Systematics of Ectrichodiella Fracker and Bruner, 1924, with Description of the First Fossil Millipede Assassin Bug Species (Insecta: Hemiptera: Reduviidae: Ectrichodiinae)

With more than 886 species in ∼137 genera, Ectrichodiinae (Hemiptera: Reduviidae) are the largest animal clade of millipede predators. Recent phylogenetic studies have created a framework for our understanding of ectrichodiine evolutionary history, but no fossil species have been described. Ectrichodiella Fracker and Bruner, 1924, belongs to the earliest diverging lineage of Ectrichodiinae, and a better understanding of the morphology and biodiversity of this genus may provide insights into the early evolution of the subfamily. The genus is composed of two described species, Ectrichodiella minima (Valdés, 1910) and Ectrichodiella rafaeli (Gil-Santana and Coletto-Silva, 2005) from Cuba and Brazil, respectively. Here, four new species of Ectrichodiella are described, with three representing extant taxa known only from French Guiana (E. caballina, n. sp., E. nouraguensis, n. sp., and E. obscura, n. sp.), while the fourth is based on a Miocene Dominican amber fossil (Ectrichodiella electrina, n. sp.). Diagnoses, descriptions, habitus and detailed morphological images, an identification key, and a distribution map are provided. A cladistic analysis based on 45 morphological characters that includes the fossil species corroborates the monophyly of Ectrichodiella, but the relationship of the fossil species to the five extant species remains ambiguous. Nevertheless, this phylogenetic placement makes Ectrichodiella electrina, a valuable fossil calibration for future divergence dating analyses, despite its relatively young age.