Zoosphaerium ignotum, 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 : 97-100

Zoosphaerium ignotum , new species

Derivatio nominis: ignotum , adjective, refers to the unknown type locality of this species.

Studied material: 1 M, 2 F

Holotype: 1 M (30 mm long), SMF, Locus typicus: Madagascar: details unclear. Label stating "Wasserfälle des Uamotna" (= waterfalls of the Uamotna), East Coast , leg. K. L. Koch, 02.1953.

Paratypes: 2 F, SMF, same collection data as holotype .

Distribution & Ecology: Only known from the type locality, which could not be located.

Diagnosis: Up to 37 mm long. Natural coloration unknown, legs and antenna green. Texture of tergites glabrous. Anal shield well-rounded, in male covered with dense field of minute setae. Disc of antenna with 25–32 apical cones (Fig. 67B). First sternite greatly enlarged, with well-rounded tip (Figs 66A, B). Movable finger of posterior telopods almost glabrous, broad, with well-rounded tip and four sclerotized spines (Fig. 66F); posterior side with circa 15 small sclerotized teeth (Fig. 66G). Fixed finger long, slender, curved, basally with single small spine, distally with sclerotized spots (Fig. 66F). Fixed finger shorter than movable finger. Single stridulation rib on each male harp (Fig. 66D) and two on each half of female washboard. Anal shield with two locking carinae, both small, of similar length. Operculum of vulva elongated into single process (Fig. 66C). Apical-most point of tip almost planar, very weakly notched (Fig. 66C).

Similar species: Z. ignotum , n. sp. features a unique combination of characters, like a single stridulation rib on the harp (Fig. 66D), more than 20 apical cones on the antennae (Fig. 67B) and strongly protruding lateral plateau on the third podomere of anterior telopods (Fig. 66D). The shape of the female operculum is unique among all known Sphaerotheriida (Fig. 66C).

Description: Body length: Holotype male: length 30 mm, width of thoracic shield 16.7 mm, height of thoracic shield 8.6 mm. Female paratypes (2 specimens): length 37 mm, width up to 22.4 mm, height up to 11.4 mm.

FIGURE 066. Zoosphaerium ignotum n. sp., A, B, D–G holotype, C female paratype A: first left coxa and prefemur with first stigmatic plate, anterior view, B: first stigmatic plate, posterior view; C: second left coxa with vulva, posterior view; D: left half of anterior telopods, anterior view; E: last two podomeres of anterior telopod, lateral view; F: posterior telopod, anterior view; G: posterior telopod, posterior view. Abbreviations: cav = cavity; Cx = coxa; EP = external plate of vulva; IP = mesal plate of vulva; O = operculum; Pre = prefemur; s-p = sclerotized spot; scl-t = sclerotized teeth; SR = stridulation rib; St = stigmatic plate. Scale bars = 1 mm.

Habitus: Medium sized, glabrous pill millipede.

Coloration: Strongly faded after more than 50 years in alcohol. Head, collum, thoracic shield, tergites and anal shield faded light-green to light-brown colorized, posterior margin of all tergites thin, dark-brownish. Antennae and legs green.

Head: Eyes with>75 ocelli.

Antennae: Length of antennomeres: 1=2>3>4=5<<6, sixth antennomere longest, disc bearing 25–32 sensory cones (Fig. 67B). First antennomere remarkably broader than others, short, with groove and 1 or 2 rows of sensilla basiconica (Fig. 67A). Sclerotized teeth at base of antennomeres 1–5 (Fig. 67B).

Mandible: Six rows of pectinate lamellae, number of teeth declining apically to proximally (Fig. 67C). Condylus with strongly developed step near apical margin (Fig. 67C).

Gnathochilarium: Laterally of palpi 3 or 4 sensory cones, located together. Depression on posterior side of palpi with some sensory cones.

Collum: Median part of collum glabrous.

Thoracic shield: Thoracic shield surface like tergites.

Tergites: Paratergites slightly projecting posteriorly.

FIGURE 067. Zoosphaerium ignotum n. sp., paratype, SEM, A: antenna, first antennomere with sensilla basiconica (arrow); B: antenna, lateral view; C: right mandible, mesal view. Abbreviations: 3iT = 3 inner teeth; Co = condylus; eT = external tooth; mp = molar plate; pL = pectinate lamella; sb = sensilla basiconica.

Endotergum: Inner area with broad conical spines and long hair. Single row of small, circular cuticular impression, regularly distributed (Fig. 74B). Two or three rows of short marginal bristles, reaching up towards 1/3 of way to tergite margin (Fig. 74B).

Anal shield: Well-rounded, neither bell-shaped nor tapered. Completely covered with dense field of minute setae. Underside carries two same-sized, black locking carinae.

Legs: Tarsi of first pair of legs with two or three, second with three or four and third pair 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, 12 or 13 ventral spines and one apical spine. In 9th leg femur 2.1 times, tarsi 5.4 times longer than wide.

Stigmatic plates: First lobe enlarged, with well-rounded, blunt tip (Figs 66A, B).

Female sexual characters: Subanal plate with washboard, consisting of well-developed stridulation ribs, two ribs on each half. Stridulation ribs symmetrical and strong. Vulva large, covering more than 2/3 of coxa surface (Fig. 66C). Operculum large, protruding to apical edge of coxa, with one medial process. Apical margin of operculum on tip only shallowly notched. Mesal plate long and broad, reaching 1/4 to half of operculum height (Fig. 66C).

Male sexual characters: Anal shield covered with dense field of setae.

Anterior telopods (Figs 66D, E): Syncoxite on both sides with only very few, isolated hairs. First podomere broad, width greater than height, harp with one stridulation rib, rib straight, very long and welldeveloped. Second podomere process lobe-like and little curved with rounded edges, reaching up to half of third podomeres height, apically with sclerotized spots. Third podomere long, cavity mesally with numerous sclerotized spots and three sclerotized spines. One sclerotized spot located closely to tip.

Posterior telopods (Figs 66E, F): Movable finger of chela thick, 2.1 times longer than wide, weakly curved, apically tapering. Hollowed-out inner margin with four sclerotized spines, posterior aspect with circa 15 small, sclerotized teeth. Fixed finger shorter and more slender than movable finger. Fixed finger tip weakly curved, anterior side basally with single sclerotized spine and apically with numerous sclerotized spots juxtaposed. Fixed finger on both sides covered with few long hairs. Movable finger on posterior side medially with few hairs, remaining parts of posterior telopods glabrous. Inner horns of syncoxite apically curved posteriorly. Tips sharp, whole horns covered with numerous short hairs.