Comprehensive DescriptionRead full entry
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).
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 wordadiastolos, meaning not separated or confused, and refers to the original placement of these specimens within Phyzelaphryne miriamae (Hoogmoed and Lescure 1984).