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

Etymology. Latin, “a widow”, used as a noun in apposition. The choice of this name reflected the belief of the author that this species might be all-female [9]. Holotype. KU 120082, adult female obtained 15 km E Ciudad Loja, Provincia Zamora- Chinchipe, Ecuador, 2800 m, on 10 June 1968 by John D. Lynch. Paratypes. KU 120083–88, KU 120090–91, topotypes; KU 141994, 15 km E Loja, Provincia Zamora-Chinchipe, Ecuador, 2710 m; KU 120089, 13–14 km E Loja, Provincia Loja, Ecuador, 2850 m; KU 120092, 8–9 km N San Lucas, Provincia Loja, Ecuador, 3000–3100 m. Diagnosis. Pristimantis vidua is a small species distinguished by the following combination of traits: (1) skin on dorsum finely tuberculated (in life the tuberculated texture of the skin is more evident); skin on venter areolate; discoidal fold visible; dorsolateral folds present; low middorsal fold present; (2) tympanic membrane absent; ventral part of tympanic annulus visi- ble, concealed by skin; its length about 43% of the length of eye; supratympanic fold present; (3) snout short, rounded in dorsal view and in profile; canthus rostralis weakly concave in dor- sal view, rounded in profile; (4) upper eyelid bearing several small tubercles, similar in size and shape with the ones from the dorsum (trait more visible in life), about 61% IOD in females and 69% IOD in males; cranial crests absent; (5) dentigerous processes of vomers prominent, oblique, round or slightly ovoid, separated medially by distance lower than width of processes;

each processes bearing 3 to 9 teeth; (6) males with a large subgular vocal sac and vocal slits; nuptial pads absent; (7) Finger I shorter than Finger II; discs on fingers slightly expanded, rounded; circumferential grooves present; fingers lacking lateral fringes; (8) subarticular tuber- cles prominent, round; supernumerary palmar tubercles evident; palmar tubercle completely divided into a larger (inner) and a smaller (outer) tubercles; thenar tubercle oval, smaller than the inner palmar tubercle; (9) small, inconspicuous, ulnar tubercles present (trait more visible in life); (10) heel with 2 or 3 larger and several smaller tubercles (trait more visible in life); outer edge of tarsus bearing a row of small tubercles; inner tarsal tubercles coalesced into a long tarsal fold; (11) inner metatarsal tubercle broadly ovoid, about 1.5 to 2x rounded outer metatarsal tubercle; supernumerary plantar tubercles present; (12) Toe V slightly longer than Toe III; discs on toes slightly expanded, rounded, about same size as those on fingers; circum- ferential grooves present; toes lacking lateral fringes; webbing absent; (13) in life, dorsum tan to brown or grey, mottled with darker brown or bearing dark dorsolateral stripes; venter cream or pinkish white; no markings in axilla, groin or on concealed limb surfaces; iris whitish gray, with a reddish broad median horizontal streak, that seems to cover all the lower part of the iris, and with fine black reticulations; (14) SVL 17.9–26.8 mm in adult females (22.4 ± 2.35 SD, n = 16) and 16.1–19.5 mm in adult males (17.6 ± 1.28 SD, n = 11).

Variation. Morphometric variation is shown in Table 1. The females are more colorful and variable than the males (Fig 8). The female specimen MUTPL 312 (Fig 8A) had a coloration very similar with the holotype KU 120082 and paratype KU 120089 (Fig 13D in [9]), with light orange dorsolateral stripes and spots and pale dorsolateral folds that continue with stripes onto the snout. Many females have particular dark dorsolateral stripes on lighter background (orange, yellow or cream), as in the case of MUTPL 164 and 586 (Fig 8B and 8C). One female, MUTPL 590, had the head and snout distinctly yellowish beige, contrasting with the rest of the body which was dark brown (Fig 8D). Other females are dark brown with light upper lips and canthal stripes (MUTPL 153, Fig 8E), or completely pinkish beige, as MUTPL 150 (Fig 8F). Most of the encountered males are similar in color with MUTPL 495, with reddish brown mid- dorsal band and members, dark dorsolateral folds and lighter flanks (Fig 8G), or alternatively have a uniform grey coloration, with some darker stripes and black supratympanic stripes, as in MUTPL 496 (Fig 8H). One male, MUTPL 148 had a different coloration, with a brown mid- dorsal band, and yellowish dorsolateral stripes that continued onto the snout and yellowish flanks (Fig 8I). 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 17 / 59