Open Access

Tiphallus torreon n. sp., the fi rst rhachodesmid milliped from Coahuila, Mexico, displays an iridescent turquoise pigmentation with patterned white paranotal markings and a truncated, subapical projection from the broad, non-descript gonopodal acropodite. Four genera – Strongylodesmus Saussure, Mexidesmus Loomis, and Ceuthauxus and Tiphallus, both by Chamberlin – contain forms exhibiting this general condition, but the last is the only one whose type species does. Synthetic treatments are essential to advance familial knowledge beyond the descriptive stage, and revising these four taxa would constitute a meaningful initial study. Rhachodesmidae extend from northern Nuevo León, Mexico, ca. 77 km (48 mi) from the Rio Grande, to central Costa Rica; Glomeridae (Glomerida), Platydesmidae (Platydesmida), and Stemmiulidae (Stemmiulida) show similar distributions whereas Allopocockiidae (Spirobolida) and Rhysodesmus Cook (Polydesmida: Xystodesmidae) traverse the river and occupy southernmost Texas. Tridontomidae, the other component of Rhachodesmoidea, occupies a small enclave in Alta Verapaz, Guatemala. Rhachodesmidae/oidea do not occur in Panama and are initially recorded from Belize; localities are needed from Honduras.