Eutrichodesmus is a genus of millipedes in the family Haplodesmidae. Containing 54 species, this genus is among the genera with the greatest number of species not only in the family Haplodesmidae but also in the order Polydesmida. This genus includes the species E. peculiaris, notable for featuring sexual dimorphism in segment number: The adult females have 20 segments (counting the collum as the first segment and the telson as the last), but the adult males have only 19 segments. Millipedes in this genus are found in southern Japan, Taiwan, southern China, mainland Southeast Asia, Indonesia, and Vanuatu.
Description Millipedes in this genus are small, ranging from 3.5 mm to 14 mm in length. These millipedes can have 19 or 20 segments. Species in this genus are capable of volvation, which is usually complete but sometimes incomplete.
The basal element of the gonopod (coxa) in adult males in this genus usually features abundant setae. The distal element of the gonopod (telopodite) is usually slender and long, with dense setae on the basal half. The telopodite often features a conspicuous outgrowth on the lateral side. The distal part of the telopodite is conspicuous and well developed but rarely branches into a separate lobe.
The millipedes in this genus resemble those in the genus Doratodesmus, which are also capable of volvation. Like the adult males in Eutrichodesmus, those in Doratodesmus also usually feature gonopod coxae with abundant setae. The adult males in Doratodesmus, however, feature gonopod telopodites that are usually stout and markedly enlarged toward the sides, unlike those usually observed in Eutrichodesmus, which are slender.
Species This genus includes the following species: Eutrichodesmus arcicollaris Zhang, 1993 Eutrichodesmus armatocaudatus Golovatch, Geoffroy, Mauriès & VandenSpiegel, 2009 Eutrichodesmus aster Golovatch, Geoffroy, Mauriès & VandenSpiegel, 2009 Eutrichodesmus asteroides Golovatch, Geoffroy, Mauriès & VandenSpiegel, 2009 Eutrichodesmus basalis Golovatch, Geoffroy, Mauriès & VandenSpiegel, 2009 Eutrichodesmus cavernicola Sinclair, 1901 Eutrichodesmus communicans Golovatch, Geoffroy, Mauriès & VandenSpiegel, 2009 Eutrichodesmus curticornis Golovatch, Geoffroy, Mauriès & VandenSpiegel, 2009 Eutrichodesmus demangei Silvestri, 1910 Eutrichodesmus deporatus Liu, Golovatch & Wesener, 2017 Eutrichodesmus distinctus Golovatch, Geoffroy, Mauriès & VandenSpiegel, 2009 Eutrichodesmus dorsiangulatus Zhang, 1993 Eutrichodesmus filisetiger Golovatch, Geoffroy, Mauriès & VandenSpiegel, 2009 Eutrichodesmus gremialis Hoffman, 1982 Eutrichodesmus griseus Golovatch, Geoffroy, Mauriès & VandenSpiegel, 2009 Eutrichodesmus incisus Golovatch, Geoffroy, Mauriès & VandenSpiegel, 2009 Eutrichodesmus latus Golovatch, Geoffroy, Mauriès & VandenSpiegel, 2009 Eutrichodesmus macclurei Hoffman, 1977 Eutrichodesmus monodentus Zhang, 1993 Eutrichodesmus multilobatus Golovatch, Geoffroy, Mauriès & VandenSpiegel, 2009 Eutrichodesmus paraster Liu, Golovatch & Wesener, 2017 Eutrichodesmus parvus Liu, Golovatch & Wesener, 2017 Eutrichodesmus peculiaris Murakami, 1966 Eutrichodesmus reclinatus Hoffman, 1977 Eutrichodesmus reductus Golovatch, Geoffroy, Mauriès & VandenSpiegel, 2009 Eutrichodesmus regularis Golovatch, Geoffroy, Mauriès & VandenSpiegel, 2009 Eutrichodesmus similis Golovatch, Geoffroy, Mauriès & VandenSpiegel, 2009 Eutrichodesmus steineri Liu, Golovatch & Wesener, 2017
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References
Further reading Hoffman, R. L. 1977: The systematic position of the diplopod family Doratodesmidae, and description of a new genus from Malaya (Polydesmida). Pacific insects, 17: 247-255. PDF Hoffman, R. L. 1977b: Diplopoda from Malayan caves, collected by M. Pierre Strinati. Revue suisse de Zoologie, 84(3): 699-719. Hoffman, R. L. 1982: A new genus and species of doratodesmid milliped from Thailand. Archives des sciences (Geneva), 35(1): 87-93. Murakami, Y. 1966: Postembryonic development of the common Myriapoda in Japan XXI. A new genus of the family Oniscodesmidae and a new species of the genus Arachandrodesmus (Cryptodesmidae). Zoological magazine, 75(2): 30-33. Silvestri, F. 1910: Descrizione preliminari di nuovi generi di Diplopodi. Zoologischer Anzeiger, 35: 357-364.