Description

Adelophryne adiastolais a minute Andean frog (adult SVL 13.0-13.9 mm) that has pointed discs on the toes and a distinctly reduced fourth finger with only two phalanges (Hoogmoed and Lescure 1984). The head is narrower than the body and slightly wider than long. The snout is rounded to truncate in lateral profile and rounded in dorsal view. The tip of the snout extends past the anterior edge of the upper jaw. The pupil is a horizontal oval. The tympanum is small but distinct and is surrounded by a distinct but incomplete tympanic annulus, with the posterior dorsal margin obscured by a thick, glandular, indistinct supratympanic skin fold. A row of glandular warts runs from the tympanum to the forelimb insertion. Nostrils are not protuberant. Choanae are medium-size and rounded. Vomerine teeth are absent in the juvenile female specimen but the two prevomerine processes bear 2-8 teeth each in the adults. The tongue is mushroom-shaped and is not notched at the posterior. The hand has one palmar tubercle and lacks ulnar tubercles. Fingers and toes are depressed. Fingers lack discs but have asymmetrically pointed tips. Terminal phalanges of fingers are either bluntly pointed or are T-shaped. Supernumerary palmar tubercles are present at the base of the second, third, and fourth fingers. Toe tips have expanded discs that are asymmetrically pointed and also have circumferential grooves. The terminal phalanges of the toes are T-shaped. Toes lack lateral fringes and webbing. The outer metatarsal tubercle is large, flat, and oval-shaped, while the inner metatarsal tubercle is smaller and rounded and protrudes. Dorsal skin is shagreened to granular, while the venter is smooth. Males have large, subgular vocal sacs, and lack nuptial pads on their thumbs (Hoogmoed and Lescure 1984; Lynch 1986).

In preservative, the dorsal skin is tan with reddish-brown or darker brown spots which form a reticulation. Pale dorsolateral stripes lie within the patterns. There is a white spot below the eye and on the lip in front of the tympanum. The side of the head is brown. Postrictal tubercles are white. Limbs possess brown transverse bands: there are two on the forearm, four on the shank, and three on the tarsus. The anterior and posterior surfaces of the thighs are reddish-brown while the ventral surfaces possess melanophores. The throat and chest have reticulated brown spots (Hoogmoed and Lescure 1984; Lynch 1986).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Brazil, Colombia, Ecuador, Peru

View distribution map in BerkeleyMapper.

Found in northwestern Brazil, southeastern Colombia (Yapima, Departamento Vaupes, and Leticia, Departamento Amazonas), northeastern Peru (Departamento Loreto), and Ecuador, at elevations below 200 m asl (Angulo et al. 2004). The type locality in Yapima, Colombia is tropical lowland rainforest (Hoogmoed and Lescure 1984). This species is found in both primary and secondary forest (Angulo et al. 2004). All specimens were collected in leaf litter near streams, with one adult male found calling in leaf litter (Heyer 1977; Hoogmoed and Lescure 1984); the juvenile female was also found in leaf litter (Lynch 1986).

Life History, Abundance, Activity, and Special Behaviors
The adult female specimen from Yapima, Colombia contained large, white ovarian eggs, and stomach contents included a small harvest-man (Chelicerata) (Hoogmoed and Lescure 1984).

Trends and Threats
This species occurs in both primary and secondary lowland tropical moist forest; it is not known whether it can adapt to strongly disturbed habitat. It is common in Colombia but uncommon in Peru. No major threats have been identified since the range is not highly inhabited by humans, although habitat loss due to crops and livestock grazing affects some local populations. It may occur within some protected areas: Parque Nacional Natural Amacayacu and El Pure National Park, Colombia, and Pacaya Samiria National Reserve, Peru (Angulo et al. 2004).

Possible reasons for amphibian decline

General habitat alteration and loss
Intensified agriculture or grazing

Comments
One of the male specimens (UTACV 4940) lacked a subgular vocal sac, though it had fully developed testes and was found calling in the leaf litter; it also lacked a tympanic annulus, supratympanic fold, and glandular row between the tympanum and forelimb insertion (Hoogmoed and Lescure 1984). Epiphyses of this specimen were large, indicating it was still growing to full adult size (Hoogmoed and Lescure 1984).

The name of the genus Adelophryne is derived from the Greek word adelos, which means unseen, obscure, or unknown, and phryne, or toad (Hedges et al. 2008). The specific name derives from the Greek word adiastolos, meaning not separated or confused, and refers to the original placement of these specimens within Phyzelaphryne miriamae (Hoogmoed and Lescure 1984).

References

Angulo, A., Icochea, J., Castro, F., and Rueda, J. V. 2004. Adelophryne adiastola. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.1. www.iucnredlist.org. Downloaded on 07 April 2010.

Duellman, W. E., and Mendelson, J. R. III (1995). ''Amphibians and reptiles from northern Departamento Loreto, Peru: taxonomy and biogeography.'' University of Kansas Science Bulletin, 55, 329-376.

Hedges, S. B., Duellman, W. E., Heinicke, M. P. (2008). ''New World direct-developing frogs (Anura: Terrarana): Molecular phylogeny, classification, biogeography, and conservation.'' Zootaxa, 1737, 1-182.

Heyer, W. R. (1977). ''Taxonomic notes on frogs from the Madeira and Purus rivers, Brasil.'' Papeis Avulsos de Zoologia, 31, 141-162.

Hoogmoed, M. S., and Lescure, J. (1984). ''A new genus and two new species of minute leptodactylid frogs from northern South America, with comments upon Phyzelaphryne (Amphibia: Anura: Leptodactylidae).'' Zoologische Mededeelingen, 58, 85-115.

Lynch, J. (1986). ''New species of minute Leptodactylid frogs from the Andes of Ecuador and Peru.'' Journal of Herpetology, 20(3), 423-431.

Ortega-Andrade, H. M. (2009). ''Amphibia, Anura, Eleutherodactylidae, Adelophryne adiastola Hoogmoed and Lescure, 1984: First countries records and distribution extension from Ecuador and Brazil.'' Check List, 5(1), 139-143.

Rodríguez, L. O., and Duellman, W. E. (1994). Guide to the Frogs of the Iquitos region, Amazonian Perú. The University of Kansas, Lawrence, Kansas.

Ruiz-Carranza, P.M., Ardila-Robayo, M.C., and Lynch, J.D (1996). ''Lista actualizada de la fauna de Amphibia de Colombia.'' Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales, 20(77), 365-415.

Species Account Citation: AmphibiaWeb 2010 Adelophryne adiastola <https://amphibiaweb.org/species/2548> University of California, Berkeley, CA, USA. Accessed Apr 3, 2025.

Citation: AmphibiaWeb. 2025. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 3 Apr 2025.

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