Reptilia, Viperidae, Crotalinae, Porthidium nasutum : distribution extension and remarks on its range and records

Abstract

We report a southern extension in the distribution range of Porthidium nasutum.

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Check List 1(1)
NOTES ON GEOGRAPHIC DISTRIBUTION
Reptilia, Viperidae, Crotalinae, Porthidium
nasutum: distribution extension and remarks on
its range and records.
Diego F. Cisneros-Heredia1
Mario Yánez-Muñoz2
1College of Biological and Environmental
Sciences, Universidad San Francisco de Quito,
Casilla Postal 17-12-841, Quito, Ecuador. e-mail:
diegofrancisco_cisneros@yahoo.com
2División de Herpetología, Museo Ecuatoriano de
Ciencias Naturales, Calle Rumipamba y Ave. de
Los Shyris. Quito, Ecuador.
Porthidum nasutum inhabits the humid lowlands of
Middle America and adjacent northwestern South
America from Mexico (Chiapas) southward to
Ecuador (Manabí) (Porras et al. 1981, Schätti and
Kramer 1993, Campbell and Lamar 2004,
Cisneros-Heredia 2004). In Ecuador, it has been
reported in the provinces of Esmeraldas, Imbabura,
Pichincha, and Manabí, where it inhabits the
lowland rainforest, tropical moist forest, and lower
montane wet forest of the Chocó region (Porras et
al. 1981, Campbell and Lamar, 2004, Pérez-Santos
and Moreno 1991, Schätti and Kramer 1993).
Herein we report a southern extension in the
distribution range of Porthidium nasutum.
Localities and their geographic coordinates and
elevations were determined from researchers’ field
notes, and museum records, and revised according
with a physical map of the Republic of Ecuador
(IGM 2000).
A specimen of Porthidium nasutum deposited at
the Museo Ecuatoriano de Ciencias Naturales
(DHMECN 068) was collected at the Cerro San
Sebastían, Machalilla National Park (ca. 01º36’ S,
80º42’ W, 750 m a.s.l.), province of Manabí, on
September 1991 (Figure 1). It represents the
southernmost record of the species, extending its
range ca. 105 km S from the closest known locality
(11 km W of Bahía de Caráquez, Cisneros-Heredia
2004) (Figure 1). Cerro San Sebastian is a small
hill covered by foothill evergreen and low montane
cloud forest. This population of P. nasutum
appears fairly isolated from other populations of
the species by surrounding dry forest.
The specimen reported by Cisneros-Heredia (2004)
was the first report of the species from the
province of Manabí and it is the same animal
pictured by Campbell & Lamar (2004: Fig. 736).
However the information accompanying Figure
736 erroneously cited the specimen number as
“FHGO-live 698” and the locality as “Kilometer 5,
Bahía-Santo Domingo de los Colorados road,
Manabí, Ecuador, elevation 56 m”.
Another specimen, deposited at the Fundación
Herpetológica G. Orcés (FHGO 1256), collected at
the Jordán River, near Golondrinas (ca. 00°21’ N,
79°02’ W, 280 m a.s.l.) on 06 July 1995,
represents the second known locality of the species
from the province of Imbabura. The species was
otherwise known in the province just from
Paramba (Schätti & Kramer 1993, Cisneros-
Heredia 2004) (Figure 1).
Figure 1. Localities mentioned in the text on the
distribution of Porthidium nasutum in Ecuador.
Provinces are encoded on letters and localities on
numbers. E = Esmeraldas, M = Manabí, G =
Guayas, P = Pichincha, R = Los Ríos, C =
Cotopaxi. 1 = Paramba, 2 = Río Jordán, 3 = Santo
Domingo Area, 4 = 11 km W of Bahía de
Caráquez, 5 = Cerro San Sebastián.
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NOTES ON GEOGRAPHIC DISTRIBUTION
The distribution of Porthidium nasutum as
currently understood reaches its southernmost limit
along the northern region of the province of
Manabí and in the Santo Domingo de Los
Colorados area in the province of Pichincha
(Porras et al. 1981, Cisneros-Heredia 2004, this
paper). Its distribution seems to be related with the
extension of the Unseasonal Evergreen Forests of
western Ecuador (Porras et al. 1981, D.F.
Cisneros-Heredia pers. obs., see Anderson & Jarrín
2002 for definition of Unseasonal Evergreen
Forests), as both localities in Manabí (Bahía de
Caráquez and Cerro San Sebastián) are at the
contact zone of Unseasonal Evergreen Forests and
Seasonally Dry Forests lower 300 m.a.s.l.
Although in Central America P. nasutum invades
xeric habitats, the species does not seem to invade
dry areas in Ecuador, where Porthidium arcosae
occurs (Campbell & Lamar 2004, D.F. Cisneros-
Heredia pers. obs.).
Towards the slopes of the Cordillera de Los Andes,
the Unseasonal Evergreen Forests extends down to
the provinces of Guayas and Cotopaxi. Because no
barriers are known to restrict the dispersion of
Porthidium nasutum into southern Unseasonal
Evergreen Forests near the slopes of the Andes, it
is very probable that the species will be recorded in
the near future in Guayas and Cotopaxi provinces.
Acknowledgments
We are grateful to Hernán Román for collecting
the MECN specimen herein reported, to Jean-Mark
Touzet and Ana Ma. Velasco for access to FHGO
material, to Marco Altamirano, director of MECN,
for support and encouragement, and to María Elena
and Laura Heredia for financial and moral support.
Museo Ecuatoriano de Ciencias Naturales and
Universidad San Francisco de Quito provided
institutional support and laboratory space.
Literature Cited
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Campbell, J. A. and W. W. Lamar. 2004. The
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Cisneros-Heredia, D. F. 2004. Porthidium
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IGM. 2000. Republica del Ecuador, Mapa Físico,
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Received May 2005
Accepted October 2005
Published online October 2005
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