Fifty years after: A taxonomic revision of the amphibian species from the Ecuadorian biodiversity hotspot Abra de Zamora, with description of two new Pristimantis species

horizontal streak and with fine black reticulations; (14) SVL 17.1–20.7 mm in adult females (19.3 ± 1.58 SD, n = 4) and 14.7–16.9 mm in adult males (16.0 ± 1.17 SD, n = 3). Comparisons with similar species. Pristimantis samaniegoi is morphologically similar to its closest relatives, the species from the P. orestes group, but it can be easily distinguished from all the resembling species. From the 14 species that are currently included in this group, only three species lack tympanic annulus and tympanic membrane: P. samaniegoi, P. matildae sp. nov. and P. colodactylus. However, P. colodactylus and P. matildae sp. nov. belong to the P. colodactylus subgroup of species (Fig 7), specialized to live inside bromeliads, that have a very distinct habitus, with longer snouts/heads, longer legs, head as wide or wider than the body and usually very short fingers and toes (Table 1). Additionally, P. samaniegoi can be easily dis- tinguished from P. matildae sp. nov. and P. colodactylus as follows (characters of P. samaniegoi in parenthesis): discoidal fold absent (thoracic and discoidal folds evident), supratympanic fold absent (present), upper eyelid bearing one prominent tubercle (upper eyelid bearing only several small tubercles), dentigerous processes of vomers concealed in buccal mucosa (denti- gerous processes of vomers prominent), Toe V much longer than Toe III (Toe V slightly lon- ger than Toe III), and males lacking vocal sac and slits (males with large subgular vocal sac and vocal slits). Pristimantis samaniegoi can be easily distinguished from other closely related species,

which are somewhat similar, as follows (characters of P. samaniegoi in parenthesis): P. quinta- nai, P. saturninoi, P. simonbolivari, P. bambu and P. mazar have spots—black, white or yellow —in axilla, groin, concealed limb surfaces, or on venter (spots absent) and P. tiktik has tuber- culated dorsum (finely tuberculated) and the venter, axillae and groins of the females is white with black reticulum (venter dark gray, without reticulum). From the sympatric species, P. andinognomus is significantly smaller, with females on average 16 mm, males 13 mm (larger, with females on average 19 mm, males 16 mm), has inguinal spots (no inguinal spots), and Toe V is much longer than Toe III (Toe V is slightly longer than Toe III), P. cajanuma has inguinal spots (spots absent) and P. vidua is larger, with females on average 22 mm, males 17 mm (smaller, with females on average 19 mm, males 16 mm) and has dorsolateral folds (dorso- lateral folds absent). And finally, none of the other species have the typical dark coloration with white spots of the females of P. samaniegoi. Description of the holotype. Adult female (MUTPL 357; Figs 10–13A), head narrower than body, wider than long, head length 92% of head width, head width 33% of SVL; head length 30% of SVL; snout short (snout to eye distance 13% of SVL), rounded in dorsal view and in profile (Fig 12A and 12B); canthus rostralis weakly concave in dorsal view, rounded in profile; loreal region flat; eye diameter notably greater than eye-nostril distance; nostrils not

protuberant; lips not flared; cranial crests absent; upper eyelid bearing several small tubercles (two slightly larger than the others), width of upper eyelid 64% of IOD; tympanic annulus and tympanic membrane absent (Fig 12B); evident supratympanic fold present; one larger, rounded postrictal tubercle present; choanae large, oval, not concealed by palatal shelf of max- illary arch; dentigerous processes of vomers prominent, slightly larger than the choanae, obli- que, situated posterior and median to choanae, triangular in outline, separated medially by distance almost equal to the width of processes, each processes bearing 4 to 5 teeth; tongue 1.5x as long as wide, slightly notched posteriorly, posterior half not adherent to floor of mouth. Skin on dorsum finely tuberculated; thin, low middorsal fold starting at tip of snout and ending at cloaca; dorsolateral folds absent; skin on throat, chest, belly, and ventral surfaces of thighs coarsely areolate; thoracic and discoidal folds evident (trait more visible in preservative; Figs 10B and 11B); ornamentation in cloacal region absent. Ulnar tubercles absent; outer palmar tubercle prominent, completely divided into a larger (inner) and a smaller (outer) tubercles; thenar tubercle oval, smaller than the inner palmar PLOS ONE Taxonomic revision of the amphibian species from Abra de Zamora PLOS ONE | https://doi.org/10.1371/journal.pone.0238306 September 10, 2020 25 / 59