Cochranella erminea Torres-Gastello, Suarez-Segovia
Creators: name: Twomey, Evan
name: Delia, Jesse
name: Castroviejo-Fisher, Santiago
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Amphibia
Anura
Centrolenidae
Cochranella
Cochranella erminea

description: Cochranella erminea Torres-Gastello, Suárez-Segovia, and Cisneros Heredia 2007
Figure 17
Cochranella erminea Torres-Gastello, Suárez-Segovia, and Cisneros-Heredia 2007. Holotype MUSM 24056, collected from “Sabetari stream (11° 14' 31" S, 73° 31' 33" W, 370 m), on the Tambo River Basin, 9 km NNE of the indigenous community of Quitepampani2, province of Satipo, department of Junín, Peru.”
Rulyrana erminea— Guayasamin, Castroviejo-Fisher, Trueb, Ayarzagüena, and Vilà 2009.
Rulyrana erminae— Guayasamin, Castroviejo-Fisher, Trueb, Ayarzagüena, and Vilà 2009. Incorrect subsequent spelling.
2. The original description states that the type locality is " [...] 9 km NNE of the indigenous community of Quitepampani, province of Satipo, department of Junín". Kitepampani (correct spelling) is a Machiguenga community located in Cusco, not Junín. The type locality is situated in the Mayapo community, which is an Asháninka community.
Cochranella erminea— Castroviejo-Fisher, Guayasamin, Gonzalez-Voyer, and Vilà 2014.
Background information. This species was described on the basis of a single adult female collected from Departamento Junín in south-central Peru (Torres-Gastello et al. 2007), and was distinguished from other centrolenid species by its combination of extensive webbing between fingers III and IV, transparent visceral peritonea, and dorsum covered in abundant white enameled spots with scattered dark spots. The authors considered the placement of this species in the genus Cochranella tentative, as no males were available and thus the condition of the humeral spine was unknown at the time of description. Guayasamin et al. (2009) moved this species to the newly-erected genus Rulyrana, as more recent observations indicated that males of this species lack humeral spines. Mercado (2012) added four specimens from three new localities from the department of Cusco, Peru, extending the range of this species 111.5 km to the south and up to 870 m elevation.
New data. In February 2010, during field work in northern Peru, ET, M. Pepper, M. Sanchez-Rodriguez, and J. Tumulty encountered two individuals of Cochranella erminea, confirmed by comparisons of morphology, bioacoustics, and phylogenetics (Figs. 2c and 17). These specimens were collected from two sites north of Bagua, Amazonas, Peru. The first site was a small stream running through an overgrown cacao plantation, roughly 92 km N of Bagua, 2.3 km south (airline) from the village of Huabico, Amazonas (4°57'16.59"S, 78°12'39.92"W, 349 m). The second site was roughly 49 km N of Bagua, 14 km north (airline) from the Pongo de Rentema near the town of Muyo (5°17'53.87"S, 78°24'1.99"W, 629 m), in a small stream with a relatively open forest cover. Three months later, we (SC-F and ET) returned to this area and encountered another two specimens in a relatively large stream flowing through undisturbed forest, close to the second site mentioned above (5°18'3.86"S, 78°23'44.57"W, 682 m). These records extend the known distribution of Co. erminea 875 km northwest from the type locality. In 2011, we filled in this 875 km sampling gap with a single specimen of Co. erminea (CORBIDI 10477) taken from a site 28 km S (airline) from the city of Juanjui, San Martín, Peru (7°25'38.62"S, 76°39'53.28"W, 366 m), which is located 545 km NW from the type locality. This was an adult male observed calling from a leaf 4 m above the edge of a waterfall. An additional record (uncollected specimen) of Co. erminea was obtained from the Río Shunté drainage, 26.2 km SW from the city of Tocache, San Martín, Peru (8°19'25.68"S, 76°42'35.82"W, 923 m) on 12 March 2012 by JD and ET.
Variation. Cochranella erminea exhibits moderate morphological variation over its large range. While our records from near Juanjui and Tocache appear nearly identical to material from the type locality, individuals from northern Peru are notable in that they have a distinctly pinkish-red iris, and they show variation in the number and distribution of dorsal spots (Fig. 17). Furthermore, the white enameled spots as mentioned in the holotype are less notable in these northern populations.
Vocalizations. The following call description is based on a single call from a male recorded by SC-F and ET on 3 April 2010 from Pongo de Rentema (5°18'3.86"S, 78°23'44.57"W, 682 m), temperature 21.4°C. The call consists of two harsh buzz-notes given in quick succession. The first of these notes starts quietly and increases in amplitude throughout, with a duration 0.313 s, 14 pulses, dominant frequency 4870 Hz. This is followed by a single “chirp” given 0.173 s after the first note. This chirp is 0.054 s in duration, with 3 pulses, dominant frequency 4866 Hz. In the field, this sounds like a “zzzZZZT ZT”. We have heard calls from other populations (i.e., Juanjui and the type locality), and the calls all sound similar to the ear, with the only noticeable difference is that the number of trailing chirps can vary from zero to two. This call is similar to the call of Cochranella granulosa, which has a “pulsed primary note followed by 0–5 shorter pulsed secondary notes” (Ibáñez 1991). The call of Co. guayasamini new species (see below) is superficially similar to Co. erminea, except that Co. guayasamini tends to use a two-note call only in groups (often just one note when alone), whereas Co. erminea typically uses a two-note call even when alone. In addition, in Co. guayasamini the first and second notes are equal in duration, and not amplitude modulated (vs. first note amplitude modulated and longer than second note in Co. erminea).
Distribution and ecology. This species is widely distributed throughout the east-Andean versant in Peru, occurring from roughly 11° south latitude to 5° south latitude, at elevations between 349 and 923 m (Fig. 18). However, Cochranella erminea appears to be patchily distributed within this region. For example, this species has not been registered from the mountains surrounding Tarapoto, Peru, despite frequent searches in this area. Some of this patchiness may be attributable to the presence of the closely related Co. guayasamini. These two species are sister taxa, have similar calls, occur at similar elevations, and appear to overlap in the montane regions extending from northern San Martín to central Amazonas. However, these two species have never been found together in the same site (N = 7 sites for Co. erminea and N = 8 sites for Co. guayasamini). It is possible that competitive exclusion or microhabitat preferences could be important regulators of community structure at small spatial scales. Cochranella erminea occurs in a wide variety of habitats ranging from primary premontane forest to relatively disturbed, lowland foothill habitats. The site where we have witnessed the highest density of this species was an overgrown cacao plantation at 349 m. The only notable behavior we have observed in this species has been male calling activity. Males call from the tops of leaves, typically in groups of 2–5 individuals, although solitary males have also been observed calling. When calling in groups, males seem to stagger their calls sequentially and calls of different males do not typically overlap. At one site, males called sequentially downstream, with the chorus starting with an upstream male and finishing with a downstream male. See details below on Co. guayasamini for noted similarities among Cochranella. We observed two egg clutches near a chorus of Co. erminea males that correspond to Cochranella eggs; a globular cluster of pigmented eggs dangling from leaf tips.
At the type locality as well as our record from near Juanjui, Cochranella erminea was the only centrolenid species registered (Torres-Gastello et al. 2007). In the Río Shunté site, Co. erminea was found alongside Hyalinobatrachium carlesvilai and Rulyrana cf. flavopunctata. In northern Peru, Co. erminea has been found alongside Centrolene charapita, Teratohyla amelie, T. midas, and Rulyrana mcdiarmidi.
Taxonomic remarks. Based on results from our phylogenetic analysis (Fig. 2c), Cochranella erminea is wellsupported as a member of the genus Cochranella (JK = 100; GB = 16) and is similar in overall morphology to Co. granulosa. Furthermore, this species shows substantial similarity in advertisement call to other members of Cochranella, most notably Co. granulosa and Co. guayasamini.
description: Published as part of Twomey, Evan, Delia, Jesse & Castroviejo-Fisher, Santiago, 2014, A review of Northern Peruvian glassfrogs (Centrolenidae), with the description of four new remarkable species, pp. 1-87 in Zootaxa 3851 (1) on pages 27-29, DOI: 10.11646/zootaxa.3851.1.1, http://zenodo.org/record/286921