Sunday, August 19, 2012

[Ornithology • 2005] Planalto Tapaculo | Scytalopus pachecoi • Taxonomy of new populations in the Scytalopus speluncae group, with description of a new species and remarks on the systematics and biogeography of the complex (Passeriformes: Rhinocryptidae)

Scytalopus speluncae (above) and Scytalopus pachecoi (below)
Planalto Tapaculo | Scytalopus pachecoi

Scytalopus pachecoi in Rio Grande do Sul, Brazil 

  Scytalopus pachecoi sp. nov.
Planalto Tapaculo (English name)
Tapaculo-ferreirinho (Portuguese name)

Some populations traditionally identified as Scytalopus speluncae populations in southern Brazil and Misiones, Argentina, actually represent an unnamed species, which is described in this paper. Field and museum studies showed that male plumage differs from traditional  S.  speluncae by the presence of black and buff barring over the flanks in all ages (absent in the adult male plumage of  S. speluncae) and by having paler gray underparts. Also, this new species differs from S. speluncae by its slower paced song (2.01-3.36 notes/s vs. 4.56–5.86 notes/s), by having two types of calls that differ in general structure and note shape from the calls of S. speluncae and by having an almost unique song type marked by the ending, in which it rapidly accelerates the pace into a trill (trill absent in S. speluncae). The new species also differs consistently in plumage and vocal characters from the other described taxa in the S. speluncae group, namely S. iraiensis and S. novacapitalis. The distribution of the new species encompasses three distinct areas: Serra do Sudeste (southern Rio Grande do Sul), the Argentinian Province of Misiones and adjacent areas of Brazil and the highest areas of the plateau (Planalto) of northeastern Rio Grande do Sul and southeastern Santa Catarina. Also, the data suggest that the “traditional”  S. speluncae  probably comprises other undescribed species, whose range would encompass the southern areas of the range admitted for S. speluncae (from São Paulo to Rio Grande do Sul). The new species shares the accelerating song type mentioned above, which is apparently unique in the genus, with S. novacapitalis and populations in Minas Gerais (also possibly new species), suggesting that these species are more closely related to each other than to any other species in the genus. Taxonomic research on the group is still incipient and populations recently discovered in Minas Gerais and Bahia may be additional, unnamed species. However, analyses based upon few museum specimens and without vocal data are discouraged. Additionally, alternative biogeographic hypotheses to explain the origins and the diversification of the S. speluncae group are presented.

Key words: Scytalopus, new species, S. speluncae, S. iraiensis, S. novacapitalis, biogeography, southern Brazil.

Figure 1. Ventral view of adult males of taxa in the Scytalopus speluncae group. From left to right:  S. novacapitalis (MCP no. 1481),  Spachecoi (MCP no. 962), Siraiensis (MCP no. 957)

Figure 1. Ventral view of adult males of taxa in the Scytalopus speluncae group. From left to right:  S. novacapitalis (MCP no. 1481),  Spachecoi (MCP no. 962), S. iraiensis (MCP no. 957), southern S. speluncae (MCP no. 988) and northern S. speluncae (MCP no. 1172). This picture illustrates differences in plumage color tonality between S. pachecoi and the other taxa: S. pachecoi is conspicuously darker than Snovacapitalis, somewhat lighter on belly and darker on throat and breast than S. iraiensis (though S. pachecoi may have lighter throat and breast) and is much lighter than both southern and northern S. speluncae. Note the barred flanks of S. novacapitalis and S. pachecoi.

Scytalopus pachecoi in Rio Grande do Sul, Brazil 

Maurício, Giovanni Nachtigall. 2005. Taxonomy of new populations in the Scytalopus speluncae group, with description of a new species and remarks on the systematics and biogeography of the complex (Passeriformes: Rhinocryptidae). Ararajuba. 13 (1):7-28.