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

expanded, rounded; circumferential grooves present; fingers bearing narrow lateral fringes; (8) subarticular tubercles prominent; supernumerary palmar tubercles present; palmar tubercle partially divided into a larger (inner) and a smaller (outer) tubercles; thenar tubercle elliptical, smaller than the inner palmar tubercle; (9) small, inconspicuous, ulnar tubercles present (trait more visible in life); (10) heel with several small, rounded tubercles; outer edge of tarsus with a row of small tubercles; inner tarsal tubercles present, sometimes coalesced into a tarsal fold; (11) inner metatarsal tubercle broadly ovoid, about 4x ovoid, subconical (in profile), outer metatarsal tubercle; supernumerary plantar tubercles present; (12) Toe V slightly longer than Toe III; discs on toes broadly expanded, rounded, about same size as those on fingers; circum- ferential grooves present; toes bearing narrow lateral fringes; webbing absent; (13) in life, dor- sum gray or brown, with black flecks; venter light gray without markings; no markings in axilla, groin or on concealed limb surfaces; iris bronze with a reddish median horizontal streak and fine black reticulations; (14) SVL 28.4–32.4 mm in adult females (n = 2; [9]) and 23.6–25.8 mm in adult males (24.7 ± 0.83 SD, n = 6). Variation. Morphometric variation is shown in Table 3. Most of the encountered individu- als had a generally gray coloration, as was the case of the female MUTPL 392 (Fig 25A) and male MUTPL 677 (Fig 25B). The male MUTPL 677 (Fig 25B) had the same coloration as the

holotype KU 142136 (Fig 3B in [9]). Male MUTPL 487 (Fig 25C) was reddish brown, the juve- nile MUTPL 489 (Fig 25D) had a reddish brown back and gray flanks, juvenile MUTPL 490 (Fig 25E) had a brown broad middorsal band and gray flanks and juvenile MUTPL 491 (Fig 25F) had a dark brown broad middorsal band and beige flanks. All the encountered individu- als had the characteristic black flecks but some had only a few (MUTPL 490, 491), others had many flecks especially on the center of their backs (MUTPL 677, 487, 489), and in some cases all their dorsum and dorsal surfaces of hindlimbs and arms were covered with flecks (MUTPL 392). Advertisement call. The advertisement call of one male from Reserva Madrigal del Podo- carpus was recorded in 2018 and of two males from Abra de Zamora were recorded in 2019. Descriptive statistics of the acoustic variables are provided in Table 2 (the detailed information of each of the separate recordings is presented in the S4 Table). Pristimantis balionotus has an advertisement call characterized by a call series composed by whistles repeated over a period of time, somewhat similar to the calls of P. jimenezi and P. phoxocephalus (Fig 26). The calls Fig 25. Color variation of Pristimantis balionotus in life. A. female: MUTPL 392; B–C males: B. MUTPL 677, C. MUTPL 487; D–F juveniles: D. MUTPL 489, E. MUTPL 490, F. MUTPL 491. Abra de Zamora (A, B), Reserva Madrigal del Podocarpus (C, D, E, F). Most common coloration of this species is presented in B. https://doi.org/10.1371/journal.pone.0238306.g025 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 45 / 59