Zoosphaerium nigrum, Wesener & Sagorny, 2021

Wesener, Thomas & Sagorny, Christina, 2021, Seven new giant pill-millipede species and numerous new records of the genus Zoosphaerium from Madagascar (Diplopoda, Sphaerotheriida, Arthrosphaeridae), European Journal of Taxonomy 758 (1), pp. 1-48 : 9-14

Zoosphaerium nigrum sp. nov.

urn:lsid:zoobank.org:act:4F170F43-C7A9-44A4-A004-47FD58FDBA2F

Figs 2A , 3–4 , 5A

Diagnosis

Posterior telopods ( Fig. 4H–I ) identify this species as a member of the Z. libidinosum species-group. Within this group, Zoosphaerium nigrum sp. nov. shares a number of characters with only Z. anomalum (de Saussure & Zehntner, 1902) and Z. pulchellum Wesener, 2009 . These include the presence of two locking carinae, four apical cones on each antenna, and shiny, glossy tergites. Moreover, the second and third podomeres of the posterior telopods are covered with numerous minute hairs. Zoosphaerium nigrum sp. nov. differs from these two species in the black coloration (jade-like green in the others), the presence of only a single weak stridulation rib on the anterior telopod and differently shaped podomeres.

Etymology

‘Nigrum’, adjective, after the dark colour of the species.

Material examined

Holotype MADAGASCAR – Fianarantosa • ♂; Parc National Befotaka-Midongy , Papango, 28.5 km S of Midongy-Sud, Mount Papango; 23°50′27″ S, 46°57′27″ E; alt. 1250 m; montane rainforest; 17 Nov. 2006; B.L. Fisher et al. leg.; coll. no. BLF14945; CASENT 9068289 .

Description

Male

BODY LENGTH. Holotype male: length ca 28 mm, width of thoracic shield 13.1 mm, of tergite 7 13.5 mm (widest), height of thoracic shield 7.1 mm, of tergite 7 7.4 mm (highest).

COLORATION. Some discoloration may have occurred because of preservation in ethanol. Tergites, head, anal shield and appendages dark green to black ( Fig. 2A ). Posterior margin of tergites with a thin brown margin.

HEAD. Wide and short. Eyes with>120 ommatidia. Aberrant ocellus located in antennal groove. Antennae short, with cylindrical joints, reaching posteriorly to leg pair 3. Length of antennomeres 1= 2=3= 4=5<6. A shallow groove present on antennomere 1. Male apical disc with four apical sensory cones. Organ of Tömösváry located in antennal groove.

GNATHOCHILARIUM AND MANDIBLE. Not dissected.

STIGMATIC PLATES. First stigmatic plate triangular, apex well rounded, nearly as wide as at base. Mesal margin straight, not curved towards coxa. Hair most abundant on apical margin, very few hairs on basal and lateral margins ( Fig. 4C ).

PLEURITES. First pleurite laterally modified and extending backwards with a broad, apically rounded process. Other pleurites well-rounded.

COLLUM. Glabrous with very sparse setae around margins, mostly located at corners on either side of head.

THORACIC SHIELD. Smooth and glabrous, without protuberances.

TERGITES. Surface glabrous and shiny, lacking small pits. Tips of paratergites of midbody tergites projecting posteriorly.

ENDOTERGUM. Inner section with numerous short triangular spines and very few longer setae. Middle area above spines with single row of sparse, circular cuticular impressions slightly varying in size. Apically a single row of short marginal bristles, protruding to ⅔ distance to tergite margin. Bristles with numerous small spines ( Fig. 5A ).

ANAL SHIELD. Large and slightly bell-shaped. Several tiny setae present in posterior part. Underside with two black locking carinae, posterior one 2 times as long as anterior one, both located close to anal shield margin.

LEGS. Leg 1 with 5 ventral spines, leg 2 with 3, leg 3 with 3–5. First two leg pairs without an apical spine, spine present on leg 3. Leg pairs 4–21 with 5–7 ventral spines and an apical spine. On leg 9, femur 1.8 and tarsus 4.6 times as long as wide. All podomeres with setae ( Fig. 4A ).

Male sexual characters

GONOPORE. Covered with a single undivided, rounded membranous plate ( Fig. 4B ).

ANTERIOR TELOPODS. Harp with a single weak stridulation rib ( Fig. 4E ). First podomere with only a few setae, restricted to apical parts of lateral margins, 1.5 times wider than long. Process of second podomere as long as ⅔ of third podomere, not visible in anterior view, with apical mound of a few sclerotized spots juxtaposed to third podomere. Third podomere without sclerotized teeth, but with a conspicuous process carrying sclerotized spots ( Fig. 4F–G ); base of process with four spines ( Fig. 4G ). Second and third podomeres sparsely setose.

POSTERIOR TELOPODS.Movable finger weakly curved; hollowed-out inner margin with two non-sclerotized lobes and ca three smaller sclerotized spines, posterior aspect with ca 29 crenulated teeth. Fixed finger thinner than movable finger, with slightly curved tip; basally with single membranous lobe, on inner margin covered with numerous sclerotized spots. Second and third podomeres without any long hair, but on both sides densely covered with very small pits, one very small seta standing in each pit. First podomere without those pits but with some isolated, standard longer hairs.

Female

Unknown.

Distribution and ecology

Zoosphaerium nigrum sp. nov. is currently known only from the montane rainforests of Midongy- Befotaka ( Fig. 3 ) where it coexists with another species of the genus, Z. spinopiligerum sp. nov. (see below), as well as with a species of the genus Sphaeromimus ( Moritz & Wesener 2017) .

Figures

Fig. 2. Habitus photographs of the seven new species of Zoosphaerium, lateral view. A. Zoosphaerium nigrum sp. nov., holotype (CASENT 9068289). B. Z. silens sp. nov., holotype (FMNH-INS 3119887). C. Z. ambatovaky sp. nov., holotype (CASENT 9068294/1).D. Z. beanka sp. nov., holotype (FMNH-INS 3119897). E. Z. voahangy sp. nov., holotype (FMNH-INS 3119921). F. Z. masoala sp. nov., holotype (FMNH-INS 3195651). G. Z. spinopiligerum sp. nov., holotype (FMNH-INS 3119885). Not to scale.

Fig. 3. Distribution map of the newly described species of Zoosphaerium. Vegetation color marks modified from Moat & Smith 2007. 1 = Z. nigrum sp. nov.; 2 = Z. silens sp. nov.; 3 = Z. ambatovaky sp. nov.; 4 = Z. beanka sp. nov.; 5 = Z. voahangy sp. nov.; 6 = Z. masoala sp. nov.; 7 = Z. spinopiligerum sp. nov. Numbers followed by ‘a’ mark additional, non-type localities.

Fig. 4. Zoosphaerium nigrum sp. nov., holotype (CASENT 9068289). A. Left leg 9, posterior view. B. Left coxa 2 with gonopore, posterior view. C. Left coxa 1 with stigmatic plate, posterior view. D. Left anterior gonopod, mesal view. E. Left anterior gonopod, anterior view. F. Left anterior gonopod, posterior view. G. Left anterior gonopod, lateral view. H. Right posterior telopod, posterior view. I. Right posterior telopod, anterior view. Abbreviations: as = apical spine; cl = claw; cr-t = crenulated teeth; cx = coxa; fe = femur; gp = gonopore; pof = postfemur; pref = prefemur; s-ps = sclerotized spots; sr = stridulation rib; st = stigmatic plate; syn = syncoxite; ta = tarsus; ti = tibia; vs = ventral spines. Roman numerals indicate telopoditomeres. Scale bars = 1 mm.

Fig. 5. Scanning electron micrographs of the endoterga of midbody rings. A. Zoosphaerium nigrum sp. nov., holotype (CASENT 9068289). B. Z. silens sp. nov., holotype (FMNH-INS 3119887). C. Z. ambatovaky sp. nov., holotype (CASENT 9068294/1). D. Z. beanka sp. nov., holotype (FMNH- INS 3119897). E. Z. voahangy sp. nov., holotype (FMNH-INS 3119921). Scale bars = 100 µm.