Key to males of Dibolostethus Hoffman, 2009

1. Sternite of 5 th body ring with two pairs of short, blunt projections (Fig. 3D); apex of gonopodal prefemoral process with large, tongue-shaped lobe, best seen in anterior view (Fig. 7B); Colombia .......................................................... D. kattani Means, Bouzan, Martínez-Torres & Ivanov sp. nov.

– Sternite of 5 th body ring without modifications; apex of gonopodal prefemoral process not as above; Ecuador ............................................................................................................................................. 2

2. Projections on sternite of 4 th body ring stout, conical, curving at tip between coxae, appressed along entire length (Fig. 4C–D); prefemoral process and solenomere together resembling blacksmithing bolt tongs in lateral and mesal views (Fig. 6A, C); body length approximately 30 mm; color of appendages and body uniform ............................... D. inopinatus Means, Bouzan & Ivanov sp. nov.

– Projections on sternite of 4 th body ring thin, blade-like, curving beyond coxae, separated along entire length (Fig. 4A–B); prefemoral process enveloping, and partially obscuring solenomere in mesal view (Fig. 5C); body length less than 25 mm; color of appendages lighter and contrasting with that of body ..................................................................................................... D. sicarius Hoffman, 2009

A total of 34 chelodesmid genera have been reported from the Tropical Andes Biodiversity Hotspot (Table 1). These include 24 genera from 9 nine tribes and 10 additional genera currently unassigned to a tribe. Of the 34 genera known from the Tropical Andes, 9 (25%) are monotypic. The most species rich genera in the region include Trichomorpha Silvestri, 1897 (26 spp.), Leptodesmus de Saussure, 1859 (13 spp.), Chondrodesmus Silvestri, 1897 (11 spp.), and Biporodesmus Attems, 1898, Trachelodesmus Peters, 1865, and Leiodesmus Silvestri, 1897 (5 spp. each). Conversely, 15 genera are represented in the region by a single species (Table 1).

Taxa have been reported from six of the seven (excluding Chile) countries falling within the boundaries of the Tropical Andes (Fig. 9). The most widespread genus in the region is Leptodesmus, stretching from northwestern Venezuela to northwestern Argentina (> 3800 km). It is important to note that Hoffman (1971) restricted the genus to only 21 species endemic to Brazil, with the remaining taxa considered incertae sedis, and without assignment at the generic level (Bouzan et al. 2021).

The number of species and records (in parentheses) from each country are as follows: Colombia – 49 species (61 records); Venezuela – 21 (26); Peru – 19 (27); Ecuador – 13 (13); Argentina – 5 (6); and Bolívia – 4 (4); for a total of 110 species and 137 records (Supp. file 1). A.kmz file of the Chelodesmidae of the Tropical Andes is provided as Supp. file 2.