Phyllonastes plateadensis, Ortega & Cisneros-Heredia & Camper & Romero-Carvajal & Negrete & Ron, 2025

Phyllonastes plateadensis sp.nov.

LSID: urn:lsid:zoobank.org:act:73A895D9-46FE-4DA0-AF85-18FF11503A30

Holotype ( Figs 20 View Figure 20 , 21 View Figure 21 , 22B View Figure 22 , 23A View Figure 23 ): QCAZ 65015 View Materials (field no. SC-PUCE56489) adultfemalefromEcuador, ZamoraChinchipe Province , Canton Palanda , La Canela Parish , Cerro Plateado Biological Reserve, surroundings of Camp 3 , trail from Mirador to Camp 3 (4.6027°S, 78.8310°W), 2055 m a.s.l. Collected by Diego Almeida, Kunam Nusirquia, Fernando Ayala, Javier Pinto, Alex Áchig, and Malki Bustos on 23 September 2016. GoogleMaps

Paratypes (N = 1; Fig. 20 View Figure 20 ): QCAZ 65016 View Materials juvenile from Ecuador, Zamora Chinchipe Province, Canton Palanda , La Canela Parish , Biological Reserve Cerro Plateado , surroundings of Camp 3 , trail of the upper section of Río Negro (4.5993°S, 78.8350°W) 1980 m a.s.l. Collected by Diego Almeida, Kunam Nusirquia, Fernando Ayala, Javier Pinto, Alex Áchig and Malki Bustos on 26 September 2016 GoogleMaps .

Proposed standard English name: Cerro Plateado leaflitter frog.

Proposed standard Spanish name: Cutín de Hojarasca de Cerro Plateado.

Definition ( Figs 20 View Figure 20 , 21 View Figure 21 , 22B View Figure 22 , 23A View Figure 23 ; Tables 2 View Table 2 and 3 View Table 3 ): We assign the new species to the genus Phyllonastes based on its phylogenetic relationships. The new species is characterized by: (1) skin on dorsum and flanks finely shagreen, dorsolateral folds absent, ventral surfaces weakly areolate, discoidal fold present; (2) tympanic membrane not differentiated, tympanic annulus present but inconspicuous, supratympanic fold and postrictal tubercles absent; (3) snout broadly rounded in dorsal view and rounded and lateral view; (4) upper eyelid without tubercles, cranial crests absent; (5) vomerine teeth absent; (6) vocal slits and nuptial pads unknown; (7) fingers not expanded distally, finger tips subacuminate, without papillae, finger I shorter than finger II, supernumerary tubercles present; (8) fingers bearing narrow lateral fringes, ill-defined pads and circumferential grooves; (9) distal phalanges blunt or T-shaped, phalangeal formula of hand 2-2-3-3; (10) ulnar tubercles absent; (11) knees and heels without tubercles, outer edge of tarsus without tubercles, inner edge of tarsus bearing one rounded tubercle; (12) inner metatarsal tubercle small, rounded in ventral view and very low in lateral view, smaller than rounded outer metatarsal tubercle; (13) toes slightly expanded distally, with acuminate toe tips and lacking papillae, supernumerary tubercles ill defined, narrow lateral fringes on toes, toe basal webbing absent, all toes bearing ill-defined circumferential grooves, toe V shorter than Toe III; (14) in life, dorsal surfaces light brown with scattered white dots; circular dark brown sacral lateral marks delineated by a paler line, cloacal region cream surrounded by a dark brown stripe, facial mask dark brown extending from tip of snout to groins, flanks brown, ventral surfaces brown with white spots; and (15) SVL in adult males unknown, adult female 19.35 mm (N = 1) ( Table 4 View Table 4 ).

Diagnosis: Phyllonastes plateadensis resembles its closest species, P. dicaprioi and P. heyeri , by having the snout rounded in lateral view, a tympanic annulus, supernumerary palmar tubercles, three phalanges in finger IV, and by the absence of papillae in fingers and toes. It differs from both by lacking a supratympanic fold (present in P. dicaprioi and P. heyeri ) and by having a broadly rounded snout in dorsal view (snout rounded in P. dicaprioi and subacuminate in P. heyeri ), rounded inner tarsal tubercle (inner tarsal tubercle conical in P. dicaprioi and P. heyeri ), and circumferential grooves of fingers (fingers without circumferential grooves in P. dicaprioi and P. heyeri ). For a comparison with other Phyllonastes species that are more phylogenetically distant, see Tables 2 View Table 2 and 3 View Table 3 .

Description of the holotype ( Figs 20 View Figure 20 , 21 View Figure 21 , 22B View Figure 22 , 23A View Figure 23 ): Adult female (QCAZ 65015). Measurements (in millimetres): SVL, 19.35; tibia length, 7.79; foot length, 8.66; head length, 5.74; head width, 7.05; eye diameter, 2.14; tympanum diameter, 1.18; interorbital distance, 1.93; upper eyelid width, 1.31; internarial distance, 1.79; eye–nostril distance, 1.51.

Head wider than long, head wider than body; canthus rostralis straight in lateral view; loreal region slightly concave in dorsal view; cranial crests absent; upper eyelid lacking tubercles. Tympanic annulus inconspicuous but visible beneath skin; tympanic membrane not differentiated; supratympanic fold and postrictal tubercles absent. Vomerine teeth absent, vocal slits and nuptial pads absent. Snout broadly rounded in dorsal view and rounded in lateral view, without rostral papilla.

Skin on dorsum and flanks finely shagreen; dorsolateral folds absent; ventral surfaces weakly areolate; skin in cloacal region areolate; discoidal fold present. Ulnar tubercles absent; palmar tubercles low, outer palmar tubercle circular, larger than elongate thenar tubercle; subarticular tubercles ill defined, more conspicuous at the base of fingers, round in ventral and lateral view; three supernumerary tubercles present at the base of fingers; narrow lateral dermal fringes on fingers, fingers not expanded distally; discs narrow, bearing round and inconspicuous pads with an ill-defined circumferential groove; fingertips subacuminate lacking papillae; relative length of fingers is I <IV <II <III; phalangeal formula of hand is 2-2-3-3.

Hindlimbs robust; knees and heels without tubercles; tarsal folds (inner and outer) absent, outer tarsal tubercle absent; inner tarsal tubercle present, small and round; inner metatarsal tubercle small (ill defined in preservative), rounded in ventral and lateral views; well-defined and round outer metatarsal tubercle, bigger than the inner one; plantar surface with ill-defined supernumerary tubercles; round subarticular tubercles ill defined; toes with narrow dermal lateral fringes; webbing between toes absent; toes slightly expanded distally, discs on toes ill defined (ill defined in preservative), narrow with acuminated tip, papilla on tip not visible; ill-defined circumferential grooves; relative lengths of toes I <II <V <III <IV; toe III longer than toe V (toe III reaches the distal border of the second subarticular tubercle of toe IV; toe V almost reaches the proximal border of the second tubercle of toe IV).

Colour of holotype in life (based on digital photographs) ( Fig. 20 View Figure 20 ): Dorsal surfaces light brown, with some scattered white dots; circular dark brown sacral lateral patches well defined, delineated by a paler line. Cloacal region cream, surrounded by a dark brown stripe. Facial mask dark brown extending from tip of snout to groins and delineated along its dorsal edge by a light orange line, more conspicuous rostrally. Flanks light brown, bearing the dark brown mask extension. Lips bearing small and white spots. Forearms with two dark brown blotches delineated by a paler line; the proximal blotch is bigger than the distal one. Heels bearing a dark brown blotch with a paler border; tarsus bearing dark brown blotches surrounded by a paler border dorsally. Ventral surfaces brown with white spots that become bigger towards the cloacal region.

Colour of holotype in preservative ( Fig. 20 View Figure 20 ): Dorsal surfaces light brown, with dark brown sacral lateral circular blotches surrounded by a cream edge. Facial mask dark brown extending from tip of snout to near groins, limited on its upper side by a thin cream-coloured line. Ventral surfaces light brown, bearing ill-defined white spots that become bigger posteriorly. Posterior surfaces of thighs light brown. Cloacal region white, surrounded by a dark brown stripe, and bearing small and dispersed dark brown flecks. Forearms dorsally with two dark brown blotches delineated by a paler line; the proximal blotch is bigger and better defined than the distal one.

Variation ( Fig. 20 View Figure 20 ): This section refers to living individuals unless otherwise mentioned. Juvenile QCAZ 65016 has more and better-defined dark brown circular marks on the tarsus. Facial mask can be ill defined and weakly contrasting, as in QCAZ 65016. Juvenile ventral coloration is darker than in adult, with a darker throat and white spots restricted to belly and thighs, as in QCAZ 65016. Tip of toes may be subacuminate, as in QCAZ 65016. Juvenile presents more inconspicuous palmar and plantar tubercles, round and lower than those in adults in lateral view. Morphometric variation is detailed in Table 4 View Table 4 .

Distribution, natural history, and conservation status ( Fig. 3 View Figure 3 ): Phyllonastes plateadensis is known from the surroundings of the Biological Reserve Cerro Plateado from 1980 to 2093 m a.s.l. Cerro Plateado is in Cordillera del Cóndor, a sub-Andean cordillera separate from the main Andean chain. Individuals were collected in primary Eastern Montane Forest, at night (22:00– 23:00 h), on mossy soils and on leaf litter, at the edge of creeks next to water pools. Cerro Plateado is a sandstone formation. Forests in sandstone at Cordillera del Cóndor are characterized by dwarf trees with a canopy of ~ 5 m (Schulenberg and Awbrey 1997). Because of the lack of information related to population size and geographical range, we assign P. plateadensis to the Data Deficient IUCN Red List Category (based on IUCN Standards and Petitions Committee 2023).

Etymology: The specific epithet plateadensis is a toponym noun in apposition and it refers to the type locality.