Zoosphaerium masoala, 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 : 30-33

Zoosphaerium masoala sp. nov.

urn:lsid:zoobank.org:act:F62E0E9E-172D-4076-BD01-509AD42BAE89

Figs 2F , 3 , 10A , 11

Diagnosis

The shape and position of the locking carinae, as well as the slender posterior telopods place Z. masoala sp. nov. in the Z. platylabum species-group. Zoosphaerium masoala sp. nov. differs from all other species of the group in the combination of the presence of two stridulation ribs on the male harp, slender posterior telopods in which both fingers reach almost the same length and>10 apical cones on the antenna.

Etymology

‘Masoala’, noun in apposition, after the forest and peninsula of Masoala, the largest remaining area of lowland rainforest on Madagascar, for which the species described here is the first recorded giant pillmillipede species ( Fig. 3 ).

Material examined

Holotype MADAGASCAR – Toamasina • ♂; Région Sava, Parc National de Masoala, Forêt de Tampolo , 1.2 km S of Ambodiforaha village; 15°43′45.6″ S, 49°57′49.4″ E; alt. 15 m; pitfall buckets, littoral forest; 11 Dec. 2015; V. Soarimalala leg.; coll. no. VS-2582; FMNH-INS 3195651 .

Description

Male

BODY LENGTH. Length 23.9 mm, width of thoracic shield 14.2 mm (widest), height of thoracic shield 7.2 mm (highest).

COLORATION. Head, collum, thoracic shield and tergites dark brown to black. Grooves of thoracic shield greenish, anal shield lighter brown ( Fig. 2F ). Antennae and legs green.

HEAD. Eyes with more than 50 ommatidia. Antennae short, protruding back to leg 4. Length of antennomeres 1>2>3=4 =5<6. A shallow groove present on antennomere 1, disc with 33/12 apical cones.

GNATHOCHILARIUM AND MANDIBLE. Not dissected.

STIGMATIC PLATES. First stigmatic plate triangular, apex well-rounded, slender, curved towards coxa. Hair most abundant on apical margin ( Fig. 11C ).

PLEURITES. First pleurite extending slightly posteriorly in a long, thin process.

COLLUM. Margins covered with a few short hairs, central part glabrous.

THORACIC SHIELD. Surface like those of tergites, glabrous.

TERGITES. Smooth and glabrous, no small pits. Paratergites projecting slightly posteriorly.

ENDOTERGUM. Inner section with numerous short spines and isolated bristles. Between marginal ridge and inner area a single row of sparse large, circular cuticular impressions, distance between impressions larger than their diameter. Marginal brim wavy towards inner area. Externally 1 or 2 rows of marginal bristles. Bristles scaly, of medium length, longest reaching slightly above tergite margin ( Fig. 10A ).

ANAL SHIELD. Rounded, neither bell-shaped nor tapered, covered with numerous short setae. Ventral side of anal shield with two black locking carinae, located close to laterotergites. Anterior carina small and posterior carina 3 times as long as anterior carina.

LEGS. Leg 1 with 1 ventral spine, leg 2 with 2–4, leg 3 with 3 or 4. First two leg pairs without an apical spine, spine present on leg 3. Leg pairs 4–21 with 7 or 8 ventral spines and an apical spine. On leg 9, femur 2.4 and tarsus 4.2 times as long as wide. All podomeres with setae ( Fig. 11A ).

Male sexual characters

GONOPORE. Covered with a single undivided, rounded, apically membranous, basally sclerotized plate, covering ¼ of surface of coxa. Gonopore located basally on joint ( Fig. 11B ).

ANTERIOR TELOPODS. Harp with two stridulation ribs, mesal rib smaller than lateral one, both ribs well developed, located in mesal corner ( Fig. 11D ). First podomere 1.1 times as wide as long. Second podomere process lobe-like and slightly curved, with rounded edges, protruding up to half of third podomere height, apically with sclerotized spots. Third podomere long, as long as first; cavity mesally with numerous sclerotized spots and three thin, sclerotized spines; one sclerotized spot located close to tip; laterally with up to 12 crenulated teeth. Podomeres 1–3 covered on both sides with numerous long, isolated hairs.

POSTERIOR TELOPODS. Movable finger with a well-rounded tip, tapering towards tip; hollowed-out inner margin without lobes but with 5 sclerotized spines, 2 located apically, 2 at midpoint and 1 basally ( Fig. 11H ). Posterior aspect of movable finger with ca 14 small sclerotized teeth ( Fig. 11G ). Movable finger slightly longer than fixed finger, the latter slender (4 times as long as wide), apically curved towards former. Fixed finger basally with a single spine, at margin with numerous sclerotized spots. First podomeres almost glabrous, movable and immovable finger covered on both sides with numerous long, isolated hairs, only tips of chela glabrous.

Female

Unknown.

Distribution and ecology

This species is currently known only from the vast lowland rainforests of the Masoala Peninsula on the east coast ( Fig. 3 ).

Remarks

Despite several attempts, no DNA could be extracted from the male holotype. Therefore, its degree of similarity to the two much larger females known and sequenced from the Masoala area ( KY399024 and KY399025 ) could not be assessed (see Fig. 1 ).

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. 10. Scanning electron micrographs of the endoterga of midbody rings. A. Zoosphaerium masoala sp. nov., holotype (FMNH-INS 3195651). B. Z. spinopiligerum sp. nov., holotype (FMNH-INS 3119885). Scale bars = 100 µm.

Fig. 11. Zoosphaerium masoala sp. nov., holotype (FMNH-INS 3195651). A. Left leg 9, posterior view. B. Right coxa 2 with gonopore, posterior view. C. Right coxa 1 with stigmatic plate, posterior view. D. Left anterior gonopod, anterior view. E. Left anterior gonopod, lateral view. F. Left anterior gonopod, posterior view. G. Right posterior telopod, posterior view. H. 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. 1. Maximum likelihood tree inferred from the COI dataset with 1000 bootstrap pseudoreplicates implementing the GTR+I+ G model. Colors representing newly described species of Zoosphaerium: orange = Z. nigrum sp. nov.; green = Z. silens sp. nov.; red = Z. ambatovaky sp. nov.; yellow = Z. beanka sp. nov.; purple = Z. voahangy sp. nov.; blue = Z. masoala sp. nov. Round-cornered rectangles indicate well-supported sister group relationships.