# Discovery of a peculiar insular race of Ravenna nivea (Nire, 1920) (Lepidoptera: Lycaenidae) endemic to Yinggeling Mountain of Hainan, suggesting heterogeneous geological history of mountain formation of the island

## TL;DR

A new subspecies of butterfly found in Hainan shows genetic and physical differences, suggesting unique geological history of the island's mountains.

## Contribution

Discovery of a new subspecies and evidence that Hainan's mountains may have acted as glacial refuges.

## Key findings

- Yinggeling population of R. nivea shows 1.1% COI barcode difference from nearby Bawangling population.
- High haplotype diversity in Hainan and Taiwan suggests these islands were glacial refuges for the species.
- Relict populations of montane butterflies may help understand island mountain formation history.

## Abstract

A peculiar population of Ravenna nivea (Nire, 1920) was discovered from the Yinggeling Mountain Mass of central Hainan. Its wing pattern and COI barcode data show considerable distinction from other geographic populations of R. nivea, including that of Bawangling, approximately only 40 km away and also located in Hainan. The p-distance value of the COI barcode between the Yinggeling and Bawangling populations was 1.1%, considerably higher than the value (0.6%) between Bawangling population and populations in eastern China, where the subspecific name howarthi Saigusa, 1993 applies. The population is regarded as a distinct subspecies ngiunmoiae Lo & Hsu, subsp. nov. The distinctness and high degree of COI haplotype diversity of R. nivea found in Hainan and Taiwan suggest continental islands may serve as glacial refugees for the butterfly and other organisms during previous glaciations, and the presence of the relict populations of montane butterflies like R. nivea may provide useful clues towards a better understanding of the geological history of mountain formation within islands.