Agenodesmus is a genus of millipedes in the family Fuhrmannodesmidae,[1] which some authorities consider a junior synonym of Trichopolydesmidae.

[2] The type species A. reticulatus is notable as the first polydesmidan millipede discovered with only 18 segments in adults, the smallest number recorded in the order Polydesmida.

[7] A closely related species with only 18 segments in adults, Hexadesmus lateridens, was discovered in Cuba in 1931, with Loomis finding additional specimens in Saint Kitts and Carriacou in 1932.

[6] In 1987, the biologists William A. Shear and Stewart B. Peck described the second species of Agenodesmus to be discovered, A. nullus, based on a male holotype and two female paratypes found on Santa Cruz island in the Galapagos islands in 1985.

[9][10] The small sizes of Agenodesmus and Hexadesmus make them likely to be transported in soil undetected and spread by humans.

[11] Thus, females of the species A. nullus go through the eight stages typically observed in polydesmidans and reach maturity with the usual 20 segments and 31 pairs of legs, but females of the species A. reticulatus go through only six stages and reach maturity with only 18 segments and 27 leg pairs.