Abstract
Arlesminthurus Bretfeld is a small genus of Neotropical Bourletiellidae, with only four described species so far. Calvatomina Yosii is a widespread taxon of Dicyrtomidae, with most species known from the tropics. Here, we describe two new species from northeastern Brazil: Arlesminthurus caatinguensis sp. nov. and Calvatomina gladiata sp. nov. We also provide a detailed chaetotaxic study for Arlesminthurus for the first time, with updated diagnoses and identification keys for the Neotropical species of both genera and notes on their morphology. Arlesminthurus caatinguensis sp. nov. resembles A. aueti Arlé in body color pattern, male head and dental chaetotaxy. The discovery of one bothriotrichum-like sens on the large abdomen of the new species needs to be investigated as a possible generic diagnostic feature, but we suggest that this structure is homologous to the S-sens seen in at least four Bourletiellinae genera, and they are likely related to each other. Calvatomina gladiata sp. nov. belongs to the rufescens-group and resembles C. rufescens Reuter and C. guyanensis Nayrolles and Betsch in some aspects of the head, dental and abdominal chaetotaxy. These descriptions represent the first record of Arlesminthurus from Caatinga and the first nominal species of Calvatomina from Brazil.