Wednesday, February 28, 2018

[Ornithology • 2018] Athene blewitti The Critically Endangered Forest Owlet Heteroglaux blewitti is nested within the Currently Recognized Athene Clade: A Century-old Debate Addressed

Athene blewitti  (Hume, 1873)

in Koparde, Mehta, Reddy, et al., 2018.

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.

Athene (Heteroglaux) blewittiAthene brama Glaucidium radiatum

Fig 1. Co-distributed Indian owlets show plumage similarity, however can be identified based on size and markings on the chest and forehead.
Presence of white spots and brown bars in case of Athene brama and Glaucidium radiatum respectively are identification keys.
Photo credits: color banded H. blewitti individual by Prachi Mehta,
A. brama and G. radiatum by Pankaj Koparde.

Distribution of few Palearctic and Oriental owlets as per Birdlife International (2015).
H. blewitti is the only range-restricted, rare owlet among Indian owlets.

Pankaj Koparde, Prachi Mehta, Sushma Reddy, Uma Ramakrishnan, Shomita Mukherjee and V. V. Robin. 2018. The Critically Endangered Forest Owlet Heteroglaux blewitti is nested within the Currently Recognized Athene clade: A Century-old Debate Addressed.  PLoS ONE. 13(2): e0192359. DOI: 10.1371/journal.pone.0192359