Lithobius (Ezembius) longibasitarsus, Qiao, Penghai, Qin, Wen, Ma, Huiqin, Zhang, Tongzuo, Su, Jianping & Lin, Gonghua, 2018

Qiao, Penghai, Qin, Wen, Ma, Huiqin, Zhang, Tongzuo, Su, Jianping & Lin, Gonghua, 2018, Two new species of Lithobius on Qinghai-Tibetan plateau identified from morphology and COI sequences (Lithobiomorpha: Lithobiidae), ZooKeys 785, pp. 11-28 : 12

Lithobius (Ezembius) longibasitarsus sp. n.

Type material.

Holotype: female labelled GH3 (Figure 1 A, D–E, H–G), body length 17.0 mm, from Gonghe County, Qinghai province, China, 36.64508° N 100.80747° E, 14 July 2011, 3287 meters above sea level, collected by Gonghua Lin. Paratypes: one female, one male, same data as holotype.

Habitat.

Specimens were collected under stones on steppes covered with legume shrubs and grass composed mainly of Poaceae . The sampling point belongs to the Gonghe Basin region of the Tibet plateau severely affected by desertification.

Etymology.

The specific name refers to the new species with a long tarsus I of leg XV, tarsus I approx. 1.7 times longer than tarsus II.

Diagnosis.

Body length 17.0-18.0 mm; head slightly widened; antennae of 20 articles; 10-14 ocelli arranged in three irregular rows; To oval to round, slightly smaller in size to neighbouring ocelli; lateral margins of forcipular coxosternite slanting; anterior margin with 2+2, 3+2 or 2+3 blunt teeth and with strong setiform porodonts; tergites without triangular posterolateral process; legs XIV and XV thicker and longer than anterior ones in both sexes; coxal pores 4-6, round to ovate arranged in one row; female gonopods with two moderately long, bullet-shaped spurs; terminal claw of the third article simple, with a small triangular protuberance on basal ventral side; male gonopods short and small.

Description.

Holotype (♀), body 17.0 mm long, cephalic plate width 2.1 mm, length 2.0 mm.

Colour: antennae light yellow; tergites pale yellow-brown; cephalic plate and terminal tergite yellow-brown; pleural region and sternites pale yellow; distal part of forcipules dark brown, maxillipede coxosternum and SXV yellow; legs pale yellow with grey hue, pretarsal claw brown.

Antennae composed of 20+20 articles (Figure 1 A), length 3.31 mm, basal article slightly wider than long, second article with equal length and width, the following articles longer than wide, distal article 2.6 times as long as wide; abundant setae on antennal surface.

Ocelli area translucent with dark pigment, 1+5, 3, 2 ocelli on each side of cephalic plate, arranged in three irregular rows. The posterior ocellus is the biggest. To oval, smaller than the adjacent ocelli, situated ventrally on anterolateral margin of cephalic plate.

Cephalic plate smooth, slightly broader than long; as broad as TIII or slightly broader. Frontal marginal of head with clear transverse suture. Posterior margin slightly concave; projection of lateral marginal conspicuously discontinuous; posterior marginal ridge slightly concave with median thickening.

Coxosternite subtrapezoidal, anterior margin narrow, lateral margins of the coxosternite slightly longer than medial margins. Median diastema shallow, U-shaped; anterior margin with 3+2 blunt nipple-like teeth (Figure 1E). Porodonts thick and strong separated from the lateral tooth ventrolaterally. Scattered short setae on the ventral side of coxosternite, longer setae near the dental margin and the porodonts.

Tergites all smooth, without wrinkles, TI narrower posterolaterally than anterolaterally, generally trapezoidal, narrower than the cephalic plate and TIII, the cephalic plate almost the same width as TIII. Posterior marginal ridge of TI straight; of TT III, V shallow concave; of TT VIII, X, XII slightly concave; of TXIV deeply concave; TT VI– XIV bordered laterally only (Figure 1A). Posterior angles of all tergites rounded without triangular projections. Only one or two pairs of setae on anterior angles of each tergite.

Sternites: posterior part of sternites narrower than anterior, generally trapezoidal, smooth; 2-8 setae on anterior angle, anterior lateral side, posterior angle and posterior lateral side; some minute setae on SS XIV and XV, most of which distributed on posterior lateral margins and posterior borders.

Legs: tarsal articulation well defined on legs I-XV. All legs with fairly long curved claws. Legs I–XIV with anterior and posterior accessory spurs, anterior accessory spur moderately long and slender ca. 33%-50% the length of principle claw, the posterior one stouter forming slightly larger angles with tarsal claws, ca. 0.25 the length of principal claw. Legs XV lacking anterior and posterior accessory spurs. Dense glandular pores on the surface of prefemur, femur, tibia, and tarsi of legs XIV and XV. Short to long setae sparsely scattered over the surface of prefemur, femur, tibia, and tarsi of legs I-XIII, more setae on the tarsal surface, with two rows of comb-like setae along ventral side, fewer setae on legs XIV and XV. Legs XIV and XV moderately thicker and longer than anterior legs, tarsus I ca. 6.6 times as long as wide, tarsus II ca. 37% length of the whole tarsus on leg XV. Leg plectrotaxy as presented in Table 1.

Coxal pores circular on legs XII–XV, separated by a distance 1-2 times larger than diameter of pore; inner pores smaller; formula 6, 5, 5, 5. Coxal pores set in a shallow groove arranged in a row with short to long setae scattered over the surface of apophysis (Figure 1J).

Female posterior segment: S XV generally trapeziform, straight posteromedially; sternite of genital segment wider than long with posterior margin moderately concave between condyles of gonopods, except for a small, median bulge; distal part lightly sclerotised; short to long setae scattered over the surface of genital segment and lateral margins. The first article of gonopod moderately broad bearing 22-24 short to moderately long setae arranged in three rows with 2+2 moderately long, bullet-shaped spurs, inner spur slightly smaller and more anterior than the outer (Figure 1J), four short setae, and three long setae on dorsolateral ridge (Figure 1H). The second article of gonopod with 8-10 setae, three long setae along the dorsolateral ridge (Figure 1H). Third article of gonopod with six moderately long setae. Terminal claw simple, slender and sharp, having small triangular protuberance on ventral side (Figure 1I).

Male posterior segment: S XV subtrapeziform, long setae scattered sparsely over its surface and posterior margins. Male genital sternite slightly wider than long; posterior margin quite deeply concave between the gonopods, no bulge medially; ca. 69 short to medium setae scattered sparsely over its surface and at lateral margins; gonopods of a single small semicircular article with 3-5 seta on its surface (Figure 1K). Male leg XV not modified.

Variations.

Body length 17.0-18.0 mm; ocelli 1+5, 4, 4 or 1+5, 3, 2 or 1+4, 3, 2 (Figure 1 B–D); coxal pores 5544, 5554 or 6555; coxosternal teeth 2+2, 3+2 or 2+3 (Figure 1 E–G).

Remarks.

Lithobius (E.) longibasitarsus sp. n. can be distinguished from all the other known Chinese species of subgenus Ezembius Chamberlin, 1919 by 2+2, 2+3 or 3+2 moderately blunt teeth on the forcipular coxosternite and the terminal claw of the female gonopod simple, slender and sharp, having a small triangular protuberance on its ventral side. It has a larger body (17.7-18.0 mm), more ocelli (10-14), more coxal pores (5544, 5554 or 6555), and DaC spine on legs XII and XV.

Morphologically it resembles L. (E.) tetraspinus but can be readily distinguished by the following characters: more ocelli (10-14 vs. 9-10), more coxosternal teeth (2+3, 3+2 vs. 2+2), more coxal pores (4-6 vs. 2-5), and less spurs on female gonopods (2+2 contrary to 2+3 or 3+2).