Nurse frog of the Serranía de Perijá, Rana nodriza de la Serranía de Perijá
Species Description: Anganoy-Criollo M 2012 A new species of Allobates (Anura,Dendrobatidae) from the western flank of the Serrania de Perija, Colombia. Zootaxa 3308: 49-62.
Free-swimming tadpoles have been described at Gosner stages 25 - 29. The average total length of the tadpoles is 12.2 mm at stages 25 - 26, 16.2 mm at stage 27, and 19.4 mm at stages 28 - 29. Tadpoles have an ovoid body, and the tail makes up more than half the total length. The snout is rounded, the nostrils are circular or ovoid, and the nostrils and eyes are positioned dorsally. The oral disc is positioned ventrally and is mostly surrounded by papillae, except on the anterior side. The jaw sheaths are keratinized, and the lower jaw sheath has serrations with rounded tips. The spiracle is cylindrical and positioned sinistrally, and the vent is short and positioned dextrally. The inner intestines can be seen through the translucent skin. In addition, the lateral line system is visible and symmetrical from the supraorbital to the ventral trunk lateral lines. The tail tip is rounded, and the dorsal fin starts where the tail meets the body (Granda-Rodríguez et al. 2018).
Unlike all other Allobates species, A. ignotus has three continuous stripes down each side, basal webbing between toes two through four, and the preaxial side of the third finger enlarged in adult males. The back is smoother than in other Allobates species. Morphologically, of all Allobates, A. ignotus most closely resembles A. wayuu. However, A. ignotus has a cream-colored ventral region in both sexes and a dark brown chest region in males, whereas A. wayuu has a mottled ventral region and no sexual dimorphism in the chest coloration. Additionally, the dorsolateral stripes reach the thigh in A. wayuu but not in A. ignotus, and adult A. ignotus are larger than adult A. wayuu (Anganoy-Criollo 2012). With regards to vocalizations, A. ignotus’ mating calls have more notes, on average, than others of the Allobates genus (between six and 116 notes per call). Allobates myersi and A. paleovarsensis only give 5 - 10 and 3 - 21 notes per call, respectively (Granda-Rodríguez et al. 2018).
Live adults are brown overall with dark brown markings on the back and head. A broad, dark brown lateral band above a thin, pale lateral stripe extends along the frog’s sides from snout to vent. The forelimbs are dull-yellow. Females have dull-yellow hind limbs, and males have brown hind limbs. All the limbs have dark brown rings. The coloration in preservative is similar, but the forelimbs are more cream-colored and the ventrums are cream-colored in preserved females and darker in males (Anganoy-Criollo 2012).
Tadpoles in preservative are translucent with brown dots that are uniformly distributed on the body, and the jaw sheaths are black or dark brown (Granda-Rodríguez et al. 2018).
Adult males and females have slight sexual dimorphism in their coloration. Females have dull-yellow hind limbs, and males have brown hind limbs. The frogs’ undersides are cream-colored in preserved females, and darker in males: the chest and throat region are mostly brown in preserved males, and mostly black in live males (Anganoy-Criollo 2012).
Distribution and Habitat
Life History, Abundance, Activity, and Special Behaviors
The male’s advertisement call consists of a series of pulsed notes with an average overall call duration of about 8 seconds, an average rate of 3.94 notes per second, and a frequency range of 4,600 - 14,000 Hz. Calls can have between six and 116 notes per call. Males show some degree of call site fidelity (Granda-Rodríguez et al. 2018).
Their reproductive mode is characterized by indirect development and free-swimming tadpoles. Tadpoles have been found in puddles near the edges of a stream (Granda-Rodríguez et al. 2018).
Trends and Threats
The population has fluctuated and is suspected to be in decline according to surveys performed between 2010 and 2014 in the Canime Creek Basin of Columbia. However, Granda-Rodríguez et al. (2018) recorded the species in six new locations and recommended downgrading their conservation status from “Endangered” to “Vulnerable.”
Relation to Humans
Possible reasons for amphibian decline
General habitat alteration and loss
The species epithet, “ignotus” means “unknown” in Latin, and refers to the lack of research on Columbian species in the genus Allobates (Anganoy-Criollo 2012).
Anganoy-Criollo, M. (2012). "A new species of Allobates (Anura, Dendrobatidae) from the western flank of the Serranía de Perijá, Colombia." Zootaxa, 3308(1), 49-62. [link]
Granda-Rodríguez, H.D., Montes-Correa, A.C., Jimenez, J.D., Criollo, M.A. (2018). “Natural history and conservation of the Nurse Frog of the Serranía del Perijá Allobates ignotus (Dendrobatoidea: Aromobatidae) in northeastern Colombia.” Acta Herpetologica, 13(1), 51-64. [link]
IUCN SSC Amphibian Specialist Group. (2017). "Allobates ignotus." The IUCN Red List of Threatened Species 2017: e.T77187242A85872707. https://dx.doi.org/10.2305/IUCN.UK.2017-2.RLTS.T77187242A85872707.en. Downloaded on 15 February 2021.
Originally submitted by: Claire Short, Timothy Her, Laura Poikonen (2021-07-01)
Description by: Claire Short, Timothy Her, Laura Poikonen (updated 2021-07-01)
Distribution by: Claire Short, Timothy Her, Laura Poikonen (updated 2021-07-01)
Life history by: Claire Short, Timothy Her, Laura Poikonen (updated 2021-07-01)
Trends and threats by: Claire Short, Timothy Her, Laura Poikonen (updated 2021-07-01)
Relation to humans by: Claire Short, Timothy Her, Laura Poikonen (updated 2021-07-01)
Comments by: Claire Short, Timothy Her, Laura Poikonen (updated 2021-07-01)
Edited by: Ann T. Chang (2021-07-01)
Species Account Citation: AmphibiaWeb 2021 Allobates ignotus: Nurse frog of the Serranía de Perijá <https://amphibiaweb.org/species/7824> University of California, Berkeley, CA, USA. Accessed Jan 22, 2022.
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Citation: AmphibiaWeb. 2022. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 22 Jan 2022.
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