One comparatively long thick seta on both anterior angles of each sternite; more setae on surface of anterior and middle parts than posterior part of each sternite.

Legs relative robust; tarsi fused on legs 1-13; well-defined on legs 14-15. All legs with fairly long, curved claws. Legs 1-12 with anterior and posterior accessory spurs; anterior accessory spurs moderately long and slender, forming a moderately small angle with claw; posterior accessory spurs slightly more robust, forming a comparatively large angle with claw; legs 13 with anterior accessory spurs; legs 14 and 15 lacking accessory spurs. Short to long setae sparsely scattered over surface of coxa, trochanter, prefemur, femur, and tibia of all legs; more setae on tarsal surface; setae on dorsal surface of tarsus slightly shorter than ventral surface. Legs 14 and 15 in female thicker than anterior pairs; legs 15 in male considerably thicker and stronger than anterior pairs. Leg plectrotaxy presented in Tables 1 and 2 .

Coxal pores 3-5 in a row, round or slightly oval, size of pores varies greatly from 19.3 μm to 48.7 μm; coxal pore field set in a relatively deep groove; coxal pore-field fringe with prominence; prominence with 4-8 moderately long setae sparsely scattered over the surface.

Female. S15 anterior margin broader than posterior, generally trapezoidal, postero-medially slightly convex. Short to long setae sparsely scattered on S15 surface. Surface of lateral sternal margin of genital segment well chitinised, posterior margin of genital sternite deeply concave between condyles of gonopods, except for a small, median, tongue-shaped bulge. Relatively long setae scattered over ventral surface of genital segment, slightly more setae near S15. Gonopods: first article fairly broad, bearing 13 short to moderately long setae, arranged in three irregular rows; with 2+2 small coniform spurs; inner spur slightly smaller than the outer (Fig. 1E ); second article ventrally with five or seven long setae, arranged in two irregular rows; third article ventrallywith two long setae, with a bidentate apical claw (Fig. 2F, G ).

Male. S15 posterior margin narrower than anterior, postero-medially straight; sparsely covered with long setae, more than the anterior; sternite of genital segment slightly smaller than in female, usually weaker sclerotised; posterior margin deeply concave between gonopods, without medial bulge. Long setae scattered on ventral surface of genital segment; fewer setae near S15, fringed with 16-18 longer setae along posterior margin. Gonopods short, appearing as small finger-like bulges, with two long setae, apically slightly sclerotised (Fig. 2H ). Legs 15 prominently modified, very thick; prefemur and femur very short, of unusual thickness (Fig. 2H-L ); posterior spines of dorsal end of femur curved backward toward base of tibial segment at approximately 60° angle (Fig. 2H-K ); anterior tibia raised inwards medially (Fig. 2L ).

Figures

Figure 1. Lithobius (Sinuispineus) sinuispineus sp. nov. (holotype A-D, paratype female E) A habitus, dorsal view B ocelli and Toemoesvary's organ (To), lateral view C cephalic plate, ventral view D forcipular coxosternite, ventral view E posterior segments and gonopods of female, ventral view.

Figure 2. Lithobius (Sinuispineus) sinuispineus sp. nov. (paratype female F, G; holotype H-L) F claw of female gonopod, ventral view G claw of female gonopod, dorsal view H posterior segments and gonopods in male, ventral view I posterior spurs of the femur of legs 15, dorsal view J posterior spurs of the femur of legs 15, ventral view K posterior spurs of the femur of legs 15, ventral view, showing minor teeth L tibia of legs 15 raised inward.