Description
Craugastor loki is a frog with an adult snout-vent length range of 21.09 - 29.14 mm in males and 30.23 - 39.67 mm in females (Streicher et al. 2014).

Craugastor loki can typically be differentiated from the other two species of the C. rhodopis Species Group as follows (character condition in parentheses): Unlike C. occidentalis, C. loki has a small supratympanic fold that is often subtended by two tubercles that are occasionally fused (‘Y-shaped’ supratympanic fold that extends onto the lateral surfaces of the flanks). Unlike C. rhodopis, C. loki has a relatively short shank rarely exceeding 54% of the snout-vent length (relatively long shank up to 65% of the snout-vent length). In general, this species possesses a more uniformly colored dorsum than most C. rhodopis Species Group taxa; however, some individuals from Guatemala possess mottled dorsum (Streicher et al. 2014).

Most individuals of C. loki possess distinctive black canthus rostalis and supratympanic masks. Dorsal ground color can be orange, tan, brown or almost cream white. The dorsum is covered by many small glands (substantially smaller than those observed in C. occidentalis) and many individuals have faint linear ridging that runs the length of the dorsum. Some individuals have a thin mid-dorsal pinstripe. Some individuals from populations in southern Veracruz, Mexico (and the holotype, a female) have a white subocular patch (Shannon and Werler, 1955; Streicher et al. 2014).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Belize, Guatemala, Honduras, Mexico

	View distribution map in BerkeleyMapper.
	View Bd and Bsal data (5 records).

Craugastor loki was described as endemic to the Volcán San Martín in the Los Tuxlas region of southern Veracruz, Mexico. Its distribution is now understood to include lower elevation sites (sea level to 2100 m) from San Luis Potosí southward across the Isthmus of Tehuantepec to Belize, El Salvador and northwestern Honduras (Lynch 2000). Most individuals of C. loki have been observed in tropical wet forests (Campbell 1998).

Life History, Abundance, Activity, and Special Behaviors
It has been observed at night along the edges of aguadas (Campbell 1998).

Craugastor loki calls almost continuously throughout the year (Figueroa-Huitrón et al. 2020). Calling starts in early April, likely coinciding with the arrival of the wet season, and continues until November and December (Gottsberger and Gruber 2004).

Larva
Presumed to be direct-developing like other species of Craugastor.

Trends and Threats
Craugastor loki is the most abundant anuran species observed in regions of Chiapas, Mexico (Javier-Vázquez et al. 2022).

Relation to Humans
Lives adjacent to agricultural areas (IUCN 2020).

Comments
Bayesian and Maximum Likelihood analysis of 12s mtDNA found that C. loki is sister to C. rhodopis and together they are sister to C. occidentalis. However, the amount of sequence divergence within each species indicate that there may be more potential taxonomic subdivision (Streicher et al 2014).

The original description of Craugastor loki (named after the Teutonic god of strife and fire) used two color pattern characteristics to distinguish it from congeners (Shannon and Werler 1955); however, these traits seem to be regionally restricted to southern Veracruz. Several populations of C. loki were previously referred to as C. rhodopis (Streicher et al. 2014).

References
Campbell, J.A. (1998). Amphibians and reptiles of northern Guatemala, the Yucatan, and Belize. The University of Oklahoma Press, USA, pp. 380. Figueroa-Huitrón, R., Ochoa-Ochoa, L.M. and Sánchez-Ochoa, D. (2020). Calling phenology of four anurans in tropical Mexico. Revista Mexicana de Biodiversidad 91, e912945. [link]

Gottsberger, B. and Gruber, E. (2004). Temporal partitioning of reproductive activity in a neotropical anuran community. Journal of Tropical Ecology, 20(3), 271–280. [link]

IUCN SSC Amphibian Specialist Group. 2020. Craugastor loki. The IUCN Red List of Threatened Species 2020: e.T56726A53965108. https://dx.doi.org/10.2305/IUCN.UK.2020-1.RLTS.T56726A53965108.en. Accessed on 28 November 2023.

Javier-Vázquez E., Luna-Reyes, R. and Moreno-Ovando, A. (2022). Amphibian diversity and conservation in the Ejido Tierra y Libertad, southwestern Chiapas, Mexico. Herpetological Conservation and Biology 17(3), 451-466. [link]

Lynch, J.D. (2000). The relationships of an ensemble of Guatemalan and Mexican frogs (Eleutherodactylus: Leptodactylidae: Amphibia). Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales 24, 129–156.[link]

Shannon, F.A. and Werler, J.E. (1955). Notes on amphibians of the Los Tuxtlas range of Veracruz. Transactions of the Kansas Academy of Sciences 58(3), 360–386. [link]

Streicher, J.W., García-Vázquez , U.O., Ponce-Campos, P., Flores-Villela, O., Campbell, J.A. and Smith, E.N. (2014) Evolutionary relationships amongst polymorphic direct-developing frogs in the Craugastor rhodopis species group (Anura: Craugastoridae). Systematics and Biodiversity 12(1), 1–22. [link]

Species Account Citation: AmphibiaWeb 2024 Craugastor loki: Common Leaf-Litter Frog <https://amphibiaweb.org/species/6604> University of California, Berkeley, CA, USA. Accessed Sep 18, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 18 Sep 2024.

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