Karoo Long-billed Lark (Certhilauda subcoronata) - HBW 9, p. 566

Taxonomy: Certhilauda subcoronata A. Smith, 1843, Deelfontein, Northern Cape, South Africa.
All members of genus with exception of C. chuana formerly treated as conspecific, but recent research indicates that they are genetically, morphologically and vocally distinct. Although genetic data suggest that present species has no close relatives within the complex, it is very similar to C. benguelensis in morphology and vocalizations. Range overlaps narrowly with that of C. curvirostris in NW, and abuts that of C. semitorquata at karoo-grassland interface (roughly along 24º E longitude); possible overlap with C. brevirostris in S (Breede Valley). Exhibits strong N-S clines in size, colour and streaking. Race damarensis possibly belongs with C. benguelensis, but plumage and morphology suggest that it represents N end of cline of reduction in size and streaking of present species (by comparison, S race kaokoensis of C. benguelensis slightly larger, darker and more streaked); this argument supported by a gap in atlas records S of Brandberg, which approximates with geographical boundary between the two taxa. Race gilli intergrades with nominate, and bradshawi with damarensis. Four subspecies recognized.