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Phylogenetic relationships in Pterodroma petrels are obscured by recent secondary contact and hybridization.

Brown RM, Jordan WC, Faulkes CG, Jones CG, Bugoni L, Tatayah V, Palma RL, Nichols RA - PLoS ONE (2011)

Bottom Line: The classification of petrels (Pterodroma spp.) from Round Island, near Mauritius in the Indian Ocean, has confounded researchers since their discovery in 1948.The breakdown of species boundaries in Round Island petrels followed environmental change (deforestation and changes in species composition due to hunting) within their overlapping ranges.Such multi-species interactions have implications not only for conservation, but also for our understanding of the processes of evolutionary diversification and speciation.

View Article: PubMed Central - PubMed

Affiliation: Institute of Zoology, Zoological Society of London, London, United Kingdom. rthbwn@bas.ac.uk

ABSTRACT
The classification of petrels (Pterodroma spp.) from Round Island, near Mauritius in the Indian Ocean, has confounded researchers since their discovery in 1948. In this study we investigate the relationships between Round Island petrels and their closest relatives using evidence from mitochondrial DNA sequence data and ectoparasites. Far from providing clear delimitation of species boundaries, our results reveal that hybridization among species on Round Island has led to genetic leakage between populations from different ocean basins. The most common species on the island, Pterodroma arminjoniana, appears to be hybridizing with two rarer species (P. heraldica and P. neglecta), subverting the reproductive isolation of all three and allowing gene flow. P. heraldica and P. neglecta breed sympatrically in the Pacific Ocean, where P. arminjoniana is absent, but no record of hybridization between these two exists and they remain phenotypically distinct. The breakdown of species boundaries in Round Island petrels followed environmental change (deforestation and changes in species composition due to hunting) within their overlapping ranges. Such multi-species interactions have implications not only for conservation, but also for our understanding of the processes of evolutionary diversification and speciation.

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Distribution of selected Pterodroma petrels.P. arminjoniana (blue1, 2), P.                            neglecta (red2, 3, 6, 7, 8, 11, 13, 15, 16), light                        morph P. heraldica (yellow2, 4, 5, 9, 10, 12, 13, 14,                            15) and P. atrata/dark morph P.                            heraldica (green11, 12, 13, 15).                        1Trindade Island, 2Round Island, 3Juan                        Fernandez, 4Raine Island, 5New Caledonia,                        6Lord Howe Island, 7Phillip Island,                        8Kermadec Islands, 9Tonga, 10Cook Islands,                            11Australs, 12French Polynesia,                        13Tuamotus, 14Easter Island, 15Pitcairn                        Islands (including Henderson and Ducie), 16Desventuradas.
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pone-0020350-g001: Distribution of selected Pterodroma petrels.P. arminjoniana (blue1, 2), P. neglecta (red2, 3, 6, 7, 8, 11, 13, 15, 16), light morph P. heraldica (yellow2, 4, 5, 9, 10, 12, 13, 14, 15) and P. atrata/dark morph P. heraldica (green11, 12, 13, 15). 1Trindade Island, 2Round Island, 3Juan Fernandez, 4Raine Island, 5New Caledonia, 6Lord Howe Island, 7Phillip Island, 8Kermadec Islands, 9Tonga, 10Cook Islands, 11Australs, 12French Polynesia, 13Tuamotus, 14Easter Island, 15Pitcairn Islands (including Henderson and Ducie), 16Desventuradas.

Mentions: At least three species of Pterodroma have been recorded breeding on Round Island (Fig. 1), and historical records suggest that extensive breeding only became established within the last century. The fauna and flora of Round Island have been documented by visiting naturalists since 1844 [3], and a variety of seabird species have been recorded on the island. However, it was not until the mid 1940s that breeding petrels were first unambiguously reported [2]. The Round Island population was initially identified as a single species, P. arminjoniana [4], but in the mid 1980s a second petrel species, P. neglecta, was also discovered to be breeding there, though in much smaller numbers than P. arminjoniana [5]. Since the mid 1990s, small, very pale petrels with a white ventral surface and a greyish head have been recorded at Round Island which might be a third species, P. heraldica (C. Jones pers. obs.). One of these small petrels has been clearly identified as P. heraldica from banding data. This bird was caught on Round Island in April 2006 and its band number confirmed it as a P. heraldica banded on Raine Island, Australia (Fig. 1), in July 1984 [6]. Prior to their discovery on Round Island, the range of P. arminjoniana was thought to be restricted to the Atlantic Ocean, where it breeds on a single island (Trindade Island, 1200 km east of the Brazilian coast) and the ranges of P. heraldica and P. neglecta were thought to be restricted to the Pacific Ocean, where they breed sympatrically, in some cases on the same island [7] (Fig. 1). The presence of a breeding population of P. neglecta on Trindade Island has been suggested in a single paper by Imber [8]. However, Imber's evidence is derived largely from second-hand sources and is highly questionable. A convincing rebuttal of Imber's conclusion has been published by Tove [9]. In addition, L. Bugoni spent a considerable amount of time on Trindade Island and has examined numerous live birds in the field. He found no birds with the pale primary shafts characteristic of P. neglecta, nor did he hear any neglecta-type calls on the island. Current evidence therefore suggests that P. neglecta are not present on Trindade Island.


Phylogenetic relationships in Pterodroma petrels are obscured by recent secondary contact and hybridization.

Brown RM, Jordan WC, Faulkes CG, Jones CG, Bugoni L, Tatayah V, Palma RL, Nichols RA - PLoS ONE (2011)

Distribution of selected Pterodroma petrels.P. arminjoniana (blue1, 2), P.                            neglecta (red2, 3, 6, 7, 8, 11, 13, 15, 16), light                        morph P. heraldica (yellow2, 4, 5, 9, 10, 12, 13, 14,                            15) and P. atrata/dark morph P.                            heraldica (green11, 12, 13, 15).                        1Trindade Island, 2Round Island, 3Juan                        Fernandez, 4Raine Island, 5New Caledonia,                        6Lord Howe Island, 7Phillip Island,                        8Kermadec Islands, 9Tonga, 10Cook Islands,                            11Australs, 12French Polynesia,                        13Tuamotus, 14Easter Island, 15Pitcairn                        Islands (including Henderson and Ducie), 16Desventuradas.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3105042&req=5

pone-0020350-g001: Distribution of selected Pterodroma petrels.P. arminjoniana (blue1, 2), P. neglecta (red2, 3, 6, 7, 8, 11, 13, 15, 16), light morph P. heraldica (yellow2, 4, 5, 9, 10, 12, 13, 14, 15) and P. atrata/dark morph P. heraldica (green11, 12, 13, 15). 1Trindade Island, 2Round Island, 3Juan Fernandez, 4Raine Island, 5New Caledonia, 6Lord Howe Island, 7Phillip Island, 8Kermadec Islands, 9Tonga, 10Cook Islands, 11Australs, 12French Polynesia, 13Tuamotus, 14Easter Island, 15Pitcairn Islands (including Henderson and Ducie), 16Desventuradas.
Mentions: At least three species of Pterodroma have been recorded breeding on Round Island (Fig. 1), and historical records suggest that extensive breeding only became established within the last century. The fauna and flora of Round Island have been documented by visiting naturalists since 1844 [3], and a variety of seabird species have been recorded on the island. However, it was not until the mid 1940s that breeding petrels were first unambiguously reported [2]. The Round Island population was initially identified as a single species, P. arminjoniana [4], but in the mid 1980s a second petrel species, P. neglecta, was also discovered to be breeding there, though in much smaller numbers than P. arminjoniana [5]. Since the mid 1990s, small, very pale petrels with a white ventral surface and a greyish head have been recorded at Round Island which might be a third species, P. heraldica (C. Jones pers. obs.). One of these small petrels has been clearly identified as P. heraldica from banding data. This bird was caught on Round Island in April 2006 and its band number confirmed it as a P. heraldica banded on Raine Island, Australia (Fig. 1), in July 1984 [6]. Prior to their discovery on Round Island, the range of P. arminjoniana was thought to be restricted to the Atlantic Ocean, where it breeds on a single island (Trindade Island, 1200 km east of the Brazilian coast) and the ranges of P. heraldica and P. neglecta were thought to be restricted to the Pacific Ocean, where they breed sympatrically, in some cases on the same island [7] (Fig. 1). The presence of a breeding population of P. neglecta on Trindade Island has been suggested in a single paper by Imber [8]. However, Imber's evidence is derived largely from second-hand sources and is highly questionable. A convincing rebuttal of Imber's conclusion has been published by Tove [9]. In addition, L. Bugoni spent a considerable amount of time on Trindade Island and has examined numerous live birds in the field. He found no birds with the pale primary shafts characteristic of P. neglecta, nor did he hear any neglecta-type calls on the island. Current evidence therefore suggests that P. neglecta are not present on Trindade Island.

Bottom Line: The classification of petrels (Pterodroma spp.) from Round Island, near Mauritius in the Indian Ocean, has confounded researchers since their discovery in 1948.The breakdown of species boundaries in Round Island petrels followed environmental change (deforestation and changes in species composition due to hunting) within their overlapping ranges.Such multi-species interactions have implications not only for conservation, but also for our understanding of the processes of evolutionary diversification and speciation.

View Article: PubMed Central - PubMed

Affiliation: Institute of Zoology, Zoological Society of London, London, United Kingdom. rthbwn@bas.ac.uk

ABSTRACT
The classification of petrels (Pterodroma spp.) from Round Island, near Mauritius in the Indian Ocean, has confounded researchers since their discovery in 1948. In this study we investigate the relationships between Round Island petrels and their closest relatives using evidence from mitochondrial DNA sequence data and ectoparasites. Far from providing clear delimitation of species boundaries, our results reveal that hybridization among species on Round Island has led to genetic leakage between populations from different ocean basins. The most common species on the island, Pterodroma arminjoniana, appears to be hybridizing with two rarer species (P. heraldica and P. neglecta), subverting the reproductive isolation of all three and allowing gene flow. P. heraldica and P. neglecta breed sympatrically in the Pacific Ocean, where P. arminjoniana is absent, but no record of hybridization between these two exists and they remain phenotypically distinct. The breakdown of species boundaries in Round Island petrels followed environmental change (deforestation and changes in species composition due to hunting) within their overlapping ranges. Such multi-species interactions have implications not only for conservation, but also for our understanding of the processes of evolutionary diversification and speciation.

Show MeSH
Related in: MedlinePlus