Oxidus

Cook, 1911

greenhouse millipedes

Species Guides

Oxidus gracilis(Greenhouse Millipede)

Oxidus is a of flat-backed millipedes in the Paradoxosomatidae, containing approximately nine described , though recent revision recognizes five valid species with one . The genus is characterized by a member, Oxidus gracilis (the greenhouse ), which has achieved global distribution in temperate and sub-tropical regions, while other species exhibit restricted ranges. Phylogenetic analysis based on mitochondrial COI and 16S rRNA genes confirms Oxidus as monophyletic and closely related to the genus Tylopus. Species within the genus are distinguished primarily by , coloration, and body size.

Oxidus by (c) João Coelho, some rights reserved (CC BY). Used under a CC-BY license.

Oxidus gracilis by (c)
Zoltán Korsós, some rights reserved (CC BY). Used under a CC-BY license.

Pronunciation

How to pronounce Oxidus: /ˈɒksɪdəs/

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Identification

of Oxidus are distinguished from one another by characters, coloration patterns, and body size. The is most reliably separated from related genera (Sellanucheza, Kronopolites) by molecular phylogenetic analysis and detailed examination of male gonopods. Oxidus obtusus remains of doubtful taxonomic status pending examination of fresh material. An identification key to species is available in the taxonomic revision by Korsos et al. (2017).

Images

Habitat

associations are best documented for Oxidus gracilis, which has been observed in tropical rainforest environments around streams, in areas with soil, leaf litter, and rock cover. The demonstrates with respect to environmental parameters, potentially contributing to its success. Habitat preferences for other Oxidus species remain poorly documented.

Distribution

Oxidus gracilis: , widely distributed in temperate and sub-tropical regions worldwide, including continental Chile (/introduced), Italy, Russia, Denmark, and Norway. Oxidus gigas: northern Vietnam. Oxidus riukiaria: Ryukyu Islands, Japan. Oxidus avia: Ryukyu Islands, Japan. Oxidus obtusus: status doubtful, distribution unclear.

Behavior

Oxidus gracilis has been observed to exhibit innate congregating , demonstrated in experimental trials where individuals aggregated on food resources (Tahitian chestnut fruits). This congregation is not strongly predicted by such as soil moisture, leaf litter cover, or rock cover, suggesting behavioral . The function of congregation may relate to mating or defense; chemical cues have been hypothesized but not experimentally confirmed.

Human Relevance

Oxidus gracilis, the greenhouse , is a notable with established in multiple continents outside its native range. It has been recorded as in continental Chile and is widely distributed in temperate and sub-tropical regions globally. Its secretory compounds have been studied, indicating potential for chemical defense research.

Similar Taxa

TylopusPhylogenetically the closest related to Oxidus based on mitochondrial COI and 16S rRNA analysis; both belong to Paradoxosomatidae but differ in and geographic distribution patterns.
SellanuchezaPreviously considered potentially related, but phylogenetic analysis shows Oxidus is more distant from this than from Tylopus; distinguished by molecular and morphological characters.
KronopolitesAnother paradoxosomatid phylogenetically more distant from Oxidus than Tylopus; differs in structure and biogeographic patterns.

More Details

Taxonomic revision

The was revised in 2017 (Korsos et al., European Journal of 293), reducing the number of recognized valid from nine to five, with Oxidus obtusus designated as pending further material.

Molecular phylogeny

Phylogenetic relationships within Oxidus show O. gigas and O. gracilis forming a monophyletic sister group to O. riukiaria; O. avia occupies a separate lineage. The as a whole is monophyletic.