Assessing a generic synapomorphy of Pseudodebis Forster, 1964 (Lepidoptera : Nymphalidae : Satyrinae) and a recent speciation with a shift in elevation between two new species in the western Andes

Abstract

The field of systematics and our understanding of phylogenetic relationships have been invigorated by the use of molecular data, but analyses based on DNA sequence data are not always corroborated by diagnostic morphological characters. In particular, several taxonomic changes in butterflies (Papilionoidea) have been made solely on the basis of molecular data without identifying morphological synapomorphies that might have aided in diagnosing taxa from butterfly collections or specimens with no accessible DNA. We here focus on the butterfly genus Pseudodebis Forster, 1964 in the so-called ‘Taygetis clade’, which is one of the major clades in the diverse Neotropical nymphalid subtribe Euptychiina. We inferred the evolution of a male genitalic character using the most comprehensive molecular phylogeny for the ‘Taygetis clade’ to date. This approach allowed us to identify a synapomorphy for Pseudodebis Forster, 1964, which can be used to morphologically diagnose this genus and to distinguish it from other genera in the ‘Taygetis clade’. In addition, we describe two new species of Pseudodebis, P. nakamurai Nakahara & Willmott, sp. nov. and P. pieti Nakahara & Willmott, sp. nov., recovered as sister species based on molecular data, with an estimated time of divergence of 0.3 Ma (Bayesian confidence interval 0.03–1.61 Ma). Despite the low genetic divergence between these two Pseudodebis species, they can be readily distinguished by wing morphology. Pseudodebis nakamurai, sp. nov. and P. pieti, sp. nov. occur in partial sympatry across an elevational gradient along the western Andes, and the inferred recent speciation event might be related to a shift in elevation and possibly a change in larval hostplant preference. urn:lsid:zoobank.org:pub:38B4AF76-79E9-4D4D-BF16-FCD8F53A7277