Zoosphaerium neptunus

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Zoosphaerium neptunus
Zoosphaerium neptunus 1.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Myriapoda
Class: Diplopoda
Order: Sphaerotheriida
Family: Arthrosphaeridae
Genus: Zoosphaerium
Species:
Z. neptunus
Binomial name
Zoosphaerium neptunus
(Butler 1872)
Synonyms
    • Sphaerotherium digitale De Saussure & Zehntner, 1902
    • Sphaerotherium neptunus Butler, 1872
    • Sphaerotherium pygidiale Saussure & Zehntner, 1897
    • Zoosphaerium digitale (De Saussure & Zehntner, 1902)

Zoosphaerium neptunus, also known as the giant emerald pill millipede, is a species of millipede within the family Arthrosphaeridae. [1] It is an example of island gigantism, [2] being the largest known pill-millipede in the world, with some individuals reaching a maximum length of 90 mm (3.5 inches) long. [2] The species is endemic to Madagascar, where it is known to swarm at certain times of the year. [2] Z. neptunus is the only known species within the order Sphaerotheriida that is known to exhibit this mass swarming behaviour. [3]

Contents

Description

Zoosphaerium neptunus is a large species of pill millipede which ranges in colour from a shiny light green to a darker olive green. The species is characterized by smooth and hairless tergites. The tergites display a green coloration, with a thin brown line along the posterior margin. The head possesses over 80 ocelli, and the antennae consist of six joints. The sixth joint is the longest, and it bears a disc with 18-26 sensory cones on the tip. The first segment has long isolated hairs along its anterior margin and a row of even more strongly isolated hairs along the posterior margin. The legs exhibit varying numbers of ventral spines on different tarsi. [3] Sexual dimorphism is present within the species, with females reaching larger sizes than males. [4] Males reach up to around 45 mm (1.8 inches) long, while females can reach up to 90 mm (3.5 inches) long. [2] Preserved specimens may darken in alcohol, becoming light brown. [3]

Male traits

Female Zoosphaerium neptunus are significantly larger than the males. Hands full of rolled up Zoosphaerium neptunus.jpg
Female Zoosphaerium neptunus are significantly larger than the males.

Males have an average length of 45.5 mm, the width of the thoracic shield is 21.5 mm, and a height of the thoracic shield is 11.35 mm. The mandible possesses six rows of pectinate lamellae, and the gnathochilarium has numerous bristles. The tergites of males are smooth and hairless with green coloration. The anal shield in males is strongly bell-shaped and covered laterally with numerous small round pits, some of which support a short hair. The legs have weakly curved claws on the first two leg pairs and tarsi that are 4.6 times longer than wide, with curved claws and 8-10 ventral spines. The anterior telopods, used for reproduction, possess a stridulation harp and one stridulation rib on the first joint, with a process on the second joint reaching about half to three-fifths of the third joint's height. The posterior telopods have a slimmer third joint towards the tip and a chela covered with isolated long hairs on the posterior side. [3]

Female traits

Females can reach an average length of around 80.9 mm and a width of 45.85 mm. The vulva of females is large, covering more than two-thirds of the coxa. The operculum is elongated, protruding up to the apical edge of the coxa, with an apical margin that is notched and two rounded tips. The subanal plate in females has a washboard-like structure consisting of well-developed stridulation ribs, with 2-3 ribs on each side. The anal shield in females is weakly bell-shaped and covered laterally with numerous small round pits. Females have tarsi that are 4.6 times longer than wide, with curved claws, 8-10 ventral spines, and one apical spine. The stigma-carrying plates in females consist of a short lobe covered with long hairs and curved towards the coxa. [3]

Distribution and habitat

A swarm of Zoosphaerium neptunus. Zoosphaerium neptunus Swarming.jpg
A swarm of Zoosphaerium neptunus.

Zoosphaerium neptunus is an endemic species found only in Madagascar where it is widely distributed on the island. [3] Z. neptunus can be found living among leaf litter in moist lowland rainforest habitats up to elevations of 850 metres above sea level. [5] Z. neptunus is a detritovore, which feeds on decaying organic matter such as rotten wood and dead leaves. [6]

Pet trade

Due to its beautiful colouration and large size Zoosphaerium neptunus is often harvested from the wild and distributed into the pet trade. [5] It is a popular species and often sold in pet stores within Europe, North America and Japan. [5] Captive populations tend to have a scarcity of males, possibly because their smaller size renders them less desirable to collectors compared to the larger females. [3] Despite their popularity, the species is notoriously known for being difficult to keep alive in captivity.

Related Research Articles

<span class="mw-page-title-main">Millipede</span> Class of arthropods

Millipedes are a group of arthropods that are characterised by having two pairs of jointed legs on most body segments; they are known scientifically as the class Diplopoda, the name derived from this feature. Each double-legged segment is a result of two single segments fused together. Most millipedes have very elongated cylindrical or flattened bodies with more than 20 segments, while pill millipedes are shorter and can roll into a tight ball. Although the name "millipede" derives from Latin for "thousand feet", no species was known to have 1,000 or more until the discovery of Eumillipes persephone, which can have over 1,300 legs. There are approximately 12,000 named species classified into 16 orders and around 140 families, making Diplopoda the largest class of myriapods, an arthropod group which also includes centipedes and other multi-legged creatures.

Stridulation is the act of producing sound by rubbing together certain body parts. This behavior is mostly associated with insects, but other animals are known to do this as well, such as a number of species of fish, snakes and spiders. The mechanism is typically that of one structure with a well-defined lip, ridge, or nodules being moved across a finely-ridged surface or vice versa, and vibrating as it does so, like the dragging of a phonograph needle across a vinyl record. Sometimes it is the structure bearing the file which resonates to produce the sound, but in other cases it is the structure bearing the scraper, with both variants possible in related groups. Common onomatopoeic words for the sounds produced by stridulation include chirp and chirrup.

<span class="mw-page-title-main">Pill millipede</span> Order of millipedes

Pill millipedes are any members of two living orders of millipedes, often grouped together into a single superorder, Oniscomorpha. The name Oniscomorpha refers to the millipedes' resemblance to certain woodlice (Oniscidea), also called pillbugs or "roly-polies". However, millipedes and woodlice are not closely related ; rather, this is a case of convergent evolution.

<span class="mw-page-title-main">Tergum</span> Dorsal sclerite of arthropod

A tergum 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'. A given tergum may be divided into hardened plates or sclerites commonly referred to as tergites.

<span class="mw-page-title-main">Sphaerotheriidae</span> Family of millipedes

Sphaerotheriidae is a family of giant pill millipedes of the class Diplopoda. Millipedes of this family are distributed in southern Africa.

<span class="mw-page-title-main">Glomerida</span> Order of millipedes

Glomerida is an order of pill-millipedes found primarily in the Northern Hemisphere. Also known as northern pill millipedes, they superficially resemble pill-bugs or woodlice, and can enroll into a protective ball. They have twelve body segments, 17 to 19 pairs of legs, and males have enlarged rear legs involved in mating. The order includes about 30 genera and at least 280 species, including Glomeris marginata, the common European pill-millipede. The order contains members in Europe, South-east Asia and the Americas from California to Guatemala. Although historically considered closely related with the similar sphaerotheriidans that also enroll, some DNA evidence suggest they may be more closely related to glomeridesmidans, a poorly known order that does not enroll.

<span class="mw-page-title-main">Sphaerotheriida</span> Order of millipedes

Sphaerotheriida is an 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 Hemisphere pill millipedes of the order Glomerida, these millipedes can roll into a ball when disturbed. When they are rolled-up, most sphaerotheriidans reach a maximum size of a cherry or golf ball, but some species from Madagascar can even reach the size of an orange. When rolled-up, predators are unable to unravel giant pill millipedes since the margins of their second and last dorsal plates fit perfectly into one another, creating a sealed ball. A few giant pill millipede species are able to produce sound, the only millipedes known to do this. This order of millipedes is also unique in that some African species are used for medicinal purposes.

<i>Sphaeromimus</i> Genus of millipedes

Sphaeromimus, or the chirping giant pill millipedes, is a genus of giant pill millipedes endemic to southeastern Madagascar. Though described in 1902, the genus was up to 2005 known from a single male specimen, whose appearance was so unusual that the authors suspected a mislabeled giant pill-millipede from India. Their unusual and distinct morphology includes well-developed stridulation organs, probably as devices for courtship. These are the male ‘harp’ and the female ‘washboard’, which contain more stridulation ribs than in other members of the order Sphaerotheriida. They have a closer affinity with the Indian genus Arthrosphaera than to other Malagasy genera, though all belong to the Arthrosphaeridae.

Tridontomidae is a small family of millipedes. Its members are endemic to Guatemala. These millipedes range from 22 mm to 28 mm in length and are uniformly grayish in color; their legs and antennae are unusually long and slender. This family includes the remarkable species Aenigmopus alatus, in which adult males feature no gonopods. This millipede is the only species in the infraclass Helminthomorpha without gonopods.

<span class="mw-page-title-main">Zephroniidae</span> Family of millipedes

Zephroniidae is a family of giant pill millipedes in the taxonomic order Sphaerotheriida. They occur in southeast Asia from the Himalayas and China south and east to Sulawesi and to Australia, and also inhabit some Philippine islands.

<span class="mw-page-title-main">Glomeridesmida</span> Order of millipedes

Glomeridesmida is an order of millipedes in the infraclass Pentazonia containing 2 families and at least 31 species. Glomeridesmida is the only living order of the superorder Limacomorpha. Also known as slug millipedes, glomeridesmidans are small and somewhat flattened, and unlike other orders of Pentazonia, are unable to roll into a ball. Ocelli (eyes) are absent.

<span class="mw-page-title-main">Arthrosphaeridae</span> Family of millipedes

Arthrosphaeridae is a family of 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 belongs to this family and is known to swarm at certain times of the year.

<span class="mw-page-title-main">Zephronia</span> Genus of millipedes

Zephronia is a genus of giant pill millipedes in the family Zephroniidae. This genus includes 47 species distributed throughout N. India, Myanmar, Thailand, Malayan Peninsula, Java, Sumatra and Borneo.

<i>Trachysphaera</i> Genus of millipedes

Trachysphaera is a genus of dwarf pill millipedes in the order Glomerida. Just over 30 species are known, making it the third most species-rich genus of Glomerida. Trachysphaera species are patchily distributed throughout Europe and western Asia, extending from Spain to Caucasia. Members of this genus are tiny, with modified appearances resembling that of calcareous stones.

Glomeridesmidae, is a millipede family of the order Glomeridesmida. This family includes two genera: The genus Glomeridesmus includes most species in this family; the genus Glomeridesmoides includes one species.

<i>Armadillidium atticum</i> Species of crustacean

Armadillidium atticum is a European species of woodlouse endemic to Greece. It is a relatively small species and belongs to the so called "Armadillidium insulanum complex".

<i>Armadillidium maniatum</i> Species of crustacean

Armadillidium maniatum is a European species of woodlouse endemic to Greece.

<i>Zoosphaerium darthvaderi</i> Species of millipede

Zoosphaerium darthvaderi, also known as the Darth Vader giant pill millipede, is a species of giant pill millipede endemic to the island state of Madagascar. It is named after the Star Wars character Darth Vader. The millipede is restricted to the Ambohitantely Reserve and is considered an extremely endangered species.

<i>Zoosphaerium</i> Genus of myriapods

Zoosphaerium is a genus of giant pill millipedes endemic to Madagascar. Some species within this genus express island gigantism. The largest of the known species of giant pill millipede known is Zoosphaerium neptunus, which is capable of growing to lengths of 90 mm.

<i>Sphaerophoria bifurcata</i> Species of fly

Sphaerophoria bifurcata, the symmetric globetail, is a species of syrphid fly in the family Syrphidae. The larvae of this genus are predators of aphids and other small hymenoptera. The larvae of this particular species is not known.

References

  1. "Zoosphaerium neptunus (Butler, 1872)". MilliBase (www.millibase.org). 2023-05-18. Retrieved 2023-05-18.
  2. 1 2 3 4 Wesener, Thomas; Kai Schütte (2010). "Swarming behaviour and mass occurrences in the world's largest giant pill-millipede species, Zoosphaerium neptunus, on Madagascar and its implication for conservation efforts (Diplopoda: Sphaerotheriida)". Madagascar Conservation & Development. 5 (2): 89–94.
  3. 1 2 3 4 5 6 7 Wesener, Thomas & Wägele, J. Wolfgang. (2008). The giant pill-millipedes of Madagascar: Revision of the genus Zoosphaerium (Myriapoda, Diplopoda, Sphaerotheriida). Zoosystema. 30. 5-85.
  4. Wesener, Thomas (2016). "The Giant Pill-Millipedes, order Sphaerotheriida – An annotated species catalogue with morphological atlas and list of apomorphies (Arthropoda: Diplopoda)" (PDF). Bonn Zoological Bulletin (zoologicalbulletin.de). Retrieved 2022-10-26.
  5. 1 2 3 "Emerald Green Giant Pill-Millipede". IUCN Red List . 2023-01-23. Retrieved 2023-01-23.
  6. "Pill Millipedes". Australian Museum . 2020-10-12. Retrieved 2023-05-18.