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Ancient DNA elucidates the controversy about the flightless island hens (Gallinula sp.) of Tristan da Cunha.

Groenenberg DS, Beintema AJ, Dekker RW, Gittenberger E - PLoS ONE (2008)

Bottom Line: Others suppose that it still inhabits Tristan.There is no consensus about Gallinula comeri, the name introduced for the flightless moorhen from the nearby island of Gough.This study confirms that among gallinules seemingly radical adaptations (such as the loss of flight) can readily evolve in parallel on different islands, while conspicuous changes in other morphological characters fail to occur.

View Article: PubMed Central - PubMed

Affiliation: National Museum of Natural History Naturalis, Leiden, The Netherlands. groenenberg@naturalis.nl

ABSTRACT
A persistent controversy surrounds the flightless island hen of Tristan da Cunha, Gallinula nesiotis. Some believe that it became extinct by the end of the 19th century. Others suppose that it still inhabits Tristan. There is no consensus about Gallinula comeri, the name introduced for the flightless moorhen from the nearby island of Gough. On the basis of DNA sequencing of both recently collected and historical material, we conclude that G. nesiotis and G. comeri are different taxa, that G. nesiotis indeed became extinct, and that G. comeri now inhabits both islands. This study confirms that among gallinules seemingly radical adaptations (such as the loss of flight) can readily evolve in parallel on different islands, while conspicuous changes in other morphological characters fail to occur.

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Map showing the location of Tristan da Cunha and Gough in the Mid Atlantic.
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pone-0001835-g001: Map showing the location of Tristan da Cunha and Gough in the Mid Atlantic.

Mentions: Until recently it was assumed that the flightless moorhen of remote Tristan da Cunha in the southern Atlantic (Fig. 1), Gallinula nesiotis (Sclater, 1861) [1], became extinct by the end of the 19th century [2]. A few decades after its description, a very similar moorhen that was also flightless namely G. comeri (Allen, 1892), was described [3] from the island of Gough, ca. 400 km SE of Tristan. In the period between these descriptions G. nesiotis became rare [4], [5] and by the turn of the century it had probably gone extinct [7], [6]. Authentic remnants are two skins and a skeleton in the Natural History Museum, Tring [8]. Since unequivocal G. nesiotis had been collected only once from Tristan, and because of the presence of a healthy population of similar moorhens on the nearby island of Gough, some authors doubted whether an endemic moorhen had ever existed on Tristan [9]. Eber [10] compared Sclater's description of G. nesiotis from Tristan with her series of G. comeri from Gough and concluded that the differences fall within the range of variation of the latter. In her opinion it was very unlikely that moorhens from two islands in the same region would have independently lost the ability of flight, without differentiating in other characters. She suggested that Sclater's material might have been labelled inaccurately and that his specimens in fact also came from Gough. Consequently, Eber considered G. comeri a junior synonym of G. nesiotis [10] and controversy surrounded future illustrations of both taxa (Fig. 2).


Ancient DNA elucidates the controversy about the flightless island hens (Gallinula sp.) of Tristan da Cunha.

Groenenberg DS, Beintema AJ, Dekker RW, Gittenberger E - PLoS ONE (2008)

Map showing the location of Tristan da Cunha and Gough in the Mid Atlantic.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2266797&req=5

pone-0001835-g001: Map showing the location of Tristan da Cunha and Gough in the Mid Atlantic.
Mentions: Until recently it was assumed that the flightless moorhen of remote Tristan da Cunha in the southern Atlantic (Fig. 1), Gallinula nesiotis (Sclater, 1861) [1], became extinct by the end of the 19th century [2]. A few decades after its description, a very similar moorhen that was also flightless namely G. comeri (Allen, 1892), was described [3] from the island of Gough, ca. 400 km SE of Tristan. In the period between these descriptions G. nesiotis became rare [4], [5] and by the turn of the century it had probably gone extinct [7], [6]. Authentic remnants are two skins and a skeleton in the Natural History Museum, Tring [8]. Since unequivocal G. nesiotis had been collected only once from Tristan, and because of the presence of a healthy population of similar moorhens on the nearby island of Gough, some authors doubted whether an endemic moorhen had ever existed on Tristan [9]. Eber [10] compared Sclater's description of G. nesiotis from Tristan with her series of G. comeri from Gough and concluded that the differences fall within the range of variation of the latter. In her opinion it was very unlikely that moorhens from two islands in the same region would have independently lost the ability of flight, without differentiating in other characters. She suggested that Sclater's material might have been labelled inaccurately and that his specimens in fact also came from Gough. Consequently, Eber considered G. comeri a junior synonym of G. nesiotis [10] and controversy surrounded future illustrations of both taxa (Fig. 2).

Bottom Line: Others suppose that it still inhabits Tristan.There is no consensus about Gallinula comeri, the name introduced for the flightless moorhen from the nearby island of Gough.This study confirms that among gallinules seemingly radical adaptations (such as the loss of flight) can readily evolve in parallel on different islands, while conspicuous changes in other morphological characters fail to occur.

View Article: PubMed Central - PubMed

Affiliation: National Museum of Natural History Naturalis, Leiden, The Netherlands. groenenberg@naturalis.nl

ABSTRACT
A persistent controversy surrounds the flightless island hen of Tristan da Cunha, Gallinula nesiotis. Some believe that it became extinct by the end of the 19th century. Others suppose that it still inhabits Tristan. There is no consensus about Gallinula comeri, the name introduced for the flightless moorhen from the nearby island of Gough. On the basis of DNA sequencing of both recently collected and historical material, we conclude that G. nesiotis and G. comeri are different taxa, that G. nesiotis indeed became extinct, and that G. comeri now inhabits both islands. This study confirms that among gallinules seemingly radical adaptations (such as the loss of flight) can readily evolve in parallel on different islands, while conspicuous changes in other morphological characters fail to occur.

Show MeSH