Sphaerobelum, Verhoeff, 1924

Wesener, Thomas, 2019, First records of giant pill-millipedes from Laos (Diplopoda, Sphaerotheriida, Zephroniidae), Zootaxa 4563 (2), pp. 201-248 : 240

Sphaerobelum sp. L07

Material examined: 1 F (ZMUC00040261) from Laos; Khammouane Province, Ban Khounkham [Khun Kham] (Nahin), 300 m; disturbed primary lowland evergreen forest, flight intercept trap (N18°13.027', 104°30.880'E), leg. 4-18.VI.2008, A. Solodovnikov & J. Pedersen.

Unique characters: Medium sized species, tergites brown with a darker posterior margin. Antennae and legs conspicuously yellow. Tergites covered by pits. Anal shield with single, long locking carinae. First laterotergite extending posteriorly in a long, pointed process. Legs unmodified with a high number of ventral spines (10–12, Fig. 27B ). Operculum of vulva unique for species from Laos, protruding completely up to basal 2/3 of prefemur with one triangular, widely rounded tip ( Fig. 27C ). Coxa 2 lacking a process ( Fig. 27C ).

Description: Measurements: Body length ca 24.6 mm. Width, of thoracic shield = 13.5 mm. Height, of thoracic shield = 7.9 mm. Coloration: in preserved specimens orange to brown with darker posterior margin. Head and collum same colour as tergites. Antennae and legs yellow.

Head: Eyes with ca. 55 ocelli. Last antennomere thickened. Apical disc with 31/27 apical cones. All antennomeres covered by long setae. Organ of Tömösváry located inside antennal groove. Gnathochilarium: structure typical of the order. Palpi sensory cones in several clusters. Mandibles: not dissected.

Stigmatic plates: first stigmatic plate widely rounded, apex well-rounded, slightly curved towards coxa 1 ( Fig. 27A ). Laterotergites: laterotergite 1 strongly elongated into a long, sharp process. Laterotergite 2 slightly elongated into a pointed process. Collum: with glabrous surface, margins with few isolated setae. Thoracic shield: surface glabrous, setae only in grooves. Shallow grooves beset with numerous long setae, slope towards groove without keels. Tergites: glabrous. Tips of paratergites of midbody tergites projecting posteriorly. Anal shield: well rounded. Underside without locking carinae. Legs: leg-pair 1 with 2 ventral spines, leg-pair 2 with 5, leg-pair 3 with 7. First two leg-pairs without an apical spine. Leg-pairs 4–21 with 10–12 ventral spines and one dorso-apical spine. In leg 9 femur 1.6 times, tarsus 5 times longer than wide ( Fig. 27B ). All podomeres densely setose. Coxa with a well rounded process. Coxa process absent at first leg ( Fig. 27A ) and weakly developed at second ( Fig. 27C ).

Female sexual characters: Vulva large, covering mesal 3/4 of coxa, extending mesally to basal 2/3 of prefemur ( Fig. 27C ). Operculum unique for Laotian millipedes, rounded, elongated into a well-rounded, wide triangle. Subanal plate: large and wide, undivided, central margin slightly recessed. Densely setose ( Fig. 27D ).

Figures

FIGURE 27. Sphaerobelum sp. L07 (ZMUC); A: coxa of first left leg with first stigmatic plate; B: 9th left leg; C: coxa and prefemur of second leg with vulva; D: subanal plate. Abbreviations: Cx = coxa; O = operculum of vulva; Pre = prefemur; St-Pl = stigmatic plate. Scale bars = 1 mm.