Taxonomy and Evolution of Species of the Genus Euchroa Brullé (Subgenus Dyschromus Chaudoir) of Central Mexico and the Island of Hispaniola (Coleoptera: Carabidae: Pterostichini: Euchroina)

Abstract

Provided are a key to, and descriptions of, adults of 35 species of Dyschromus Chaudoir, which is treated as a subgenus of Euchroa Brullé. Twenty-eight species are from central Mexico; seven are from the island of Hispaniola. Twenty-five species are new (type-localities in parentheses): Euchroa independencia n. sp. (DOMINICAN REPUBLIC, Independencia, 5.5 km. n.n.w. Angel Feliz), Euchroa pedernales n. sp. (DOMINICAN REPUBLIC, Pedernales, 1 km. s. Los Arroyos), Euchroa huautla n. sp. (MEXICO, Oaxaca, Rio Santiago, 11.7 km. e. Huautla de Jiminez), Euchroa cuiyachapa n. sp. (MEXICO, Veracruz, between Cuiyachapa and Ixtapa), Euchroa zongolica n. sp. (MEXICO, Veracruz, 5 km. s.w. San Andres de Tenejapa), Euchroa lasvigas n. sp. (MEXICO, Veracruz, 15.7 km. e. Las Vigas), Euchroa teotitlan n. sp. (MEXICO, Oaxaca, 24.5 km. e. Teotitlan Puerto de Soledad), Euchroa citlaltepetl n. sp. (MEXICO, Veracruz, Volcan Citlaltepetl, east slope), Euchroa perote n. sp. (MEXICO, Veracruz, 16 km. s. Las Vigas), Euchroa harrisoni n. sp. (MEXICO, Tamaulipas, 12.8 km. n.w. Gomez Farias), Euchroa soladevega n. sp. (MEXICO, Oaxaca, 14.9 km. n. Sola de Vega), Euchroa juchatengo n. sp. (MEXICO, Oaxaca, 32 km. s. Juchatengo), Euchroa nizavaguiti n. sp. (MEXICO, Oaxaca, n.w. of Santa Maria Nizavaguiti), Euchroa jalisco n. sp. (MEXICO, Jalisco, ca. 19.8 km. s. Tecalitlan), Euchroa tenancingo n. sp. (MEXICO, Mexico, Rio de Molino, near Valle de Bravo), Euchroa ixtapa n. sp. (MEXICO, Guerrero, crest of Sierra Madre del Sur, n.e. of Ixtapa), Euchroa atoyac n. sp. (MEXICO, Guerrero, 66.4 km. n.e. Atoyac de Alvarez), Euchroa puertogallo n. sp. (MEXICO, Guerrero, 32 km. n.w. Filo de Caballo), Euchroa filodecaballo n. sp. (MEXICO, Guerrero, 39.4 km. n.w. Filo de Caballo), Euchroa yucuyacua n. sp. (MEXICO, Oaxaca, Cerro Yucuyacua, summit e. of Nundaco), Euchroa santacatarina n. sp. (MEXICO, Oaxaca, 35.5 km. s. Juchatengo), Euchroa zempoaltepetl n. sp. (MEXICO, Oaxaca, 10.5 km. s. San Pedro y San Pablo Ayutla), Euchroa carbonera n. sp. (MEXICO, Oaxaca, 7.9 km. n.w. La Carbonera), Euchroa miahuatlan n. sp. (MEXICO, Oaxaca, 27.2 km. s. Miahuatlan), and Euchroa suchixtepec n. sp. (MEXICO, Oaxaca, 41.8 km. s. Suchixtepec). Larvae are also described of E. perote, E. harrisoni, E. soladevega, Euchroa dimidiata Chaudoir, E. atoyac, and E. filodecaballo. Species of the subgenus Dyschromus live on the ground under cover in montane forests of tropical to temperate aspect, at elevations of 900 to 3400 meters. Adults are flightless, and potentially long-lived. Adults of most species are metallic colored dorsally. All seven species from the island of Hispaniola are placed in the opaca group, and all 28 species from Mexico are placed in the nitidipennis group. The opaca group is divided into the opaca and cupripennis subgroups, but support for monophyly of the opaca subgroup is inconclusive.f The nitidipennis group is divided into the nitidipennis, soladevega, and dimidiata subgroups. The nitidipennis subgroup contains all species of the subgenus Dyschromus in the mountains of eastern Mexico, north of the Rio Santo Domingo; the dimidiata subgroup comprises most of the other species in Mexico, except for three species from western Oaxaca that make up the soladevega subgroup. Body color and the condition of the elytral striae and microsculpture of adults, and some traits of the larvae, as well as certain ecological and distributional correlates, provide evidence that each of the three subgroups is monophyletic, but structure of the distal part of the median lobe of the aedeagus indicates that four or five members of the dimidiata subgroup from Oaxaca, including the only species from eastern Oaxaca, as a group, actually belong to the nitidipennis subgroup, as does one of the three species in the soladevega subgroup, while the other two species in the soladevega subgroup really belong to the dimidiata subgroup. Just one species in Mexico is comparatively widespread, E. dimidiata, which