Nymphargus mariae ( Duellman & Toft, 1979)
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( Fig. 2
View FIGURE 2
)
Centrolenella mariae Duellman & Toft, 1979
.
Centrolenella puyoensis
–
Flores & McDiarmid, 1989. Holotype: MCZ 91187, by original designation. Type locality: “1.0 km W Puyo, Provincia de Pastaza, Ecuador, between 1000-1050 m elevation”. New synonymy.
Cochranella mariae
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– Ruiz-Carranza & Lynch, 1991. Cisneros-Heredia & McDiarmid, 2007.
Cochranella puyoensis
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– Ruiz-Carranza & Lynch, 1991. Cisneros-Heredia & McDiarmid, 2006.
Centrolene mariae
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– Duellman & Schulte, 1993.
Centrolene puyoensis
– Duellman & Schulte, 1993.
Centrolene puyoense
– Stuart et al., 2008.
Nymphargus mariae
– Guayasamin et al., 2009.
Nymphargus puyoensis
– Guayasamin et al., 2009.
Centrolenella mariae Duellman & Toft
was described based on one female specimen collected at Serranía de Sira, department of Huánuco, Peru ( Duellman & Toft, 1979). Flores & McDiarmid (1989) described
Centrolenella puyoensis
and
Centrolenella azulae
, hypothesising that, together with
C. mariae
, they formed a monophyletic group (the
C. mariae
species-group). Subsequent authors ( Ruiz-Carranza & Lynch, 1991, 1995; Duellman & Schulte, 1993) followed this hypothesis, but Cisneros-Heredia & McDiarmid (2006, 2007) questioned the validity of the
C. mariae
species-group, further pointing out that although
C. azulae
is diagnosable,
C. mariae
and
C. puyoensis
are very similar and probably conspecific ( Cisneros-Heredia & McDiarmid, 2007).
Centrolenella mariae
and
C. puyoensis
were placed in the genus
Nymphargus
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by Guayasamin et al. (2009) based on morphological and molecular data, respectively. Flores & McDiarmid (1989) separated
N. puyoensis
from
N. mariae
by tympanum exposure (three-quarters in
N. puyoensis
, one-half in
N. mariae
), hand and foot webbing (slightly more extensive in
N. mariae
), ulnar fold (present in
N. puyoensis
, absent in
N. mariae
), intricate cloacal ornamentation (present in
N. puyoensis
, absent in
N. mariae
) and differences in proportions (greater eye-nostril/eye diameter and shank length/ snout-vent length in
N. puyoensis
).
We examined 16 specimens assignable to
Nymphargus puyoensis
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from Ecuador and the holotype of
Nymphargus mariae
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and found no evidence to support their differentiation. All characters used to diagnose these two species can be attributed to subtle differences that fall inside the intraspecific variation of a single species. Flores & McDiarmid (1989) proposed a polarization of characters that is rather subjective and biased due to their small sample size (one specimen for each of their “species”). Variation of tympanum exposure, webbing, and body proportions observed among
N. puyoensis
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and
N. mariae
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is continuous and similar, or even lower than the natural differences observed within populations of other species of centrolenids. The absence of ulnar folds and cloacal ornamentations in the type specimen of
N. mariae
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could be attributed to natural variation, but also due to preservation artifacts (see Cisneros-Heredia & McDiarmid, 2006 for information on the variation of specimens of
N. puyoensis
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). Either way it has also been observed in specimens of
N. puyoensis
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.
In the absence of valid discriminating evidence to support the hypothesis that
Nymphargus puyoensis
and
Nymphargus mariae
are different lineages, we place
Centrolenella puyoensis
Flores & McDiarmid, 1989 as a synonym of
Centrolenella mariae Duellman & Toft, 1979
. Thus,
Nymphargus mariae
, as herein redefined, inhabits Foothill Evergreen Forest and Lowland Evergreen Forest flooded by White-water Rivers on the Amazonian versant of the Andes of Ecuador and Peru (Cordillera del Sira), between 300 and 1550 m ( Flores & McDiarmid, 1989; Cisneros-Heredia & McDiarmid, 2006, 2007; Yánez-Muñoz et al., 2010).
This synonym reflects the absence of evidence to support the hypothesis that the population from the Serranía del Sira in eastern Amazonian Peru (typelocality of
Nymphargus mariae
) is different from those of eastern Amazonian Ecuador. Although it might be argued that the Serranía del Sira is a rather isolated mountain range that likely contains several amphibian endemics, our decision to place
Nymphargus puyoensis
in the synonymy of
N. mariae
is based on the fact that there are no morphological traits that support the existence of two putative species, and that potential biogeographic barriers cannot justify specific status without the corroboration of traits intrinsic to the organisms. We encourage future researchers to analyse other lines of evidence to evaluate the status of these populations.
