The critically endangered forest owlet Heteroglaux blewitti is nested within the currently recognized Athene clade: A century-old debate addressed

Abstract

Range-restricted species generally have specific niche requirements and may often have unique evolutionary histories. Unfortunately, many of these species severely lack basic research, resulting in poor conservation strategies. The phylogenetic relationship of the Critically Endangered Forest Owlet Heteroglaux blewitti has been the subject of a century-old debate. The current classifications based on non-phylogenetic comparisons of morphology place the small owls of Asia into three genera, namely, Athene, Glaucidium, and Heteroglaux. Based on morphological and anatomical data, H. blewitti has been alternatively hypothesized to belong within Athene, Glaucidium, or its own monotypic genus Heteroglaux. To test these competing hypotheses, we sequenced six loci (~4300 bp data) and performed phylogenetic analyses of owlets. Mitochondrial and nuclear trees were not congruent in their placement of H. blewitti. However, both mitochondrial and nuclear combined datasets showed strong statistical support with high maximum likelihood bootstrap (>/ = 90) and Bayesian posterior probability values (>/ = 0.98) for H. blewitti being nested in the currently recognized Athene group, but not sister to Indian A. brama. The divergence of H. blewitti from its sister taxa was between 4.3 and 5.7 Ma coinciding with a period of drastic climatic changes in the Indian subcontinent. This study presented the first genetic analysis of H. blewitti, a Critically Endangered species, and addressed the long debate on the relationships of the Athene-Heteroglaux-Glaucidium complex. We recommend further studies with more data and complete taxon sampling to understand the biogeography of Indian Athene species.

Quaternary climatic fluctuations and resulting climatically suitable areas for Eurasian owlets

“…During this time period, other Indian owlets had relatively constricted climatically suitable areas in the Indian Subcontinent. During the LIG, Jungle Owlet which is currently associated with forest and scrubland habitats and has a relatively younger divergence (1.8–0.1 Ma, Koparde et al, ), might have survived in the pockets of the south Western Ghats, especially in the eastern parts of the Western Ghats (Figure ). Considering the LIG scenario (Figure ), it appears that Jungle Owlet had an insignificant presence in Peninsular India and hence would have played a negligible role as a possible competitor to other Indian owlets at this time.…”

“…The Little Owl Athene noctua (Scopoli) of Palearctic region partially overlaps in distribution with the Spotted Owlet. The four owlets with varying range extents, habitat requirements and degrees of overlap with each other are phylogenetically closely related (Koparde et al, ). Understanding how their ecological and evolutionary histories shaped their current distribution can provide vital information on how they respond to climatic changes, which will help plan their conservation strategies in the current scenario, especially in case of the Endangered Forest Owlet.…”

“…Such comparative biogeography studies are scarce and have been recommended to comprehend community responses to global climate change (Berg et al, 2010). (Koparde et al, 2018). Understanding how their ecological and evolutionary histories shaped their current distribution can provide vital information on how they respond to climatic changes, which will help plan their conservation strategies in the current scenario, especially in case of the Endangered Forest Owlet.…”

“…Divergence estimates from the phylogeny of Indian owlets indicate that the Plio‐Pleistocene climate change may have played an important role in the speciation of Athene and Glaucidium owlets (Koparde et al, ) that could explain patterns of their current ranges. Pellegrino et al, (), suggest that the Little Owl survived in the European Southern Refugia (Iberian, Italian, and Balkan Peninsula) during the LGM, when much of its distributional range was covered in ice, and later expanded into its current range.…”

Re-assessing the phylogenetic status and evolutionary relationship of Forest Owlet [Athene blewitti(Hume 1873)] using genomic data

“…This was also followed in the International Ornithological Committee bird list (IOC World Bird List v8.2, 2018) and Birds of the World (Holt et al, 2020). However, there was a discordance between mitochondrial and nuclear genes with regard to the placement of Forest Owlet within the genus Athene (Koparde et al, 2018). Hence, in this study, we proposed to investigate the Forest Owlet's phylogenetic placement, evolutionary relationships and re-assess relationships with other Athene species with additional data, using several thousand Ultra Conserved Elements.…”