Zoosphaerium tigrioculatum 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 : 144-148

Zoosphaerium tigrioculatum Wesener & Bespalova , sp. n.

Figs 9 , 10 , 17C

Etymology: From Latin tigris (tiger) and oculus (ornament).

Differential diagnosis: The shape of the posterior telopods ( Figs 9E–G ) of Z. tigrioculatum clearly identifies this species as a member of the Z. coquerelianum species-group. The presence of one large triangular membranous lobe on the fixed finger and two large membranous lobes on the movable finger ( Fig. 9G ) is a character shared only with Z. isalo Wesener, 2009 and Z. bilobum Wesener, 2009 . Z. tigrioculatum has a unique combination of characters, like crenulated teeth on the third podomere of the anterior telopods ( Fig. 9C ), separating it clearly from the latter two (Table 1).

Description:

Male.

Body length: Holotype: length 20.7 mm, width of thoracic shield 11.8 mm, height of thoracic shield 6.3 mm.

Habitus: Small, glabrous pill-millipede.

Colouration: Some discolouration may have occurred because of preservation in alcohol. Tergites anteriorly khaki coloured, followed by seaweed-green stripe, followed by dark brown margin at posterior. Dorsal side of anal shield same colour as tergites, ventral side of anal shield has light green tint. Legs bright teal under light. Head, collum and antennae dark olive-green.

Head: Eyes with ca 65 ocelli.Antennae long and thin, with cylindrical joints ( Fig. 10A ). Length of antennomeres: 1=2>3>4=5<6. Small shallow concavity at base of first antennomere ( Fig. 10B ). Many sclerotised teeth at base of antennomere 1–3. Two rows of sensilla basiconica present on first antennomere ( Fig. 10B ), isolated sensilla also present on second antennomere ( Fig. 10C ). Apical disc bearing 4 sensory cones ( Fig. 10D ). Mouthparts not dissected. Collum glabrous with few setae at corners on either side of head.

Thoracic shield: Surface like tergites.

Tergites: Surface glabrous, shiny and smooth. Under magnification (50×) tergites display leathery pattern. Under SEM, surface covered by miniscule pits holding stubby sensory hair. Tips of paratergites projecting posteriorly and fairly rounded.

Endotergum: Double row of marginal bristles of varying lengths, some extending far past edge of margin. Two rows of regularly distributed cuticular impressions between marginal ridge and inner area. Internal section with short spines and very few isolated long bristles ( Fig. 17C ).

Anal shield: Fairly well-rounded with very slight indication of bell shape because of some bulge toward dorsal side. Surface like tergites. Underside carrying 2 black locking carinae, anterior one short, about 1/4 length of posterior one. Carinae separated by a space about as long as 1/2 anterior carina.Anterior carina slightly curving towards margin of anal shield.

Legs: Tarsi 1 with 4 or 5, 2 with 6 or 7, 3 with 8 or 9, and 4–21 with 8–10 ventral spines. First 2 leg pairs with an apical spine. Tarsi of legs 4–21 with an apical spine. In leg 10 femur 1.89×, tarsi 4.70× longer than wide ( Fig. 9A ).

Stigmatic plates: First plate with triangular lobe. Lobe short and thin, pinched, triangular area at apex projecting towards coxa.

Female. Unknown.

Male sexual characters: Gonopore covered with a single, medially divided, elliptical sclerotised plate. Small apical portion of plate membranous. Covers 1/2 height and 2/3 width of coxa. Anal shield with slight bell shape, covered with very short setae.

Anterior telopods ( Figs 9B–D ): Harp with one strongly pronounced stridulation rib. Process of second podomere only slightly bent towards third podomere; apical portion facing third podomere covered with sclerotised spots. Below spots at base of projection with a sclerotised spine. Third podomere basally also including sclerotised spine. Large lobe covered by a mound of sclerotised spots located on mesal half of process, concavity on lateral half. A brown sclerotised spot located at very apex of podomere. Tiny sclerotised spine lateral to brown sclerotised spot, 3 or 4 sclerotised spines meso-apically, small sclerotised spine close to lateral margin of mound of sclerotised spots. Two sclerotised, crenulated teeth on apicolateral margin of concavity.

Posterior telopods ( Figs 9E–G ): Movable finger moderately thick (2.32× longer than wide), weakly hooking towards fixed finger. One spine located apically, second slightly below first, third at midpoint of finger. Two membranous lobes present, one at midpoint, posteriorly to spine, second between midpoint and apex. On apical posterior margin are 11 sclerotised, crenulated teeth. Fixed finger slightly shorter than movable finger, curving towards latter. Membranous lobe located basally. Tip of fixed finger covered by some sclerotised spots. Telopods shiny and glabrous except for a small patch anteriorly and laterally on first podomere. Inner lobes fairly thin. Tips of inner horns slightly curving inward.

Holotype: ơ ( CASC BLF 13757 ( CASENT 9032798 )). MADAGASCAR: Fianarantsoa Prov.: Parc National d’Andringitra, Plateau d’Andohariana, 35.9 km 205° Ambalavao , ericoid thicket, 2000 m, 22°09'08"S: 46°53'57"E, B.L. Fisher et al., 15.iv.2006.

Distribution & Ecology: Z. tigrioculatum is a giant pill-millipede species found at the highest elevation (2000 m) on Madagascar. It seems to live in the ericoid shrub above the tree line. This species has only been recorded from the summit of Andringitra ( Fig. 2 ).

New species not assigned to any existing Zoosphaerium species-groups

Currently, there are only three species, Z. subreflexum Jeekel, 1999 , Z. fisheri Wesener, 2009 and Z. analavelona Wesener, 2009 , which could not be assigned to a species-group. The two newly described species do not share any special characters with each other or with the three species mentioned above. They feature unusual characters which place them in an isolated position inside Zoosphaerium .

Figures

Fig. 9. Zoosphaerium tigrioculatum sp. n., holotype: (A) 9th left leg; (B–D) left anterior telopod: (B) anterior view, (C) posterior view, (D) lateral view; (E–G) posterior telopods: (E) anterior view, (F) posterior view, (G) right posterior telopod, posterior view, detail. Roman numerals refer to number of podomere. Abbreviations: cr-t – crenulated, sclerotised teeth, ml – membranous lobe, IH – inner horns, IL – inner lobes, s-p – sclerotised spot, SR – stridulation rib. Scale bars = 1 mm.

Fig. 10. Zoosphaerium tigrioculatum sp. n., holotype, left antenna, SEM: (A) lateral view; (B) sensilla basiconica on first antennomere; (C) sensilla basiconica on second antennomere (apomorphy of the species); (D) apical view on disc. Arrows point to sensilla. Abbreviation: sb – sensilla basiconica.

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.