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First country record of Atractus medusa (Serpentes, Dipsadidae) in Ecuador


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We present the first country record of Atractus medusa Passos, Mueses-Cisneros, Lynch & Fernandes from Ecuador, based on a specimen collected at Tundaloma, province of Esmeraldas, Ecuador (1º10’57.7” N, 78º45’10.1” W, 55 m). Atractus medusa was recently described based on a single specimen from Gorgona Island, Colombia, and this new locality is the second known for the species, the first record for Ecuador, and represents an extension of A. medusa’s geographic range of ca. 207 km SSW from the type locality (Passos et al. 2009). We present information on the scamation, colouration, and natural history of this rare ground snake.
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The Pacific lowlands on Colombia and Ecuador hold an
exceptional concentration of biological diversity (Myers
et al., 2000), but suffer heavily from on-going, extensive
habitat loss (Beck et al., 2008). Increasing knowledge on
the biodiversity of this region is a key factor to support
and develop strategies for its long-term conservation and
sustainable development. Unfortunately, information
on the amphibians and reptiles of western Ecuador is
limited, with several species undescribed, unreported, or
little known, and many areas unexplored (Bustamante
et al., 2007; Guayasamin et al., 2008; Torres-Carvajal
et al., 2008; Cisneros-Heredia et al., 2010; Salazar-
Valenzuela et al., 2015; Torres-Carvajal et al., 2015).
Herein, we present the first country record of Atractus
medusa Passos, Mueses-Cisneros, Lynch & Fernandes
from Ecuador.
A specimen of Atractus medusa (deposited at the
Laboratorio de Zoología Terrestre, Universidad San
Francisco de Quito, DFCH-USFQ 191.101109, Figs.
1–2) was collected by Ana Romero at Tundaloma, a
private lodge located ca. 14.7 km SSE from the town
of San Lorenzo, province of Esmeraldas, Republic of
Ecuador (1º10’57.7” N, 78º45’10.1” W, 55 m) on 10
November 2009 (Fig. 3). Atractus medusa was recently
described based on a single specimen collected at
Playa Blanca, Gorgona Island, department of Cauca,
Colombia (Passos et al., 2009). The new locality (Fig.
3) is the second known for the species, the first record
for Ecuador, and represents an extension of A. medusas
geographic range of ca. 207 km SSW from the type
locality (Passos et al., 2009).
The Ecuadorian specimen of A. medusa exhibits all
diagnostic features described by Passos et al. (2009),
including: 17-17-17 smooth dorsal scale rows; two
postoculars; one long loreal; temporals 1+2; seven
supralabials (third and fourth contacting orbit on one
side, just fourth contacting on the other side); seven
infralabials; first four contacting chinshields; five
prediastemal and one postdiastemal maxillary teeth;
three gular scale rows; two preventrals; dark brown
head with beige temporal region; light brown body with
light occipital band, dark nuchal collar, and round dark
blotches; light venter with diffuse dark dots concentrated
posteriorly; dark ventral surface of tail; and rather long
Atractus medusa was described on the basis of a single
male specimen, and no females have been reported so
far (Passos et al., 2009). The Ecuadorian specimen is
a juvenile female, chromatic and structurally similar to
the holotype, differing by having more ventrals (146)
and less subcaudals (33). These differences are easily
explained by usual sexual dimorphism displayed by the
genus (Savage, 1960; Passos et al., 2005).
No information about the colouration in life or natural
history of Atractus medusa was provided in the original
description. The colouration in life of the Ecuadorian
specimen of A. medusa was similar to the pattern
described for the preserved holotype, but with some
minor variation (underlined): Dark brown head with
invasion of beige towards the temporal region; light
brown dorsum with light occipital band followed by dark
nuchal collar and round dark brown blotches, decreasing
in size posteriorly; darker brown, black and beige scales
surrounding the black body blotches, ventral surfaces
yellowish cream with diffuse dark brown dots towards
the lateral borders of the scales and concentrated on
posterior half of body; dark brown tail with some small
Herpetology Notes, volume 8: 417-420 (published online on 12 August 2015)
First country record of Atractus medusa (Serpentes, Dipsadidae)
in Ecuador
Diego F. Cisneros-Heredia* and Ana Romero
Universidad San Francisco de Quito (USFQ), Colegio de
Ciencias Biológicas & Ambientales, Laboratorio de Zoología
Terrestre, campus Cumbayá, Casilla Postal 17-1200-841,
Quito, Ecuador.
* Corresponding author e-mail:
Diego F. Cisneros-Heredia & Ana Romero
cream marks (Fig. 1–2). The Ecuadorian specimen of A.
medusa was found active at night (19h00) among leaf-
litter on the floor of the forest. It was on a hilly area
covered by secondary non-seasonal lowland evergreen
forest. An individual of Oxyrhopus petola was found ca.
0.2 m apart from the A. medusa.
Atractus Wagler is the most diverse snake genus in the
world, with over 140 described species (Passos et al.,
2013; Köhler and Kieckbusch, 2014; Salazar-Valenzuela
et al., 2014), but the taxonomy, distribution and natural
history of the Atractus from the Pacific lowlands on
western Ecuador remain largely unknown (Passos et al.,
Figure 1. Dorsal view of Atractus medusa (USFQ 191.101109) collected at Tundaloma, province of Esmeraldas, Republic of
Figure 2. Ventral view of Atractus medusa (USFQ 191.101109) collected at Tundaloma, province of Esmeraldas, Republic of
First country record of Atractus medusa in Ecuador 419
Figure 3. Map of southwestern Colombia and western Ecuador
showing the two known localities of Atractus medusa: Gorgona
island, Colombia (type-locality, black circle) and Tundaloma,
Ecuador (open circle).
2009). Four species of Atractus are currently known to
inhabit the Pacific lowlands of Ecuador (below 1000 m):
Atractus microrhynchus (Cope), endemic to central and
southwestern Ecuador and northwestern Peru; A. medusa
Passos, Mueses-Cisneros, Lynch & Fernandes herein
reported; A. multicinctus (Jan) with records from the
provinces of Esmeraldas and Imbabura in Ecuador; and
A. paucidens Despax, endemic to Ecuador and known
from the provinces of Pichincha and Santo Domingo de
los Tsáchilas (Savage, 1960; Passos et al., 2009; Passos
et al., 2012). A photographic report of Atractus sp. (cf.
melas) from the Bilsa Biological Station, province of
Esmeraldas, northwestern Ecuador (Ortega-Andrade
et al., 2010) corresponds to A. multicinctus, showing
an Atractus with bright red nuchal collar and ventral
Acknowledgements. We are grateful to Universidad San
Francisco de Quito for institutional support; to Andrés Chiriboga
for allowing fieldwork at Tundaloma; to Germania Lucero and
Jaime Romero for her financial and moral support; to Verónica
Garcés and local staff of Tundaloma for fieldwork assistantship;
to Ma. Elena Heredia, and Laura Heredia for their constant
support; to Pablo Riera for laboratory support; and to Paulo
Passos for providing comments on an earlier draft of this paper.
The specimen herein reported was obtained under the research
and collection permit issued to Ana Romero by the Ministry of
Environment of Ecuador (No. 0037 Fauna-DPE-MA).
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Centrolenidae, Cochranella pulverata, Hyalinobatrachium
aureoguttatum: distribution extension, Ecuador. Check List
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Beck, E., Bendix, J., Kottke, I., Makeschin, F., Mosandl, R. (2008):
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Cisneros-Heredia, D.F., Yánez-Muñoz, M.H. Ortega-Andrade,
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Accepted by Igor Kaefer
Diego F. Cisneros-Heredia and Ana Romero
... However, when referring to this work to compare previously unexamined material from Ecuador, it became clear to us that several Ecuadorian specimens of Pacific lowland Atractus could not be assigned to any taxa currently recognized to occur in the country. Some specimens identified as A. medusa (Passos et al. 2009a) matched the coloration of the first specimen reported in Ecuador by Cisneros-Heredia and Romero (2015), but they did not match the coloration of the holotype (Passos et al. 2009a). Other specimens were closer in coloration and lepidosis to A. iridescens (Peracca, 1860) from Colombia, and others resembled both A. microrhynchus (Cope, 1868) and A. occidentalis (Savage, 1955). ...
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Resumen La especie Rhabdosoma microrhynchum (ahora Atractus microrhynchus) se basó en un solo espécimen colectado por la Expedición Orton en “Guayaquil,” provincia de Guayas, costa Pacífica del Ecuador. El holotipo está actualmente perdido y todos los especímenes previamente referidos a esta especie fueron identificados erróneamente sobre la base de material de la Amazonía Peruana. Durante la revisión de colecciones de museos y la realización de trabajo de campo en las tierras bajas del Pacífico de Ecuador y Perú, encontramos especímenes que se pueden asignar a A. microrhynchus. En este estudio, reportamos sobre la variación morfológica de estos nuevos especímenes de A. microrhynchus y evaluamos el estado taxonómico de las especies Amazónicas previamente confundidas con esta. Restringimos el concepto de A. microrhynchus para las poblaciones de las tierras bajas del Pacífico de Ecuador y Perú y designamos un neotipo para la especie. Basados en la revisión de los tipos de A. emersoni y A. natans de la Amazonía, encontramos que hay una amplia superposición de las características de ambos taxones. Por lo tanto, A. emersoni se coloca bajo la sinonímia de A. natans. Más aún, comparamos A. microrhynchus con todos sus congeners y sus afinidades con el grupo-de-especies A. multicinctus son discutidos sobre la base de las características hemipenianas exclusivas compartidas.