Zoosphaerium isalo, Wesener, 2009

Wesener, Thomas, 2009, Unexplored richness: discovery of 31 new species of Giant Pill-Millipedes endemic to Madagascar, with a special emphasis on microendemism (Diplopoda, Sphaerotheriida), Zootaxa 2097 (1), pp. 1-134 : 87-90

Zoosphaerium isalo , new species

Derivatio nominis: isalo , noun in apposition, after the type locality, Isalo, SW Madagascar.

Studied material: 3 M

Holotype: 1 M (24 mm long), CAS BLF 7301 , Locus typicus: Madagascar, Province Fianarantsoa, Parc National d'Isalo , 9.1 km 354°N Ranohira, 725 m, gallery forest, 22°28'54"S, 045°27'42"E, coll. Fisher, Griswold et al., 27–31.i.2003.

FIGURE 058. Zoosphaerium isalo n. sp., A–D holotype, E, F specimen from Zombitse ( CAS Mei-99 Ma-14) A: left anterior telopods, anterior view; B: last two podomeres of anterior telopod, lateral view; C: posterior telopod, anterior view; D: chela of posterior telopod, posterior view; E: posterior telopod, anterior view; F: chela of posterior telopod, posterior view. Abbreviations: cav = cavity; ml = membranous lobe; s-p = sclerotized spot; scl-t = sclerotized teeth; SR = stridulation rib. Scale bar = 1 mm.

FIGURE 059. Zoosphaerium isalo n. sp., paratype, SEM, antenna A: first antennomere with sensilla basiconica; B: lateral view. Abbreviation: sb = sensilla basiconica.

Paratype: 1 M, CAS BLF 7301 , same data as holotype ;

Other material: 1 M, CAS BLF Mei-99 Ma-14, Province Toliara, Zombitse Nature Reserve , 16 km E Sakaraha, 825 m, tropical forest on sand, 22.88231°S, 44.70062°E, coll. E. L. Schlinger, M. E. Irwin, 15–18.xii.1999 .

Distribution: Recorded from the forest Isalo and Zombitse in South-Western Madagascar (Fig. 50).

Diagnosis: Small species, up to 25 mm long. Head, tergites and anal shield shiny blackish, appendages dark olive-green. Surface of tergites shiny, at high magnification leather-like texture becomes visible. Anal shield excavated at hindmost point, in contrast to glabrous tergites covered with numerous minute hairs. First antennomere with groove and sensilla basiconica (Fig. 59A), disc with four apical cones (Fig. 59B). Movable finger of posterior telopods broad, 2.3 times longer than wide (Fig. 58D), with two triangular membranous lobes and circa 4 or 5 sclerotized spines (Fig. 58C), at posterior side with circa 9 or 10 small, sclerotized teeth (Fig. 58D). Fixed finger long and broad, basally with one membranous lobe and one small spine, distally at inner margin with numerous sclerotized spots (Fig. 58C). Fixed finger reaching 4/5 of movable fingers length. One stridulation rib on each male harp (Fig. 58A). Cavity of anterior telopods third podomere mesally with plateau covered with numerous sclerotized spots (Fig. 58B). Anal shield with two locking carinae, first small, second three times longer than first. Endotergum with one row of large elliptical cuticular impressions and two rows of marginal bristles, reaching up to posterior margin (Fig. 63E).

Similar species: Zoosphaerium isalo , n. sp. features a unique combination of characters in the Z. coquerelianum species-group, like one stridulation rib on the male harp, four apical apical cones on the antenna, a triangular membranous lobe on the basis of posterior telopods second podomere, and the presence of two triangular, membranous lobes on the third podomere of posterior telopods (Figs 58A–F). Z. isalo , n. sp. is very similar to Z. bilobum , n. sp., however in the latter species overreach the endotergum bristles strongly the tergite margin and the anterior telopod second podomere is not visible in anterior view.

Description: Body length: Male holotype: length 24 mm, width of thoracic shield 12.7 mm, height of thoracic shield 7.2 mm.

Coloration: Faded in alcohol. Head, collum, thoracic shield, tergites and anal shield uniformly blackish, antennae and legs dark olive green.

Head: Eyes with>75 ocelli.

FIGURE 060. Zoosphaerium isalo n. sp., paratype, SEM, A: gnathochilarium, ventral view; B: left mandible, mesal view. Abbreviations: 3iT = 3 inner teeth; Ca = rudiments of cardines; Co = condylus; eT = external tooth; iP = inner palpus; LL = fused lamella linguales; Me = mentum; mp = molar plate; St = stipites; pL = pectinate lamella.

Antennae: Length of antennomeres: 1>2>3>4<5<6, sixth antennomere longest, cylindrical, disc with four sensory cones (Fig. 59B). First antennomere remarkably broader than others, short, with groove and 1 or 2 rows of sensilla basiconica (Fig. 59A). Sclerotized teeth at base of antennomeres 1–4 (Fig. 59B).

Mandible: Five rows of pectinate lamellae, number of teeth declining apically to proximally (Fig. 60B). Condylus with strongly developed step near apical margin (Fig. 60B).

Gnathochilarium: Ventral side with numerous, long setae (Fig. 60A). Lateral of palpi four sensory cones, located together. Depression on posterior side of palpi with some sensory cones.

Collum: Only at margins with isolated hair of medium length.

Thoracic shield shaped like in other species of genus.

Tergites: Surface shiny, at high magnification (90x) leather-like texture becomes visible. Paratergites straight, not projecting posteriorly.

Endotergum: Inner area with thin conical spines and long hair. Single row of few scattered, large, elliptical cuticular impressions (Fig. 63E). Two rows of marginal bristles, slightly protruding to tergite margin (Fig. 63E).

Anal shield: Tapered at hindmost point. Covered with numerous hairs, each located in minute pit. Underside carries two well-developed black locking carinae, anterior one small, but well developed. Posterior carina three times longer than anterior one, straight. Carinae located closely to anal shield margin.

Legs: Tarsi of first pair of legs with three or four, second with four or five and third with six to eight ventral spines. First two leg pairs with only weakly curved claws and without apical spine. Tarsi of legs 3–21 with curved claws, 10–12 ventral spines and one apical spine. In 9th leg femur 1.9 times, tarsi 4.25 times longer than wide.

Stigmatic plates: First lobe triangular, with pointed tip.

Female unknown

Male sexual characters: Male gonopore covered by sclerotized, undivided plate.

Anterior telopods (Figs 58A, B): Width of first podomere slightly larger than height. Harp with one straight and well-developed stridulation rib, located basally at lateral part of first podomere. Second podomere process lobe-like and little curved with rounded edges, protruding to 2/3 of third podomere height, visible laterally in anterior view, apically with sclerotized spots and one spine. Third podomere elongated, cavity mesally with several sclerotized spots and two sclerotized spines. One sclerotized spot located closely to tip.

Posterior telopods (Figs 58C, D): Movable finger of chela thick, 2.3 times longer than wide, weakly curved, apically slightly tapering. Hollowed-out inner margin with two triangular membranous lobes and 4 or 5 sclerotized spines, posterior aspect with circa 9 or 10 small, sclerotized teeth. Fixed finger wide, but more slender and shorter than movable finger. Tip of fixed finger almost straight, only weakly curved; anterior side basally with one short sclerotized spine, on tip with numerous sclerotized spots. Fixed finger on posterior side covered with numerous, on anterior side with very few long hairs. Third podomere on both sides almost glabrous. Inner horns of syncoxite apically curved posteriorly. Tips pointed, whole horns covered with numerous short hairs.

Intraspecific variation: The specimen from Zombitse is very similar to the holotype. Especially the posterior telopods (Fig. 58E, F) are almost identical with those of the holotype (Fig. 58C, D). However, more specimens from both, the Isalo type locality and from Zombitse are necessary to evaluate if the specimens from Zombitse belong to Z. isalo , n. sp. or represent an undescribed species.