Lost in Time: Re-description and Ecological Re-assessment of two Indian Endemic Elattoneura Cowley, 1935 (Playcnemidiae) Damselflies

The Indian Elattoneura are a difficult group to identify due to their extreme morphological similarity and sparse information in identification keys and on geographical distribution. The ambiguity is prominent among two Peninsular Indian Elattoneura species, E. nigerrima (Laidlaw, 1917) and E. tetrica (Laidlaw, 1917), described a hundred years ago. Both species were described based on male specimens with scant information on their females. The species are IUCN Red-listed, E. nigerrima (Data Deficient) and E. tetrica (Least Concern). Hitherto it was thought that E. nigerrima was smaller than E. tetrica and both have non-overlapping geographical distribution. Here, we re-described both sexes of E. nigerrima; E. tetrica along with morphometric data and geospatial analysis. We found that E. nigerrima is significantly larger than E. tetrica. The species are largely allopatric in distribution, with the former having a much wider spatial distribution than previously thought. Based on our geospatial analysis, we provide occurrence data useful for the future IUCN assessments of E. nigerrima and E. tetrica. We highlight the importance of updating taxonomic status information and data on spatiotemporal distribution to proceed with the conservation of endemic insects such as Elattoneura damselflies. Our study indicates reassessments of Indian Odonata species are urgently needed.