Genitalia, DNA barcodes, larval facies, and foodplants place the mimetic species neoxeniades molion in rhinthon (Hesperiidae: Hesperiinae)

Abstract

Facies can fool taxonomists as well as predators. Neoxeniades molion (Godman)-one of the many, large neotropical skippers in the major mimicry group that includes all the cryptic species of the Asiraptes fulgerator complex-is misclassified. It really relates to a species of Rhinthon that differs greatly from it in facies and size. In both sexes, the genitalia of Rhinthon molion, new combination, and R. osea (Plötz) are nearly identical, even down to a peculiar titillator on the left side of the aedeagus of the male. Males also share a secondary sex character along vein 2A of the forewing. DNA barcodes unite K. osea and K. molion in a tight, two-taxon cluster: their sequence divergence is about 3.5%. Caterpillars of the two species are alike but distinguishable, and, in Costa Rica, they have been found feeding on various native species of Marantaceae-seven of which are the same-and also on one and the same introduced species of Cannaceae (these are closely related plant families grouped in the order Zingiberales). Because Rhinthon is widespread and relatively speciose in Central and South America, it can no longer be considered a genus primarily of the Greater Antilles. DNA barcodes, which are useful for identifying known species and for indicating possible cryptic species, are useful in this study (in combination with other, more traditional, taxonomie characters) for pulling supposedly unrelated species together into the same genus.