Maluridae (1 Viewer)

Reassessment of a possible case of intraspecific gene flow across Australia’s Great Dividing Range in the variegated fairy wren, Malurus lamberti (Aves: Maluridae), and its systematic consequences
Alison J. Mclean, Leo Joseph, Alicia Toon, Daniel J. Schmidt, Alex Dre, Ian J. Mason, Jane M. Hughes
Biol J Linn Soc
Published: 02 June 2017
link

Abstract
Two subspecies of the variegated fairy wren Malurus lamberti, Malurus lamberti lamberti and Malurus lamberti assimilis, are thought to exemplify a surprisingly rare case of intraspecific gene flow across eastern Australia’s Great Dividing Range. We screened 71 individuals within and beyond their putative hybrid zone for diversity in one mitochondrial and two anonymous nuclear loci, four microsatellite markers and diagnostically different plumage traits. Almost all supposed hybrid zone individuals were genotypically and phenotypically M. l. assimilis, but some carried mitochondrial DNA typical of M. l. lamberti. We infer an intermittently ‘leaky’ genetic boundary between the two taxa. Integrating this study with our earlier work on the M. lamberti group, we argue that speciation, albeit with some gene flow, between M. l. lamberti and all other taxa recently assigned to M. lamberti is essentially complete. A two-species taxonomy whereby one species, M. lamberti Vigors and Horsfield, 1827 (variegated fairy wren), comprises only what is currently called M. l. lamberti, and a second species, Malurus assimilis North, 1901 (purple-backed fairy wren), is for all other populations recently assigned to M. lamberti should be adopted and further tested.


In a nutshell, this paper shows limited, one-way mtDNA (but not nuclear) introgression of lamberti into assimilis, but otherwise very weak evidence for an 'intergrade', and as with the previous related paper makes an unusually clear recommendation to split Variegated Fairy-wren into two species (i.e. split M. assimilis Purple-backed Fairy Wren).

Corrigendum

martin_WA said:

Reassessment of a possible case of intraspecific gene flow across Australia’s Great Dividing Range in the variegated fairy wren, Malurus lamberti (Aves: Maluridae), and its systematic consequences
Alison J. Mclean, Leo Joseph, Alicia Toon, Daniel J. Schmidt, Alex Dre, Ian J. Mason, Jane M. Hughes
Biol J Linn Soc
Published: 02 June 2017
link

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Corrigendum
Alison J. McLean Alicia Toon Daniel J. Schmidt Jane M. Hughes Leo Joseph. Phylogeography and geno-phenotypic discordance in a widespread Australian bird, the Variegated Fairy-wren, Malurus lamberti (Aves: Maluridae).

The Variegated Fairy-wren split now posted on PS by IOC

PS 7.3 Purple-backed Fairywren Malurus assimilis Variegated Fairywren M. lamberti McLean et al. 2017. M. lamberti would be monotypic. Working hypothesis

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Yandell, D. D., Hochachka, W. M., Pruett-Jones, S., Webster, M. S. and Greig, E. I. (2017), Geographic patterns of song variation in four species of Malurus fairy-wrens. J Avian Biol. Accepted Author Manuscript. doi:10.1111/jav.01446

Abstract:

Geographic variation in song is widespread among birds, particularly in species that learn vocalizations. The relationship between geographic distance and song variation is likely related to the degree of isolation between populations. To assess this effect of geographic isolation on song divergence, we examined patterns of geographic song variation in four species of Australian fairy-wrens (Malurus), two with suspected histories of geographic isolation and two without. Song variation in all four species was consistent with patterns of isolation by distance, and allopatric subspecies in two species were more divergent in song than predicted by distance alone. Each species' pattern was unique, and some interspecific variation could not be explained by geographic distance. These results indicate that patterns of geographic variation can be influenced by more than geographic distance and historical isolation alone. We suggest that morphological constraints, environmental influences, and sexual selection may all contribute to the variation observed for each species.

Malurus assimilis

martin_WA said:

Reassessment of a possible case of intraspecific gene flow across Australia’s Great Dividing Range in the variegated fairy wren, Malurus lamberti (Aves: Maluridae), and its systematic consequences
Alison J. Mclean, Leo Joseph, Alicia Toon, Daniel J. Schmidt, Alex Dre, Ian J. Mason, Jane M. Hughes
Biol J Linn Soc
Published: 02 June 2017
link

Click to expand...

IOC Updates Diary Jan 20

Accept Purple-backed Fairywren

Is there anywhere where a reasonably precise map can be found as to where the two Fairywren species (Variegated/Purple-backed) can be found?

Thanks
Niels

There has been a discussion on that issue on the Australian Twitchers Facebook page this week. I haven't read through all the comments, but I don't think anyone knows where the border is exactly. Somewhere to the west of the great dividing range.

Thank you. How about some places like Hattah-Kulkune (spelling) and little desert in the borderlands between Victoria and Southern Australia, and Sundown NP in Queensland - Can anything be said about which is present at those locations?

thanks
NIels

I think Hattah would clearly be Purple-backed (Malurus assimilis). Sundown is in the questionable zone. Schodde and Mason's Directory of Australian Birds, the most comprehensive review of Australian passerine subspecies, had an area around there that they showed as being an intergradation zone between the two. Which of course is hard to reconcile with them being separate species.

Murray Lord said:

I think Hattah would clearly be Purple-backed (Malurus assimilis). Sundown is in the questionable zone. Schodde and Mason's Directory of Australian Birds, the most comprehensive review of Australian passerine subspecies, had an area around there that they showed as being an intergradation zone between the two. Which of course is hard to reconcile with them being separate species.

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Narrow, stable hybrid zones with limitations on gene flow is an argument for species status; wide hybrid zone and gene flow through the zone is an argument against. That is why the details of the study made here are necessary.

Niels

Thick-billed Grasswren: Thick-billed grasswren (Amytornis modestus) songs differ across subspecies and elicit different subspecific behavioural responses

Amytornis whitei parvus Black, subsp. nov., Amytornis whitei aenigma Black, subsp. no

Andrew B. Black, Christopher A. Wilson, Lynn P. Pedler, Scott R. McGregor, Leo Joseph. Two new but threatened subspecies of Rufous Grasswren Amytornis whitei (Maluridae). Bulletin of the British Ornithologists’ Club, 140(2):151-163 (2020). https://doi.org/10.25226/bboc.v140i2.2020.a6

Abstract:

Rufous Grasswren Amytornis whitei is the most widely distributed of three species formerly included within the Striated Grasswren A. striatus complex. Included among four phenotypically, geographically and ecologically distinct populations are A. w. whitei of the Pilbara ironstone ranges of Western Australia and A. w. oweni of inland sandy deserts. The other two are the little-known small-billed isolate of the limestone plateau of the Cape Range, North West Cape Peninsula, Western Australia, and a larger form present in the mallee of the Eyre Peninsula, South Australia. We present morphometric and other data and describe these two populations as new subspecies; both are of conservation concern.

[full article]

Peter Kovalik said:

Andrew B. Black, Christopher A. Wilson, Lynn P. Pedler, Scott R. McGregor, Leo Joseph. Two new but threatened subspecies of Rufous Grasswren Amytornis whitei (Maluridae). Bulletin of the British Ornithologists’ Club, 140(2):151-163 (2020). https://doi.org/10.25226/bboc.v140i2.2020.a6

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IOC Updates Diary July 7

Split polytypic Rufous Grasswren Amytornis whitei from Striated Grasswren (Black et al. 2020). English name follows Black et al. (2020). Includes whitei, oweni and newly described parvus and aenigma.

Split Opalton Grasswren Amytornis rowleyi from Striated Grasswren (Christidis et al. 2013; Black et al. 2020). English name follows Black et al. (2020).

Amytornis striatus

Andrew Black, Gaynor Dolman, Christopher A. Wilson, Catriona D. Campbell, Lynn Pedler & Leo Joseph (2020) A taxonomic revision of the Striated Grasswren Amytornis striatus complex (Aves: Maluridae) after analysis of phylogenetic and phenotypic data, Emu - Austral Ornithology, DOI: 10.1080/01584197.2020.1776622

Abstract:

Taxonomy of the Striated Grasswren Amytornis striatus complex has long been contentious and remains incompletely resolved. Its many populations are distributed widely but disjunctly and show only subtle distinction in morphology and plumage. Genetic data are meagre and have not been correlated with phenotype. We conducted a phenotypic analysis across its range and obtained mitochondrial DNA sequences from most populations. We recognise three species: south-eastern Striated Grasswren Amytornis striatus sensu stricto, Opalton Grasswren Amytornis rowleyi in central Queensland and Rufous Grasswren Amytornis whitei in the remainder of the range, with subspecies in the Pilbara and in the central and western deserts. In A. striatus as so circumscribed, we separate allopatric Murray Mallee and central New South Wales populations subspecifically. Isolated populations of Rufous Grasswren, from the North West Cape Peninsula, Western Australia and Eyre Peninsula, South Australia are also distinct. Awareness of such unanticipated diversity within the group has profound implications for conservation.

Striated Grasswren splits

I’m interested in what everyone thinks of the three way Striated Grasswren split outlined in the two papers above this post, particularly the one in Emu.

The papers show there are no consistent plumage differences between the various forms: “Our review of plumages failed to provide diagnostic criteria for intraspecific division within the Striated Grasswren complex, thus corroborating the observation that plumage patterns are poor indicators of phylogenetic relationships within the genus as a whole (Christidis et al. 2010)“. The 2010 paper is actually entitled “Plumage patterns are good indicators of taxonomic diversity, but not of phylogenetic affinities, in Australian grasswrens Amytornis”. So plumage patterns aren’t a good indicator of taxonomic diversity if the results of these papers are accepted.

The papers show there is significant genetic divergence amongst the various forms, particularly those east and west of the Eyrean barrier. This is similar to the situation with the two Thick billed Grasswrens that were split a few years ago, as well as many other species. The divergence is of a similar level to that between other species, hence tends to support some degree of splitting.

There is a detailed analysis of specimen measurements which is too complex for me to succinctly summarise, but the rowleyi form seems shorter winged and tailed (albeit from a very small sample) and some of the differences are pretty small - for example the differences in bill depth are less than a millimetre. Some forms on each side of the Eyrean divide are dimensionally similar to each other, but others are not.

The paper then says “In proposing the number and rank of taxa to be recognised, we acknowledge debate about the relative importance of phenotypic and molecular data, especially in recognising intraspecific taxa (Sangster 2009; Patten 2015; Burfield et al. 2017; Patten and Remsen 2017). We formulate our discussion in relation to the Phylogenetic and General Lineage Species Concepts (reviews in Hausdorf 2011; Sangster 2014) and approaches outlined by Gill (2014) and Patten and Remsen (2017).” This wording left me unclear as to whether these splits are only being justified from a PSC perspective. Reading the last cited paper didn’t help as it was about how you can’t expect to distinguish subspecies genetically.

It says “Both morphometric and genetic data support species rank” for the forms each side of the Eyrean barrier. And on rowleyi “Though weakly differentiated phenotypically (e.g. deep bill profile, short tail), lengthy independent evolution is shown by substantial genetic divergence, so justifying recognition at species rank.”

I got to the end of the paper and when I tried to summarise it in my own mind I thought:

• There are significant genetic differences between Striated Grasswren populations, as you’d expect of populations that have been isolated for a long time. The level of divergence is consistent with multiple species. But unlike some other recent Australian splits (eg Golden Whistlers), this is not a case where the traditional species turns out to be non monophyletic.
• There are no consistent plumage differences.
• There is no analysis of call differences, but I note previous authors have said calls don't differ across the group. So neither plumage or call can be regarded as a potential isolating mechanism.
• The only morphological differences are small ones in size and relative shape

Is this really enough to justify splitting these forms on any of the species concepts used by major checklists (i.e. on anything other than the PSC)? Or have I oversimplified their conclusions?

Simon Yung Wa Sin, Fushi Ke, Guoling Chen, Pei-Yu Huang, Erik Enbody, Jordan Karubian, Michael S. Webster, and Scott V. Edwards (2024) Genetic basis and evolution of structural color polymorphism in an Australian songbird [White-winged Fairywren Malurus leucopterus ]. Molecular Biology and Evolution, posted 28 February 2024
Genetic basis and evolution of structural color polymorphism in an Australian songbird

Abstract:
Island organisms often evolve phenotypes divergent from their mainland counterparts, providing a useful system for studying adaptation under differential selection. In the white-winged fairywren (Malurus leucopterus), subspecies on two islands have a black nuptial plumage whereas the subspecies on the Australian mainland has a blue nuptial plumage. The black subspecies have a feather nanostructure that could in principle produce a blue structural color, suggesting a blue ancestor. An earlier study proposed independent evolution of melanism on the islands based on the history of subspecies divergence. However, the genetic basis of melanism and the origin of color differentiation in this group are still unknown. Here, we used whole-genome resequencing to investigate the genetic basis of melanism by comparing the blue and black M. leucopterus subspecies to identify highly divergent genomic regions. We identified a well-known pigmentation gene ASIP and four candidate genes that may contribute to feather nanostructure development. Contrary to the prediction of convergent evolution of island melanism, we detected signatures of a selective sweep in genomic regions containing ASIP and SCUBE2 not in the black subspecies but in the blue subspecies, which possesses many derived SNPs in these regions, suggesting that the mainland subspecies has re-evolved a blue plumage from a black ancestor. This proposed re-evolution was likely driven by a pre-existing female preference. Our findings provide new insight into the evolution of plumage coloration in island versus continental populations, and, importantly, we identify candidate genes that likely play roles in the development and evolution of feather structural coloration.