Pristimantis yonke, Chávez & Aznaran & Wong & Victoriano-Cigüeñas & García-Ayachi & Valencia-Málaga & Ormeño & Gulman & Sumiano-Mejía & Thompson & Catenazzi, 2025

Chávez, Germán, Aznaran, Wilmar, Wong, Ivan, Victoriano-Cigüeñas, Karen Y., García-Ayachi, Luis A., Valencia-Málaga, Juan D., Ormeño, Jesús R., Gulman, Michael, Sumiano-Mejía, Ronal, Thompson, Michelle E. & Catenazzi, Alessandro, 2025, Over the top: Three new species of terrestrial breeding frogs (Anura, Terrarana, Pristimantis) from the highlands of the Cordillera de Huancabamba, northwestern Peru, Evolutionary Systematics 9 (1), pp. 145-166 : 145-166

Pristimantis yonke sp. nov.

Type material.

Holotype • Adult male CORBIDI 26399 (Figs 11 A ‒ D , 12 A ‒ E ) from Laguna Negra trail , Ayabaca Province, Piura Region, Peru (4°55'52.58"S, 79°29'8.41"W; 2933 m a. s. l.) collected on 6 September 2023 by Juan D. Valencia-Málaga and Germán Chávez.

Paratypes • Adult female CORBIDI 26398 , male CORBIDI 26402 collected with the holotype , • adult males CORBIDI 26413 ‒14 collected at the type locality on 9 and 10 September 2023, respectively by Juan D. Valencia-Málaga, and Germán Chávez . • Adult female CORBIDI 26929 from Bosque de Ramos , Ayabaca Province, Piura Region, Peru (4°42'25.75"S, 79°27'51.24"W; 2949 m a. s. l.), collected on 9 July 2024 by Wilmar Aznaran, Karen Y. Victoriano-Cigüeñas, Jesús R. Ormeño, Ronal Sumiano-Mejía, and Germán Chávez (Fig. 13 A ‒ H ) .

Referred specimens.

Juvenile CORBIDI 26403 from the type locality; juveniles CORBIDI 26924 ‒25 from Bosque de Ramos, Ayabaca Province, Piura Region, Peru (4°42'25.75"S, 79°27'51.24"W; 2949 m a. s. l.), collected on 9 July 2024 by Wilmar Aznaran, Karen Y. Victoriano-Cigüeñas, Jesús Ormeño-Benavides, Ronal Sumiano-Mejía, and Germán Chávez.

Diagnosis.

Pristimantis yonke sp. nov. is a small species with broad flat head, which may be distinguished by the following combination of traits: (1) skin on dorsum finely tuberculate without crests or ridges on scapular region, incomplete and low dorsolateral fold occasionally present; skin on venter areolate; discoidal fold present; thoracic fold absent; skin on flanks as on dorsum; longitudinal middorsal fold evident; (2) tympanic membrane and tympanic annulus evident, its length about 50 % of the length of eye; supratympanic fold present, going from the distal edge of tympanum to the level of the insertion of forelimbs; (3) snout short, dorsoventrally compressed, acuminate in dorsal view, protruding and inclined posteroventrally in profile, rostral papillae present; canthus rostralis concave; (4) upper eyelid having small, low rounded tubercles, about 70 % IOD in males, 50 % in females; cranial crests absent; (5) dentigerous processes of vomers absent; (6) males with a subgular vocal sac and vocal slits; (7) Finger I slightly shorter than Finger II; discs on fingers broadly expanded, elliptical (Fig. 12 C ); (8) fingers having lateral fringes; (9) ulnar tubercles absent; (10) heel and tarsus lacking conical tubercles, only low rounded tubercles present; (11) inner metatarsal tubercle elliptical, elevated, about 3 times the size of round outer metatarsal tubercle; supernumerary tubercles low; (12) toes with lateral fringes; basal webbing on feet; Toe V longer than Toe III (disc on Toe III slightly surpasses distal edge of the penultimate subarticular tubercle on Toe IV, disc on Toe V clearly surpasses the distal edge of the distal subarticular tubercle on Toe IV) (Fig. 12 D ); (13) in life, dorsum dark brown to cinnamon brown, with or without dark blotches; flanks same color as dorsum; head having dark supratympanic fold, pale interorbital bar occasionally present; groins, axillae and posterior surface of thighs creamy white to dark brown with or without yellow mottling; throat cream, creamy yellow or yellow with or without dark brown reticulations; belly creamy white or creamy yellow with dark dots, ventral surfaces of thighs yellowish pink or yellow with dark dots; iris gold with thin black reticulations, and a broad horizontal reddish brown streak (Fig. 11 A – D ); (14) average SVL in adult males: 19.6 ± 0.3 mm (19.3–20.1 mm; n = 4); in females: 30.6 ± 2.4 mm (28.9–32.3 mm; n = 2).

Comparisons.

Pristimantis yonke sp. nov. is closely related, and also similar in appearance, to P. morlaco Sánchez-Nivicela, Toral-Contreras and Urgiles 2022 , however, the new species can be differentiated by having an acuminate snout from dorsal view (vs subacuminate), inclined posteroventrally from profile (vs acuminate), palmar tubercle oval (vs “ U ” shaped), lacking dentigerous processes of vomers (vs present, oblique) and males being smaller with a SVL of 19.3–20.1 mm (vs 24.1–26.6 mm). The new species shares with members of the P. lacrimosus group ( Duellman and Lehr 2009; Rivera-Correa and Daza 2020; Carrión-Olmedo and Ron 2021; Castillo-Urbina et al. 2023) and members of the P. colodactylus subgroup ( Székely et al. 2016) the dorsoventrally compressed body and the flat, broad, pointed head. From members of the P. lacrimosus group, Pristimantis yonke sp. nov. can be easily distinguished by having a dorsum predominantly brown (vs olive green, green, yellow, gold or orange in P. achupalla , P. acuminatus , P. bromeliaceus , P. ecuadoriensis , P. enigmaticus , P. eremitus , P. galdi , P. jorgevelosai , P. lacrimosus , P. latericius , P. limoncochensis , P. loeslein , P. mendax , P. moro , P. nankints , P. olivaceus , P. omeviridis , P. ornatissimus , P. padiali , P. pardalinus , P. petersi , P. petersioides , P. pseudoacuminatus , P. rhodoplichus , P. romeroae , P. royi , P. schultei , P. tantanti , P. tayrona , P. urani , P. waoranii , and P. zorro ). Only P. amaguanae , P. aureolineatus , P. mindo , P. nyctophylax , P. pluvialis , P. pulchridormientes , P. subsigillatus and P. zimmermanae have a brown dorsum among their color patterns, but the new species is distinguishable by having a snout protruding in profile (vs acuminate in P. nyctophylax and P. zimmermanae , rounded in P. mindo and P. pluvialis ), having a rostral papillae on the tip of the snout (vs absent in P. aureolineatus , P. mindo , P. nyctophylax , P. pulchridormientes , and P. subsigillatus ), having skin on dorsum finely tuberculated (vs. shagreen in P. amaguanae , P. aureolineatus , and P. pulchridormientes ; smooth in P. mindo , P. pluvialis , P. subsigillatus , and P. zimmermanae ), lacking vomerine teeth (vs present in P. aureolineatus , P. mindo , P. nyctophylax , and P. subsigillatus ), and lacking conical tubercles (vs present on heels in P. amaguanae , P. nyctophylax , and P. subsigillatus ). From members of the P. colodactylus subgroup, P. yonke may be differentiated by the combination of the following features (characters for other species in parenthesis): having an average SVL of 20.7 mm in males and 30.6 mm in adult females (vs 16.9 mm in males and 20.3 in females of P. colodactylus , 20.4 mm in males and 22.5 in females of P. matildae , 16.8 mm in males and 22.1 in females of P. muranunka ), snout acuminate in dorsal view (vs rounded in P. muranunka ), skin on dorsum tuberculate (vs areolate in P. colodactylus ), longitudinal middorsal fold present (vs absent in P. colodactylus and P. muranunka ), tympanic membrane and annulus present (vs absent in P. colodactylus and P. matildae ), conical tubercles on upper eyelid and heels absent (vs present in P. matildae ), larger feet size being about 44 % of the SVL (vs 36 % of SVL in P. colodactylus , 38 % of SVL in P. muranunka , 40 % in P. matildae ), and iris coloration gold (vs bronze in P. colodactylus , reddish bronze in P. matildae and P. muranunka ). Moreover, Pristimantis yonke is genetically related to Pristimantis cf. cajamarcensis ( KU 217845). But it can be distinguished by being smaller, with males reaching up to 20.1 mm of SVL (vs males up 24.1 mm of SVL in P. cf. cajamarcensis ), having dorsum tuberculate (vs shagreen in P. cajamarcensis ), lacking dentigerous processes of vomers (vs present in P. cf. cajamarcensis ), and lacking red or orange blotches on groins and posterior surface of thighs (vs present in Pristimantis cf. cajamarcensis, sensu Lynch 1979 ).

Description of the holotype.

An adult male ( CORBIDI 26399 ). Measurements (in mm): SVL 19, 6.3; TL 10.2; FL 8.6; HL 7.3; HW 7.7; ED 2.6; TD 1.2; IOD 2.6; EW 1.9; IND 1.4; EN 2.4; FeL 9.5. Head wider than long, narrower than body; snout acuminate in dorsal view, protruding in profile, having a rostral papilla on the tip of the snout (Fig. 12 E ); cranial crests absent; nostrils slightly protuberant, directed anterolaterally; canthus rostralis slightly concave in dorsal view, rounded in cross section; loreal region slightly concave; upper eyelid lacking conical tubercles, only small rounded present; tympanic annulus present, visible through the skin, its upper and posterolateral edge concealed by supratympanic fold; tympanic membrane visible; postrictal tubercles absent. Choanae median, ovoid, non-concealed by palatal shelf of maxilla; dentigerous processes of vomers absent; tongue slightly longer than wide, not notched, posterior half free; vocal slits slightly curved, positioned at posterior half of mouth floor in between tongue and margin of jaw; medium sized vocal sac. Dorsal surfaces of body and flanks finely tuberculate; skin on chest and belly areolate, that on throat shagreen, ventral surfaces of limbs shagreen, ventral surfaces of thighs coarsely areolate; discoidal fold present, thoracic fold absent. Ulnar tubercles absent; nuptial pads absent; outer palmar tubercle ovoid low, as large as ovoid thenar tubercle; subarticular tubercles low, rounded; large supernumerary tubercles at base of fingers, distinct; fingers bearing lateral fringes; Finger I shorter than Finger II; discs on fingers expanded and rounded; pads on fingers surrounded by circumferential grooves on all fingers (Fig. 12 C ). Hindlimbs slender; dorsal surfaces of hindlimbs finely tuberculate; posterior surfaces of thighs smooth, ventral surfaces of thighs coarsely areolate; heel bearing low rounded tubercle; outer and inner edge of tarsus lacking tubercles; inner metatarsal tubercle elliptical, elevated, 1.5 × the size of oval outer metatarsal tubercle; plantar surface with small, low and rounded supernumerary tubercles; subarticular tubercles prominent, rounded; toes bearing lateral fringes; basal webbing between toes III and IV, and IV and V; discs on toes slightly smaller than those on fingers, expanded and rounded; all toes having pads surrounded by circumferential grooves; relative lengths of toes: I <II <III <V <IV; Toe V longer than Toe III (disc on Toe III reaches the distal edge of penultimate subarticular tubercle on Toe IV, disc on Toe V barely reaches the distal edge of distal subarticular tubercle on Toe IV); (Fig. 12 D ).

Coloration of holotype in life. Based on photographs taken in the field. Dorsal surfaces of body and flanks cinnamon brown, two dark brown dorsal stripes that start at dorsal surface of the head, one of them going beyond the level of groins, the other is discontinuous at the level of the groins; supratympanic stripe chocolate brown, canthal area cinnamon brown with irregular pale brown blotches, upper eyelids dark brown; groins and anterior surface of thighs cream; posterior surfaces of thighs, shanks and tarsus cream, some dark brown flecks present on posterior surface of thighs; venter creamy yellow covered by dark spots; chest and throat yellow, both suffused with brown reticulation; ventral surfaces of thighs pinkish yellow with dark spots, shanks and tarsus light yellow; plantar and palmar surfaces light yellow with dense dark brown flecks; iris gold with thick black reticulations and a broad transversal bronze streak (Fig. 11 A ‒ D ).

Coloration of holotype in preservative. Dorsal surfaces of body and flanks grayish yellow with two dark dorsal stripes that start at the level of the orbits, extending beyond the level of groins; supratympanic stripe gray; groins, anterior, and posterior surfaces of thighs, shanks and tarsus cream; venter, belly and throat creamy yellow suffused with dark flecks; ventral surfaces of limbs creamy yellow; ventral surfaces of fingers and toes gray (Fig. 12 A ‒ E ).

Variation. Females CORBIDI 26398 and CORBIDI 26929 have a more tubercled dorsal skin, with higher tubercles than rest of the type series. Tympanic annulus is prominent in females CORBIDI 26398 , 26929, less visible in males CORBIDI 26399 , 26402, 26413‒14. Supratympanic fold is barely pigmented in female CORBIDI 26929 . Middorsal fold is barely visible in male CORBIDI 26402 . Variation in measurements is given in table 1 and color variation is shown in Fig. 13 .

Distribution, natural history and conservation status.

This species is known from two localities on the western slopes of the Cordillera de Huancabamba: Laguna Negra trail and Bosque de Ramos, which are 28.8 km (airline) apart, at 2949 and 3000 m a. s. l. respectively (Fig. 1 ). All individuals were found in primary montane forests where arboreal vegetation consists of Myrcianthes sp. and Podocarpus sp. , both trees that reach up to 15 m high. Tree trunks are usually covered with lichens, mosses, and some epiphytic bromeliads. Also, we observed scattered bushes and small clearings inside the forest (Fig. 7 C, D ). The soil is wet, muddy in some sections and partially covered by leaf litter. All individuals were found at night, inside bromeliads (1–3 m from the ground). Bromeliads where we found CORBIDI 26398 -99, 26403, 26413-14 were close to a rocky stream, whereas CORBIDI 26929 was caught inside a bromeliad in the middle of the forest, without water bodies nearby. Our collections were made during the dry season, and no calling activity was recorded. In addition, we observed P. rhodoplichus in sympatry with P. yonke sp. nov. Based on the extension of our night walks, the sum of the area of occupation in the two localities where we found P. yonke sp. nov. is less than 10 km 2. However, the surroundings remain unexplored, so we do not have accurate information about its geographic distribution, nor about its population size. We suggest that further surveys in the area are needed to collect additional data and assign the species to some threat category. Therefore, following the IUCN guidelines (IUCN, 2019), we suggest this species should be included in the Data Deficient (DD) category of the IUCN Red List.

Remarks.

Despite its similar appearance (presence of rostral papillae, acuminate snout profile, distinct tympanic membrane, moderately long limbs, Finger I shorter than Finger II, and expanded digital discs), we do not allocate Pristimantis yonke sp. nov. into the putative P. lacrimosus group sensu Arteaga-Navarro et al. (2013) and Carrión-Olmedo and Ron (2021) because of phylogenetic evidence.

Etymology.

The specific epithet is a noun in apposition. It refers to the traditional drink “ yonke ” or “ yonque ”, which is obtained from sugar cane distillation and only drunk by local people from northwestern Andes to keep themselves warm during their journeys through the cold highlands, which may include night camps to get to other villages.

Figures

Figure 1. Map showing localities of distribution of the Pristimantis species described herein. White square = P. chinguelas type locality, red triangle = P. nunezcortezi type locality, blue star = P. yonke type locality and blue romboid = second known locality for P. yonke.

Figure 7. Habitat in the localities inhabited by the new species described herein. A. Habitat in the type locality of P. chinguelas sp. nov.; B. Stream where we found P. nunezcortezi sp. nov.; C. Primary forest in the type locality of P. yonke sp. nov.; D. Panoramic view of the primary forest in the type locality of P. yonke sp. nov.

Figure 11. Dorsolateral (A), ventral (B), lateral (C), and dorsal (D) view of the holotype (CORBIDI 26399) of Pristimantis yonke sp. nov. in life.

Figure 12. Holotype of Pristimantis yonke sp. nov. in preservative (CORBIDI 26399). A. Dorsal; B. Ventral view of the body; C. Ventral view of the right hand; D. Ventral view of the right foot; E. Lateral view of the head. Scale bars: 5 mm.

Figure 13. Coloration in life of Pristimantis yonke paratypes. A, B. CORBIDI 26398, adult female; C, D. CORBIDI 26929, adult female; E, F. CORBIDI 26414, adult male; G, H. CORBIDI 26402, adult male.