''Zoosphaerium album'', also known as the giant opal pill millipede, is a species of

pill millipede Pill millipedes are any members of two living (and one extinct) orders of millipedes, often grouped together into a single superorder, Oniscomorpha. The name Oniscomorpha refers to the millipedes' resemblance to certain woodlice (Oniscidea), also ...

within the family

Arthrosphaeridae Arthrosphaeridae is a family (biology), family of Sphaerotheriida, giant pill millipedes that are found in Madagascar, the Western Ghats of India, and Sri Lanka. The largest pill-millipede in the world, ''Zoosphaerium neptunus'' (Butler 1872) bel ...

and order

Sphaerotheriida Sphaerotheriida is an order (biology), order of millipedes in the infraclass Pentazonia, sometimes known as giant pill millipedes. They inhabit Southern Africa, Madagascar, South and Southeast Asia, Australia and New Zealand. Like the Northern He ...

. It is an

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

species, found only within the Vohibasia forest of Western

Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...

. The species name ''album'', refers to the white colouration of the pill millipedes exoskeleton.

Description

''Zoosphaerium album'' reach lengths of up to 34 mm long, with both males and females reaching a similar size.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. 1-134. 10.11646/zootaxa.2097.1.1. ''Z. album'' exhibits yellowish white

tergites A ''tergum'' (Latin for "the back"; : ''terga'', associated adjective tergal) is the dorsal ('upper') portion of an arthropod segment other than the head. The anterior edge is called the 'base' and posterior edge is called the 'apex' or 'margin'. ...

, which form the segmented dorsal

exoskeleton An exoskeleton () . is a skeleton that is on the exterior of an animal in the form of hardened integument, which both supports the body's shape and protects the internal organs, in contrast to an internal endoskeleton (e.g. human skeleton, that ...

of the pill millipede. These tergites are adorned with a light, shiny-green field that extends dorso-laterally on each side.Wesener, T. and Sagorny, C. (2021) “Seven new giant pill-millipede species and numerous new records of the genus Zoosphaerium from Madagascar (Diplopoda, Sphaerotheriida, Arthrosphaeridae)”, ''European Journal of Taxonomy'', 758(1), pp. 1-48. doi: 10.5852/ejt.2021.758.1423. The anterior margin of the collum, thoracic shield, and tergites displaying a green colour, while the rest of the texture appears yellowish-white. The head, antenna, and legs of ''Z. album'' are also green. The walking legs of ''Z. album'' hosts tarsi of usual size, measuring approximately 3.8 times as long as they are wide. Additionally, the third podomere of the anterior telopods possesses a single large, sclerotized tooth. ''Z. album'' also exhibits endotergal marginal bristles that slightly extend beyond the tergite. The texture of the tergites is smooth and glabrous, and the antennomeres 1–5 possess sclerotized teeth. The disc is adorned with 14–19 (-28) apical cones, and the antennomeres lack a groove. The third podomere of the posterior telopods in ''Z. album'' is weakly curved, featuring approximately 25 large, sclerotized teeth on the posterior side. Additionally, it has two large, non-sclerotized lobes and five thin spines. The male harp exhibits two stridulation ribs, while each side of the washboard contains 2 or 3 ribs. Notably, ''Z. album'' does not possess locking carinae on its anal shield. The operculum of the vulva has a unique shape, with only a very weak notch on the apical margin, sometimes appearing well-rounded in certain specimens. The coloration pattern of ''Z. album'' tends to fade in preserved specimens, with the green colouration gradually turning brown as the specimens are stored in alcohol.

Similar species

''Zoosphaerium album'' shares similarities with another species, '' Z. libidinosum'', in terms of the shape of their posterior telopods. However, there are distinguishing features that set the species apart. ''Z. album'' can be distinguished by features such as its weakly bell-shaped male anal shield, smaller size, unique colouration pattern, and slight variations in the shape of the anterior telopods and vulva.

Distribution and habitat

''Zoosphaerium album'' is currently known to exist solely in the subhumid forest of Vohibasia, which is part of the Zombitse-Vohibasia National Park. The forest is located in the

Toliara Toliara (also known as ''Toliary'', ; formerly ''Tuléar'') is a city in southern Madagascar. It is the capital of the Atsimo-Andrefana region, located 936 km southwest of the national capital Antananarivo. The current spelling of the name ...

Province of Southwest Madagascar. This species appears to be

to this specific region and has not been documented elsewhere. The forest habitat is a transitional zone between the dry Western and humid Eastern forests of Madagascar. The forest of Vohibasia provides the primary habitat for ''Z. album,'' where it resides in the leaf litter and understory vegetation of the forest floor. ''Z. album'' has been recorded at elevations of 780 meters above sea level.

References

{{Taxonbar, from=Q81849334 Sphaerotheriida Endemic fauna of Madagascar Arthropods of Madagascar Animals described in 2009