Barlow's Lark: a new species in the Karoo LarkCerthilauda albescenscomplex of southwest Africa

Abstract

The Karoo Lark Certhilauda albescens complex, endemic to southwest Africa, is characterized by regional phenotypic variation. Recent consensus has been to recognize two species, Dune Lark Certhilauda erythrochlamys and Karoo Lark Certhilauda albescens, but intermediate forms around the mouth of the Orange River have resulted in some authors treating it as a single polytypic species complex. We reexamined the status of taxa in this group by sequencing a segment of the mitochondrial DNA cytochrome b gene. Most samples were from the area around the mouth of the Orange River, where there is considerable local phenotypic variation. Our results indicate that the complex comprises three species, Karoo Lark, Dune Lark and Barlow's Lark Certhilauda barlowi, separated by 1.9‐5.5% sequence divergence. There were no sequence differences among described subspecies, but there was limited variation among Dune Lark individuals (sequence divergence values 0.2‐0.4%). The Red Lark Certhilauda burra is closely related to the Karoo Lark complex; indeed, it may be that Karoo Lark is the ancestral form. There was morphological (biometrics and plumage) and behavioural (male display song structure) support for the recognition of Barlow's Lark as a separate species. Species ranges within the complex are allopatric or narrowly parapatric, and they occur in different habitats and climatic conditions. Discriminant function analysis correctly identified 99% of skins assigned to taxa based on range, but a few individuals collected in the contact zone between Karoo and Barlow's Larks exhibited intermediate phenotypes, and further investigations are warranted to search for evidence of hybridization. The newly recognized Barlow's Lark has a maximum range of 18,000 km2. It appears to have disappeared from heavily grazed farms around Aus, southern Namibia, and occurs almost exclusively in diamond mining areas, where domestic livestock are excluded. Changes to land use practices which reduce vegetation cover could seriously impact this species.

A tale of the nearly tail‐less: the effects of Plio‐Pleistocene climate change on the diversification of the African avian genus Sylvietta

“…Results suggest that several avian species within this region have demonstrated that historic habitat variation may have led to genetic divergences across ecotones (Ryan et al . ; Ryan & Bloomer ; Outlaw et al . ; Ribeiro et al .…”

Multilocus phylogeny of the avian family Alaudidae (larks) reveals complex morphological evolution, non-monophyletic genera and hidden species diversity

“…Ryan et al (1998) suggested, based on a study of cytb, morphology and song, that three species should be recognized, and this has been followed by most subsequent authors (Dickinson, 2003;de Juana et al, 2004;Gill and Donsker, 2012;Hockey et al, 2005). The relationships among these are uncertain, as cytb and 16S support different topologies in relation to C. burra.…”

“…Recent studies based on molecular and/or vocal data have revealed considerable hidden diversity and taxonomic confusion in some taxa (Alström, 1998;Ryan et al, 1998;Ryan and Bloomer, 1999;Guillaumet et al, 2005Guillaumet et al, , 2006Guillaumet et al, , 2008, and it seems likely that the total number of recognised lark species is underestimated.…”

A review of the recent advances in the systematics of the avian superfamily Sylvioidea

“…Recent studies have revealed considerable hidden diversity in some taxa, such as Mirafra assamica, which was proposed to be split into four species based mainly on vocal, behavioral and morphological data (Alström, 1998; corroborated by molecular study by Alström et al, 2013); the Calendulauda (previously Certhilauda) albescens complex, which was suggested to consist of three instead of two species based on mitochondrial, morphological and vocal data (Ryan et al, 1998); the Certhilauda curvirostris complex, which was recommended to be treated as five instead of one species based on mitochondrial and morphological evidence (Ryan and Bloomer, 1999); and Galerida cristata, which was shown to consist of two partly sympatric and largely reproductively isolated species in Morocco, G. cristata sensu stricto and G. macrorhyncha (Guillaumet et al, 2005(Guillaumet et al, , 2006(Guillaumet et al, , 2008. In an analysis of mitochondrial data, Alström et al (2013) found several unexpectedly deep divergences between taxa presently treated as conspecific (e.g.…”

“…Ryan and Bloomer, 1999]; Calendulauda barlowi-C. erythrochlamys [cf. Ryan et al, 1998]; Mirafra cantillans-M. javanica). Moreover, Zink et al (2008) found a deep divergence in mitochondrial DNA between eastern and western populations of Alauda arvensis.…”