Sphaerobelum bolavensis new species

Figures 6A, 7, 8, 9A, 10.

Material examined: Type specimens. 1 M holotype (ZMUC00040256) from Laos, Champasak Province, Bolaven Plateau, Ban Houayteuay, 1200 m (N 15°4.655', E 106°16.848') disturbed montane forest, leg. 10.XII.2007, by hand, S. Tarasov. 1 F paratype (ZFMK MYR8100), same data as holotype.

Non-type material: 1 F (MHNG LT-10/24) from Laos, Champasak Province, Bolaven Plateau, 3 km S of Ban Nong Luang, Tad Kameud, 1270 m (N 15°04'23", 106°12'36" E), undisturbed evergreen hill forest, 1.X.2010, leg. P. Schwendinger.

Diagnosis: S. bolavensis n. sp. belongs to a group of Sphaerobelum species in which the mesal margin of the femur is extended and apically tipped with several teeth (Fig. 8A). Sphaerobelum bolavensis n. sp. and S. bicorne from Vietnam are the only species with an extension only in the apical part of the femur. Sphaerobelum bolavensis n. sp. possesses a female vulval operculum only projecting in a single mesal process (Fig. 8B); in contrast, S. bicorne has two processes. Sphaerobelum bolavensis n. sp. has a telopoditomere 4 of the posterior telopod straight, apically without a recessed hook (Figs 10E, F); in contrast S. bicorne possesses a hook. Sphaerobelum bolavensis n. sp. has a short locking carina on the anal shield; whereas the carina is long in S. bicorne .

Description. Based on holotype male and paratype female.

Measurements: Holotype male. Body length ca 32.9 mm. Width, of thoracic shield = 14.2 mm, of tergite 8 = 14.9 mm (= broadest). Height, of thoracic shield = 7.1 mm, of tergite 7 = 8.2 mm (= highest). Female: body length = ca 28.8 mm. Width, of thoracic shield = 12.6 mm, of tergite 8 = 13.6 mm (=broadest). Height, of thoracic shield = 7.6 mm, of tergite 7, 8.3 mm (= highest). Coloration: in preserved specimens dark green, tergites with black posterior margin. Head and collum chestnut brown. Antennae orange, legs brown (Fig. 6A).

Head: Eyes with>70 ocelli. Aberrant ocellus located inside antennal groove. Antennae short, with rounded joints, extending posteriorly to leg-pair 3. First antennomere with cuticular scales (Fig. 7A). Lengths of antennomeres: 1>2=3=4=5<<6 (Fig. 7A). All antennomeres densely pubescent, sensilla basiconica surrounding apical disc. Shape of antennae sexually dimorphic, cylindrical in female; thickened, apically widened and slightly flattened in male (Fig. 7B). Apical disc with ca 47/52 apical cones (male) (Fig. 7B) or 30/32 (female). Apical cone shape typical of Diplopoda (Fig. 7B). Organ of Tömösváry located inside antennal groove. Gnathochilarium: structure typical of the order. Palpi with sensory cones arranged in clusters. Mandibles not dissected.

Stigmatic plates: first stigmatic plate widely rounded, apex well-rounded, weakly curved towards coxa 1. Laterotergites: laterotergite 1 strongly projecting into a sharp tip. Laterotergite 2 with a broad, stout, much shorter projection. Collum with glabrous surface, margins with few isolated setae. Thoracic shield: surface glabrous unlike tergites, setae only in grooves. Shallow grooves beset with numerous long setae, sloped towards groove with 9 continuous anterior and posterior keels. Tergites: surface densely setose with short setae. Tips of paratergites of midbody tergites projecting posteriorly. Endotergum: inner section lacking any spines or setae. Middle area with a single row of large, sparse, elliptical, cuticular impressions. Distance between impressions twice as wide as their diameter. Apically, 2 dense rows of long marginal bristles, their tips slightly protruding beyond tergal margin (Fig. 9A). Bristles not smooth, but with numerous small spicules. Anal shield: large, sexually dimorphic: in female weakly bell-shaped, in male strongly bell-shaped. Surface in both sexes completely covered by tiny setae. Underside with a single, short, black, locking carina, the latter located close to last laterotergite. Legs: leg-pair 1 with 2 ventral spines, leg-pair 2 with 4, leg-pair 3 with 5 or 6. First two leg-pairs without an apical spine. Leg-pairs 4–21 with 7–9 ventral spines and one dorso-apical spine. In leg-pair 9, femur 1.3 times, tarsus 4 times longer than wide (Fig. 8A). All podomeres densely setose. Coxa with a large and well-rounded process. Coxal process absent on leg-pair 1 and 2. Prefemur apico-mesally with a weak projection. Femur in apical part extended mesally into a dentate margin tipped with 4–6 teeth.

Female sexual characters: vulva large, covering 2/3 of coxa, extending mesally to anterior third of prefemur (Fig. 8B). Operculum rounded, very slightly invaginated medially, mesal margin strongly projecting into a wellrounded lobe twice as long as operculum. Subanal plate: damaged.

Male sexual characters: gonopore covered with a single, undivided, circular, sclerotized plate (Fig. 10A). Anterior telopods (Figs 10 B–D): consisting of only 3 telopoditomeres above syncoxite. Telopoditomeres 3 and 4 apparently fused. Telopoditomere 1 rectangular, as long as wide. Telopoditomere 2 large, half as long as telopoditomere 3. Process of telopoditomere 2 located posteriorly, visible in anterior view; process slender, projecting to half length of telopoditomere 3. Process of telopoditomere 2 conspicuously 'hooked' apically with a sharp tip. Telopoditomere 3 massive, cylindrical, straight, apically slightly tapering; posterior side with a black sclerotized spot and a small, triangular spine. Telopoditomere 1 in apical view covered with long setae. In posterior view all telopoditomeres almost glabrous. Posterior telopods (Figs 10E, F): telopoditomere 1 short, half as long as wide. Immovable finger (process of telopoditomere 2) shorter than movable finger, consisting of telopoditomeres 3 and 4. Immovable finger with a characteristic distally swollen apex; well rounded, apex therefore twice as wide as base. Telopoditomere 3 rectangular, well rounded. Telopoditomere 4 as long as but slightly slenderer than telopoditomere 3. Telopoditomere 4 2.7 times longer than wide; apically weakly tapering, very slightly curved towards immovable finger. Telopoditomere 1 at both sides covered by setae, remaining telopoditomeres in posterior view almost glabrous, in anterior view with few isolated setae except for immovable finger which is more densely setose.

Remarks: This species occurs in syntopy with a female of an undetermined species, Zephroniidae sp. L04b (see below).

Derivatio nominis: bolavensis, noun in apposition, from the Bolaven plateau in Laos where this species was discovered (Fig. 5).