Sphaerobelum phouloei, Wesener, 2019

Wesener, Thomas, 2019, First records of giant pill-millipedes from Laos (Diplopoda, Sphaerotheriida, Zephroniidae), Zootaxa 4563 (2), pp. 201-248 : 215-216

Sphaerobelum phouloei new species

Figures 6B , 9B , 11 , 12 .

Sphaerobelum sp. II 1 M

Material examined: Type specimen. 1 M holotype (ZMUC00040257) from Laos, Houaphan Province, Phou Loei, way from camp 1 to camp 2, ~ 1200 m, leg. 9.VIII.2008; S. Tarasov.

Diagnosis: S. phouloei n. sp. belongs to a group of Sphaerobelum species in which the mesal margin of the femur is extended in several teeth ( Fig. 11B ). S. phouloei n. sp. shares only with S. denticulatum n. sp. a curved telopoditomere 4 of the posterior telopods which overlaps the immovable finger ( Figs 12E, F ). S. phouloei n. sp. differs in several characters from S. denticulatum n. sp.: male antenna with only 30–35 apical cones (> 50 in S. denticulatum n. sp.), prefemur mesal margin well-rounded (indentated in S. denticulatum n. sp.), tergites covered with short setae (glabrous in S. denticulatum n. sp.), legs orange (brown in S. denticulatum n. sp.).

Description. Measurements: Body length: holotype male: length ca 25.8 mm. Width, of thoracic shield 13.3 mm, of tergite 8 = 14.1 mm (= broadest). Height, of thoracic shield = 8.9 mm, of tergite 8 = 9.3 mm (= highest).

Coloration: in preserved specimens anterior 2/3 of tergites dark olive green, posterior 1/3 black. Head, ventral side, anal shield orange ( Fig. 6B ). Legs and antennae orange.

Head: Eyes with 65–70 ocelli. Aberrant ocellus located inside antennal groove. Antennae short, with rounded joints, extending posteriorly to leg-pair 4. First antennomere with cuticular scales. Lengths of antennomeres: 1=2=3<4<5<<6. All antennomeres densely pubescent, sensilla basiconica surrounding apical disc. Last antennomere thickened, apically widened and well rounded. Apical disc with ca 36/33 apical cones. Organ of Tömösváry located inside antennal groove. Gnathochilarium: structure typical of the order. Palpi sensory cones located in several clusters. Mandibles: not dissected.

Stigmatic plates: first stigmatic plate widely rounded, apex well-rounded, curved towards coxa 1 ( Fig. 11A ).

Laterotergites: laterotergite 1 and 2 with a broad, stout 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, slope towards groove with 3 weak anterior and 2 or 3 posterior keels. Tergites: anterior 2/3 of surface densely setose with short setae, posterior 1/3 glabrous. Tips of paratergites of midbody tergites projecting posteriorly ( Fig. 6B ). Endotergum ( Fig. 9B ): inner section lacking any spines or setae. Middle area with a single row of large, sparse, elliptical, cuticular impressions. Distance between impressions as wide as their diameter. Apically, 1–2 sparse rows of long marginal bristles, strongly protruding beyond tergal margin. Bristles not smooth, but with numerous small spinicles. Anal shield: large, surface completely covered by tiny setae. Underside with a single, long, black locking carina, located close to last laterotergite. Legs: leg-pair 1 with 2 ventral spines, leg-pair 2 with 5, leg-pair 3 with 6 or 7. First two leg-pairs without an apical spine. Leg pairs 4–21 with 9 or 10 ventral spines and one dorso-apical spine. In leg 9, femur 1.3 times, tarsus 3.7 times longer than wide ( Fig. 11B ). All podomeres densely setose. Coxa with a large and marginally toothed process. Coxa process absent at first leg ( Fig. 11B ) and sharply projecting at second ( Fig. 12A ). Prefemur at apical margin with a projection laterally and mesally. Lateral projection triangular and sharply edged, juxtaposed to coxal process. Femur extended mesally into a dentate margin featuring 12–14 teeth.

Female unknown.

Male sexual characters: gonopore covered with a single, undivided, circular, sclerotized plate ( Fig. 12A ). Anterior telopods ( Figs 12 B–D): consisting of 4 telopoditomeres above syncoxite, but telopoditomere 3 and 4 only divided by thin suture. Telopoditomere 1 rectangular, as long as wide. Telopoditomere 2 large, almost as long as telopoditomere 3 and 4 combined. Process of telopoditomere 2 located posteriorly, not visible in anterior view. Process of telopoditomere 2 wide, projecting to half of telopoditomere 4, apically with a well-rounded tip. Telopoditomere 3 cylindrical, straight, as long as telopoditomere 4. Telopoditomere 4 cylindrical, well-rounded, posterior side with a black sclerotized spot and a small, triangular spine. Telopoditomeres 1–4 in anterior view covered with long setae. In posterior view all telopoditomeres with fewer setae. Posterior telopods ( Figs 12E, F ): telopoditomere 1 elongated, twice 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 wider than base. Immovable finger in anterior view with a large spine, at tip opposite to tip of telopoditomere 4 with sclerotized spots. Telopoditomere 3 rectangular, towards immoveable finger with a triangular expansion carrying a spine. Telopoditomere 4 reaching 2/3 of length of telopoditomere 3, apically strongly tapering into acute tip, very slightly curved towards immovable finger. Inner margin with single spine towards immovable finger. Telopoditomere 1 at both sides covered by setae. Telopoditomeres 2 and 3 in anterior view covered by long setae, in posterior view mostly glabrous. Telopoditomere 4 only with marginal setae.

Derivatio nominis: phouloei, noun in apposition, after the Phou Loei Mountain, the type locality ( Fig. 5 ).

Figures

FIGURE 5. Distribution map of Sphaerobelum species, including the unnamed females.

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 9. Endoterga of the body ring 9 of different Sphaerobelum species. A: Sphaerobelum bolavensis n. sp.; B: Sphaerobelum phouloei n. sp.; C: Sphaerobelum spinatum n. sp.; D: Sphaerobelum splendidum n. sp. Abbreviations: cp = cuticular patterns; iA = inner area.

FIGURE 11. Sphaerobelum phouloei n. sp., male holotype (ZMUC); A: left first coxa with stigmatic plate; B: 9th left leg. Abbreviations: Cx = coxa; St-Pl = stigmatic plate. Scale bars = 1 mm.

FIGURE 12. Sphaerobelum phouloei n. sp., holotype (ZMUC); A: coxa of second left leg with gonopore; B: left anterior telopod, anterior view; C: left anterior telopod, posterior view; D: left anterior telopod, lateral view; E: right posterior telopod, anterior view; F: right posterior telopod, posterior view. Abbreviations: Cx = coxa; Syn-Cx = syncoxite. Scale bars = 1 mm.