Haplodesmidae is a family of
millipedes in the order
Polydesmida. Species occur in
East Asia
East Asia is the eastern region of Asia, which is defined in both geographical and ethno-cultural terms. The modern states of East Asia include China, Japan, Mongolia, North Korea, South Korea, and Taiwan. China, North Korea, South Korea and ...
,
Southeast Asia
Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical United Nations geoscheme for Asia#South-eastern Asia, south-eastern region of Asia, consistin ...
, and
Oceania
Oceania (, , ) is a region, geographical region that includes Australasia, Melanesia, Micronesia, and Polynesia. Spanning the Eastern Hemisphere, Eastern and Western Hemisphere, Western hemispheres, Oceania is estimated to have a land area of ...
, although some species have been introduced to the
New world tropics. Species are small bodied (generally less than 10 mm), often with elaborate sculpturing on the
tergites (dorsal portion of exoskeleton), and some species are capable of rolling into a near-complete ball.
[ pp. 430-433]
This family includes some species that feature unusual deviations from the 20 segments (including the
telson
The telson () is the posterior-most division of the body of an arthropod. Depending on the definition, the telson is either considered to be the final segment of the arthropod body, or an additional division that is not a true segment on accou ...
) normally observed in the order Polydesmida. For example, some species exhibit
sexual dimorphism
Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...
in segments number, including not only ''Prosopodesmus panporus'' and ''
Eutrichodesmus peculiaris'' (adult females with the usual 20 segments, but adult males with only 19) but also ''Doratodesmus pholeter'' (adults females with 19 segments, adult males with 18).
This family also includes two species notable for being among the few species in Polydesmida to feature only 18 segments in adults (both sexes in ''D. hispidus'' and males only in ''D. pholeter'').
Species arrive at these lower numbers of segments by going through the same stages of
teloanamorphosis observed in other polydesmids but reaching maturity one moult earlier for 19 segments or two moults earlier for 18 segments.
Genera
*''
Agathodesmus''
*''
Atopogonus''
*''
Cylindrodesmus''
*''
Doratodesmus''
*''
Eutrichodesmus''
*''
Gonomastis''
*''
Helodesmus''
*''
Prosopodesmus''
References
Polydesmida
Millipedes of Asia
Millipedes of Oceania
Millipede families
{{Myriapoda-stub