Zoosphaerium heleios Wesener & Bespalova, 2010

Wesener, Thomas, Bespalova, Ioulia & Sierwald, Petra, 2010, Madagascar’s living giants: discovery of five new species of endemic giant pill-millipedes from Madagascar (Diplopoda: Sphaerotheriida: Arthrosphaeridae: Zoosphaerium), African Invertebrates 51 (1), pp. 133-133 : 152-157

Zoosphaerium heleios Wesener & Bespalova , sp. n.

Figs 14– 16 , 17E

Etymology: From Greek helos (marsh), meaning “of a marsh”, referring to the unusual type locality of this species.

Differential diagnosis: Z. heleios cannot be assigned to any of the existing species-groups, neither does it share any similarity in the posterior telopods ( Figs 15A–C ) with those species currently not assigned to any group ( Z. fisheri Wesener, 2009 and Z. analavelona Wesener, 2009 ). There are some similarities in the general shape of the posterior telopods to those of Z. corystoides Wesener, 2009 and Z. ambrense Wesener, 2009 , with a strongly elongated, slender movable finger and a much shorter fixed finger ( Figs 15A–C ), but Z. heleios differs from those two species in almost all other aspects, like the shape of the anterior telopods, endotergum, female vulva and antenna. Z. heleios differs from all other Zoosphaerium species in the presence of a (reduced?) very narrow operculum ( Fig. 14D ) of the female vulva.

Description:

Male.

Body length: Holotype: length 25.0 mm, width of thoracic shield 13.5 mm, height of thoracic shield 7.2 mm.

Habitus: Small sized, mostly glabrous pill-millipede.

Colouration: Some discolouration may have occurred because of preservation in alcohol. Tergites dark chestnut, with dark olive-green on indent of paratergites, on concave lateral extension of thoracic shield, on ventral side of tergites, and on legs (olive-green colour only seen well under bright light). Head and antennae dark olive-green, with yellow undertones. Collum dark chestnut fading to dark olive-green towards head.Anal shield as tergites.

Head: Eyes with 83–87 ocelli.Antennae long and thin, with cylindrical joints ( Fig. 16A ). Length of antennomeres: 1=2=3>4<5<6. First antennomere with groove and two rows of sensilla basiconica ( Fig. 16A ). Sclerotised teeth prominently present on antennomeres 1–5. Apical disc bearing 31–42 sensory cones ( Fig. 16B ). Mouthparts not dissected. Sparse field of isolated setae all over collum, mostly located at margin closest to head.

Thoracic shield: Surface like tergites, except for a field of short hairs at margin nearest to head.

Tergites: Surface appears to have small depressions like an orange peel (50×). Very few short isolated setae found on posterior margin of paratergites. Tips of paratergites projecting posteriorly, forming blunt points.

Endotergum: Double row of marginal bristles reaching past edge of margin. Single row of irregular, circular cuticular patterns. Internal section with short spines and very few isolated long bristles ( Fig. 17E ).

Anal shield: Glabrous, top well rounded, lower margin slightly tapering downwards posteriorly ( Figs 14A, B ). Underside with 2 black locking carinae; anterior one short, about 1/3 length of posterior one. Carinae separated by a space about as long as 1/2 anterior carina. Posterior carina slightly rounded towards margin of anal shield.

Legs: Tarsi 1 with 4 or 5, 2 with 7 or 8, 3 with eight, and 4–21 with 9–11 ventral spines. First two leg pairs without an apical spine. Tarsi of legs 3–21 with an apical spine. In leg 10, femur 2.08×, tarsi 4.8× longer than wide ( Fig. 14C ).

Stigmatic plates: First plate with triangular lobe. Lobe short and stout, apex very thin and strongly curving towards coxa.

Male sexual characters: Gonopore covered with a single undivided, elliptical sclerotised plate. Apical portion of plate membranous. Covers 2/3 height and 2/3 width of coxa. Top of anal shield fairly well rounded, a little humped, lower margin at posterior end tapering downwards ( Fig. 14A ). Upper surface covered by a sparse carpet of very short setae, lower surface glabrous.

Anterior telopods ( Figs 14G–I ): Harp with two strongly pronounced stridulation ribs – upper rib protrudes robustly, creating a sort of triangular plateau. A few tiny sclerotised spines located basally on lateral part of first podomere. Lateral edge of syncoxite near first podomere also with many tiny sclerotised spines. Second podomere process has rectangular mound of sclerotised spots apically, directly juxtaposed to large mound of sclerotised spots on third podomere. Third podomere’ s sclerotised mound takes up 2/3 of process, and laterally a fairly deep concavity rimmed by podomere’s lateral margin takes up 1/3. Sclerotised spine located on lateral rim of mound, and another at base of mound. Lateral apical margin has 5–7 sclerotised, crenulated teeth, 2 or 3 sclerotised spines at apex, and 2 brown sclerotised spots mesally of spines.

Posterior telopods ( Figs 15A–C ): Movable finger rather elongated (3.19× longer than wide), weakly curving towards fixed finger. Four sclerotised spines on mesal side in shallow cavity; 1 apically, 1 at median of cavity, and 2 (one positioned below the other) at base of cavity. On meso-apical posterior margin are 16 or 17 sclerotised teeth. Fixed finger slightly shorter than movable finger, hooking towards latter. Sclerotised spots on apicolateral part of fixed finger. Movable finger anteriorly and posteriorly except for area around apex densely covered in long hairs. Second podomere anteriorly, as well as mesal portion of fixed finger, covered in hairs. First podomere mostly glabrous except for a small patch on mesal margin facing inner horns.

Female.

Body length: Paratypes: length up to 32.6 mm, width of thoracic shield up to 16.3 mm, height of thoracic shield up to 9.4 mm.

Female sexual characters: Vulva large, covering more than 3/4 of coxa ( Fig. 14D ). Operculum short, flat and disc-shaped, with shallowly indented middle. Mesal plate long and fairly thin, extending beyond coxa and operculum, and hooking towards prefemur, covered apically in long hairs. Suture between inner and outer plates containing some sort of structure under membrane of which two parallel strips poke up and out of membrane ( Fig. 14E ). Subanal plate with washboard possessing up to 3 stridulation ribs on each half; 2 long and well-developed, a third short rib sometimes present mesally ( Fig. 14F ). Holotype: ơ ( CASC BLF 10673 ( CASENT 9032796 )). MADAGASCAR: Toamasina Prov.: Torotorofotsy , on low vegetation, marsh edge, montane rainforest, 1070 m, 18°52'15"S: 48°20'51"E, leg. Malagasy ant team, 28.iii.2004.

Paratypes: 1ơ 2^2 immatures ( CASC BLF 10673 ), same data as holotype .

Distribution & Ecology: Z. heleios is currently only known from the marshes of Torotorofotsy ( Fig. 2 ). This species is the only Malagasy giant pill-millipede species ever recorded from marshes.

Description of new females

Figures

Fig. 14. Zoosphaerium heleios sp. n., (A–C, G–I) holotype; (D–F) female paratype: (A) anal shield, lateral view; (B) anal shield, dorsal view; (C) 9th left leg, posterior view; (D) coxae and prefemura of second leg pair with vulvae, posterior view; (E) second right coxa with vulva, detail; (F) female subanal plate with washboard and stridulation ribs; (G–I) left anterior telopod: (G) anterior view, (H) posterior view, (I) lateral view. Roman numerals refer to number of podomere.Abbreviations: 12T – tergite 12, AS – anal shield, cr-t – crenulated, sclerotised teeth, Cx – coxa, EP – external, lateral plate of vulva, IP – inner, mesal plate of vulva, ml – membranous lobe, Pre – prefemur, s-p – sclerotised spot, s-ps – sclerotised spots, SR – stridulation rib. Scale bars = 1 mm.

Fig. 15. Zoosphaerium heleios sp. n., holotype, posterior telopods: (A) anterior view; (B) posterior view; (C) right posterior telopod, posterior view. Roman numerals refer to number of podomere.Abbreviations: cr-t – crenulated, sclerotised teeth, IH – inner horns, IL – inner lobes, s-ps – sclerotised spots. Scale bars = 1 mm.

Fig. 16. Zoosphaerium heleios sp. n., holotype, left antenna, SEM: (A) lateral view, (B) sensilla basiconica on 1st antennomere, (C) apical view on disc.

Fig. 17. Endoterga of tergites 10, arrows point to cuticular impressions: (A) holotype of Zoosphaerium muscorum sp. n., (B) holotype of Z. bambusoides sp. n., (C) holotype of Z. tigrioculatum sp. n., (D) holotype of Z. darthvaderi sp. n., (E) holotype of Z. heleios sp. n.Abbreviations: ci – cuticular impressions, IA – inner area with spines and long setae, mr – marginal ridge, mb – marginal bristles.

Fig. 2. Distribution map of new Zoosphaerium species.