therya-5_2

Pacheco, Rengifo and Vivas
P. anitae and P. alisosiensis, both from Argentina (Jayat et al. 2007; Ferro et al. 2010,
respectively); and P. pearsoni (this work).
Steppan et al. (2007) based on a molecular analysis of Phyllotis species using cyt b,
found that P. pearsoni (reported as Phyllotis sp. nov. 1) was closely related to P. andium, P.
amicus and P. gerbillus, members of the “andium/amicus group,” a monophyletic group
with a distributional range restricted to northwestern Peru and southern Ecuador. Other
species that occur within the distribution of this group are P. haggardi and P. definitus
(Pearson 1958). Unfortunately, these species were not included in Steppan et al. (2007)´s
analysis, and consequently it is uncertain whether these species belong to the andium/
amicus group. A systematic study including P. haggardi and P. definitus is needed to test
the hypothesis that North-Andean Phyllotis species are a monophyletic group.
Figure 8. Projection of
specimen scores for factors
1 and 2 (above) and factors
1 and 3 (below) extracted
from principal component
analyses, comparing
samples of Phyllotis andium
and Phyllotis pearsoni
nov. sp. See Table 3 for
variable correlations and
explanation of percent
variance.
Phyllotis pearsoni is an endemic Peruvian species (Pacheco et al. 2009) that occurs only
on the western Andes in Northern Peru. Based on present records we hypothesize that
the distributional limits of this species are the Río Santa to the south, Río Marañón to
the east, and the Huancabamba depression to the north. These geographic features are
barriers to bird species (Vuilleumier 1969; Parker et al. 1985; Schulenberg et al. 2007,
www.mastozoologiamexicana.org
497