© 2010 Jose Ernesto Perez Villota (1 of 1)
Atelopus lynchi measures from 34.5 to 40.8 mm SVL. The head is narrow and somewhat elongated, and the snout is acuminate and protrudes past the lower jaw. The canthus rostralis is distinct. Lips are not flared. The tympanum is absent. A conspicuous postorbital crest is present. Vocal slits were present in three of the five male specimens. Ostia pharyngea were present in only one of the five male specimens. The fingers are basally webbed with distinct, round digital pads, and lack fringes. Weak thenar and subarticular tubercles are present, along with a large indistinct palmar tubercle, but the palms generally appear relatively smooth. A thin horny nuptial excrescence is located on the male thumb. On the foot, toes are webbed and have distinct round digital pads, with webbing extending to the digital pads of all except the fourth toe. The inner metatarsal tubercle is barely visible but the outer metatarsal tubercle is distinct and round. Indistinct, rounded subarticular tubercles are present, but the plantar surface of the foot is generally smooth. The dorsal skin is finely granular, while the skin on the belly is only slightly granular and other ventral surfaces are finely granular. Tubercles are present only on the hand and foot. The skin is partially adherent to the postorbital crests and the vertebral neural arches (Cannatella 1981).
In life, A. lynchi ground coloration is brown and lacks patterning, with indistinct dull yellow-gray markings on the dorsum. The snout tip and canthus are yellow-gray, as are the upper lip and postorbital ridge. The chin is yellow-cream, the throat is cream-colored and the venter is bluish gray. The iris is black with a pale green area immediately around the pupil (Cannatella 1981).
Atelopus lynchi is considered part of the A. longirostris species group, and is sometimes confused with A. longirostris. However, A. lynchi can be distinguished by a lack of discrete yellow spots on the dorsum, and the lack of an elongate blotch behind each eye, as well as a shorter, wider snout (Cannatella 1981).
Distribution and Habitat
A. lynchi is found only on the Pacific slopes of the Cordillera Occidental in northern Ecuador (Provincia Carchi), at elevations of 800-1410 m. The type locality is Maldonado, in Carchi province, Ecuador, on the Río San Juan, which forms the border between Ecuador and Colombia (Cannatella 1981). The habitat is thus also on the border between lowland tropical rainforests and lower montane forests (IUCN 2008).
Life History, Abundance, Activity, and Special Behaviors
Trends and Threats
The major threat is likely chydridiomycosis (La Marca et al. 2005, IUCN 2008). La Marca et al. (2005) evaluated land use at known localities for a number of Atelopus species, including A. lynchi in Ecuador. For this species, almost 90% of the habitat at the localities surveyed was natural vegetation, with just over 10% being pasture/agricultural lands, and no habitat classified as "fragmented." Thus habitat loss is unlikely to be the major threat.
Possible reasons for amphibian decline
Rivero and Serna (1993) asserted that specimens from Valle del Cauca, Colombia, are incorrectly assigned to this species, and represent an as-yet undescribed species.
The genus Atelopus, with 113 described and putative species, appears to be the most threatened clade of amphibians (La Marca et al. 2005). At least 30 species appear to be extinct, having been missing from all known localities for at least 8 years (La Marca et al. 2005). Only 52 of the surviving species have sufficient data with which to evaluate population trends; of these, 81% (42 of 52) have population sizes that have been reduced by at least half (La Marca et al. 2005). Only 10 of the 52 species appear to have stable populations (La Marca et al. 2005). Higher-elevation species (those living at least 1000 m asl) have been hit the worst, with 75% (21 of 28) having disappeared entirely (La Marca et al. 2005). In Venezuela there are ten endemic Atelopus species (La Marca and Reinthaler 1991); nine are classified as Critically Endangered and one is thought extinct (Rodríguez and Rojas-Suárez 1995; Rodríguez-Contreras et al. 2008; IUCN 2008). Chytridiomycosis is thought to be a primary factor in the decline and disappearance of species in this genus (La Marca et al. 2005). Most Atelopus species are restricted to very limited areas (no more than two localities) and occur along mid- to high-elevation streams (1500-3000m asl, though the maximum vertical range is from sea level to permanent snow; Lötters 2007), a habitat preference frequently associated with the co-occurrence of chytridiomycosis (La Marca et al. 2005). Habitat loss has occurred within the ranges of many Atelopus species, but does not appear to be a major factor in the decline of most Atelopus species; 22 species declined despite occurring in protected areas (La Marca et al. 2005). Many Atelopus species are local endemics, putting them at particular risk of extinction, with at least 26 species known only from a single population inhabiting a narrow altitudinal range (La Marca et al. 2005). Due to their restricted ranges, they are thought to have limited ability to adapt to warming climatic conditions (Lötters 2007).
Cannatella, D.C. (1981). ''A new Atelopus from Ecuador and Colombia.'' Journal of Herpetology, 15(2), 133-138.
La Marca, E., Lötters, S., Puschendorf, R., Ibáñez, R., Rueda-Almonacid, J. V., Schulte, R., Marty, C., Castro, F., Manzanilla-Puppo, J., García-Pérez, J. E., Bolaños, F., Chaves, G., Pounds, J. A., Toral, E., and Young, B. E. (2005). ''Catastrophic population declines and extinctions in neotropical harlequin frogs (Bufonidae: Atelopus).'' Biotropica, 37(2), 190-201.
La Marca, E., and Reinthaler, H. P. (1991). ''Population changes in Atelopus species of the Cordillera de Merida, Venezuela.'' Herpetological Review, 22, 125-128.
Lötters, S. (2007). ''The fate of the Harlequin Toads — help through a synchronous multi-disciplinary approach and the IUCN ‘Amphibian Conservation Action Plan’.'' Zoosystematics and Evolution, 83( Supplement 1), 69-73.
Rivero, J. A., and Serna, M. A. (1993). ''A new species of Atelopus (Amphibia: Bufonidae) from Antioquia, Colombia.'' Brenesia, 36, 15-20.
Rodríguez, J.P. and Rojas-Suárez, F. (1995). Libro Rojo De La Fauna Venezolana. PROVITA, Caracas.
Rodríguez-Contreras, A., Celsa Señaris, J., Lampo, M., and Rivero, R. (2008). ''Rediscovery of Atelopus cruciger (Anura: Bufonidae): current status in the Cordillera de La Costa, Venezuela.'' Oryx, 42, 301-304.
Originally submitted by: Keith Lui (first posted 2008-10-10)
Edited by: Kellie Whittaker (2009-01-25)
Species Account Citation: AmphibiaWeb 2009 Atelopus lynchi <https://amphibiaweb.org/species/60> University of California, Berkeley, CA, USA. Accessed Jun 14, 2021.
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Citation: AmphibiaWeb. 2021. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 14 Jun 2021.
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