Phylogeny of the Eurasian Wren Nannus troglodytes (Aves: Passeriformes: Troglodytidae) reveals deep and complex diversification patterns of Ibero-Maghrebian and Cyrenaican populations

Abstract

The Mediterranean Basin represents a Global Biodiversity Hotspot where many organisms show high inter-and intraspecific differentiation. Extant phylogeographic patterns of terrestrial circum-Mediterranean faunas were mainly shaped through Pleistocene range shifts and range fragmentations due to retreat into different glacial refugia. Thus, several extant Mediterranean bird species have diversified by surviving glaciations in different hospitable refugia and subsequently expanded their distribution ranges during the Holocene. Such a scenario was also suggested for the Eurasian Wren (Nannus troglodytes) despite the lack of genetic data for most Mediterranean subspecies. Our phylogenetic multi-locus analysis comprised 18 out of 28 currently accepted subspecies of N. troglodytes, including all but one subspecies which are present in the Mediterranean Basin. The resulting phylogenetic reconstruction dated the onset of the entire Holarctic radiation of three Nannus species to the early Pleistocene. In the Eurasian Wren, two North African subspecies represented separate basal lineages from the Maghreb (N. t. kabylorum) and from the Libyan Cyrenaica (N. t. juniperi), being only distantly related to other Mediterranean populations. Although N. troglodytes appeared to be paraphyletic with respect to the Nearctic Winter Wren (N. hiemalis), respective nodes did not receive strong statistical support. In contrast, paraphyly of the Ibero-Maghrebian taxon N. t. kabylorum was strongly supported. Southern Iberian populations of N. t. kabylorum did not clade with Maghrebian populations of the same subspecies but formed a sister clade to a highly diverse European clade (including nominate N. t. troglodytes and eight further taxa). In accordance with a pattern also found in other birds, Eurasian

Integrative taxonomy documents two additional crypticErithacusspecies on the Canary Islands (Aves)

“…A previous study based on mitochondrial CO1 sequences also reported a high level of sequence divergence between a single bird from the Caucasus (Krasnodar, Russia) and six individuals from elsewhere in Russia (Kerr et al, 2009; see also Bilgin et al, 2016). Genetic distinctiveness of Caucasian populations was already documented for other Palearctic species, such as the Eurasian Nuthatch, Sitta europaea (Nazarizadeh et al, 2016; Päckert et al, 2020), the Coal Tit, Periparus ater (Tietze et al, 2011), the Dunnock, Prunella modularis (Drovetski et al, 2018) and the Eurasian Wren, Troglodytes troglodytes (Albrecht et al, 2020). Morphologically, E. r. caucasicus differs from European E. rubecula by its rufous uppertail‐coverts and basal half of the tail (Roselaar in Cramp, 1988).…”

Phylogeography of Lanius senator in its breeding range: conflicts between alpha taxonomy, subspecies distribution and genetics

“…The second challenge is particularly important in relation to the southern areas of Europe, several of which are known glacial refugia. It is clear that these refugia played a decisive role in shaping intra and interspecific geographical variations, with phylogeographic studies identifying Iberia, Southern Italy or the Balkans as regions where populations accumulated genetic differences (e.g., Brito 2005;Pellegrino et al 2015;Drovetski et al 2018a;Albrecht et al 2020). Strong intraspecific differentiation is rare in migratory WP species (Pârâu & Wink 2021), being instead largely confined to sedentary or short-distance (intra-Palearctic) species.…”

Phylogeography of Lanius senator reveals conflicts between alpha taxonomy, subspecies ranges and genetics

“…The second challenge is particularly important in relation to the southern areas of Europe, several of which are known glacial refugia. It is clear that these refugia played a decisive role in shaping intra and interspecific geographical variations, with phylogeographic studies identifying Iberia, Southern Italy or the Balkans as regions where populations accumulated genetic differences (e.g., Brito 2005;Pellegrino et al 2015;Drovetski et al 2018a;Albrecht et al 2020). Strong intraspecific differentiation is rare in migratory WP species (Pârâu and Wink 2021), being instead largely confined to sedentary or short-distance (intra-Palearctic) species.…”