Historical diversification of Pseudonympha Wallengren, 1857 (Lepidoptera: Nymphalidae: Satyrinae)

ABSTRACTThe butterfly genus Pseudonympha and several related genera are endemic to southern Africa. Although many of the species are montane, some inhabit the arid interior of South Africa, offering an opportunity to study the palaeobiogeography of this biome. Morphological data (for all species of Pseudonympha and allied African and Asian genera) and molecular data (WG and COI genes for nine of the 15 species of Pseudonympha and all of the southern African endemic genera of Ypthimina) were compiled. Phylogenetic analysis indicated that Pseudonympha apparently originated in the Cape Fold Mountains about 15 Mya ago and spread steadily eastwards and northwards along the Great Escarpment during the aridification of the region, perhaps assisted by orogeny in the east and oceanic cooling in the west. Aridification cycles seem to have intermittently isolated some early lineages in elevated habitats in the interior, so that those lineages show lower speciation rates (or perhaps higher extinction rates) than those in the east. Four species delineation techniques indicated that some species are taxonomically oversplit. Based on genetic polyphyly and morphological similarity, we propose that the status of P. swanepoeli be reduced to that of a subspecies of P. varii, such that all the north-eastern populations from Harrismith to Tzaneen fall under P. varii swanepoeli van Son stat. n., and all the southern populations fall under P. varii varii van Son stat. n. Ultimately, the diversification of both of these lineages seems tied to their host plants’ response to aridification brought on by continental drift and orogeny. Sympatric organisms (eg cicadas) with biologies focused around different resources (eg savanna trees) show other patterns of diversification. The phylogenetic analysis of the subtribe Ypthimina also supports the monophyly of Paternympha, paraphyly of Ypthima, recognition of Thymipa Moore stat. rev. as a phylogenetic independent genus, and new relationships for Strabena.http://www.zoobank.org/urn:lsid:zoobank.org:pub:C3B34CBC-4BC2-44F3-8349-9DBC82FFBBF3KEYWORDS: ButterfliesSouth Africaendemic radiationpalaeobiogeographyYpthimina AcknowledgementsWe thank David Edge, Niklas Wahlberg, Vincent Clarke, Etienne Terblanche and Andrew Morton for providing specimens, DNA sequences, and/or literature; Shelley Edwards for laboratory facilities; the late Mark Williams for permission to use his photographs in our figures; Terence Bellingan for access to the Albany Museum collection and the photographs in Figure 5; and the Rhodes University Research Committee for funding.Disclosure statementNo potential conflict of interest was reported by the authors.Data availability statementThe genetic sequence data that support the findings of this study are openly available on GenBank (https://www.ncbi.nlm.nih.gov/genbank/), with accession numbers OK668392–OK668431 (COI); OL311554–OL311597 and OM953781 (WG).Supplementary dataSupplemental data for this article can be accessed online at https://doi.org/10.1080/00222933.2023.2257373.Additional informationFundingThis work was supported by the Rhodes University Research Committee, Rhodes University.