Peter Kovalik
Well-known member
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Acrocephalus (1 Viewer)
- Thread starter Peter Kovalik
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Peter Kovalik
Well-known member
Richard Klim
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Well spotted, Peter! Although I receive Sandgrouse, I now realise that issue 37(2) had disappeared under a huge pile of rubbish on my desk.
A quick survey...
septimus is recognised by Kennerley & Pearson 2010 (as septima) and H&M4 – both citing Leisler et al 1997 – and also by IOC.
Dyrcz 2006 (HBW 11) additionally recognises capistratus.
eBird/Clements treats A agricola as monotypic, and Kirwan et al 2008 suggests likewise.
l_raty
laurent raty
In practice, I'm unsure why it is so surprising, as Helbig & Seibold 1999 [pdf] had already found a divergence of only 0.19% (instead of the 4.5% reported by Leisler et al.) between the cytb of an A. a. agricola and that of an A. a. septimus.
It seems that Leisler et al. had problems with their two sequences of septimus (AJ004247 and AJ004248), as both start and end in a quite agricola-like fashion, but have a large central part (~bp400-840) that is closest to Acrocephalus australis.
(I always wonder how it is possible that this type of problem affects more than one sequence in a data set in exactly the way, thus producing apparently congruent results... It's not really exceptional either, though, so there is presumably a mechanism that yields such situations...? Note that "problems" involving evidently wrong sequences [obvious chimaeras as here, or sequences that appear to come from an organism that could hardly be confused at all with the organism the sequence is claimed to represent] are by far more common in phylogenetic data sets than cases where an actual misidentification/hybrid status of the sequenced individual might be suspected. In all these cases, it hardly makes any difference whether the sequence has an associated voucher or not. The main guarantee that a sequence is correct for me remains its confirmation by another researcher.)
It seems that Leisler et al. had problems with their two sequences of septimus (AJ004247 and AJ004248), as both start and end in a quite agricola-like fashion, but have a large central part (~bp400-840) that is closest to Acrocephalus australis.
(I always wonder how it is possible that this type of problem affects more than one sequence in a data set in exactly the way, thus producing apparently congruent results... It's not really exceptional either, though, so there is presumably a mechanism that yields such situations...? Note that "problems" involving evidently wrong sequences [obvious chimaeras as here, or sequences that appear to come from an organism that could hardly be confused at all with the organism the sequence is claimed to represent] are by far more common in phylogenetic data sets than cases where an actual misidentification/hybrid status of the sequenced individual might be suspected. In all these cases, it hardly makes any difference whether the sequence has an associated voucher or not. The main guarantee that a sequence is correct for me remains its confirmation by another researcher.)
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Jacana
Will Jones
Kearns, A.M., Campana, M.G., Slikas, B., Berry, L., Saitoh, T., Cibois, A. and Fleischer, R.C. (2022), Conservation genomics and systematics of a near-extinct island radiation. Mol Ecol. Accepted Author Manuscript. https://doi.org/10.1111/mec.16382
Conservation benefits from incorporating genomics to explore the impacts of population declines, inbreeding, loss of genetic variation and hybridization. Here we use the near-extinct Mariana Islands reedwarbler radiation to showcase how ancient DNA approaches can allow insights into the population dynamics of extinct species and threatened populations for which historical museum specimens or material with low DNA yield (e.g., scats, feathers) are the only sources for DNA. Despite their having paraphyletic mtDNA, nuclear SNPs support the distinctiveness of critically endangered Acrocephalus hiwae and the other three species in the radiation that went extinct between the 1960s and 1990s. Two extinct species, A. yamashinae and A. luscinius, were deeply divergent from each other and from a third less differentiated lineage containing A. hiwae and extinct A. nijoi. Both mtDNA and SNPs suggest that the two isolated populations of A. hiwae from Saipan and Alamagan Islands are sufficiently distinct to warrant subspecies recognition and separate conservation management. We detected no significant differences in genetic diversity or inbreeding between Saipan and Alamagan, nor strong signatures of geographic structuring within either island. However, the implications of possible signatures of inbreeding in both Saipan and Alamagan, and long-term population declines in A. hiwae that predate modern anthropogenic threats require further study with denser population sampling. Our study highlights the value conservation genomics studies of island radiations have as windows onto the possible future for the world’s biota as climate change and habitat destruction increasingly fragments their ranges and contributes to rapid declines in population abundances.
Conservation benefits from incorporating genomics to explore the impacts of population declines, inbreeding, loss of genetic variation and hybridization. Here we use the near-extinct Mariana Islands reedwarbler radiation to showcase how ancient DNA approaches can allow insights into the population dynamics of extinct species and threatened populations for which historical museum specimens or material with low DNA yield (e.g., scats, feathers) are the only sources for DNA. Despite their having paraphyletic mtDNA, nuclear SNPs support the distinctiveness of critically endangered Acrocephalus hiwae and the other three species in the radiation that went extinct between the 1960s and 1990s. Two extinct species, A. yamashinae and A. luscinius, were deeply divergent from each other and from a third less differentiated lineage containing A. hiwae and extinct A. nijoi. Both mtDNA and SNPs suggest that the two isolated populations of A. hiwae from Saipan and Alamagan Islands are sufficiently distinct to warrant subspecies recognition and separate conservation management. We detected no significant differences in genetic diversity or inbreeding between Saipan and Alamagan, nor strong signatures of geographic structuring within either island. However, the implications of possible signatures of inbreeding in both Saipan and Alamagan, and long-term population declines in A. hiwae that predate modern anthropogenic threats require further study with denser population sampling. Our study highlights the value conservation genomics studies of island radiations have as windows onto the possible future for the world’s biota as climate change and habitat destruction increasingly fragments their ranges and contributes to rapid declines in population abundances.
