Seven new giant pill-millipede species and numerous new records of the genus Zoosphaerium from Madagascar (Diplopoda, Sphaerotheriida, Arthrosphaeridae)

Seven new species of the giant pill-millipede genus Zoosphaerium Pocock, 1895 are described from Madagascar: Z. nigrum sp. nov., Z. silens sp. nov., Z. ambatovaky sp. nov., Z. beanka sp. nov., Z. voahangy sp. nov., Z. masoala sp. nov. and Z. spinopiligerum sp. nov. All species are described based on drawings and scanning electron microscopy, while genetic barcoding of the COI gene was successful for six of the seven new species. Additional COI barcode information is provided for the fi rst time for Z. album Wesener, 2009 and Z. libidinosum (de Saussure & Zehntner, 1897). Zoosphaerium nigrum sp. nov. and Z. silens sp. nov. belong to the Z. libidinosum species-group, Z. ambatovaky sp. nov. to the Z. coquerelianum species-group, Z. beanka sp. nov., Z. voahangy sp. nov. and Z. masoala sp. nov. to the Z. platylabum species-group and Z. spinopiligerum sp. nov. to the Z. piligerum species-group. Updated identifi cation keys are provided for each species-group. Two western dry forest species, Z. silens sp. nov. and Z. voahangy sp. nov. are recorded from two localities, while the other fi ve species are currently only known from their type localities. Of special conservation concern might be Z. ambatovaky sp. nov. from the lowland rainforest fragment of Ambatovaky, a nowadays isolated lowland rainforest, rapidly shrinking due to slash and burn agriculture. In addition to the new species, new locality data is provided for 11 species and numerous unidentifi able species of Zoosphaerium: Z. neptunus (Butler, 1872), Z. platylabum (de Saussure & Zehntner, 1902) and Z. piligerum (de Saussure & Zehntner, 1897) from the central eastern montane forests, as well as Z. ambrense Wesener, 2009, Z. aureum Wesener, 2009, Z. libidinosum, Z. corystoides Wesener, 2009, Z. discolor Wesener, 2009, Z. smaragdinum Wesener, 2009, Z. villosum Wesener & Sierwald, 2005 and Microsphaerotherium anjozorobe Wesener, 2009.


Introduction
Madagascar, located off the eastern coast of Africa, has been isolated from other continents for more than 120 my. Its separation from India took place ca 90 my ago (Krause 2003;Ali & Aitchison 2008). As a result of this long period of isolation, many Malagasy plant and animal groups have a high percentage of endemics, making the island an import biodiversity hotspot (Myers et al. 2000). Around 86% of the occurring invertebrate species solely live on Madagascar (Goodman & Benstead 2005). Some of the most striking members of this endemic mega-invertebrate fauna belong to the millipedes, order Diplopoda. The so-called fi re millipedes of the order Spirobolida have a conspicuous red and black coloration (Wesener et al. 2009a(Wesener et al. , 2009b(Wesener et al. , 2011a, whereas giant pill-millipedes of the order Sphaerotheriida possess stridulation organs in both sexes (Wesener & VandenSpiegel 2009;Wesener et al. 2011b) and (only on Madagascar) can reach the size of a small orange when rolled-up (Enghoff 2003). During the last 12 years, numerous new species and genera of both groups have been described from the island (Wesener et al. , 2011aWesener , 2011Wesener & Enghoff 2009).
All Malagasy giant pill-millipedes belong to the family Arthrosphaeridae, which comprises four genera. Three genera are strictly endemic to Madagascar, while a fourth genus is found in southern India and Sri Lanka (Wesener & VandenSpiegel 2009;Wesener et al. 2010a). This peculiar biogeographic pattern represents the shared connection between Madagascar and India until 90 my ago. Species of the geographically closest family, Sphaerotheriidae, are found in South Africa. The strictly endemic Malagasy giant pill-millipedes belong to the genera Sphaeromimus de , Microsphaerotherium Wesener & VandenSpiegel, 2007and Zoosphaerium Pocock, 1895 In the genus Zoosphaerium, comprising the vast majority of species, 42 new species have been described since 2005. Many of these species are endemic to very restricted geographical areas and are therefore listed as critically endangered on the IUCN Red List (e.g., Rudolf & Wesener 2017a, 2017b. In an eff ort to understand Madagascarʼs role as a major biodiversity hotspot, two general inventory programs have recently been undertaken: one organized by the Field Museum, Chicago and headed by Steve Goodman and his team, and a second organized by the California Academy of Sciences, headed by Brian Fisher and his team. Both programs yielded numerous samples of Malagasy giant pill-millipedes. In total, these samples contained specimens of 11 already described species as well as seven new species which are described here. Table 1. Material examined for molecular data. CAS = California Academy of Sciences, San Francisco; FMNH = Field Museum of Natural History, Chicago; MZUF = Museum "La Specola", Florence, Italy; ZFMK = Zoological Research Museum Alexander Koenig, Bonn, Germany. Specimens marked by an asterisk (12) were newly sequenced for this study. M = Madagascar.

Species Voucher number Genbank # Locality
Procyliosoma leae (Silvestri, 1917 (Brolemann, 1922) 14. Anal shield glabrous, golden. Tergites with unique pitch-black/reddish-brown pattern.   and Z. pulchellum . These include the presence of two locking carinae, four apical cones on each antenna, and shiny, glossy tergites. Moreover, the second and third podomeres of the posterior telopods are covered with numerous minute hairs. Zoosphaerium nigrum sp. nov. diff ers from these two species in the black coloration (jade-like green in the others), the presence of only a single weak stridulation rib on the anterior telopod and diff erently shaped podomeres.

Etymology
'Nigrum', adjective, after the dark colour of the species.

C
. Some discoloration may have occurred because of preservation in ethanol. Tergites, head, anal shield and appendages dark green to black ( Fig. 2A). Posterior margin of tergites with a thin brown margin.

G
. Not dissected.  S . First stigmatic plate triangular, apex well rounded, nearly as wide as at base. Mesal margin straight, not curved towards coxa. Hair most abundant on apical margin, very few hairs on basal and lateral margins (Fig. 4C).

P
. First pleurite laterally modifi ed and extending backwards with a broad, apically rounded process. Other pleurites well-rounded.

C
. Glabrous with very sparse setae around margins, mostly located at corners on either side of head. T . Smooth and glabrous, without protuberances.
T . Surface glabrous and shiny, lacking small pits. Tips of paratergites of midbody tergites projecting posteriorly.

E
. Inner section with numerous short triangular spines and very few longer setae. Middle area above spines with single row of sparse, circular cuticular impressions slightly varying in size. Apically a single row of short marginal bristles, protruding to ⅔ distance to tergite margin. Bristles with numerous small spines (Fig. 5A). A . Large and slightly bell-shaped. Several tiny setae present in posterior part. Underside with two black locking carinae, posterior one 2 times as long as anterior one, both located close to anal shield margin.

Male sexual characters G
. Covered with a single undivided, rounded membranous plate (Fig. 4B).
A . Harp with a single weak stridulation rib (Fig. 4E). First podomere with only a few setae, restricted to apical parts of lateral margins, 1.5 times wider than long. Process of second podomere as long as ⅔ of third podomere, not visible in anterior view, with apical mound of a few sclerotized spots juxtaposed to third podomere. Third podomere without sclerotized teeth, but with a conspicuous process carrying sclerotized spots ( Fig. 4F-G); base of process with four spines (Fig. 4G). Second and third podomeres sparsely setose.

P
. Movable fi nger weakly curved; hollowed-out inner margin with two non-sclerotized lobes and ca three smaller sclerotized spines, posterior aspect with ca 29 crenulated teeth. Fixed fi nger thinner than movable fi nger, with slightly curved tip; basally with single membranous lobe, on inner margin covered with numerous sclerotized spots. Second and third podomeres without any long hair, but on both sides densely covered with very small pits, one very small seta standing in each pit. First podomere without those pits but with some isolated, standard longer hairs.

Female
Unknown.

Distribution and ecology
Zoosphaerium nigrum sp. nov. is currently known only from the montane rainforests of Midongy-Befotaka (Fig. 3) where it coexists with another species of the genus, Z. spinopiligerum sp. nov. (see below), as well as with a species of the genus Sphaeromimus (Moritz & Wesener 2017).

Diagnosis
The posterior telopods ( Fig. 6H-I) identify Z. silens sp. nov. as a member of the Z. libidinosum speciesgroup. Zoosphaerium silens sp. nov. shares the absence of locking carinae with a number of spiny forest species. It diff ers from all other species except Z. libidinosum in the color of the tergites, the glabrous anal shield and the presence of at least two rows of very long endotergal bristles. Zoosphaerium silens sp. nov. diff ers from Z. libidinosum in the wider tarsus (3.5 versus 3.8 times as long as wide), the presence of only two rows of endotergal bristles (three rows in Z. libidinosum) and the absence of a lateral triangular projection on the third podomere of the anterior telopods (present in Z. libidinosum).
Z. silens sp. nov. diff ers by more than 14% uncorrected p-distance in the COI gene from Z. album and Z. libidinosum.

Etymology
'Silens' (= 'quiet'), noun in apposition, after the reduced stridulation ribs in the male. . Some discoloration may have occurred because of preservation in ethanol. Tergites dorsally orange to brown, especially at posterior margin, laterally green except for paratergite depressions which are yellow. Anal shield light brown to yellowish dorsally as well as posteriorly, laterally green. Thoracic shield green, but grooves and margins yellow-brownish (Fig. 2B). Head and antennae green, legs basally light brown, apically green.

G
. Not dissected. S . First plate triangular, apex well rounded, nearly as wide as at base. Mesal margin slightly curved towards coxa. Hairs most abundant on apical margin, very few hairs on basal and lateral margins (Fig. 6B).
C . Glabrous with very sparse setae around margins, mostly located at corners on either side of head. T . Smooth and glabrous, without protuberances.
T . Surface glabrous and matte, lacking small pits. Tips of paratergites of midbody tergites projecting posteriorly.

E
. Inner section with numerous short triangular spines and very few longer setae. Middle area above spines with a single row of sparse elliptical cuticular impressions slightly varying in size. Apically two rows of dense marginal bristles, every second bristle strongly protruding above tergite margin (Fig. 5B). Bristles with numerous small spines. A . Large and well-rounded. In both sexes glabrous. Underside lacking locking carinae.

Male sexual characters G
. Covered with a single undivided, rounded membranous plate, very wide, located on basal half of coxa (Fig. 6A).

A
. Harp with two weak stridulation ribs (Fig. 6E). First podomere with numerous setae mainly at lateral margin, as wide as long. Process of second podomere as long as basal fi fth of third podomere, not visible in anterior view, with apical mound of a few sclerotized spots juxtaposed to third podomere. Third podomere with an apical sclerotized spot and a lateral crenulated tooth, mesally with an elevated area carrying sclerotized spots (Fig. 6D, F); lower area carrying 4 spines ( Fig. 6D, F). Second and third podomeres sparsely setose.

P
. Movable fi nger weakly curved; hollowed-out inner margin with two non-sclerotized lobes and ca fi ve smaller sclerotized spines, posterior aspect with ca 15 large crenulated teeth. Fixed fi nger wider than movable fi nger, with slightly curved tip; basally with single membranous lobe, on inner margin covered with a few sclerotized spots. Second and third podomeres lacking long hair, almost completely glabrous. First podomere glabrous except for a few setae at mesal margin.

Female sexual characters
Washboard with two short interrupted stridulation ribs on each half (Fig. 6G). Vulva covering more than ⅔ of coxa surface. Operculum large, ending before coxal margin. Apical margin of operculum wellrounded, reaching apicalmost point medially. Mesal plate reaching up to half of operculumʼs height (Fig. 6J).

Distribution and ecology
Zoosphaerium silens sp. nov. is currently known from the western dry forest of Kirindy-Mite as well as from the dry forest of Andranomena further north (Fig. 3). These populations diff er by an uncorrected p-distance of 2.8% (Table 2).

Remarks
Species can be identifi ed as members of the Zoosphaerium coquerelianum species-group based on morphological characters of the posterior telopods . Telopoditomere 3 only carries small sclerotized teeth and is always slightly longer and > 1.5 times as wide as the immovable fi nger. Similar telopod characters occur in some members of the Z. platylabum species-group, but the locking carinae in this group are located close to the last pleurites, while they are positioned close to the anal shield margin in species of the Z. coquerelianum group. The speciesgroup now contains 23 described species distributed in humid to subhumid forests all over Madagascar. Species of this group are conspicuously absent from the spiny forest ecosystem and the western dry forest Wesener et al. 2010b;Sagorny & Wesener 2017;Wesener & Anilkumar 2020).

Diagnosis
The presence of only 7 or 8 ventral spines on the walking legs in Z. ambatovaky sp. nov., especially in combination with a glossy green color, two stridulation ribs on the male harp and more than 10 apical cones on the antenna, is only shared with Z. muscorum Wesener & Bespalova, 2010. The new species diff ers from Z. muscorum in the presence of an apical spine on the third leg pair (absent in Z. muscorum), the movable fi nger of the posterior telopod being 2.5 times as long as wide (2 times as long as wide in Z. muscorum) and the second locking carina of the anal shield being 2-3 times as long as the fi rst (4-5 times as long as the fi rst in Z. muscorum).

Etymology
'Ambatovaky', noun in apposition, after the forest of Ambatovaky, the only known locality for this species (Fig. 3).

C
. Some discoloration may have occurred because of preservation in ethanol. Head, collum, thoracic shield and tergites shiny green with a conspicuous narrow light posterior margin (Fig. 2C). Anal shield of a diff erent color, jade-like green. Antennae green, legs basally dark green, apically brownish.

G
. Not dissected.
S . First stigmatic plate triangular, apex well rounded, nearly as wide as at base, slightly turned towards coxa. Hair most abundant on apical margin, very few hairs on basal and lateral margins (Fig. 7C).

P
. First pleurite well-rounded, not projecting.  T . Surface glabrous and shiny, lacking small pits. Tips of paratergites of midbody tergites projecting posteriorly.

E
. Inner section with numerous short triangular spines and longer setae. Middle area above spines with a single row of sparse circular cuticular impressions slightly varying in size. Apically with 1-2 rows of short marginal bristles, protruding to ⅔ of distance of tergite margin (Fig. 5C). Bristles with numerous small spines.

A
. Male anal shield bell-shaped, without hairs, glabrous. Underside with two black locking carinae, posterior one 2-3 times as long as anterior one, both located close to anal shield margin.
L . Leg 1 with 4 ventral spines, leg 2 with 6 or 7, leg 3 with 6. First two leg pairs without an apical spine, spine present on leg 3. Leg pairs 4-21 with 7 or 8 ventral spines and an apical spine. On leg 9, femur 2 and tarsus 4.5 times as long as wide. All podomeres with setae ( Fig.).

Male sexual characters G
. Covered with a single undivided, rounded membranous plate, covering ¼ of surface of coxa. Gonopore located on basal half of joint (Fig. 7B).

A
. Harp with two stridulation ribs, one long and well pronounced rib located laterally of a less pronounced and shorter mesal rib (Fig. 7D). First podomere with only a few setae, restricted to apical parts of lateral margins, 1.5 times as wide as long. Process of second podomere nearly as long as basal ⅔ of third podomere, not visible in anterior view, and with an apical mound of a few sclerotized spots juxtaposed to third podomere ( Fig. 7E-F). Third podomere with an apical brown sclerotized spot and a fi eld of elevated sclerotized spots at inner margin below brown spot; two small spines located below sclerotized spot (Fig. 7F); depression lateral to fi eld of spots with one small sclerotized spine, lateral margin with up to 6 crenulated teeth (Fig. 7E-F). Second podomere densely setose, third podomere with setae mainly apically and laterally.

P
. Movable fi nger (podomere 3) 2.5 times as long as wide, weakly curved towards immovable fi nger (process of podomere 2). Shallowly hollowed-out inner margin with fi ve sclerotized spines, three positioned apically and two in middle of cavity next to small membranous lobe. Additional sclerotized spine at base of movable fi nger. Posterior aspect with ca 12 small crenulated teeth (Fig. 7H). Immovable fi nger thinner and shorter than movable fi nger, curved towards the latter. Sclerotized spine located on anterior side near base of immovable fi nger. Inner part of immovable fi nger apically covered with a few sclerotized spots (Fig. 7I). Movable fi nger glabrous on both sides except for a few hairs basolaterally. Second podomere in posterior view setose, in anterior view with a few setae on fi nger.

Female
Unknown.

Distribution and ecology
Zoosphaerium ambatovaky sp. nov. is currently known only from the type locality, a lowland rainforest close to the Ille Sainte Marie (Fig. 3). This species seems to be closely related to Z. muscorum from the montane forest of Anjanaharibe-Sud, the only species with which it shares the presence of only 7 or 8 ventral spines on the walking legs, as well as a glossy green color, two stridulation ribs on the male harp and more than 10 apical cones on the antenna. A female Zoosphaerium from the same forest (CASENT 9068291B) belongs to a diff erent species. The forest of Ambatovaky is isolated and shrinking rapidly (Rakotondrasoa et al. 2017).

Remarks
Species can be identifi ed as members of the Zoosphaerium platylabum species-group based on the number of locking carinae (always 2) of the anal shield that are located close to the last pleurite, as well as on morphological characters of the female vulva, whose apical processes are usually sharpedged (with the exception of those in Z. tsingy ). The posterior telopods  show two vastly diff erent modifi cations: the movable fi nger is either very thick, or quite elongated and slender. The species-group now contains 6 + 3 described species distributed in humid as well as western dry forests all over Madagascar. Species of this group are conspicuously absent from the southern spiny forest ecosystem

Diagnosis
The shape and position of the locking carinae place Z. beanka sp. nov. in the Z. platylabum speciesgroup, but the telopods of Z. beanka sp. nov. have almost no similarities to those of any other described giant pill-millipede species except Z. tsingy. Both species share characters of the posterior telopods, namely the presence of spines and at least one large membranous lobe on the movable fi nger, and an uncurved, wide immovable fi nger (2.7 times as long as wide) that is parallel to the movable fi nger. Zoosphaerium beanka sp. nov. diff ers from the latter in the light brown color (olive in Z. tsingy), the presence of only four apical cones on the antenna (> 15 in Z. tsingy) and the diff erently shaped anterior telopods, in which telopoditomere 3 lacks crenulated teeth (present in Z. tsingy).

Etymology
'Beanka', noun in apposition, after the type and only known locality for this species, the dry forest of Beanka (Fig. 3).
S . First stigmatic plate triangular, apex well rounded, nearly as wide as at base, slightly turned towards coxa. Hairs most abundant on apical margin, very few hairs on basal and lateral margins (Fig. 8C).

P
. First pleurite slightly extending posteriorly in a well-rounded process.
C . Margins covered with a few short hairs, central part glabrous.
T . Surface like those of tergites, glabrous.
T . Smooth and glabrous, no small pits present. Paratergites projecting slightly posteriorly.
E . Inner section with numerous short spines and isolated bristles. Between marginal ridge and inner area, a single row of sparse large, circular cuticular impressions. Externally one or two rows of marginal bristles, standing irregularly to each other. Bristles scaly, of medium length, longest reaching slightly above tergite margin (Fig. 5D).

A
. Rounded, neither bell-shaped nor tapered, glabrous. Ventral side of anal shield with two black locking carinae, located close to laterotergites. Anterior carina small, posterior carina 2-3 times as long as anterior carina.
L . Leg 1 with 6 or 7 ventral spines, leg 2 with 8, leg 3 with 10. First two leg pairs without an apical spine, spine present on leg 3. Leg pairs 4-21 with 9 or 10 ventral spines and an apical spine. On leg 9, femur 2 and tarsus 4.9 times as long as wide. All podomeres with setae (Fig. 8A).

Male sexual characters G
. Covered with a single undivided, rounded membranous plate, covering ¼ of surface of coxa. Gonopore located centrally on joint (Fig. 8B).

A
. Harp with two stridulation ribs, mesal rib smaller than lateral one, both ribs well developed (Fig. 8F). First podomere 1.2 times as wide as long. Second podomere process lobe-like and slightly curved, with rounded edges, protruding up to half of third podomere height, apically with sclerotized spots. Third podomere long, as long as fi rst; cavity mesally with numerous sclerotized spots and three thin, sclerotized spines; one sclerotized spot located close to tip. Podomeres 1-3 covered on both sides with numerous long, isolated hairs.

P
. Movable fi nger with a well-rounded tip, not tapering towards tip; hollowed-out inner margin with one non-sclerotized lobe and 3 or 4 sclerotized spines, posterior aspect with ca 14 small sclerotized teeth. Movable fi nger slightly longer than fi xed fi nger, the latter straight, as wide as third podomere. Fixed fi nger at margin with numerous sclerotized spots. All podomeres covered on both sides with numerous, long isolated hairs, only tips of chela glabrous (Fig. 8G-H).

Female
Unknown.

Distribution and ecology
Zoosphaerium beanka sp. nov. is currently known only from the dry forest of Beanka (Fig. 3). With most known dry forest giant pill-millipede species being widespread ), this species can be expected in surrounding dry forest fragments.

Diagnosis
The position of the locking carinae close to the last pleurite identifi es Z. voahangy sp. nov. as a member of the Z. platylabum species-group. The uniquely slender and elongated posterior telopods in combination with the presence of a single stridulation rib on the male harp and more than 35 apical cones on the antennae, are characters only shared with Z. broelemanni . Zoosphaerium voahangy sp. nov. diff ers from Z. broelemanni in the diff erently shaped anterior telopods, spination and teeth number of the movable fi nger of the posterior telopod (see key), as well as in characters of the endotergum, which has two dense rows of long marginal bristles in the former, but a single row of short bristles in the latter.

Etymology
'Voahangy', noun in apposition, to honor the great collector and Malagasy scientist Voahangy Soarimalala.

Material examined
Holotype

C
. Head, collum, thoracic shield and tergites light brown with dark posterior margins. Anal shield entirely light brown (Fig. 2E). Antennae dark green, legs basally light brown, apically green.

G
. Not dissected.

P
. First pleurite extending posteriorly in a well-rounded process. Second pleurite also with a well-rounded process, but not projecting. Remaining pleurites broadly rounded.

C
. Margins with a few short hairs, central part glabrous.
T . Surface like those of tergites, glabrous.
European Journal of Taxonomy 758: 1-48 (2021) 30 E . Inner section with numerous short spines and isolated bristles. Between marginal ridge and inner area a single row of sparse, circular cuticular impressions. Externally two dense rows of marginal bristles. Bristles scaly, the longest reaching above tergite margin (Fig. 5E).

A
. Rounded, neither bell-shaped nor tapered, glabrous. Ventral side with two black locking carinae, located closely to laterotergites. Anterior carina small and posterior carina 2-3 times as long as anterior carina.
L . Leg 1 with 4 ventral spines, leg 2 with 5 or 6, leg 3 with 7. First two leg pairs without an apical spine, spine present on leg 3. Leg pairs 4-21 with 9 or 10 ventral spines and an apical spine. On leg 9, femur 2.1 and tarsus 5.1 times as long as wide. All podomeres with setae (Fig. 9A).

A
. Harp with single stridulation rib located mesally, long and well developed (Fig. 9D). First podomere 1.1 times as wide as long. Second podomere process lobe-like and slightly curved with rounded edges, protruding up to half of third podomere height, apically with sclerotized spots (Fig. 9F). Third podomere long, almost as long as fi rst; cavity mesally with numerous sclerotized spots and three thin, sclerotized spines located apically (Fig. 9E-F); one sclerotized spot located close to tip, laterally with a row of ca 11 crenulated teeth (Fig. 9E). Podomeres 1-3 covered on both sides with numerous long, isolated hairs.

P
. Movable fi nger slender and long, with a well-rounded tip, not tapering towards tip; hollowed-out inner margin with 3 or 4 sclerotized spines located apically, posterior aspect with ca 25 small sclerotized teeth (Fig. 9G). Movable fi nger 4 times as long as wide, slightly longer than fi xed fi nger. Fixed fi nger straight, only apically curved towards movable fi nger, not tapering, more slender than third podomere. Fixed fi nger at margin with numerous sclerotized spots (Fig. 9H). First podomere in posterior view almost glabrous, podomeres 2 and 3 covered on both sides with numerous long, isolated hairs.

Female
Unknown.

Distribution and ecology
The only known habitat of Z. voahangy sp. nov., the forest of Analalava (Fig. 3), is a small (2 km south to north, 750 m east to west) fragment of disturbed and partly degraded lowland rainforest, isolated by 30 km from Betampona, the only other remaining lowland rainforest fragment in a 100 km radius.

Diagnosis
The shape and position of the locking carinae, as well as the slender posterior telopods place Z. masoala sp. nov. in the Z. platylabum species-group. Zoosphaerium masoala sp. nov. diff ers from all other species of the group in the combination of the presence of two stridulation ribs on the male harp, slender posterior telopods in which both fi ngers reach almost the same length and >10 apical cones on the antenna.

Etymology
'Masoala', noun in apposition, after the forest and peninsula of Masoala, the largest remaining area of lowland rainforest on Madagascar, for which the species described here is the fi rst recorded giant pillmillipede species (Fig. 3). . Length 23.9 mm, width of thoracic shield 14.2 mm (widest), height of thoracic shield 7.2 mm (highest).

C
. Head, collum, thoracic shield and tergites dark brown to black. Grooves of thoracic shield greenish, anal shield lighter brown (Fig. 2F). Antennae and legs green.

G
. Not dissected.
S . First stigmatic plate triangular, apex well-rounded, slender, curved towards coxa. Hair most abundant on apical margin (Fig. 11C).  E . Inner section with numerous short spines and isolated bristles. Between marginal ridge and inner area a single row of sparse large, circular cuticular impressions, distance between impressions larger than their diameter. Marginal brim wavy towards inner area. Externally 1 or 2 rows of marginal bristles. Bristles scaly, of medium length, longest reaching slightly above tergite margin (Fig. 10A). A . Rounded, neither bell-shaped nor tapered, covered with numerous short setae. Ventral side of anal shield with two black locking carinae, located close to laterotergites. Anterior carina small and posterior carina 3 times as long as anterior carina.

A
. Harp with two stridulation ribs, mesal rib smaller than lateral one, both ribs well developed, located in mesal corner (Fig. 11D). First podomere 1.1 times as wide as long. Second podomere process lobe-like and slightly curved, with rounded edges, protruding up to half of third podomere height, apically with sclerotized spots. Third podomere long, as long as fi rst; cavity mesally with numerous sclerotized spots and three thin, sclerotized spines; one sclerotized spot located close to tip; laterally with up to 12 crenulated teeth. Podomeres 1-3 covered on both sides with numerous long, isolated hairs.

P
. Movable fi nger with a well-rounded tip, tapering towards tip; hollowed-out inner margin without lobes but with 5 sclerotized spines, 2 located apically, 2 at midpoint and 1 basally (Fig. 11H). Posterior aspect of movable fi nger with ca 14 small sclerotized teeth (Fig. 11G). Movable fi nger slightly longer than fi xed fi nger, the latter slender (4 times as long as wide), apically curved towards former. Fixed fi nger basally with a single spine, at margin with numerous sclerotized spots. First podomeres almost glabrous, movable and immovable fi nger covered on both sides with numerous long, isolated hairs, only tips of chela glabrous.

Female
Unknown.

Distribution and ecology
This species is currently known only from the vast lowland rainforests of the Masoala Peninsula on the east coast (Fig. 3).

Remarks
Despite several attempts, no DNA could be extracted from the male holotype. Therefore, its degree of similarity to the two much larger females known and sequenced from the Masoala area (KY399024 and KY399025) could not be assessed (see Fig. 1).

Remarks
Species can be identifi ed as members of the Z. piligerum species-group based on morphological characters of the posterior telopods , which are slender and greatly elongated. The species-group now contains four described species distributed in the eastern rainforests at higher elevations

Diagnosis
The greatly elongated posterior telopods identify Zoosphaerium spinopiligerum sp. nov. as a member of the Z. piligerum species-group. Zoosphaerium spinopiligerum sp. nov. shares the shape of the vulva and the anal shield, as well as a similar posterior telopod with Z. pseudopiligerum. Zoosphaerium spinopiligerum sp. nov. diff ers from the latter in the non-glossy tergites, diff erences in the shape of the anterior telopods, as well as the higher number of ventral spines on the legs (see key above).

Etymology
'Spinopiligerum', noun in apposition, as a reference to the higher number of ventral spines on the legs compared to related species. . Tergites brown with dark brown posterior margin (Fig. 2G). Collum dark brown to green. Head dark green with yellow-brown markings. Anal shield brown. Antennae dark green, legs basally light brown, apically dark green.

P
. First pleurite slightly extending posteriorly in a long, thin process.
C . Median part of collum glabrous.
T . Surface similar to that of tergites.
T . Paratergites slightly projecting posteriorly. Tergites covered with small pits and hairs.
E . Inner section with numerous short spines and isolated bristles. Between marginal ridge and inner area a single row of sparse large, elliptical cuticular impressions, distance between impressions 2-3 times as large as their diameter. Marginal brim wavy towards inner area. Externally with 1 row of sparse marginal bristles. Bristles scaly, short, the longest reaching ⅓ of distance towards tergite margin (Fig. 10B).

A
. Rounded, slightly fl attened in male, covered with numerous short setae. Ventral side of anal shield with two black locking carinae, located close to laterotergites. Anterior carina small, posterior carina 6 or 7 times as long as anterior carina.

Female sexual characters
Subanal plate wide, slightly triangular. Washboard with well-developed stridulation ribs, with 3 ribs on each half (Fig. 12G). Vulva large, covering more than ⅔ of coxa (Fig. 12J). Operculum small and low, ending far before coxal margin. Apical margin of operculum medially notched, lateral tip twice as high as mesal one, well rounded. Mesal plate long, extending beyond operculum.

Distribution and ecology
Zoosphaerium spinopiligerum sp. nov. occurs in sympatry with Z. nigrum sp. nov. and Sphaeromimus midongy Moritz & Wesener, 2017 in the remote mountainous forests of Midongy in the southeast of Madagascar (Fig. 3).

Remarks
The female specimen examined here is only tentatively placed in Z. spinopiligerum sp. nov. as its COI barcode shows quite a p-distance to the male holotype (Table 2). Such a distance is far higher than usually present in millipedes.

Remarks
Zoosphaerium platylabum was previously known only from a few specimens collected near Andasibe Wesener et al. 2010b). Now, the species has been found at several additional montane rainforest sites north of Andasibe, all at elevation levels of 780-1100 m (Fig. 13B).

Remarks
This is another record of this rare miniaturized species , previously known only from the type series collected near Andranomay. This species is currently classifi ed as Critically Endangered (Rudolf & Wesener 2017e) on the IUCN Red List.

Interspecifi c distances
The lowest interspecifi c distances of the COI barcoding gene in the genus Zoosphaerium were observed between Z. beanka sp. nov. and an unidentifi ed female from Anjiamangirina with 8.6% (Table 2). Generally, interspecifi c distances vary between 9.1 and 20% in the genus Zoosphaerium. However, this genus remains poorly represented by genetic data, with only 15 of the 77 species being genetically sampled. In contrast to this, sequence data for the Malagasy giant pill-millipede genus Sphaeromimus is available for 11 of the 12 known species. In Sphaeromimus, whose species have a distribution restricted to southern Madagascar, interspecifi c distances vary between 8.3 and 20.8%, with a single outlier at 5.4% Moritz & Wesener 2017), the same range that is observed in Zoosphaerium. While intraspecifi c distances are generally below 2.5% in our dataset, at most three sequences are available for a single species. Unidentifi able females show genetic distances between 4.3 and 8.6% from identifi able male specimens, but any meaningful discussion of these specimens is diffi cult without the availability of male specimens and the inclusion of nuclear markers in future studies. Low intraspecifi c distances are also visible in the maximum likelihood tree, where species represented by more than one specimen are well-supported. This shows the usefulness of COI barcoding as a basis for species identifi cation. However, the poor resolution within the genus Zoosphaerium and its non-monophyly provide clear evidence that the mitochondrial COI gene -containing little resolution at deeper evolutionary splitsdoes not allow a reconstruction of the phylogeny.

Giant pill-millipede diversity and endemism in Madagascar
Most of the known species of Zoosphaerium are highly endemic to small scattered areas in Madagascar, which are rarely visited by scientists collecting soil arthropods, so that occurrence data is still sparse for many species. Numerous species in Madagascar, including giant pill-millipedes, are severely threatened by habitat fragmentation and destruction (Harper et al. 2007). As of today, 19 of 70 assessed giant pill-millipede species from Madagascar are in one of the top three categories of the IUCN Red List (e.g., Rudolf & Wesener 2017a, 2017b, 2017c, 2017d. Therefore, further locality data for all species in this group is greatly needed in order to protect them. Although giant pill-millipedes have adapted to diff erent ecosystems, several species show a striking microendemism. This microendemism is especially prevalent in rainforest and montane rainforest ecosystems of the island, with samples from forests never studied before often yielding undescribed species. In contrast to humid forests, species of Zoosphaerium from the spiny and western dry forest ecosystems appear to be more widespread, something that is not known for other millipede groups such as Spirobolida (Wesener et al. 2009a;Wesener 2020aWesener , 2020b.