Russian Journal of Herpetology
Vol. 14, No. 3, 2007, pp. 199 – 202
DISTRIBUTION AND NATURAL HISTORY
OF THE ECUADORIAN SNAKE Dipsas andiana (BOULENGER, 1896)
(COLUBRIDAE: DIPSADINAE) WITH CONSIDERATIONS
ON ITS CONSERVATION STATUS
Diego F. Cisneros-Heredia1
Submitted November 29, 2005.
The distribution and natural history of Dipsas andiana (Boulenger, 1986), a little-known snake endemic to Ecuador, are revised, and new records are presented that extend its geographical and altitudinal range. A conservation
status assessment indicates that D. andiana would classify for the IUCN category “Near Threatened (NT).” The
ecological distribution of the species is apparently related with seasonal forests of the West Ecuadorian zone, a
recently recognized biogeographic area between the very humid Choco and the dry Tumbesian zone.
Keywords: Reptilia, Serpentes, Dipsas andiana, Ecuador, distribution, natural history, conservation.
INTRODUCTION
Dipsas andiana (Boulenger, 1896) is a species of
the clades Colubridae, Dipsadinae, endemic to the Pacific lowlands and western slopes of Ecuador. Until very
recently, the name Dipsas andiana was considered a
synonym of Dipsas oreas, but specimens were usually
reported as Dipsas variegata nicholsi (now D. nicholsi)
(Cadle and Myers, 2003). Recently, Cadle and Myers
(2003) resurrected Dipsas andiana from the Andean
oreas, restricting nicholsi as a Panamanian species, and
variegata as a taxon distributed in Venezuela, Trinidad,
French Guyana, and Brazil.
Cadle and Myers (2003) reviewed 13 specimens of
Dipsas andiana, four with uncertain localities and nine
from six localities in the Ecuadorian provinces of Los
Ríos, Bolivar, and Pichincha, between 15 and 1140 m.
Recent surveys have provided two additional localities
for the species: Río San Francisco, Punta Galeras (first
record to the province of Esmeraldas; Ortega, 2005);
and Loma Alta (first record to the province of Guayas;
C. Martínez, personal communication; Martinez et al.,
2005). Because few specimens of Dipsas andiana are
deposited in USA and Europe collections (despite considerable herpetological fieldwork in western Ecuador),
1
Universidad San Francisco de Quito, College of Biological and Environmental Sciences, Quito, Ecuador.
Present address: King's College London, Department of Geography,
Strand, London, UK. E-mail: diegofrancisco_cisneros@yahoo.com.
Cadle and Myers (2003) remarked that the species is
probably “on the brink of extinction.”
Herein, I revise and update the available information
on Dipsas andiana, providing new records for the species, commenting on its particular distribution pattern,
and analyzing its conservation status under the IUCN
categories.
MATERIAL AND METHODS
Data herein reported were collected at various localities in the Pacific lowlands and western versant of
Ecuador (Table 1). Examined material is deposited in
the following Ecuadorian collections: Departamento de
Biología, Escuela Politécnica Nacional, Quito, Ecuador
(EPN); D. F. Cisneros-Heredia’s collection housed at
Universidad San Francisco de Quito, Quito, Ecuador
(DFCH); and Fundación Herpetológica Orcés, Quito,
Ecuador (FHGO). Coordinates and elevations of the
new occurrences were determined using collector’s field
notes, and confirmed with the physical map of the Republic of Ecuador 1:1,000,000 published in 2000 by the
Instituto Geográfico Militar and the gazetteer of Lynch
and Duellman (1997) (Map 1). To assess the conservation status of Dipsas andiana, we follow the methodology suggested by IUCN SSC (2001), with optimizations
by Cisneros-Heredia and Touzet (2004) and CisnerosHeredia and McDiarmid (2006).
1026-2296/2007/1403-0199 © 2007 Folium Publishing Company
200
Diego F. Cisneros-Heredia
TABLE 1. Localities Where Dipsas andiana (Boulenger) Has Been
Recorded
Locality
Coordinates
Altitude,
m
Esmeraldas
(1)
Río San Francisco,
Punta Galera*
~00°40¢ N 80°01¢ W
~200
(2)
Alto Tambo
00°56¢ N 78°32¢ W
~750
(3)
Puerto Quito*
(4)
Hacienda La Joya
Pichincha
~00°08¢ N 79°16¢ W
00°05¢ N 78°59¢ W
(5)
San Miguel de Los Bancos 00°01¢ N 78°53¢ W
(6)
Nanegalito, near to
(7)
(8)
(9)
~280
~700
800
00°02¢ N 78°40¢ W
1600
Tandayapa
~00°01¢ N 78°39¢ W
~1750
Santo Domingo*
00°15¢ S 79°09¢ W
Las Palmas*
~00°22¢ S 78°55¢ W
920
(10)
Dos Ríos*
~00°19¢ S 78°51¢ W
1140
(11)
Puerto López,
5 km NW of Guayas
01°32¢ S 80°49¢ W
~0
(12)
Loma Alta*
01°52¢ S 80°38¢ W
~700
(13)
Babahoyo*
Los Ríos
01°49¢ S 79°31¢ W
~15
(14)
Balsapamba*
Bolivar
01°47¢ S 79°13¢ W
~800
~600
Manabí
Map 1. Localities (squares) and projected distribution (lined area) of
Dipsas andiana (Boulenger), an endemic snake of Ecuador. Numbers
of localities correspond to those on Table 1. Question marks refer to
undetermined northwestern and southwestern limits of the species’
range (see text).
* Localities correspond to secondary or literature references (see text).
RESULTS
Dipsas andiana (Boulenger, 1896)
Leptognathus andiana Boulenger, 1896:452, pl. 23,
Fig. 2a – c (original description). Type locality: “Quito,
Ecuador.” Holotype: BMNH 1946.1.20.12 (for a complete synonymy see Cadle and Myers 2003).
Six specimens deposited in Ecuadorian collections
increase our knowledge on the geographic and altitudinal range of Dipsas andiana. One male specimen
(DFCH-D116) was collected dead on the roadside below
Tandayapa, Province of Pichincha, on October 1998 by
D. F. Cisneros-Heredia and R. Phillips; increasing the
altitudinal distribution of the species from 1140 m to at
least 1750 m. One female specimen (DFCH-D115) was
collected resting during the night in the branch of a
shrub ~1 m above ground in bushes ~5 km NW of Puerto Lopez, Province of Manabí, on June 1, 2000, by D. F.
Cisneros-Heredia and D. Mosquera. This record is the
first from the province of Manabí, expanding the altitudinal range to 5 m towards the coastal area, and extending the geographic range of D. andiana 145 km west.
One individual (EPN s/n), was collected at Alto Tambo
(km 17, Lita – San Lorenzo road), province of Esmeral-
das, on December 1990 by J.-M. Touzet. This record is
the second known locality from the province of Esmeraldas.
Additionally, three specimens represent new localities in the province of Pichincha. One male specimen
(DFCH-D117) was collected dead on the roadside at Hacienda La Joya, a farm 1 km W of the town of San
Vicente de Andoas, km 109 of the Quito – Calacali –
Nanegalito – Pedro Vicente Maldonado road, Province
of Pichincha, on February 27, 2000, by D. F. CisnerosHeredia and S. Izurieta. One specimen (FHGO 332) was
collected at San Miguel de Los Bancos, Province of Pichincha, on February 25, 1990, by A. Murriaqui. One
specimen (FHGO 993) was collected apparently near
Nanegalito (FHGO catalog indicates “km 83 vía Quito – Nanegalito,” however it provides these coordinates
and altitude: “00°02¢ N 78°40¢ W, 1600 m,” suggesting
that the correct locality is somewhere near Nanegalito,
ca. km 48 of the Quito – Nanegalito road), province of
Pichincha, on October 22, 1994, by J.-M. Touzet.
Dipsas andiana is sympatric with Dipsas elegans at
Tandayapa; with Dipsas temporalis at the localities in
Distribution, Natural History, and Conservation of Dipsas andiana
201
TABLE 2. Morphological, Scalation, and Color Data of Three Specimens of Dipsas andiana (Boulenger) from Ecuador
Specimen
Sex
Dorsal rows
Ventrals
Subcaudalsa
Postocularsb
Primary temporals
Secondary temporals
Supralabials (touching eye)c
Infralabials (in contact behind mental)c
No. of dorsal blotches on body
a
b
c
DFCH-D15
Female
15–15–15
189
84
2
2
3
10(4, 5, 6)
10(2)
24
DFCH-D116
Male
15–15–15
186
90
2
2
3
10(4, 5, 6)
10(2)
22
DFCH-D117
Male
15–15–15
189
101
2
3
4
9(4, 5)/10(5, 6)
9(1)/10(1)
20
Subcaudal counts on both specimens are not precise because specimens were collected dead on the roadside.
DFCH-D115 has the lower postocular on the right side very tiny, almost unnoticeable without close inspection.
Variation left/right side.
the province of Esmeraldas; with Dipsas gracilis and Sibon nebulatus at Hacienda La Joya, Nanegalito, Puerto
Quito, Santo Domingo, and at the localities in the province of Esmeraldas; and with an non-described species
of Sibynomorphus at the locality in the province of
Manabí.
DISCUSSION
All examined specimens showed the typical coloration described by Cadle and Myers (2003) for Dipsas
andiana, including the characteristic U-shaped marking.
The number of dorsal blotches fluctuates within variation range described for the species by those authors
(Table 2) and most meristic characters also coincides
with the variation described by Cadle and Myers (2003),
except that there is one more subcaudal scale for females
and one scale less for males (Table 2).
Based on information provided by Cadle and Myers
(2003) and data presented herein, D. andiana inhabits
the following vegetation formations [sensu Sierra, 1999,
with modifications by Anderson and Jarrin (2002) and
Cisneros-Heredia (2006)]: Seasonal Lowland Evergreen
forest, Foothill Seasonal Evergreen forest, Low Montane Evergreen forest, Littoral Dry shrubs, and Montane
Dry shrubs.
Dipsas andiana has not been collected further north
in the very humid Chocoan lowlands or further south
into the extremely xeric Tumbesian area. The absence of
records from these areas, otherwise rather close to the
actual known localities of the species, could indicate
that: (1) surveys in these zones have failed to find the
species because its low natural densities or survey methods are not exploring habitats/microhabitat occupied by
the species; or (2) the ecological distribution of the species is related with the Seasonal Evergreen Forest and
the Seasonal Dry Forest, as seen in Leptodactylus labrosus (personal observation) [Seasonal Evergreen Forest
as defined by Anderson and Jarrín (2002) and CisnerosHeredia (2006)], and the species could be endemic to the
West Ecuadorian zone, a recently recognized biogeographic area between the very humid Choco and dry
Tumbesian zone.
If the geographical range of Dipsas andiana is in
fact related to the seasonal forest of western Ecuador, the
locality Alto Tambo would be conceivably the northernmost limit on its distribution as this locality is already in
the border towards non-seasonal forest. To the south,
seasonal forests extend along the western versant of the
Andes as far as to the province of Azuay and El Oro, but
the southernmost record of Dipsas andiana is at Babahoyo, in the province of Los Ríos (Map 1). More information is needed to establish the northern and southern
limits of the distribution of D. andiana.
The distribution of Dipsas andiana encompasses
~30,000 km2 (extent of distribution and polygon area,
sensu IUCN SSC, 2001), and an altitudinal range between 5 – 1750 m a.s.l. The species has been found only
in forested areas in primary and secondary forests; and it
is apparently not adapted to heavily impacted habitats,
such as grasslands or intensive-agriculture crops. The
paucity of specimens collected over the years suggests
that D. andiana has natural low densities. The poor conservation status of West Ecuadorian forest (due to extreme deforestation, uncontrolled expansion of the agricultural frontier and colonization, and indiscriminate use
of pesticides and other chemical compounds in crops)
suggest that although Dipsas andiana is probably not on
202
the verge of imminent extinction as previously suggested (Cadle and Myers, 2003), the species should be
placed under the IUCN category of Near Threatened.
This classification is justified because although the species has a rather large geographic range (larger than
20,000 km2 considered for a Vulnerable species), the habitats along this range are severely fragmented and modified, and if these tendencies continue, the species could
classified for an endangered category, such as Vulnerable or Endangered. Since D. andiana is endemic to
Ecuador, this category should apply to the national and
global level.
Our knowledge on the ecology and conservation status of Dipsas andiana and several other species of Ecuadorian Dipsadinae (e.g., Sibynomorphus petersi) is still
limited. Efforts to support basic and applied research on
Ecuadorian reptiles are urgently need, as well as recruitment and training of new students, and support to collections already established.
Acknowledgments. I thank Roberto Phillips, Diego Mosquera, Susana Izurieta, Ma. Elena Heredia and Laura Heredia
for field companionship. My gratitude to Marcelo Negrete and
Susana Izurieta for allowing access to their farm, and to Charles
Myers for discussion and useful literature. To Ana Almendáriz
(EPN), and Jean-Marc Touzet and Ana María Velasco (FHGO)
for allowing access to material under their care. To Mauricio
Ortega and Carlos Martínez for sharing data on their records of
Dipsas andiana. Fieldwork was partially financed by the Birdwatchers Club of the Corporación Ornitológica del Ecuador;
Fundación Natura (Proyecto Parques en Peligro); and María
Elena and Laura Heredia. Universidad San Francisco de Quito
provided institutional support and financial support for laboratory work.
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