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Trends in systematics Speciation in shades of grey: Grey L elegans, while other taxa were left undetermined for the time being. the great grey shrike complex The purpose of this short paper is to present an Sometimes clear-cut limits are hard to update on geographic variation in the great grey come by. A number of widespread Palearctic spe- shrike complex based on recent genetic studies cies and species complexes display an intricate (Gonzalez et al 2008, Klassert et al 2008, Olsson pattern of geographical () variation. et al 2010) and to show current implications for Information on patterns of genetic variation can species limits within this complex. Olsson et al be a tremendous help in clarifying relationships (2010) sampled by far the most extensively and between populations but the results are not al- agree with Gonzalez et al (2008) and Klassert et al ways unambiguous. The great grey shrike complex (2008) on the basic structure of the phylogeny. is one such diffcult case. Many may have been Therefore, Olsson et al (2010) is referred to below, surprised to note the treatment of great grey unless noted otherwise. in the second English edition of the Collins guide (Svensson et al 2009) in which two species Results are recognized: Great Grey Shrike excubi- The recovered mitochondrial DNA (mtDNA) tor and L meridionalis. The lat- (fgure 1) shows a deep split between two large ter now only includes the from Iberia and clades, representing up to several million years of south-eastern France. This treatment contrasts with differentiation. In this tree, the 18 taxa of the great more familiar former treatments in which these grey shrike complex are non-monophyletic, with populations were considered conspecifc with some being more closely related to North African and southern Asian taxa, together three universally recognized species: Somali forming ‘Southern Grey Shrike’. Fiscal L somalicus, L ludovi- It should be noted that the Dutch Committee for cianus and L sphenocercus Avian Systematics (CSNA) separated Grey ( L minor was not included, but Shrike L pallidirostris as a third species (Sangster et is thought to be only distantly related to the great al 1997, 1999) based on qualitative differences be- grey shrike complex (Harris & Franklin 2000)). tween pallidirostris and L excubitor and L meridi- The latter clade furthermore includes not only one onalis. More recently, Redactie Dutch Birding Nearctic (borealis) and four north-eastern Palearc- (2009) followed Gonzalez et al (2008) in regarding tic subspecies (mollis, sibiricus, funereus and bi- Iberian Grey Shrike as monotypic and the North anchii) but, remarkably, also meridionalis. The African taxa were provisionally separated as Desert second large clade contains, among others, nomi-

258 [Dutch Birding 32: 258-264, 2010] Trends in systematics

347 Iberian Grey Shrike / Iberische Klapekster Lanius meridionalis, Castillo Branco, Portugal, 29 June 2010 (René Pop/The Sound Approach) 348 Desert Grey Shrike / Woestijnklapekster Lanius elegans elegans, Zaafrane, Tunisia, 6 May 2005 (René Pop)

259 Trends in systematics nate Great Grey Shrike excubitor, North African 1998). A fnal similar case is that of Spanish taxa (eg, algeriensis, elegans and koenigi), and Imperial Eagle adalberti and Eastern south-western Asian taxa (eg, pallidirostris). Imperial Eagle A heliaca (Martinez-Cruz & Godoy Perhaps the most striking outcome is the place- 2007, González 2008), although these two spe- ment of excubitor and meridionalis (see fgure 1), cies are separated by a much smaller geographi- which is in confict with usual and sur- cal area. In all these cases, the inference is that the prising when considering both geography and now geographically restricted western European plumage variation: excubitor is morphologically populations were once connected to their eastern similar to its neighbour sibiricus while meridiona- counterparts, and that connecting populations lis is similar to nearby North African taxa, yet these have disappeared. One can speculate that a simi- pairs of populations are apparently not closely re- lar scenario may partly account for the distribu- lated. It also implies that a south-western European tion pattern in the great grey shrike complex, with endemic has its closest relative in north-eastern additional colonizations by populations from, eg, Asia. However, such a situation is reminiscent of south-western Asia ‘flling up the gaps’. This does, that in Iberian cooki and however, not readily explain the morphological Azure-winged Magpie C cyanus, which were con- variation in the complex, which is also at odds sidered conspecifc until recently as well (Fok et al with the inferred relationships. But then again, 2002), and that in Corsican Nuthatch Sitta white- plumage characteristics are not always useful phy- headi and Chinese Nuthatch S villosa (Pasquet logenetic markers as they may be infuenced by

FIGuRe 1 Summary of phylogenetic relationships in great grey shrikes Lanius found by Olsson et al (2010). All reci- procally monophyletic groups are collapsed into single branches. Colours highlight confict between tree and previ- ous taxonomic treatments in, eg, Svensson et al (1999), by showing fairly long-standing division between great (blue) and southern (red) grey shrikes. Most progressive treatment would involve recognizing each branch as species, whereas current CSNA treatment (not yet published in Dutch Birding) is indicated on right hand side.

Phylogeny CSNA treatment

lahtora, pallidirostris L lahtora (Asian Grey) aucheri, buryi

excubitor, L excubitor (Great Grey) homeyeri, leucopteros

elegans, leucopygos, L elegans (Desert Grey) algeriensis, koenigi

uncinatus L uncinatus (Socotra Grey)

mollis, sibiricus, funereus

borealis L borealis (Northern Grey)

bianchii

meridionalis L meridionalis (Iberian Grey)

L sphenocercus

L ludovicianus

L somalicus

260 Trends in systematics

349 Steppe Grey Shrike / Steppeklapekster Lanius lahtora pallidirostris, Kyzylkol, Kazakhstan, 11 September 2007 (René Pop) 350 Levant Grey Shrike / Levantklapekster Lanius lahtora aucheri, Golan, Israel, 21 March 1990 (René Pop)

261 Trends in systematics natural and sexual selection and can therefore Taxonomic implications change ‘too’ rapidly. For instance, in neighbour- What are the potential taxonomic implications of ing clades, similar may have selected for these results? If we assume that the mtDNA tree similar plumage. Conversely, a long independent correctly represents evolutionary history, none of evolutionary history does not necessarily imply the previous taxonomic treatments recognizes a that two taxa develop pronounced phenotypic monophyletic great grey shrike. Recognizing the differences: evolutionary more recently split taxa two groups/clades as species resolves the main may thus be morphologically more different to confict between the mtDNA tree and taxonomic each other, than to an older relative. treatments. This was essentially also proposed by It is also worth mentioning that a phylogeny Klassert et al (2008), even though they did not in- based on a single independent genetic unit such clude north-eastern Palearctic samples. The as mtDNA (ie, a single locus) does not necessarily Socotran uncinatus, although in plumage very represent the true evolutionary history. For exam- similar to Levant aucheri, pops up in a position ple, gene fow between Bunting Emberiza sister to, eg, excubitor, North African taxa and pal- leucocephalos and Yellowhammer E citrinella has lidirostris, and is thus perhaps best granted species led to the disappearance of the mtDNA of one of status as well. Although genetically less distinc- the species, and they have now identical mtDNA, tive, similar arguments could be made for another while most of their nuclear DNA remains species- island , bianchii, from Sakhalin, Russia, and specifc (Alström et al 2008, Irwin et al 2009). Past the southern Kuril Islands north of Japan. The gene fow between some of the great grey shrike Middle eastern aucheri-buryi clade could also be clades could similarly have affected the inferred separated (aucheri has previously been included relationships between them, although this would in Desert Grey Shrike but appears more related to require more complex scenarios. The sparse nu- pallidirostris). clear genetic data on great grey shrikes obtained Olsson et al (2010) considered several taxo- by Gonzalez et al (2008) and Olsson et al (2010) nomical options as valid, including treating the unfortunately do not allow for a robust verifca- great grey shrike complex as six species (Northern tion of the mtDNA results. L borealis, Desert L elegans, Great L excubitor, Asian L lahtora, Iberian L meridionalis and Socotran

351 Great Grey Shrike / Klapekster Lanius excubitor, Oud-Alblas, Zuid-Holland, 25 January 2005 (Arie Ouwerkerk)

262 Trends in systematics

352 Dark Desert Grey Shrike / Donkere Woestijnklapekster Lanius elegans algeriensis, Agadir, Morocco, 4 November 2005 (Arnoud B van den Berg) 353 Canary Islands Desert Grey Shrike / Canarische Woestijnklapekster Lanius elegans koenigi, Fuerteventura, Canary Islands, 23 January 2010 (René Pop/The Sound Approach)

263 Trends in systematics

Grey Shrike L uncinatus), and, alternatively, sim- Sundberg, P 2008. Phylogeny and classifcation of the ply retaining only Great and Southern (ie, Iberian) Old World emberizini (Aves, Passeriformes). Mol Grey Shrike as full species for the time being. The Phylogen Evol 47: 960-973. uncertainty is mainly caused by the disagreement Fok, K W, Wade, C M & Parkin, D T 2002. Inferring the phylogeny of disjunct populations of the Azure- between genetic data on the one hand and mor- winged Magpie Cyanopica cyanus from mitochon- phological and geographical data on the other. drial control region sequences. Proc R Soc London B CSNA (Sangster et al in prep) and Dutch Birding 269: 1671-1679. have chosen the former option (see ‘WP bird González, L M 2008. Origin and formation of the names’ under ‘Vagrancy & taxonomy’ at www. Spanish Imperial Eagle (Aquila adalberti). J Ornithol dutchbirding.nl; not yet published in Dutch 149: 151-159. Birding) which means, for instance, that L lahtora Gonzalez, J, Wink, M, Garcia-del-Rey, e & Delga do will contain Levant Grey Shrike L l aucheri and Castro, G 2008. Evidence from DNA nucleotide se- Steppe Grey Shrike L l pallidirostris as subspecies quences and ISSR profles indicates paraphyly in sub- species of the Southern Grey Shrike (Lanius meridi- (since lahtora was described earlier than either onalis). J Ornithol 149: 495-506. aucheri, buryi or pallidirostris). Harris, T & Franklin, K 2000. Shrikes & bush-shrikes. The recognition of Northern Grey Shrike as a Including wood-shrikes, helmet-shrikes, fycatcher- species is also relevant to European birders, since shrikes, philentomas, batises and wattle-eyes. at least L b sibiricus is a vagrant to Europe. In fact, London. one of the Norwegian samples from this study, a Irwin, D e, Rubtsov, A S & Panov, e N 2009. Mitochondrial museum specimen collected in November 1881, introgression and replacement between yellowham- was a sibiricus. Its identity was already suspected mers (Emberiza citrinella) and pine buntings (Emberiza on basis of its plumage and could be confrmed leucocephalos) (Aves: Passeriformes). Biol J Linn Soc 98: 422-438. genetically. Sibiricus looks similar to nominate Klassert, T e, Hernández, M Á, Campos, F, Infante, O, Great Grey Shrike but useful feld marks include Almeida, T, Suárez, N M, Pestano, J, & Hernández, M fairly strongly barred underparts, limited white on 2008. Mitochondrial DNA points to Lanius meridi- the primaries and rectrices, and a pale mask onalis as a polyphyletic species. Mol Phylogen evol throughout its frst-winter plumage. Currently, 47: 1227-1231. there is at least one other European record, in Martinez-Cruz, B & Godoy, J A 2007. Genetic evidence Finland in March 2000. for a recent divergence and subsequent gene fow be- tween Spanish and eastern imperial eagles. BMC evol Further research Biol 7: 170. Olsson, u, Alström, P, Svensson, L, Aliabadian, M & So what can we expect for the future? First, an Sundberg, P 2010. The Lanius excubitor (Aves, examination of independent genetic loci can Passeriformes) conundrum – taxonomic dilemma hopefully determine whether the mtDNA pattern when molecular and non-molecular data tell different is telling the evolutionary truth. It is also still un- stories. Mol Phylogen evol 55: 347-357. clear how several taxa interact where they come Pasquet, E 1998. Phylogeny of the nuthatches of the Sitta into contact (eg, nominate Great Grey Shrike and canadensis group and its evolutionary and biogeo- sibiricus Northern Grey Shrike). Interestingly, two graphic implications. 140: 150-156. morphologically borealis individuals actually fell Redactie Dutch Birding 2009. Naamgeving van taxa in within the Loggerhead Shrike clade in the mtDNA Dutch Birding. Dutch Birding 31: 35-37. Sangster, G, Hazevoet, C J, van den Berg, A B & Roselaar, tree, indicating ongoing occasional hybridization. C S 1997. Dutch avifaunal list: taxonomic changes in Some gene fow between many of the forms may 1977-97. be likely but a more solid and stable taxonomy Sangster, G, Hazevoet, C J, van den Berg, A B, Roselaar, will among others depend on quantifying its ex- C S & Sluys, R 1999. Dutch avifaunal list: species tent. This interesting will proba- concepts, taxonomic instability, and taxonomic bly continue to stimulate research and taxonomic changes in 1977-1998. 87: 139-166. debate, and meanwhile birders are probably best Sangster, G, van den Berg, A B, van Loon, A J & Roselaar, advised to take careful notes (and photographs...) C S in prep. Dutch avifaunal list: taxonomic changes of all variants encountered. in 2009-2010. Svensson, L, Grant, P J, Mullarney, K & Zetterström, D 1999, 2009. Collins bird guide. First and second edi- References tion. London. Alström, P, Olsson, u, Lei, F, Wang, H-t, Gao, W &

Jelmer Poelstra, Department of Evolutionary Biology, Uppsala University, Uppsala, Sweden ([email protected])

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