Ceratophrys stolzmanni 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Amphibia Anura Ceratophryidae

Scientific Name: Ceratophrys stolzmanni Steindachner, 1882
Common Name(s):
English Pacific Horned Frog, Pacific Big-Mouthed Frog, Sapo Bocón del Pacífico, Stolzmann's Horned Frog
Spanish Escuerzo
Taxonomic Source(s): Frost, D.R. 2015. Amphibian Species of the World: an Online Reference. Version 6.0. New York, USA. Available at:
Taxonomic Notes: Two subspecies are recognized: Ceratophrys stolzmanni ssp. scaphiopeza in Ecuador, and C. stolzmanni ssp. stolzmanni in Peru.

Assessment Information [top]

Red List Category & Criteria: Vulnerable C2a(i) ver 3.1
Year Published: 2018
Date Assessed: 2018-03-14
Assessor(s): IUCN SSC Amphibian Specialist Group
Reviewer(s): Luedtke, J.
Contributor(s): Angulo, A., Catenazzi, A., Cisneros-Heredia, D.F., Coloma, L.A. & Ron, S.R.
Facilitator/Compiler(s): Neam, K.
Listed as Vulnerable because the number of mature individuals is estimated to be less than 10,000 individuals, with each subpopulation having less than 1,000 individuals, and there is a continuing decline in the number of mature individuals in each subpopulation due to ongoing decline in the extent and quality of its coastal dry forest habitat.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species is found in xeric environments of the Pacific coast in northwestern Peru (Tumbes Region) and central and southwestern Ecuador (Guayas, Manabí, El Oro and Santa Elena Provinces) where it occurs at elevations from 0–130 m asl.
Countries occurrence:
Ecuador; Peru
Additional data:
Upper elevation limit (metres):130
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:It is a rare species. The entire population currently occurs in fewer than eight different subpopulations, which are severely fragmented and rather isolated from each other (D.F. Cisneros-Heredia pers. comm. 2016). The number of adult individuals is estimated to be less than 10,000 individuals, with each subpopulation having less than 1,000 individuals (Ecuador Red List Assessment Workshop July 2016). The number of mature individuals is suspected to be declining in Ecuador as a result of the destruction and fragmentation of coastal dry forests.

Three specimens were collected at Punto Los Piqueros (Minabí, Ecuador) in August 2000 (Cisneros-Heredia 2006). Eight specimens were collected during March 1991 and January 1992 (Cisneros-Heredia 2006). Fourty-four adults and sub-adults were collected at Reserva Ecológica Militar Arenillas (REMA), El Oro province, Ecuador, between 31 January and 1 February 2007 (Ortiz et al. 2013). Three juveniles were collected in March 2011 at Destacamento Pintag Nuevo, REMA, (El Oro, Ecuador) in a marshy area and at the margin of a pond, close to human habitation (Ortiz et al. 2013). Four individuals were detected during surveys in Reserva Ecológia Comunal Loma Alta (Santa Elena, Ecuador) throughout 2005–2010 (Amador and Martínez 2011). In March 2012, one individual was observed within the Bosque Protector Cerro Prosperina de Guayaquil, Guayas, Ecuador (Amador and Brito 2013). A second individual, though deceased, was found during May 2012 surveys in the same area. Subsequent surveys during June 2012 were futile, likely because of the seasonal habits of this species (Amador and Brito 2013). Surveys carried out during the rainy season (January–May) in Arenillas Ecological Reserve observed 20 amplexed pairs served in 2015 over 38 fieldwork days and 29 pairs in 2016 over 65 fieldwork days (Székely et al. 2018a).

There is no information on its population status in Peru. The species has a small range in Peru, but the coastal dry forest habitat is fairly well protected in some areas, such as Tumbes National Reserve, which is relatively remote and inaccessible (A. Catenazzi pers. comm. March 2018).
Current Population Trend:Decreasing
Additional data:
Number of mature individuals:5000-9999Continuing decline of mature individuals:Yes
Population severely fragmented:Yes

Habitat and Ecology [top]

Habitat and Ecology:These nocturnal frogs mainly inhabit Pacific coastal dry scrub, which is usually fairly open with a few trees, but remains green for about half the year. Other specimens have been collected in an open and sandy desert, with scattered, low, desert vegetation, and trees that are absent except in or near temporary streambeds (Peters 1967). Although it can inhabit altered areas, like pastures and roadsides, it relies on nearby forest and is absent from completely deforested areas (D.F. Cisneros-Heredia pers. comm. 2016). 

This species is active only during the rainy season (January–May), when individuals spend the days buried in the ground, and emerge during humid nights to feed and reproduce (Székely et al. 2018a,b). All breeding activity being concentrated in a few hours each year (Székely et al. 2018a). For the rest of the year, the frogs remain buried in the ground in a dormant state, covered in a cocoon of dead skin layers that diminishes water loss. During the breeding season, individuals have been observed in and near to temporary ponds along a trail within forest, while subadults have been observed in a disturbed area with few trees and furrowed soil (Ortiz et al. 2013). The Pacific Horned Frog has a low age at maturity and a short reproductive life-span (2–3 years; Székely et al. 2018a).
Systems:Terrestrial; Freshwater
Continuing decline in area, extent and/or quality of habitat:Yes
Movement patterns:Not a Migrant
Congregatory:Congregatory (and dispersive)

Use and Trade [top]

Use and Trade: This species has been marketed as a pet in North America and Europe (El Comercio 2010, Wikiri 2012).

Threats [top]

Major Threat(s): The major threat is habitat loss due to agriculture (especially cattle ranching), logging, and human settlement, particularly in the coastal dry forests of Ecuador. Soil pollution, due to agrochemicals, also represents a threat. Specifically within Bosque Protector Cerro Prosperina de Guayaquil, human expansion (informal settlements on the slopes of the mountain), forest fires, agriculture and roadkill caused by vehicles on the trails are threats to this species (Amador and Brito 2013). The total area occupied by Arenillas Ecological Reserve has been decreasing continuously, from 17.08 ha in 1994 to 14.28 ha in 2001, and 10.27 ha in 2012 (Camacho and Ullauri 2013), caused by illegal logging and the ongoing expansion of shrimp farms and cultivated land within the protected area (Székely et al. 2018b). A persistent drought of 2–3 consecutive years with low recruitment would endanger the survival of the whole population because of this species' short reproductive lifespan (Székely et al. 2018b). This species is also threatened by harvesting from the wild for the pet trade.

Conservation Actions [top]

Conservation Actions: Conservation Actions
It occurs in Parque Nacional Machalilla (Cineros-Heredia 2006), Reserva Ecológica Comunal de Loma Alta (Amador and Martínez 2011), Reserva Ecológica Arenillas (Ortiz et al. 2013; Székely et al. 2018a,b), Bosque Protector Cerro Prosperina de Guayaquil (Amador and Brito 2013), and Reserva Ecológica Manglares Churute in Ecuador, as well as the Reserva Nacional de Tumbes in Peru. A captive management programme for the species began in 2007 at ‘Balsa de los Sapos’ at the Pontificia Universidad Católica del Ecuador (PUCE) for conservation purposes (Coloma et al. 2010). Breeding of the frogs have been so successful that a backup colony was sent to Amaru Zoo in southern Ecuador (Azuay Province). Breeding and exporting of this species is conducted by the Centro Jambatu de Investigación y Conservación de Anfibios (Quito Ecuador) under a permit issued by the Ministerio de Ambiente del Ecuador, primarily to counteract illegal trafficking of frogs in the hobbyist industry, with all profits invested in conservation, research and education in Ecuador (Wikiri 2012). It is listed as Vulnerable (VU) in Peru and has legal protection provided by the Categorization in Endangered Species of Wild Fauna (Decreto Supremo Nº004-2014-MINAGRI), which bans all hunting, capture, possession, transport or export of the species for commercial purposes. 

Conservation Needed
Improved management of the existing protected areas is the best guarantee for the conservation of this species. Captive-management programmes should focus on the viability of populations in captivity, through genetic, pathological and behavioural studies, to ensure an efficient reintroduction of this species into its former habitats in the future (Ortiz et al. 2013). 

Research Needed
More information is needed on this species' distribution, natural history and threats. Further survey work is needed to determine the population status of this species in Peru.

Citation: IUCN SSC Amphibian Specialist Group. 2018. Ceratophrys stolzmanni. The IUCN Red List of Threatened Species 2018: e.T56341A89204905. . Downloaded on 18 August 2018.
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