Molecular phylogeny of treecreepers (Certhia) detects hidden diversity

Abstract

We sequenced a part of the mitochondrial cytochrome-b gene from the seven treecreeper species, including 18 subspecies, to reconstruct the phylogeny of the genus Certhia. Species status of all seven species could be affirmed. Certhia discolor, C. himalayana, C. nipalensis, and C. tianquanensis, the species with relatively small distribution ranges in southeast Asia and simple territorial song, are found at the base of all phylogenetic trees, although without good support. A comparatively recent sister species of C. tianquanensis is C. nipalensis, replacing C. discolor as closest relative. Certhia familiaris, C. brachydactyla and C. americana form a derived set of species (again only weak support). The closest relative of C. americana is C. brachydactyla. The C. familiaris subtree is deeply split into two well-defined population groups: a Eurasian group including populations in northern China (Qinling range northward and all Eurasia) and a Sino-Himalayan group (Himalayas and China excluding northern China). In accordance with acoustic characters, the three subspecies hodgsoni, mandellii and khamensis of the Sino-Himalayan group are combined and elevated to species rank: Certhia hodgsoni. Certhia discolor manipurensis is deeply split from nominate discolor as well, and is also promoted to species level. Within C. brachydactyla (western palearctic) and within C. hodgsoni (Himalayas, China) several populations form well-supported separate lineages that diverged quite recently and represent subspecies level. In all other species, molecular-genetic and vocal characters support traditional species delimitation. © 2006 The Authors.