Two New Platynus Bonelli (Coleoptera: Carabidae: Platynini) from Nevis and St. Kitts, Lesser Antilles

Abstract

Platynus (Dyscolus) racquelae Liebherr and Ivie, new species is described from the Crater Rim, in the Parish of St. John Capisterre, St. Kitts, and Platynus (Dyscolus) duportei Liebherr and Ivie, new species is described from Nevis Peak, Nevis. These species are placed in the Platynus (Dyscolus) memnonius (Dejean) group, with their addition to the group extending the group's aggregate distribution northward from Basse-Terre, Guadeloupe to St. Kitts. Based on extensive collections of the Coleoptera of St. Kitts, P. racquelae appears to be restricted to only the wettest areas at highest elevations, suggesting that this species requires rather specific conditions present only in the most extreme montane sites. The beetles also exhibit moderate flight wing reduction involving diminution of wing veins associated with wing-folding—specifically, veins associated with the wedge and oblongum cells—and foreshortening of the alar surface due to loss of membrane along the wing's apical margin. This suggests that individuals of P. racquelae are at best weak fliers, and that this species is not able to colonize isolated patches of suitable habitat by flight. Platynus duportei is likewise known from only the highest and wettest point on Nevis Peak, but this species exhibits fully developed flight wings. Additional records of Platynus (Dyscolus) luciae Liebherr from St Lucia, and of Glyptolenus chalybaeus (Dejean) are reported, allowing elucidation of flight wing configuration and male and female genitalia for the former, and new island records of Nevis and Saba for the latter.