Zoosphaerium trichordum, 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 : 76-80

Zoosphaerium trichordum , new species

Derivatio nominis: trichordum , a composite noun in apposition, consisting of tri- for three, and chordum = chord, referring to the three stridulation ribs on the male harp, a unique feature for members of the genus Zoosphaerium .

Studied material: 2 M, 5 F.

FIGURE 051. Zoosphaerium trichordum n. sp., A female paratype, B–E holotype, A: second left coxa with vulva, posterior view; B: last two podomeres of anterior telopod, lateral view; C: right half of anterior telopods, anterior view; D: posterior telopod, anterior view; E: chela of posterior telopod, posterior view. Abbreviations: cav = cavity; cr-t = crenulated teeth; Cx = coxa; EP = external plate of vulva; IH = inner horns; IP = mesal plate of vulva; ml = membranous lobe; O = operculum; scl-t = sclerotized teeth; SR = stridulation ribs. Scale bars = 1 mm.

Holotype: 1 M (36 mm long), CAS BLF 9973 , Locus typicus: Madagascar, Province Antsiranana, Forêt d'Ampondrabe , 26.3 km 10° NNE Daraina, 12°58'12"S, 049°42'00"E, 175 m, tropical dry forest, coll. B. L. Fisher, 10.xii.2003.

Paratypes: 2 F, CAS BLF 9973 , same data as holotype .

Other material: 1 M, 3 F, CAS BLF 9871 : Province Antsiranana, Forêt de Bekaraoka , 6.8 km 60° ENE Daraina, 13°10'00"S, 049°42'36"E, 150 m, tropical dry forest, coll. B. L. Fisher, 07.xii.2003 .

Distribution & Ecology: Recorded from the dry forests of Ampondrabe and Bekaraoka in North-Western Madagascar (Fig. 50).

Diagnosis: Up to 50 mm long. Females slightly larger than males. Tergites and appendages olive-green, tergites with light brown posterior margin. Texture of tergites orange-peel like, with numerous minute impressions. Anal shield well-rounded, in males slightly bell-shaped, covered with numerous minute hairs. Hairs on anal shield and on anterior half of tergites standing in minute impressions. First antennomere with groove (Fig. 52A) and sensilla basiconica (Fig. 52C), disc with 35–45 apical cones (Fig. 52D). Movable finger of posterior telopods broad, on both sides completely covered with dense field of long hair, only on well-rounded tip glabrous (Figs 51D, E). Movable finger with triangular membranous lobe and three sclerotized spines (Fig. 51D), posterior side with circa 8–10 small, sclerotized teeth (Fig. 51E). Fixed finger long and slender, basally with single small spine, distally with numerous sclerotized spots (Fig. 51D). Fixed finger almost as long as movable finger. Three stridulation ribs on male harp (Fig. 51C), posterior side of anterior telopods third podomere laterally with two sclerotized teeth (Fig. 51B). Anal shield with two locking carinae, first small, second 3 or 4 times longer than first, both carinae located towards laterotergites. Females with two or three stridulation ribs on each side of female washboard, operculum of vulva with two wellrounded, same sized tips not protruding above coxa (Fig. 51A).

Similar species: Z. villosum Wesener & Sierwald, 2005 displays tergite texture and antenna features similar to Z. trichordum , n. sp.. The latter is the only species in Zoosphaerium with three stridulation ribs on each male anterior telopod (Fig. 51C). The pubescence pattern of the posterior telopods third podomere (Figs 51D, E) is unique in the Z. coquerelianum species-group.

FIGURE 052. Zoosphaerium trichordum n. sp., paratype, SEM, antenna A: antennomeres 1–3, lateral view; B: antennomeres 4–6, lateral view C: 5th antennomere with sensilla basiconica; D: apical view on disc. Abbreviation: sb = sensilla basiconica

Description: Body length: Males (2 specimens): length up to 36 mm, width of thoracic shield up to 20.2 mm, height of thoracic shield up to 10.5 mm. Females (5 specimens): length up to 49 mm, width up to 25.4 mm, height up to 14.4 mm. Too few specimens are known to prove statistically that females are larger than males. All known females are larger than males.

Coloration: Faded in alcohol. Head, collum, thoracic shield, tergites and anal shield olive green with light brown posterior margins. Antennae and legs dark green. In some specimens, all olive green is replaced by brown (because of alcohol influence?).

Head: Eyes with>75 ocelli.

Antennae: Length of antennomeres: 1<2>3>4=5<6 (Figs 52A, B), sixth antennomere longest, bearing disc with 35–45 sensory cones (Fig. 52D). First antennomere remarkably broader than the others (Fig. 52A), short, with groove and two rows of sensilla basiconica (Fig. 52C). Sclerotized teeth at base of antennomeres 1–5 (Figs 52A, B).

Mandible: Five rows of pectinate lamellae, number of teeth declining apically to proximally (Fig. 53). Condylus with two strongly developed steps (Fig. 53).

FIGURE 053. Zoosphaerium trichordum n. sp., paratype, SEM, right mandible, dorsal view. Abbreviations: 3iT = 3 inner teeth; Co = condylus; eT = external tooth; mp = molar plate; pL = pectinate lamella.

Gnathochilarium: Lateral of palpi four sensory cones, located together. Depression on posterior side of palpi with some sensory cones.

Collum: Whole surface of collum covered with isolated hair of medium length.

Thoracic shield shaped like in other species of the genus.

Tergites: Texture resembles those of an orange-peel. Anterior half of tergites with numerous hairs standing inside shallow pits. Paratergites projecting slightly posteriorly.

Endotergum: Inner area with broad conical spines and long hair. Single row of large, elliptical cuticular impressions present, regularly distributed (Fig. 63B). Three rows of marginal bristles, slightly extending beyond tergite (Fig. 63B).

Anal shield: Sexually dimorphic, in females well-rounded, neither bell-shaped nor tapered. Covered with numerous hairs standing in minute impressions. Underside carries two well-developed black locking carinae, anterior one small, but well developed. Posterior carina 3.5–4 times longer than first, straight. Carinae located closer to laterotergites than towards anal shield margin.

Legs: Tarsi of first pair of legs with five or six, second with seven or eight and third with 9 or 10 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 2.0 times, tarsi 5.5 times longer than wide.

Stigmatic plates: First lobe triangular, with pointed tip.

Female sexual characters: Subanal plate with washboard, consisting of well-developed stridulation ribs, two ribs on each half. Stridulation ribs symmetrical and strong. Vulva operculum large, reaching up to apical edge of coxa, with two well-rounded, same sized lobes (Fig. 51A). Apical margin of operculum medially notched, basal margin straight. Mesal plate long and broad, protruding to half of operculum height (Fig. 51A).

Male sexual characters: Anal shield weakly bell-shaped.

Anterior telopods (Figs 51B, C): Harp with three stridulation ribs, mesal rib part of inner margin, medial rib shortest, lateral rib longest. All three ribs straight and well-developed. Second podomere process lobe-like and little curved with rounded edges, protruding up to half of third podomeres height, apically with sclerotized spots and single spine. Third podomere long mesal margin of third podomere anteriorly located on lower level than apex of joint. Cavity mesally with numerous sclerotized spots and two sclerotized spines, laterally with two crenulated, small teeth. One sclerotized spot located closely to tip.

Posterior telopods (Figs 51D, E): Movable finger of chela thick, 2.0 times longer than wide, weakly curved, apically slightly tapering. Hollowed-out inner margin with three sclerotized spines and one short lobe; posterior aspect with one row of circa 8–10 small, sclerotized teeth. Fixed finger slenderer but as long as movable finger, tip of former weakly curved. Anterior side of fixed finger basally with one short sclerotized spine, apically with numerous sclerotized spots. Fixed finger on both sides covered with dense field of long hair. Third podomere on both sides covered completely with dense field of long hair, leaving only out small, glabrous area around tip. Inner horns of syncoxite apically curved. Tips pointed, whole horns covered with numerous short hairs.