A new species of Ribautia Brölemann, 1909 (Chilopoda: Geophilomorpha: Geophilidae) from Peruvian Amazonia, with a key to the Neotropical species of the genus with coxal organs grouped in clusters

Ribautia williamsi sp. nov., a new dwarf geophilomorph centipede from the Lower Urubamba Region, Peruvian
Amazonia, is described and illustrated based on the holotype female. The new species is characterized by having
the coxal organs grouped in clusters (three of these in each coxopleuron of the ultimate leg-bearing segment) and
ventral pore-fields present along all the body; these two combined traits being shared by five other Neotropical
species currently included in the genus Ribautia Brölemann, 1909, i.e. R. centralis (Silvestri, 1907) (from Colombia
and Brazil), R. difficilis Pereira, Minelli & Barbieri, 1995 (from Brazil), R. montana Kraus, 1954 (from Peru), R.
peruana (Verhoeff, 1941) (from Peru), and R. titicacae (Turk, 1955) (from Peru). The new taxon is differentiated
from the aforementioned species by the low number of leg-bearing segments and small body length; it is included
in a key which will enable the identification of all known Neotropical members having coxal organs grouped in
clusters. R. williamsi sp. nov. is the 14th species of Ribautia recorded from Peru.