A new DNA study by Rawlence et al presents analysese indicating that Stewart Island Shag is in fact two species which they recognise as Foveaux Shag and Otago Shag.
Link to study: http://onlinelibrary.wiley.com/doi/10.1 ... 6/abstract
Link to new portraits showing the differences between the Foveaux Shag (top), Otago Shag (middle) and the related Chatham Island Shag (bottom): https://scontent-syd1-1.xx.fbcdn.net/hp ... e=575BAF70
Link to another new painting showing a juvenile Otago Shag (left) with an adult pied plumage morph (black and white, middle) and an adult dark bronze plumage morph (wholly dark, right): https://fbcdn-sphotos-g-a.akamaihd.net/ ... 1dd7ca5636
Both watercolour paintings by Derek Onley (copyright).
Foveaux shag and Otago shag
- Michael Szabo
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Foveaux shag and Otago shag
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Stewart Island Shag Split
Extract from The Linnean Society's Zoological Journal, dated 12th Feb 2016:
Leucocarbo shags are a species-rich seabird clade exhibiting a southern circumpolar distribution. New Zealand's endemic Stewart Island shag, Leucocarbo chalconotus (G. R. Gray, 1845), comprises two regional groups (Otago and Foveaux Strait) that show consistent differences in relative frequencies between pied (black and white) and bronze (wholly dark) plumages, the extent and colour of facial carunculation, body size (based on postcranial morphometrics), and breeding season. Moreover, previous genetic research on modern and historical specimens utilizing mitochondrial DNA control-region sequences has also shown that the Otago and Foveaux lineages may not be sister taxa; instead, in several analyses the Otago lineage is sister to the endemic Chatham Island shag, Leucocarbo onslowi (Forbes, 1893). We present new ancient DNA analyses of the type specimens for the Otago and Foveaux Strait lineages of L. chalconotus, including a phylogenetic reanalysis of the available ancient, historical, and modern control-region sequence data for these lineages (including L. onslowi), and additional statistical analyses incorporating new morphometric characters. These analyses indicate that under the diagnosable species concept the two lineages of Stewart Island shag represent two separate species, which we now recognize as the Otago shag, L. chalconotus (G. R. Gray, 1845), and the Foveaux shag, Leucocarbo stewarti (Ogilvie-Grant, 1898).
Leucocarbo shags are a species-rich seabird clade exhibiting a southern circumpolar distribution. New Zealand's endemic Stewart Island shag, Leucocarbo chalconotus (G. R. Gray, 1845), comprises two regional groups (Otago and Foveaux Strait) that show consistent differences in relative frequencies between pied (black and white) and bronze (wholly dark) plumages, the extent and colour of facial carunculation, body size (based on postcranial morphometrics), and breeding season. Moreover, previous genetic research on modern and historical specimens utilizing mitochondrial DNA control-region sequences has also shown that the Otago and Foveaux lineages may not be sister taxa; instead, in several analyses the Otago lineage is sister to the endemic Chatham Island shag, Leucocarbo onslowi (Forbes, 1893). We present new ancient DNA analyses of the type specimens for the Otago and Foveaux Strait lineages of L. chalconotus, including a phylogenetic reanalysis of the available ancient, historical, and modern control-region sequence data for these lineages (including L. onslowi), and additional statistical analyses incorporating new morphometric characters. These analyses indicate that under the diagnosable species concept the two lineages of Stewart Island shag represent two separate species, which we now recognize as the Otago shag, L. chalconotus (G. R. Gray, 1845), and the Foveaux shag, Leucocarbo stewarti (Ogilvie-Grant, 1898).
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Re: Foveaux shag and Otago shag
ok, so does this finally put pay to the not infrequently heard dismissal of King Shag as just a cline of Stewart Island Shag? It seems odd that they didn't include King Shag in his analysis.
And will geneticists now have a go at the Spotted Shag/Blue Shag question?
Lets hope so.
And will geneticists now have a go at the Spotted Shag/Blue Shag question?
Lets hope so.
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Re: Foveaux shag and Otago shag
Andrew
Yes to your first question. King shags have been placed nearest Bounty Island Shags by genetics I think, but I can't find the reference for this at present, so not in the picture any more.
As for the spotted shags ...? Maybe worth making a project of it yourself and taking a look at them. A bit far for me nowadays but I did try once. Pretty interesting but not immediately clear although I had a feeling it might become better if I could know them better ... and I never saw Stewart Island birds in breeding plumage. Immature plumages from Southland and Haast seemed to be a bit different, darker, especially the head, but I didn't know that before I went and didn't make a priority of seeking them out so not sure.
Ian
Yes to your first question. King shags have been placed nearest Bounty Island Shags by genetics I think, but I can't find the reference for this at present, so not in the picture any more.
As for the spotted shags ...? Maybe worth making a project of it yourself and taking a look at them. A bit far for me nowadays but I did try once. Pretty interesting but not immediately clear although I had a feeling it might become better if I could know them better ... and I never saw Stewart Island birds in breeding plumage. Immature plumages from Southland and Haast seemed to be a bit different, darker, especially the head, but I didn't know that before I went and didn't make a priority of seeking them out so not sure.
Ian
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Re: Foveaux shag and Otago shag
And it looks like there used to be yet another mainland blue-eyed shag. The newly described but extinct Kohatu Shag Leucocarbo septentrionalis from Northland related to the King Shag is reported here https://sciblogs.co.nz/guestwork/2017/0 ... hatu-shag/ So far I haven't found an available copy of the paper describing it.
Ian
Ian