Accepted by P. Simoes: 5 Oct. 2018; published: 19 Dec. 2018
ISSN 1175-5326 (print edition)
Copyright © 2018 Magnolia Press
Zootaxa 4532 (2): 441
The advertisement call of the treefrog Nyctimantis rugiceps Boulenger, 1882
(Anura: Hylidae), with notes on its natural history and toxicity
CAMILA CAMARGO DE SOUZA
, MAURICIO RIVERA-CORREA
, JOSE M. PADIAL
¹PUCRS (Pontifícia Universidade Católica do Rio Grande do Sul), Av. Ipiranga 6681, 90619-900, Porto Alegre, RS, Brasil.
Grupo Herpetológico de Antioquia, Instituto de Biología, Universidad de Antioquia, A.A. 1226, Medellín, Colombia.
Department of Herpetology, American Museum of Natural History, Central Park West & 79th St., New York, NY 10024, USA.
Department of Biological Sciences, Bronx Community College, City University of New York, 2155 University Avenue, Bronx, NY
*Corresponding author. E-mail: firstname.lastname@example.org
Nyctimantis rugiceps Boulenger, 1882 (Fig. 1A) is a Neotropical treefrog (Duellman & Trueb 1976; Faivovich et al.
2005) known only from disjunct localities in Amazonian Colombia, Ecuador, and Peru (Pérez-Villota et al. 2009). This
species has the skin of the skull co-ossified and reproduces—including calling behavior, egg deposition and tadpole
development—in water-filled tree or bamboo cavities (Duellman & Trueb 1976; Duellman 1978). Given its secretive
behavior, this is a poorly known species and, as noted by Duellman (1978: 169), “the major clue to the life history of
Nyctimantis is the calling behavior of the males”. Unfortunately, the only quantitative description of the advertisement
call of N. rugiceps is a brief passage in Duellman (1978) based on four specimens from Santa Cecilia, Ecuador, where
important variables are missing (e.g., call duration). More importantly, graphs illustrating the waveform and spectrogram
are missing. Considering these limitations and the importance of advertisement calls to the study of anurans (Köhler et
al. 2017), we provide a quantitative description using a call recording obtained in Leticia, Amazonas, Colombia.
The call description was based on 11 calls of one male of Nyctimantis rugiceps (ANDES-A 933; Fig. 1A), from the
Tacana River (04.10592° S, 69.9500° W), Km-9, Leticia, Colombia (recorded by SC-F and JMP on January 6th 2010;
20:30 h). We used a Marantz PMD660 digital recorder connected to a directional microphone (Sennheiser K6/ME66).
The recording was made at a distance of about 2.5 m from the signaler and air temperature at the end of the recording
was 26.5ºC. The recording was analyzed using Raven Pro 1.5 (Bioacoustics Research Program 2013), with a FFT of 256
points, at a sampling rate of 48 kHz and 16-bit precision, overlap 90 %, Hann’s sampling window. Call parameter
definitions follow Duellman and Trueb (1994) and Cocroft and Ryan (1995). Temporal and spectral parameters are given
in seconds (s) and Hertz (Hz), respectively. The following temporal parameters were measured from oscillograms: note
duration, interval between notes, number of notes, number of pulses, call duration, and interval between calls. We used
spectrograms to calculate the peak frequency (= dominant frequency) and the Raven parameters frequency 5% and
frequency 95% to measure lower and upper frequency. Graphs (Fig. 1B–D) were obtained with the package Seewave 1.6
(Sueur et al. 2008) for R 2.15.1 (R development core team, 2012). The recording is housed at Fonozoo (code 11226) and
the specimens were euthanized with benzocaine solution (50 mg/g) and preserved in ethanol 70 % at the amphibian
collection of the Museo de la Universidad de los Andes (ANDES-A), Bogota, Colombia.
To the naked ear, the advertisement call of Nyctimantis rugiceps sounds like a very loud and low frequency “knock-
knock”, which is audible from distances of at least 50 m. The call consists of two to three multipulsed notes of one to
four periodic pulses (Figs. 1B–C), with a constant peak frequency through the call. The call duration was 0.232 ± 0.035 s
(0.133–0.253 s) and note duration was 0.027 ± 0.009 s (0.006–0.041 s). The interval between calls was 20.947 ± 6.101 s
(15.218–35.688 s), interval between notes was 6.811 ± 10.463 s (0.059–35.688 s) and number of pulses of 3 ± 1 (1–4).
The energy of advertisement calls in N. rugiceps is subdivided in two semi-bands in each pulse, the dominant frequency
is located in the upper band [1183.2 ± 159.3 Hz (750–1312.5 Hz)], while the energy of the lower band peaks at a
frequency of ~ 750 Hz (Fig. 1D). The lowest frequency was 562.5 Hz (562.5–562.5 Hz) and the upper frequency was
1415.9 ± 94.9 Hz (1312.5–1500.0 Hz). The highest energy input was on the first two pulses of the first two notes. The
amplitude modulation of each note has a pattern consisting of decreasing intensities from the beginning to the end of the
note. Sound intensity also decreases from the first to the last note of a call (Fig. 1C). Harmonics were not detected in the
SOUZA ET AL.
· Zootaxa 4532 (2) © 2018 Magnolia Press
The recorded male was vocalizing from inside a hole in the branch (approx. diameter 25 cm) of a relatively small
tree about 4.5 meters above the ground. After the recording, the specimen continued to vocalize for a couple of minutes,
after which it emitted a single rapid series of short “kok” sounds (not recorded) and stopped vocalizing. We then
proceeded to collect the specimen—which involved a complicated operation including climbing the tree, cutting the
branch, and extracting the frog. Inside the whole we also found a gravid female (ANDES-A 934), so we suggest that the
“kok” series may represent the mating call. When we recorded the calls, more than five males of Nyctimantis rugiceps
were vocalizing in the surroundings, a varzea secondary forest. All other males vocalized from the canopy, most likely
from inside tree holes. When handled, the frog secreted a noticeable amount of thick mucus that stuck to the hand.
Unfortunately, one of us (SC-F), after handling the specimen, passed his left hand over his forehead. Almost
immediately, the left side of his face experienced a peculiar sensation that felt like receiving a strong hit by a hard
object—very different from the usual burning sensation caused by the toxin of other anurans and experienced by the
authors in different occasions. Simultaneously, his left eye and naris started secreting large and continuous quantities of
tears and mucus. Vigorously washing his face with water from a nearby swamp diminished (although did not stop) the
pain and secretions. The pain sensation as of having been hit continued for about 48 hours but without inflammation.
FIGURE 1. (A) Nyctimantis rugiceps (voucher call, ANDES-A 933); (B) spectrogram; (C) oscillogram; and (D) power spectrum of
an advertisement call recorded at Tacana River, Leticia, Colombia.
We are very thankful to our field guide Rodolfo Mesa for field assistance during our work in Leticia. To Goran and
Zootaxa 4532 (3) © 2018 Magnolia Press ·
CALL OF NYCTIMANTIS RUGIC EPS
Adriana from Tanimboca tourism resort (Leticia, Colombia) for providing working facilities in the field. To Björn Rogell
and Linn Fenna Groeneveld for their friendship and help in the field. Andrew J. Crawford and the Universidad de los
Andes supported the work of SC-F in Colombia through a visiting professor scholarship. Adolfo Amézquita kindly let us
use his recording equipment.
Bioacustics Research Program (2013) Raven Pro: Interactive Sound Analysis Program. Version 1.5. The Cornell Lab of Ornithology,
Ithaca, NY. Available from: http://www.birds.cornell.edu/raven (accessed 30 October 2018)
Boulenger, G.A. (1882) Catalogue of the Batrachia Salientia s. Ecaudata in the Collection of the British Museum. Second Edition.
Taylor and Francis, London, 563 pp.
Cocroft, R.B. & Ryan, M.J. (1995) Patterns of advertisement call evolution in toads and chorus frogs. Animal Behaviour, 49, 283–303.
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Duellman, W.E. & Trueb, L. (1994) Biology of Amphibians. Baltimore (MD): Johns Hopkins University Press, Baltimore, 670 pp.
Duellman, W.E. & Trueb, L. (1976) The systematic status and relationships of the hylid frog Nyctimantis rugiceps Boulenger.
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family Hylidae, with special reference to Hylinae: phylogenetic analysis and taxonomic revision. Bulletin American Museum of
Natural History, 294, 1–240.
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