Doratodesmus is a is a genus of flat-backed millipedes in the family Haplodesmidae. These millipedes are found in China, Indonesia, and Papua New Guinea. This genus includes two species that are notable for including adult males with only 18 segments (counting the collum as the first and the telson as the last) rather than the 20 segments normally observed in the order Polydesmida: "D. hispidus" features only 18 segments in adults of each sex, whereas "D. pholeter" exhibits sexual dimorphism in segment number, with 19 segments in adult females but only 18 segments in adult males.
Discovery, taxonomy, and distribution.
The American biologist Orator F. Cook proposed the name "Doratodesmus" in 1895 for two species previously described under the name "Doratonotus", which was already occupied. In 1894, the British zoologist Reginald I. Pocock described the type species "Doratonotus armatus" as a new species discovered on the island of Java in Indonesia. In 1895, the Italian zoologist Filippo Silvestri described "Doratonotus beccarii" as a new species discovered on the island of Sumatra in Indonesia. After moving both of these species to the genus "Doratodesmus", Cook described two more species in this genus in 1896, "D. muralis" and "D. vestitus", both discovered on the island of Java. In 1945, the American biologist Ralph V. Chamberlin described "Hoplitesmus" as a new monotypic genus and "Hoplitesmus enoplus" as a new species discovered on the island of Java. In 1955, however, the Dutch myriapodologist C.A.W. Jeekel deemed "H. enoplus" to be a junior synonym of "Doratodesmus armatus".
In 1945, Chamberlin also described "Pauroplus" as a new monotypic genus with "Pauroplus analdes" as its type species discovered on the island of Sumatra. In 1978, the American zoologist Richard L. Hoffman described "Scolopopyge" and "Selminarchus" as new monotypic genera with "Scolopopyge pholeter" and "Selminarchus hispidus" as their respective type species, both discovered in Papua New Guinea. In 1993, Zhang Chunzhou described "Crenatidorsus" as a new monotypic genus with "Crenatidorsus grandifoliatus" as its type species discovered in Yunnan province in China. In 2009, however, authorities deemed "Pauroplus", "Scolopopyge", "Selminarchus", and "Crenatidorsus" to be junior synonyms of "Doratodesmus". These genera had been placed in the family Doratodesmidae, which authorities deemed in 2009 to be a junior synonym of Haplodesmidae. Although the monotypic genus "Eucondylodesmus" was also deemed to be a junior synonym of "Doratodesmus" in 2009, authorities reconsidered in 2010 and deemed "Eucondylodesmus" to be a junior synonym of "Eutrichodesmus" instead.
Description.
The millipedes in the genus "Doratodesmus" are capable of complete volvation. The coxae (basal elements) of the gonopods in adult males usually feature abundant setae. The gonopod telopodites (distal elements) are usually stout and markedly enlarged toward the sides.
The millipedes in this genus resemble those in the genus "Eutrichodesmus", which are also usually capable of complete volvation. Like the adult males in "Doratodesmus", those in "Eutrichodesmus" also usually feature gonopod coxae with abundant setae. The adult males in "Eutrichodesmus", however, feature gonopod telopodites that are usually slender and not enlarged, unlike those usually observed in "Doratodesmus".
Species.
This genus includes the following eight species: