Wing base morphology supports paraphyly of Papilionoidea s.s. (Lepidoptera)

Abstract

Traditionally, skippers (Hesperiidae) and moth-like butterflies (Hedylidae) were classified in separate superfamilies outside the butterfly superfamily Papilionoidea sensu stricto. However, recent molecular phylogenies including phylogenomics placed the swallowtails (family Papilionidae) as the sister group to all other butterflies, including skippers and moth-like butterflies, making the traditionally recognized Papilionoidea s.s. paraphyletic. However, no morphological studies have supported this relationship to date. Here, we conducted a cladistic analysis based on wing base characters to evaluate these competing systematic hypotheses. Our results support a sister-group relationship between skippers and moth-like butterflies and their inclusion within Papilionoidea sensu lato, consistent with molecular-based phylogenies. In contrast, the wing base morphology suggests the monophyly of Pieridae + Riodinidae + Lycaenidae, a result that contradicts both molecular and other morphological evidence, highlighting the potential limitations of this character system. Based on our morphological examinations and ancestral state reconstruction, we propose a hypothetical ground plan for the butterfly wing base.