Notagonum Darlington, 1952: The Carabid Beetles of New Guinea. Part 2. The Agonini: 127. Type species: Notagonum externum Darlington, 1852, by original designation.

Diagnosis. Medium sized, fully winged, non metallic species with the complete set of setiferous punctures on head, prothorax, and elytra, slightly/weakly excised 4th tarsomere of the metatarsus, and glabrous lower surface of the 5th tarsomeres.

The genus Notagonum was founded by Darlington (1952) for a group of platynine species of medium body size and average body shape, that possess all regular setiferous punctures on head, prothorax, and elytra, usually are fully winged, and do not bear any metallic colouration. In its external appearance this genus is similar to the northern genus Platynus Bonelli, 1810 (s.l.), but is distinguished from most species of Platynus by the absence of setae at the lower surface of the 5th tarsomere. Whether the genus Notagonum can be maintained in future, has be to checked by a general taxonomic and phylogenetic revision of the Oriental-Papuan Platynini, that, however, would be a major task and probably will not be undertaken in the near future. Some provisional thoughts on the phylogeny at least of the Platynini from Melanesia have been provided by Liebherr (2005).

The genus was founded for two species from New Guinea, but additional species from Australia and the Indonesian and Philippine Archipelagos were either later described, e.g. by Louwerens (1955), or were transferred from other genera, mostly from Colpodes Macleay, 1825 s. l. (Moore et al., 1987; Lorenz, 2005). In terms of species, the genus is still most numerous in New Guinea (Darlington, 1952; 1971; Baehr, 2010a; 2010b). From Timor so far a single species was recorded, namely Notagonum pleurale (Jordan, 1894) that was originally described as a species of Colpodes.

As far as their habits have been recorded (see Darlington, 1952), most species of the genus Notagonum inhabit more or less wet environments, where some even live on the banks of rivers and creeks. Some species, however, have been collected in leaf litter in more or less closed forest. All species are ground living, and most have been sampled at low to median altitudes, but in New Guinea a few species even occur at rather high altitude.Almost all specimens from Timor likewise were collected in rain or moss forest between 735 and 1250 m, but a single specimen was sampled at 2050 m in a Eucalyptus urophyllum-Vaccinium pasture gully.

Notagonum pleurale (Jordan, 1894: 110) (Timor): not collected.