Systematic revision of the genus Isodacrys Sharp, 1911 (Coleoptera: Curculionidae: Entiminae: Tanymecini)

The genus Isodacrys Sharp, 1911 is revised. Twenty species of the genus are recognized ranging from south United States of America, Mexico, Guatemala and Honduras of which eight are herein described as new. These species are Isodacrys antrum Cortés-Hernández, new species (Mexico: Tamaulipas, Chiapas; Guatemala: Baja Verapaz); Isodacrys carlae Cortés-Hernández, new species (Mexico: Coahuila, Hidalgo, Nuevo León, San Luis Potosí, Tamaulipas); Isodacrys confusum Cortés-Hernández, new species (Mexico: Tamaulipas); Isodacrys fasciatum Cortés-Hernández, new species (Mexico: Coahuila, Durango, Nuevo León); Isodacrys frontalis Cortés-Hernández, new species (Mexico: Oaxaca; Guatemala: Sacatepéquez, Guatemala); Isodacrys kuchii Cortés-Hernández, new species (Mexico: Puebla); Isodacrys obrienorum Cortés-Hernández, new species (Guatemala: Totonicapán, Jalapa, San Marcos); and Isodacrys okuiltontli Cortés Hernández, new species (Mexico: Oaxaca). Insights into the monophyly of Isodacrys and its phylogenetic relationships with other Tanymecini based on adult morphology are given by implementing a phylogenetic analysis of 43 terminals (21 ingroup, 22 outgroup) coded for 72 adult morphological characters. Characters were discussed and highlighted for the inclusion in the phylogenetic analysis. Final analysis yielded two most-parsimonious cladograms of 242 steps, which support the monophyly of Isodacrys. Isodillex Cortés-Hernández, new genus is here described to accommodate Isodillex minutum (Sharp, 1911), new combination and Isodillex plumosum Cortés-Hernández, new species (Mexico: Zacatecas). Isodillex was recovered as sister group of Isodacrys. Key to separate Isodacrys species, occurrence map and habitus photographs are also provided.