The Central American millipede family Rhachodesmidae in Costa Rica, with the description of a new species of Aceratophallus Carl, 1902 (Diplopoda, Polydesmida)

The rather small millipede family Rhachodesmidae is endemic to Central America, and is represented in Costa Rica by only four species of the genus <i>Aceratophallus</i>, including <i>A.logunovi</i> <b>sp. nov.</b> An illustrated key is given to all four species of Rhachodesmidae (= <i>Aceratophallus</i>) presently known to occur in Costa Rica. The first detailed iconography of a species of <i>Aceratophallus</i> is provided.