Sphaerobelum lachneeis, Wesener, 2019

Wesener, Thomas, 2019, First records of giant pill-millipedes from Laos (Diplopoda, Sphaerotheriida, Zephroniidae), Zootaxa 4563 (2), pp. 201-248 : 224-227

Sphaerobelum lachneeis new species

Figures 6E , 17 , 18

Material examined: Type specimens. 1 M holotype (MHNG LT-10/12) from Laos, Oudomxai Province, ca 3 km E of Tad Lak 11, SE of Oudomxai city (= Muang Xai), (N20°36'20", 102°01'16" E), 1020 m, primary forest, leg. 18.IX.2010, P. Schwendinger. 1 F paratype (MHNG LT-10/12), same data as holotype; 1 M paratype ( ZFMK MYR8099 ), same data as holotype .

Diagnosis: S. lachneeis n. sp. belongs to a group of Sphaerobelum species in which the mesal margin of the femur is unmodified ( Fig. 17B ). S. lachneeis n. sp. shares only with S. separatum , S. truncatum and S. peterjaegeri n. sp. the absence of a "hook" at telopoditomere 4 (of the posterior telopods Figs 18C, D ). S. lachneeis n. sp. differs from all those species in the presence of an only weakly separated telopoditomere 3 and 4 of the anterior telopods ( Figs 18A, B ), very long setae at the tergites ( Fig. 6E ), and a very long mesal extension at the apex of the immovable finger of the posterior telopods ( Fig. 18C ).

Description. Based on holotype and both paratypes.

Measurements: Body length: holotype male: length ca 23.5 mm. Width, of thoracic shield = 11.8 mm, of tergite 8 = 12.4 mm (= broadest). Height, of thoracic shield = 6.8 mm (= highest). Female: length ca 26.9 mm. Width, of thoracic shield = 13.3 mm, of tergite 7 = 13.9 mm (=broadest). Height, of thoracic shield = 7.5 mm, of tergite 8 = 8.5mm (= highest). Coloration: in preserved specimens dark olive-green, paratergite depressions and groove of thoracic shield lighter green, as ventral side ( Fig. 6E ). Antennae green, legs brown- olive greenish.

Head: densely setose with very long setae (setae as long as width of tergite). Eyes with ca. 50 ocelli. Aberrant ocellus located inside antennal groove. Antennae short, with rounded joints, extending posteriorly to leg-pair 3. Lengths of antennomeres: 1>2=3=4=5<<6. All antennomeres densely pubescent, sensilla basiconica surrounding apical disc. Antennomere 6 cylindrical in both sexes. Apical disc with ca 40/42 apical cones (male), or 31/29 (female). 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 rounded, apex well-rounded, straight towards coxa 1. Laterotergites: laterotergite 1 weakly projecting into a rounded. Laterotergite 2 with a broad, stout, much shorter projection.

Collum: surface like those of tergites, densely setose with very long setae. Thoracic shield: surface like those of tergites. Slope towards groove continuous row of 9 keels. Tergites: surface densely setose with very long setae, each starting from a small pit. Tips of paratergites of midbody tergites projecting posteriorly ( Fig. 6E ). Endotergum: inner section lacking any spines or setae. Middle area with a single, dense row of large, shallow, elliptical, cuticular impressions. Distance between impressions shorter than their diameter. Apically, 1-2 dense rows of long marginal bristles, the tips of the longest setae slightly protruding beyond tergal margin. Bristles not smooth, but with numerous small spinicles. Anal shield: large, in both sexes well-rounded. Surface in both sexes completely covered by setae located in small pits. Longer setae like the ones found on the tergites in the anterior part, short setae in the posterior part. Underside with a single, black, locking carina reaching 3x the length of those of the tergites, located close to the margin. Legs: leg-pair 1 with 2 ventral spines, leg-pair 2 with 3, leg-pair 3 with 5 or 6. First two leg-pairs without an apical spine. Leg-pairs 4–21 with only 6 or 7 ventral spines and one dorsoapical spine. In leg 9, femur 1.7 times, tarsus 4.7 times longer than wide ( Fig. 17B ). All podomeres densely setose. Coxa with a large and well-rounded process. Coxa process absent at first leg, sharply projecting at second ( Fig. 17A ). Prefemur and femur without any teeth.

Female sexual characters: Vulva small, covering mesal 1/3 of coxa, extending mesally to anterior fifth of prefemur ( Fig. 17A ). Operculum rounded, mesal margin projecting into a well-rounded lobe 1/3 as high as remaining operculum. Subanal plate: large and wide, undivided. Densely setose.

Male sexual characters: gonopore covered with a single, undivided, circular, sclerotized plate. Anterior telopods ( Figs 18A, B ): consisting of three telopoditomere above syncoxite. Last telopoditomere divided by a suture still visible in lateral and posterior view. Telopoditomere 1 rectangular, as long as wide. Telopoditomere 2 large, but shorter than telopoditomere 1 or 3. Process of telopoditomere 2 located posteriorly, not visible in anterior view. Process of telopoditomere 2 wide, well-rounded, projecting to half of telopoditomere 3. Telopoditomere 3 massive, conical, well-rounded, posterior side with two small spines and a black sclerotized spot. All telopoditomeres covered with long setae. Posterior telopods ( Figs 18C, D ): 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, bone-shaped, well rounded apically, with a strong basal swelling, apex twice as wide as base. Telopoditomere 3 rectangular, well rounded, apically with a well-rounded extension carrying a small spine. Telopoditomere 4 only slightly shorter and slightly more slender than telopoditomere 3, 2.4 times longer than wide, apically weakly tapering, minimally curved, with one small spines at margin towards immovable finger. In anterior view telopoditomere 1–3 covered by setae (not drawn at telopoditomere 1 and 2), in posterior view telopoditomeres 2–4 mostly glabrous except for a few setae at the margins.

Derivatio nominis: lachneeis, noun in apposition, after lachnos (= wool).

Figures

FIGURE 6. Habitus multi-layer stacked photographs of Sphaerobelum species. A: Sphaerobelum bolavensis n. sp.; B: Sphaerobelum phouloei n. sp.; C: Sphaerobelum denticulatum n. sp.; D: Sphaerobelum spinatum n. sp.; E: Sphaerobelum lachneeis n. sp.; F: Sphaerobelum peterjaegeri n. sp.; G: Sphaerobelum nigrum n. sp.; H: Sphaerobelum splendidum n. sp.; I: Sphaerobelum laoticum n. sp. Not to scale.

FIGURE 17. Sphaerobelum lachneeis n. sp., female paratype (MHNG); A: coxa and prefemur of second leg with vulva; B: 9th left leg. Abbreviations: Cx = coxa; O = operculum of vulva; Pre = prefemur. Scale bars = 1 mm.

FIGURE 18. Sphaerobelum lachneeis n. sp., holotype (MHNG); A: left anterior telopod, anterior view; B: left anterior telopod, posterior view; C: left posterior telopod, anterior view; D: left posterior telopod, posterior view. Abbreviations: Syn- Cx = syncoxite. Scale bars = 1 mm.