CARPODACUS EOS /PULCHERRIMUS COMPLEX

The C. eos / pulcherrimus complex consists of four lineages: pulcherrimus / argyrophrys, davidianus, eos, and waltoni . The first and last two lineages are sister to each other. Subspecies argyrophrys and eos breed along the eastern edge of the Tibetan Plateau (Fig. 5), and are largely sympatric but (always?) elevationally parapatric (E. Stresemann, unpublished manuscript from the 1950s). Thus, the latter two belong to two different biological species. On the other hand, eos and waltoni should be treated as conspecific because of the young age of their MRCA (less than 1 Myr) and their close connection in the haplotype network (Fig. 4). Because of the priority rule of the International Code of Zoological Nomenclature (ICZN, 1999), this species must be named Carpodacus waltoni (Sharpe, 1905) with subspecies eos (Stresemann, 1930) and waltoni . Carpodacus pulcherrimus (F. Moore, 1856) consequently is left with only the subspecies argyrophrys Berlioz, 1929, davidianus A. Milne-Edwards, 1866, and nominate pulcherrimus . This taxonomy had already been suggested by Erwin Stresemann (in the same unpublished manuscript as mentioned above).

Carpodacus pulcherrimus and C. waltoni are also slightly ecologically segregated, with the former preferring the brushy zone just above the mountain forest ( Juniperus and Rhododendron; Diesselhorst, 1968), and the latter preferring alpine grassland, with Rosa and Berberis bushes (Lu, Gong & Ma, 2011, Lu Xin, pers. comm.). For Himalayan high-altitude finches, Landmann & Winding (1995) found that large species may persist in higher elevations, but C. waltoni is actually smaller than C. pulcherrimus (Stresemann, 1930; E. Stresemann, unpubl. data: male wing length on average 71.7 mm in eos, 79.6 mm in waltoni versus 82.1 mm in argyrophrys, 79.6 mm in davidianus, 77.6 mm in pulcherrimus) although it is found at higher elevations (see Results). Sympatric argyrophrys and eos show the largest difference in wing length (and possibly further niche dimensions).