Lithobius (Monotarsobius) meifengensis, Chao, Jui-Lung, Lee, Kwen-Shen & Chang, Hsueh-Wen, 2018

Chao, Jui-Lung, Lee, Kwen-Shen & Chang, Hsueh-Wen, 2018, Lithobius (Monotarsobius) meifengensis, a new species of centipede from high altitude forest in central Taiwan (Chilopoda, Lithobiomorpha, Lithobiidae), ZooKeys 741, pp. 181-192 : 183-188

Lithobius (Monotarsobius) meifengensis sp. n. Figures 1, 2, 3, 4, 5, 6, 7

Type material.

Holotype ♂ (NMNS7634-073): Taiwan, Nantou County, Mei-Feng Farm, apple orchard, 24°05'N, 121°10'E, 2080 m, 19 Feb 2002, leg. Sheng-Hai Wu.

Paratypes:1♂ (NMNS7634-072), grassland; 1♂ (NMNS7634-074), plum orchard; 1♂ (NMNS7634-075); 1♀ (NMNS7634-068), pear orchard; 2♀ (NMNS7634-071), waste land; 1♂1♀ (NMNS7634-070), grassland; same data as holotype.

Other material.

1♀ (NMNS7634-096), pear orchard; 3♀ (NMNS7634-098), plum orchard; 1♂1♀ (NMNS7634-099), plum orchard; 1♂ (NMNS7634-100), pear orchard; 1♂4♀ (NMNS7843-006), grassland; 2♂1♀ (NMNS7843-007), grassland; 1♂2♀ (NMNS7843-003), grassland; 2♂5♀ (NMNS7843-004), plum orchard; 2♀ (NMNS7843-005), pear orchard; 2♀ (NMNS7843-002), grassland; 1♂ (NMNS7843-001), pear orchard; 2♂5♀ (NMNS7843-009), grassland; 2♂1♀ (NMNS7843-008), pear orchard; same locality as holotype, 15 Apr 2002, leg. Sheng-Hai Wu.

Etymology.

Refers to the type locality.

Diagnosis.

A species of the genus Lithobius Leach, 1814, subgenus Monotarsobius Verhoeff, 1905, normally with 19+19 elongate antennal articles, body length approximately 9 mm; cephalic plate 0.8-0.9 times as long as wide; six ocelli [one posterior and three dorsal, two ventral] on each side, posterior ocellus comparatively large; Tömösváry’s organ moderately small, slightly larger than adjacent ocelli; 2+2 coxosternal teeth; porodonts moderately slender, posterolateral to the outer tooth; posterior angles of all tergites lacking triangular projections; tarsi fused on legs 1-13; male secondary sexual characters on legs 15, a large ventral domed swelling on femur (Figure 1), and a dorsal shallow excavation on tarsus 2; coxal pores round, 3333 in males, 3443 or 3444 in females; female gonopods with 2+2 sharp coniform spurs, claw undivided.

Description.

Body length: 7.0-9.8 mm. Body colour (in alcohol): yellowish with dark patches.

Antennae with 19 articles (Figure 2A); basal three articles typically wider than long, following articles markedly longer than wide; distal article much longer than wide, up to 2.8 times as long as wide; abundant setae on antennal surface, less so on basal articles, gradual increase in density to around fourth article, then more or less constant in number.

Cephalic plate smooth, convex, 0.8-0.9 times as long as wide; posterior marginal ridge moderately broader and weakly concave (Figure 2B); small pores of flexo-canal epidermal glands (gp), large pores of recto-canal epidermal glands (gp*) and setae scattered sparsely over the whole surface (Figure 2C) ( Müller, 2009).

Six ocelli on each side, one posterior and three dorsal, two ventral, arranged in two irregular row (Figure 3A); the posterior ocellus comparatively large; ocelli domed, translucent, usually darkly pigmented.

Tömösváry’s organ comparatively small, nearly rounded; situated at anterolateral margin of cephalic plate, slightly bigger than the adjoining ocelli (Figure 3B).

Forcipular coxosternite sub-trapezoidal, anterior margin narrow, external side lightly longer than internal side; median longitudinal cleft moderately deep (Figure 4A); anterior border with 2+2 large triangular coxosternal teeth, inner tooth slightly larger than outer one; porodonts moderately slender, setiform, posterolateral to the outer tooth (Figure 4B); some scattered setae on the ventral side of coxosternite.

Tergites smooth, without wrinkles, backside slightly hunched; T1 generally trapeziform, posterior margin narrower than anterior margin, narrower than T3 and the cephalic plate; T3 slightly narrower than the cephalic plate; posterior margin of TT1, 3, 5, 8, 10 and 12 weakly concave; TT1, 3 and 5 with continuous lateral and posterior marginal ridges, other tergites with discontinuous posterior marginal ridges; posterior angles of all tergites lacking triangular projections (Figure 2A); tiny setae scattered very sparsely over the surface.

Sternites narrower posteriorly, generally trapeziform, comparatively smooth, setae emerging from pores scattered very sparsely over the surface.

Legs: tarsi fused on legs 1-13 (Figure 5A), well-defined on legs 14-15; all legs with fairly long claws, curved ventrally; anterior and posterior accessory spines on legs 1-14, the anterior one moderately slender, the posterior spine short and thick (Figure 5B); legs15 lack anterior accessory spines; legs 14-15 with numerous large pores (9.1-11.1 μm) of the telopodal glands on the inner surfaces of femur, tibia, tarsus 1 and tarsus 2 (Figure 5C), the pores each opening into the centre of a bell-shaped cavity (3.5-3.9 μm) (Figure 5C), some small pores (1.4-1.6 μm) of flexo-canal epidermal glands sparsely distributed along the border of the epidermal cells (Figure 5D). Male 15th legs with secondary sexual character; female legs 15 and other legs without secondary sexual characters on femur or tibia (Figure 7A). Leg plectrotaxy as in Table 1.

Male secondary sexual character on leg 15: a large domed swelling on the ventral surface of femur, covering almost 50% (Figure 1, 6A); the surface of femoral swelling lacks the large pores of the telopodal glands (Figure 6B); the gently curved apical region bears approximately 20 short setae, and numerous very small pores (0.8-1.0 μm) of flexo-canal epidermal glands densely distributed (Figure 6C); a dorsal shallow excavation on the tarsus 2 (Figure 5C).

Coxal pores: 3333 in males, 3443 or 3444 in females, round, coxal pore field set in a relatively shallow groove, margin of coxal pore-field with slightly eminence.

Male sternite 15: trapeziform, posterolaterally narrower than anterolaterally, posterior margin straight, long setae scattered sparsely over the surface.

Male first genital sternite: wider than long, usually well chitinised; posterior margin quite deeply concave between the gonopods, without a medial bulge (Figure 6D); comparatively long setae evenly scattered on the ventral surface; gonopods short and small, with 2-3 long setae, apically slightly chitinized.

Female sternite 15: generally trapeziform, anterolaterally broader than posterolaterally, posterior margin straight, long setae scattered sparsely over the surface; the sternite of genital segment well chitinised, wider than long; posterior margin of genital sternite deeply concave (Figure 7B); short to long setae sparsely scattered over the ventral surface of the genital segment.

Female gonopod: first article fairly broad, bearing 11-13 long setae, arranged in three irregular rows; 2+2 sharp coniform spurs, inner spur smaller (Figure 7A, B); second article with 7-9 rather long setae arranged in two irregular rows on its ventral side; third article usually with 2-3 long setae on its ventral surface; terminal claw undivided, bearing a few thick sensilla coeloconica on its dorsodistal and ventral surface (Figure 7C).

Remarks

Some Lithobius species, all from Russia, also have distinct sexual characters on male leg 15: the proximal part of male 15th tibia of Lithobius (Monotarsobius) kurcheavae described by Zalesskaja (1978) has a large swelling bearing a tuft of long bristles, and a longitudinal deep excavation on the dorsal surface; the dorsal surface of the male 15th tibia of Lithobius (Monotarsobius) evsyukovi ( Zuev 2017) a large, flat, ovoid wart supporting a few short setae at apex; the dorsal surface of 15th tibia Lithobius (Monotarsobius) ferganensis (Trotzina, 1894) a small cylindrical wart supporting a few short setae at apex; while the male 15th tibia of Lithobius (Chinobius) yuchernovi ( Farzalieva et al. 2017) is characterized by a tubercle supporting a cluster of curved and long setae on the ventral surface. Lithobius (Monotarsobius) meifengensis sp. n. differs from those by its unique male secondary sexual character on the ventral surface of 15th femur, a large swelling with approximately 20 short setae and numerous very small pores, not found in any of those congeners.

Records of the species of Lithobius (Monotarsobius) from Taiwan by Takakuwa and Wang are listed as follows: locality: old name = new name; place name ??: unknown.

Lithobius (Monotarsobius) ramulosus (Takakuwa, 1941)

[1] Monotarsobius ramulosus Takakuwa, 1941a - Trans. Nat. Hist. Soc. Formosa 31 (213): 294-295; fig. 5, 6 (original description, key) (locality: Keisyu = Xizhou)

Monotarsobius ramulosus : Takakuwa, 1941b - Fauna Nippon. 9(8-3): 74; fig. 84; (description, key) (locality: Keisyu = Xizhou)

Monotarsobius ramulosus : Takakuwa, 1942 -Trans. Nat. Hist. Soc. Formosa 32(231): 360 (locality: Keisyu = Xizhou)

Monotarsobius ramulosus : Wang 1955 - Quar. J. Taiwan Mus. 8(1): 16 (locality: Taipei)

Monotarsobius ramulosus : Wang 1956 - Quar. J. Taiwan Mus. 9(2): 159 (locality: Hualien)

Lithobius (Monotarsobius) obtusus (Takakuwa, 1941)

[1] Monotarsobius obtusus Takakuwa, 1941a - Trans. Nat. Hist. Soc. Formosa 31 (213): 293-294; fig. 2 (original description, key) (locality: Keisyu = Xizhou, Shaka = Shalu, Tikunan = Zhunan)

Monotarsobius obtusus : Takakuwa 1941b - Fauna Nippon. 9(8-3): 75; fig. 85; (description, key) (locality: Keisyu = Xizhou, Shaka = Shalu)

Monotarsobius obtusus : Wang 1955 - Quar. J. Taiwan Mus. 8(1): 16 (locality: Shin-Tien = Hsintien)

Monotarsobius obtusus : Wang 1956 - Quar. J. Taiwan Mus. 9(2): 159 (locality: Hualien)

Monotarsobius obtusus : Wang 1957 - Quar. J. Taiwan Mus. 10(1): 28 (locality: Kao Yung ??)

Monotarsobius obtusus : Wang 1959 - Quar. J. Taiwan Mus. 12(3, 4): 198 (locality: Taipei, Kao Yung ??)

Monotarsobius obtusus : Wang 1963 - Quar. J. Taiwan Mus. 16(1, 2): 95 (locality: Rai Wu ??)

Lithobius (Monotarsobius) holstii (Pocock, 1895)

[1] Monotarsobius crassipes holstii (+ M. takakuwai ): Takakuwa 1941a - Trans. Nat. Hist. Soc. Formosa 31 (213): 292-293; fig. 1(description, key)

Monotarsobius crassipes holstii (+ M. takakuwai ): Takakuwa 1941b - Fauna Nippon. 9 (8-3): 78-79; fig. 90-91; (description, key) (locality: Puli, Taipei)

[2] Monotarsobius crassipes : Wang 1959 - Quar. J. Taiwan Mus. 12 (3, 4): 198 (locality: Nantou, Taipei)

Monotarsobius crassipes : Wang 1963 - Quar. J. Taiwan Mus. 16 (1, 2): 95 (locality: Shao Tso Kiang ??)

Chamberlin and Wang (1952) recorded two species of Monotarsobius from three specimens allegedly collected by Takakuwa in 1933 from Taiwan: Monotarsobius rhysus Attems, 1934 and Monotarsobius argaeensis Attems, 1934. However, Takakuwa never came to Taiwan, and never reported these two species in any of his publications. Wang came to Taiwan and studied Taiwanese chilopods since 1953, and he did not record these two species again. We consider that the record of the two species is questionable.

Lithobius (Monotarsobius) meifengensis sp. n. is morphologically close to Lithobius (Monotarsobius) ramulosus (Takakuwa, 1941), Lithobius (Monotarsobius) obtusus (Takakuwa, 1941) and Lithobius (Monotarsobius) holstii (Pocock, 1895), with which it shares the following characters: antennae composed of 19-20 articles, six ocelli on each side of cephalic plate, 2+2 coxosternal teeth. It can however be distinguished using the following key.

Key to the Taiwanese species of Lithobius (Monotarsobius)