Zoosphaerium alluaudi ( DeSaussure and Zehntner, 1897 )

Wesener, Thomas & Sierwald, Petra, 2005, New giant pill-millipede species from the littoral forest of Madagascar (Diplopoda, Sphaerotheriida, Zoosphaerium), Zootaxa 1097 (1), pp. 1-60 : 8-19

Zoosphaerium alluaudi ( DeSaussure and Zehntner, 1897)

Figs 1–8

Zoosphaerium alluaudi DeSaussure and Zehntner, 1897 , publication of figure

Zoosphaerium alluaudi ,— DeSaussure and Zehntner 1902, publication of description Zoosphaerium alluaudi ,— Jeekel 1999 (lists species name)

Zoosphaerium alluaudi ,— Enghoff 2003 (lists species name)

Lectotype: 1 m. (designated herewith), MNHN CB006 . Locus typicus: Madagascar; Province Toliara; Fort Dauphin ; leg. Ch. Alluaud.

Lectoparatypes: 2 f. (designated herewith), MNHN CB006 , same data as lectotype .

Other Material: 1 m., 2 f., FMNH ; 1 m., 1 f., CAS ; 1 m., 1 f., ZSMC . Locality:

Madagascar; Province Toliara; Foret Petriky ; littoral forest with dry forest elements; collected from wet leaf litter; 25°03'S 046°53'E; 17.IV.2003; leg. T. Wesener. 1 m., 3 w. same collection data. These specimens were sent to the Université de Antananarivo / Madagascar. 1 f. (immature); Foret Petriky ; littoral forest with dry forest elements; 10m NN; 25°3.72' S, 046°52.16' E; leg. 22.IX.1998; FMNH 4063

Diagnosis: Up to 43 mm long. Both sexes of equal size. Color olive­green, tergites at posterior margin brown. Surface of tergites smooth and glabrous. Joints 1–5 of antennae with sclerotized teeth. Apical joint with 4 sensorial cones. All antennal joints without a groove ( Figs. 4 a–c ). 3rd joint of posterior telopods (leg pair 23) remarkably thick ( Figs 3e–f ). Two stridulation ribs on each male harp and each side of female washboard ( Figs 2c , 3a ). Two well­developed black locking carinae on each side of the anal shield, posterior carina 2­times longer than anterior carina ( Fig. 2a ).

Similar species: Some species of the alluaudi ­group are very similar to Z. alluaudi . See Table 1 for separation of these species.

Description: Body length: males (4 specimens): length up to 42.5 mm, width of thoracic shield up to 21.5, height of thoracic shield up to 11.6. Females (7 specimens): length up to 43.0, width up to 23.1, height up to 11.6. Both sexes of equal size.

Habitus: the thoracic shield is remarkably high ( Fig. 1a ). Tergites very smooth and hairless.

Coloration: tergites olive­green, posterior margin with a thin brown line. Head, antennae and legs also olive­greenish. Preserved specimens darken in alcohol.

Head: with numerous hairs and hair­pits especially around the labrum and lateral of eyes. Some single, long hairs around the eyes and distributed on the entire head. Posterior margin of head towards the collum with a patch of small hairs.

Antennae: shape as in the description of the genus. Length of antennomeres: 1>2>3=4=5<6; sixth antennomere longest, of cylindrical shape ( Figs. 4a ) with four sensory cones ( Fig. 4c ). First antennomere remarkably broader than the others ( Fig. 4b ). Sclerotized teeth at the base of antennomere 1–5, reaching apical border only on first antennomere.

Mandible: with seven rows of pectinate lamellae; number of teeth declining from apical to proximal ( Figs. 8a–b ). Condylus with two ridge­like impressions and one strong developed step near the apical margin ( Fig. 8c ).

Gnathochilarium: ventral side with many bristles, only few on the lingual lamella ( Fig. 5a ) (homology of gnathochilarial sclerites with those found in the helminthomorph millipedes uncertain, see Hoffman, 1976: 125). Lateral of palpi a field with four sensory cones, all four located together ( Figs 5b–c ). Two different types of sensory cells on central pads: long, cylinder­shaped ones with a pit in their middle and more plain ones without a pit ( Figs. 6a–b ). Epipharynx: similar shape in all known species of giant pill­millipedes ( Figs 6c , 7a ) (see Verhoeff, 1928, p. 841; Wesener & Sierwald, in press).

Collum: anterior margin with long, isolated hairs, standing in two rows, posterior margin with 2–4 hairs, edges with up to five long hairs. Remaining parts of collum bald.

Thoracic shield (enlarged 2 nd tergite, =Brustschild sensu Verhoeff, 1928: 473): with few hairs in the concave lateral extension of the thoracic shield („Brustschildgruben“), especially located near the margins. Anterior marginal brim only little broader than the rest of the brim ( Fig. 1a ).

Tergites: anterior paratergite depressions (called ëSeitenlappení by Verhoeff, 1928: 385) of tergites 3–12 with few, isolated hairs, on the anterior margin a few ribs and some sclerotized spots ( Fig. 1b ). Tips of the posterior margins of paratergites slightly projecting posteriorly. Tergites smooth and glabrous, except for the anterior paratergite depression.

Endotergum: with one, rarely two rows of marginal bristles. Internal section with short spines and very few, isolated bristles. Between marginal ridge and internal area one row of rounded nodules. Marginal ridge lightly undulating towards the nodules ( Fig. 7b ). Bristles scaly ( Fig. 7c ).

Anal shield: rounded, neither bell­shaped nor tapered ( Fig. 1a ). In contrast to the glabrous tergites in both sexes, covered with many small (sensory?) hairs. Ventral side carries two black locking carinae on both sides, anterior one similar to those of tergites, posterior carinae three times longer than anterior one, posteriorly closer to the margin than anteriorly. Locking carinae separated from each other by a distance equal to the length of the shorter carina. Distinct suture present in the space between both carinae representing the border of a 13 th tergite fused with the anal shield. Where the suture reaches the margin of the anal shield, a small, distinct triangular invagination is visible ( Fig. 2a ).

Legs: tarsi of first and second pair of legs with only seven ventral spines, weakly curved claws and without apical spine. Tarsi of legs 3–21 with curved claws, 11–13 ventral spines and one apical spine. 9th leg pair with no coxal lobe, but a small, well­ rounded outer rim covered with many small, black triangular spines ( Fig. 1c ) on coxa. Coxae of all legs at the inside margin covered with a patch of long hairs, the following leg joints with some isolated, long hairs at the inner margin. Femora of all legs with a crenulated ridge ( Fig. 1c ).

Sternite: First sternite lobe long, reaching above the apical edge of the coxae of first leg pair, covered sparsely with hairs and curved towards the coxa ( Fig. 1e ). Anterior smooth covered with some isolated, long hairs. Posterior margin hairless, but with one row of small, triangular black spines ( Fig. 1e ). Sternites three and beyond with a spinelike process which reaches almost the stigma opening of the more anterior sternite.

Female sexual characters: second leg pair without coxal lobe, but on exterior margin with some short, triangular black spines. Subanal plate with washboard, consisting of well­developed stridulation ribs, two ribs on each side. Stridulation ribs symmetrical and short, ending just above the middle line of the subanal plate ( Fig. 2c ).

Vulvae large, covering more than 2/3 of the coxa. Operculum short, ending before the apical edge of coxae. Apical margin of operculum constricted in the middle (subreniform) with two rounded lateral tips. Space between the tips invaginated. Invagination dividing operculum in two nearly same­sized parts; operculum without a median suture. Interior tip of operculum reaching higher than the exterior tip. Basal margin of operculum straight.

Exterior and inner plates (EP, IP) of vulva below the operculum surrounding the basal margin of the operculum. Inner plate long and broad, reaching almost as high as the operculum. Exterior plate not as long as the inner one, reaching only to first quarter of the operculum. Posterior margins of both inner and exterior plate with short, triangular black spines ( Fig. 2b ). Cyphopod sclerites consisting of two triangular apical sclerites and a much larger third sclerite formed like a tuning­fork, all visible as dark structures near the suture of the vulva between inner and exterior plate ( Fig. 2b ).

Male sexual characters: second leg pair without coxal lobe, but on exterior margin with some short, triangular black spines and covered with many hairs. Male gonopore (located at inside margin of 2 nd coxae, called penes and pseudopenes by other authors, see Wesener & Sierwald in press) covered with a big, sclerotized, undivided and rounded plate. Apical part of plate membranous ( Fig. 2d ). Anal shield without any invagination or other sexual dimorphism.

Anterior telopods: syncoxite of anterior telopods on both sides without hairs. First joint with a stridulation harp and two stridulation ribs. Inner ridge short, reaching only 1/3 of the length of the lateral one. Lateral ridge long, beginning at the basal margin of the first joint and ending just at its apical margin ( Fig. 3a ). Posterior side of the first joint inside with a longitudinal depression ( Fig. 3c ). Margins of depression laterally with one row of hairs, otherwise surface hairless. Second joint on posterior side rectangular with rounded edges ( Figs 3b–d ). Point of process reaching 2/3 of the height of third joint. Towards the third joint with sclerotized spots and one spine ( Fig. 3d ). Apical margin of third joint well rounded, reaching inside higher than outside. Inner side arched strongly towards the process of the second joint, on the inner margin of the invagination with numerous sclerotized spots and three spines, juxtaposed the sclerotized structures of the second joints process ( Figs 3b, 3d ).

Posterior telopods: movable finger (3rd joint) of chela enlarged. Invagination towards the immovable process of the second joint with three non­sclerotized spines, on posterior side with one short row of crenulated teeth. Immovable digit (process of 2nd joint) with slightly curved tip. Anterior side basally with one spine, apically with sclerotized spots juxtaposed the invagination of the third joint. Chelae only at margins with a few isolated hairs, on rest of surface hairs absent. First joint basally with some small, black triangular spines ( Figs 3e–f ). Inner horns (IH) of syncoxite (=coxal horn sensu Van Den Spiegel, 2002 = “Hörner des Syncoxits” Verhoeff) with a pointed tip ( Fig. 3e ).

Distribution & Ecology: This species appears to be endemic in the littoral forest fragment of Petriky. This forest shows a transition between southern spiny forest and the more northern hylaea­forest, making the ecological condition unique; its plant species composition is unique when compared to other Malagasy littoral forests ( Dumetz 1999). Zoosphaerium alluaudi was the only sphaerotheriid species collected in this area. At the beginning of the dry season, the leaf litter was rather thick (30 cm) and dry. Moist leaf litter accumulated under a few isolated trees. Zoosphaerium alluaudi was collected only from the moist leaf litter. No juveniles were collected. One female contained bright orange to yellowish eggs, measuring about 1 mm in diameter. After dissection of female, 1539 eggs were counted, a few eggs (not counted) were lost during dissection.

Conservation: The conservation of this species is directly linked to the future of the forest Petriky. This forest is the largest still existing fragment of the southern littoral forest in Madagascar. Unfortunately, this forest is still damaged, patches of trees are separated from each other, sometimes even single trees are separated from each other by sandy areas without vegetation. Moist leaf litter was found only under trees. The forest is under significant human pressure through wood removal and grazing animals from surrounding fishing villages. The anticipated, extensive mining project in this area ( Vincelette et al. 2003) will result in a complete destruction of the remaining forest of Petriky, preserving only a very small area of 60 ha of indigenous forest. Hence, Z. alluaudi is a highly endangered species, which will not survive the next ten years, if current human activities continue and no conservation efforts are made.

Intraspecific variation: Body length of females is not significant higher than those of males. The number of stridulation ribs on the female washboard correlates with the size of female, but is constant in mature ones. Surprisingly, even very small males (20 mm body length) show fully developed telopods.

Figures

FIGURES 1 A–E: Z. alluaudi, male FMNH, a: habitus, b: 7th paratergite; c: 9th left leg, posterior view; d: 5th left pleurite; e: coxa and prefemur of 1st left leg with 1st left sternite, posterior view. S = sternite. Scale bars = 1 mm.

FIGURES 2 A–D: Z. alluaudi, a: female FMNH, left side of the anal shield (As); b: female FMNH, coxa of 2nd left leg with vulva, posterior view; c: female FMNH, subanal plate with washboard; d: male FMNH, coxa of 2nd left leg with male gonopore. As = Anal shield; O = Operculum; IP = inner plate; EP = exterior plate; 12T = 12th tergite. Scale bars = 1 mm

FIGURES3 A–F: Z. alluaudi, male FMNH. a: left anterior telopod, anterior view; b: right anterior telopod, 3rd joint, inner view; c: right anterior telopod, joint 1–3, posterior view; d: right anterior telopod, joint 2–3, inner view from above; e: left posterior telopod, anterior view; f: left posterior telopod joint 1–3 with left inner horn and inner lobe, posterior view. IH = inner horn. Scale bars = 1 mm

FIGURES4 A–C: Z. alluaudi, female FMNH, SEM, right antennae. a: lateral view; b: joints 1 and 2; c: apical view on sensorial cones.

FIGURES 5 A–C: Z. alluaudi, female FMNH, SEM, gnathochilarium. a: ventral view; b: right palpi, arrow = field of sensorial cones; c: field of sensorial cones. cP = central pads, LL = lingual lamella, P = palpus.

FIGURES 6 A–C: Z. alluaudi, female FMNH, SEM. a: gnathochilarium, central pads; b: gnathochilarium, sensorial cones on central pads; c: epipharynx, ventral view. cP = central pads, P = palpus.

FIGURES 7 A–C: Z. alluaudi, female FMNH, SEM. a: epipharynx, distal; b: endotergum, (1) = marginal ridge with external row of marginal bristles, (2) = band of flattened nodules, (3) = internal area; c: marginal bristle of endotergum.

FIGURES 8 A–C: Z. alluaudi, female FMNH, SEM, left mandible. a: overview; b: pectinate lamella; c: condylus. 3 aT = three anterior teeth, aT = apical tooth, cT = comb teeth, iL? = intermediate lobe, mp = molar plate, mpp = molar plate process.