Saussure & Zehntner, 1902
Sphaeromimus, or the chirping giant pill millipedes, is a genus of giant pill millipedes (order Sphaerotheriida) endemic to southeastern Madagascar. The genus was first described by Henri Louis Frédéric de Saussure and Leo Zehntner in 1902 but until 2005 was known only from a single male, whose appearance was so unusual that the authors thought it might represent a mislabeled giant pill millipede from India. It belongs to the family Arthrosphaeridae, which besides Sphaeromimus includes the Malagasy genera Zoosphaerium and Microsphaerotherium and the Indian genus Arthrosphaera. Recent research has shown that Sphaeromimus is more closely related to the Indian genus Arthrosphaera than to other Malagasy genera. Three species have been described within Sphaeromimus, S. musicus, S. splendidus, and S. inexpectatus, although some undescribed species have been found recently. All populations inhabit the leaf litter of the Malagasy rainforests, except for one undescribed species which was found in a cave and the type species S. musicus which has only been found in the dry spiny forest. Recent research has shown that Sphaeromimus populations are highly endemic, since individuals are not able to travel between forest patches. Movement between populations is becoming more limited, as forest is being destroyed at a rapid rate on Madagascar.
Like other giant pill millipedes, Sphaeromimus individuals can roll up into a ball for protection. The size of this ball is typically equal to that of a ping-pong ball and can sometimes even be larger. Males have a structure on their anterior telopod, known as the harp, which has several stridulation ribs and is able to produce sounds when rubbed against a sclerotized knob on the leg. They probably use this structure during courtship in order to prevent females from rolling up into a ball. When a female is receptive, it is believed that males use their posterior telopods in order to hold her down for copulation. Females, on the other hand, have a structure on their subanal plate called the washboard, which, like the male harp, contains stridulation ribs and produces sounds. The harp and washboard are present in all species of the family Arthrosphaeridae but are especially well developed in Sphaeromimus, with males having 3–7 ribs on each harp, and females 8–16 ribs on each washboard.
- T. Wesener & P. Sierwald (2005b). "The giant pill-millipedes of Madagascar: Revision of the genus Sphaeromimus with a review of the morphological terminology (Diplopoda, Sphaerotheriida, Sphaerotheriidae)" (PDF). Proceedings of the California Academy of Sciences 56: 557–599.
- H. de Saussure and L. Zehnter (1902). Myriapodes de Madagascar. Vol. 27 of Alfred Grandidier, Histoire, physique, naturelle, et politique de Madagascar. Paris: Imprimerie Nationale. pp. i–vii, 1–356, pl. 13, 14, 15.
- C. A. W. Jeekel (1999). "A new pill-millipede from Madagascar, with a catalogue of the species hitherto described from the island (Diplopoda, Sphaerotheriida)". Myriapod Memoranda I: 5–21.
- T. Wesener & D. Vanden Spiegel (2009). "A first phylogenetic analysis of Giant Pill-Millipedes (Diplopoda: Sphaerotheriida), a new model Gondwanan taxon, with special emphasis on island gigantism" (PDF). Cladistics 25: 545–573. doi:10.1111/j.1096-0031.2009.00267.x.
- U. Haacker (1969). "Das Sexualverhalten von Sphaerotherium dorsale (Myriapoda, Diplopoda)". Verhandlungen der Deutschen Zoologischen Gesellschaft 3: 454–463.