Description
Atelopus calima is a warty, slender, medium-sized frog that was described from eight males and one female. Males have a snout vent length of 26 – 34.7 mm and the adult female has a snout-vent length of 41.4 mm. In both sexes the head is longer than it is wide. The snout narrows to a point, protrudes past the lower jaw, and is slightly depressed at the tip. There is also a small protuberance, knob, or lump at the tip of its snout. The protuberant nostrils have a lateral orientation, are positioned closer to the snout tip than eyes, and are anterior to the apex of the mouth. The nostrils are not visible in the dorsal view. However, in the dorsal view, the canthus rostralis is concave, well defined, and more rounded posterior to the nostril than anterior to the nostril. The loreal region is somewhat concave. The lips and eyelids do not flare. There is a supra-tympanic crest but no parotid gland, tympanic membrane or annulus. The species has a slim body, with the sacrum width being about a third of the snout-vent length. The skin on the dorsum and lateral regions is generally smooth with a few scattered warts that are large and flat. The warts in the tympanic region are conical and the warts on the flanks are more dense and covered in small, spike-like structures called spiculae. There are also large warts on the dorsal surfaces of the limbs. The otherwise smooth ventrum is areolate on the chest, gular region, around the cloaca, and on the humerus and femur. The vertebral column is visible through the skin (Velásquez-Trujillo et al. 2024).

The fore- and hind limbs are long and slender. The palms have a well-defined, round palmar tubercle and an indistinct thenar tubercle. The relative length of the unwebbed fingers is I < II < IV < III with the first finger being distinctly short, and the phalangeal formula being 2 - 2 - 3 - 3. The subarticular tubercles of the fingers are indistinct. The tips of fingers are rounded, but not expanded. The tibia and foot are about the same length, with both being about 40% of the snout-vent length. There is no tarsal fold and the tarsal tubercle is poorly developed. The inner metatarsal tubercle is indistinct while the outer metatarsal tubercle is round. The relative length of the unfringed toes is I < II < III < V < IV and they have a phalangeal formula 2-2-3-4-3 and a webbing formula I 0 – 1 II 1 – 1 ½ III 1 – 2 ½ IV (2 ½ – 3) – 1 V. The small subarticular tubercles are still distinct and round. The toe tips are also round but not expanded (Velásquez-Trujillo et al. 2024).

DIAGNOSIS:

Atelopus calima can be distinguished from its close relatives by its medium body size, knob-like protuberance on the snout, and a dorsum characterized by scattered warts on the dorsum and spiculated warts on its flanks on an otherwise smooth surface. It is most similar to A. nocturnus and A. sonsonensis, which are central Cordillera endemics. Atelopus calima is also similar to A. carauta, A. chocoensis, A. famelicus, A. galactogaster, A. longirostris, A. lynchi, A. nicefori and A. pictiventris, which are western Cordillera endemics, to A. quimbaya, A. sanjosei and A. sernai, which are also central Cordillera endemics. However, A. calima has a larger body size, lighter flank coloring, and the presence of spiculae on the flanks that distinguish it from A. nocturnus and A. sonsonensis. Atelopus calima can be further differentiated from A. sonsonensis by the former lacking hand webbing and having supertympanic crests directed towards the flanks. Atelopus calima is smaller than A. carauta, A. famelicus, A. galactogaster, A. longirostris, and A. lynchi, but larger than A. sernai. The spiculae in A. calima differentiates from A. carauta, A. chocoensis, A. galactogaster, A. longirostris, A. lynchi, A. nicefori, A. pictiventris, A. quimbaya, and A. sernai, which all lack them, and A. calima has fewer spicules than A. sanjosei. The snout in A. calima is relatively longer than A. chocoensis, A. lynchi, A. nicefori, and A. pictiventris, but shorter than A. galactogaster. The snout is also straighter than A. chocoensis and A. nicefori, and more pointed than A. quimbaya. The knob-like projection in A. calima differentiates it from A. lynchi, A. pictiventris and A. quimbaya, which lack it. And coloration or patterning is different for all of these species. For more comparisons, please see the species authority (Velásquez-Trujillo et al. 2024).

COLORATION:

In life, both sexes have a dark brown dorsum, however, males have cream flanks and ventral area while females have yellowish to orange flanks with brown warts and orange ventral area. The venter may have tiny brown flecks and the throat has a brown wash. The ventral surface of the thighs, shanks, and tips of the feet may also have an off-white pigment. The iris is black with a pale green ring around the pupil (Velásquez-Trujillo et al. 2024).

In preservative, the dorsum ranges from light to dark brown to reddish brown with dark brown warts. The dorsal coloration darkens towards the tip of the snout and limbs with the head being dark brown. In most cases the lateral regions are generally whitish-cream to light brown with dark warts. The spiculae are whitish. Its ventral area is pale white, cream, or reddish cream with most specimens possessing brown throats and gulars (Velásquez-Trujillo et al. 2024).

VARIATION:

There is some sexual and individual variation with regards to color (please see above). The female specimen is also notably larger and has longer, more slender limbs than males, and males have nuptial pads. Individually, the density of warts differs with some individuals almost completely lacking warts on the dorsum (Velásquez-Trujillo et al. 2024).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Colombia

View distribution map in BerkeleyMapper.

At the time of the species description, the species was confirmed at two sites within the Reserva Nacional Forestal Bosque de Yotoco in Columbia at elevations of 1500 - 1900 m.a.s.l. This reserve consists of a matrix of isolated premontane forest fragments with both clouds and dry forest characters, private livestock pastures, and disturbed land from logging, hunting, and burning that took place in the area before it was established as a reserve in 1959. On average it is 20 degrees celsius or 68 degrees fahrenheit, and has an average rainfall of 1500 mm per year, with high and low rainfall seasons (Velásquez-Trujillo et al. 2024).

Ten similar looking specimens were labelled as collected at Estación Silvicultura Bajo Calima, however, given the much lower elevation (< 100 m.a.s.l) of this site, distance from the type locality, and the lack of other collecting information, the authors are doubtful these specimens have accurate location information (Velásquez-Trujillo et al. 2024).

Unfortunately, at the time of the species description, A calima had not been seen since July 1994 (Velásquez-Trujillo et al. 2024).

Life History, Abundance, Activity, and Special Behaviors
Atelopus calima is a rare species that was found active in leaf litter and rotten tree trunks near streams in the forest during the day (Velásquez-Trujillo et al. 2024).

They appear to mate during the beginning of the early rainy season as one amplectant pair was found in March 1988 (Velásquez-Trujillo et al. 2024).

At least 20 sympatric amphibians are known from the same area that A. calima is known from. They include the endemic species: Andinobates bombetes, Centrolene savagei, Pristimantis deinops, P. juanchoi, Strabomantis cerastes, and S. ruizi (Velásquez-Trujillo et al. 2024).

Trends and Threats
Despite continuous surveys since July 1994 of the Yotoco area, no new A calima individuals have been found in or around the few sites they are known from. Their habitat is severely fragmented and has undergone modifications due to human activities. The pathogenic fungus, Batrachochytrium dendrobatidis, has also been confirmed in the Yotoco area and has likely caused A. calima’s disappearance from their known localities. Because of these factors, the species authority suggests listing A. calima as “Critically Endangered” on the IUCN Red List. The species’ estimated Area of Occupancy is 12 km² (Velásquez-Trujillo et al. 2024).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Habitat fragmentation
Disease

Comments
Atelopus calima was described as a new species based on morphology. However, given it’s morphological similarities with A. nocturnus and A. sonsonensis, the authors speculate that A. calima may be part of a wide-spread western and central Andean clade that includes species from both sides of the Río Caucua Valley (Velásquez-Trujillo et al. 2024).

References
Velásquez-Trujillo, D. A., Castro-Herrera, F., Lötters, S., and Plewnia, A. (2024). A new species of harlequin toad from the Western Cordillera of Colombia (Bufonidae: Atelopus), with comments on other forms. Salamandra, 60(1), 67–81. [link]

Species Account Citation: AmphibiaWeb 2025 Atelopus calima: Calima Harlequin Toad <https://amphibiaweb.org/species/9841> University of California, Berkeley, CA, USA. Accessed May 8, 2025.

Citation: AmphibiaWeb. 2025. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 8 May 2025.

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