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

Pankaj Koparde,Pankaj Koparde,V V Robin,Uma Ramakrishnan,Shomita Mukherjee,Sushma Reddy,Prachi Mehta

doi:10.1371/journal.pone.0192359

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.

Highlights

Endemic and endangered species are often ecologically specialized and there is an urgent need to better understand the ecology and phylogenetic history of endangered species to uncover features that might be crucial for conservation
Nuclear and concatenated datasets (Figs 2 and 3, and S4– S11 Figs) show that H. blewitti is nested within the Athene clade, rejecting the Konig et al (1999) hypothesis that the species is nested within Glaucidium [23], and the Rasmussen & Collar (2013) hypothesis that Heteroglaux is a monotypic genus sister to Athene [16]
Our results support the Rasmussen & Collar (2013) interpretation of the morphological similarities in A. brama and H. blewitti being either convergence of traits or plesiomorphies, further supported by the observation that a strong arboreal nature is absent in A. noctua

Summary

Introduction

Endemic and endangered species are often ecologically specialized and there is an urgent need to better understand the ecology and phylogenetic history of endangered species to uncover features that might be crucial for conservation. Our knowledge of the evolutionary history of highly restricted, endemic species in the tropics is limited, due to their rarity and incomplete genetic sampling [4]. This could have far-reaching consequences on policy level decisions regarding species conservation. Many rare or range-restricted species such as the Critically Endangered Forest Owlet Heteroglaux blewitti (Hume, 1873), Spotted Owlet Athene brama (Temmink, 1821) and Jungle Owlet Glaucidium radiatum (Tickell, 1833) were not included in the most recently published owl phylogenies [8,9,10]

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Results

Conclusion