Systematics of minute strabomantid frogs allocated to the genus Noblella (Amphibia: Anura) with description of a new genus, seven new species, and insights into historical biogeography Author Ortega, Jhael A. Museo de Zoología, Escuela de Biología, Pontificia Universidad Católica del Ecuador, Avenida 12 de Octubre 1076 y Roca, Apartado 17 - 01 - 2184, Quito, Ecuador Author Cisneros-Heredia, Diego F. Universidad San Francisco de Quito USFQ, Colegio de Ciencias Biológicas y Ambientales, Instituto de Biodiversidad Tropical IBIOTROP, Museo de Zoología / Laboratorio de Zoología Terrestre, Quito, Ecuador & Instituto Nacional de Biodiversidad INABIO, División de Herpetología, Quito, Ecuador Author Camper, Jeffrey D. Department of Biology, Francis Marion University, Florence, SC 29506, USA Author Romero-Carvajal, Andrés Museo de Zoología, Escuela de Biología, Pontificia Universidad Católica del Ecuador, Avenida 12 de Octubre 1076 y Roca, Apartado 17 - 01 - 2184, Quito, Ecuador Author Negrete, Leonardo Museo de Zoología, Escuela de Biología, Pontificia Universidad Católica del Ecuador, Avenida 12 de Octubre 1076 y Roca, Apartado 17 - 01 - 2184, Quito, Ecuador Author Ron, Santiago R. Museo de Zoología, Escuela de Biología, Pontificia Universidad Católica del Ecuador, Avenida 12 de Octubre 1076 y Roca, Apartado 17 - 01 - 2184, Quito, Ecuador santiago.r.ron@gmail.com text Zoological Journal of the Linnean Society 2025 2025-01-13 203 1 1 60 https://doi.org/10.1093/zoolinnean/zlae162 journal article 10.1093/zoolinnean/zlae162 0024-4082 14832689 7-01-2184 Phyllonastes sardinayacu sp.nov. LSID: urn:lsid:zoobank.org:act: B12C9470-F32C-4CEA-9A1B- E2DE6D0CDBA3 Holotype ( Figs 22C , 23B , 24 , 25 ): QCAZ 58822 (field no. SC-PUCE 49151) adult female from Ecuador , Morona Santiago Province , Canton Morona , Sinaí Parish , Sangay National Park , Sardinayacu , trail to El Enmascarado Lagoon from refuge 3 ( 2.0500°S , 78.2196°W ), 1798 m a.s.l. Collected by Javier Pinto , David Velalcázar , and Darwin Núñez on 23 January 2015 . Paratype (N = 1; Fig. 24 ): Same locality, collectors, and date as holotype, QCAZ 58821 adult female . Proposed standard English name: Sardinayacu leaflitter frog. Proposed standard Spanish name: Cutín de Hojarasca de Sardinayacu. Definition ( Figs 22C , 23B , 24 , 25 ; Tables 2 and 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 smooth, discoidal fold present; (2) tympanic membrane and tympanic annulus present, supratympanic fold absent, postrictal tubercle absent; (3) snout rounded to truncate in dorsal view and rounded in 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 lacking circumferential grooves; (9) distal phalanges blunt to 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 subconical tubercle; (12) inner metatarsal tubercle elongated in ventral view and rounded in lateral view, bigger than rounded outer metatarsal tubercle; (13) toes slightly expanded distally, with acuminate toe tips and lacking papillae, supernumerary tubercles present, narrow lateral fringes on toes, toe webbing absent, all toes bearing ill-defined pads and circumferential grooves, toe V shorter than toe III; (14) in life, brown dorsum, with two dark brown sacral lateral patches with light brown border, triangular cloacal blotch dark brown with light brown border, ventral surfaces dark brown with scattered small white spots, facial mask dark brown extending from tip of snout to groins, groins orange– brown; and (15) SVL in adult males unknown, SVL in adult females 14.21 mm ( N = 2) ( Table 4 ). Figure 22. Skulls of Phyllonastes species. A , Phyllonastes myrmecoides QCAZ 53583. B, Phyllonastes plateadensis QCAZ 65015 . C, Phyllonastes sardinayacu , QCAZ 58821. Figure 23. Skeletons of Phyllonastes species. A , Phyllonastes plateadensis QCAZ 65015 , SVL = 15.70 mm. B, Phyllonastes sardinayacu QCAZ 58821, SVL = 14.32 mm. C, Phyllonastes personinus QCAZ 58818, SVL = 16.91 mm. Diagnosis: Phyllonastes sardinayacu resembles its closest related species, P. macuma , P. lochites , and P. myrmecoides , by having a tympanic annulus, tympanic membrane, fingers not expanded distally, and acuminate toe tips. It differs from P. macuma by having subconical inner tarsal tubercle (rounded in P. macuma ) and a mask extending to groins (mask extending to anterior half of flank in P. macuma ), and by the absence of papillae in toe tips (present in P. macuma ). Phyllonastes sardinayacu also differs from P. lochites and P. myrmecoides by having three phalanges in finger IV (two phalanges in finger IV in P. lochites and P. myrmecoides ). It differs further from P. lochites by having a rounded snout in lateral view (subtruncate in P. lochites ) and from P. myrmecoides by the absence of papillae in fingertips and toe tips (both present in P. myrmecoides ) and by the presence of supernumerary plantar tubercles (absent in P. myrmecoides ). For a comparison with other Phyllonastes species that are more phylogenetically distant, see Tables 2 and 3 . Figure 24. Live and preserved specimens of Phyllonastes sardinayacu . Lateral, dorsal, and ventral views of: A, B, holotype QCAZ 58822 , adult female, SVL = 14.10 mm; and C, paratype QCAZ 58821, adult female, SVL = 14.32 mm. A, in life. B, C, in preservative. Scale bars are given for preserved adults. Description of the holotype ( Figs 24 , 25 ): Adult female ( QCAZ 58822 ). Measurements (in millimetres): SVL, 14.10; tibia length, 6.53; foot length, 6.39; head length, 3.77; head width, 4.33; eye diameter, 1.66; tympanum diameter, 0.78; interorbital distance, 1.87; upper eyelid width, 1.26; internarial distance, 1.68; eye–nostril distance, 0.92. Head wider than long, head wider than body; canthus rostralis slightly convex in lateral view; loreal region straight in dorsal view; cranial crests absent; upper eyelid lacking tubercles. Tympanic annulus beneath skin; tympanic membrane present; supratympanic fold and postrictal tubercles absent. Vomerine teeth absent, vocal slits and nuptial pads absent. Snout short and round in dorsal and lateral views, without rostral papilla. Skin on dorsum and flanks finely shagreen; dorsolateral folds absent; ventral surfaces smooth; skin on cloacal region areolate; discoidal fold present. Ulnar tubercles absent, palmar tubercles low, outer palmar tubercle rounded, with a small extension pointing towards the centre of the palm, larger than elongate thenar tubercle; subarticular tubercles visible only at base of fingers, round in ventral and lateral view; supernumerary tubercles present; narrow lateral dermal fringes on fingers; discs narrow, bearing round and inconspicuous pads; fingers not expanded distally, tip of fingers subacuminate; circumferential grooves not visible; relative length of fingers is I <IV <II <III; phalangeal formula of hand is 2-2-3-3. Hindlimbs robust; heels and knees without tubercles; tarsal folds (inner and outer) absent, outer tarsal tubercles absent; inner tarsal tubercle present, small, subconical, and prominent; inner metatarsal tubercle small (ill defined in preservative), elongated in ventral view and rounded in lateral view; round outer metatarsal tubercle well defined and prominent; plantar surface with supernumerary tubercles; round subarticular tubercles, ill defined, visible only at base of toes; toes with narrow lateral dermal fringes; webbing between toes absent; discs on toes ill defined (ill defined in preservative), slightly expanded, with acuminate tip (specially on toe III), papilla on tip absent; ill-defined pads and circumferential grooves; relative lengths of toes I <II <V <III <IV; toe III longer than toe V. Figure 25. Palmar (A) and plantar (B) surfaces of Phyllonastes sardinayacu . Photographs of left hand and left foot of the holotype QCAZ 58822 . Colour of holotype in life (based on digital photographs) ( Fig. 24 ): Brown dorsum, slightly darker anteriorly, with two lateral, dark brown circular spots with a light brown border at sacrum level. Triangular cloacal blotch dark brown with light brown border. Ventral surfaces dark brown with scattered small white spots. Ventral surfaces of thighs and lower abdomen with irregular orange–brown blotches. Facial mask dark brown extending from tip of snout to groins and delineated dorsally by a light line. Flanks brown, with dark brown band along anterior half, connecting anteriorly with dark brown face mask. Groins brownish orange. Lips bearing small and white spots. Forearms, elbows, and knees with dark brown blotches delineated by a paler line. Colour of holotype in preservative ( Fig. 24 ): Dorsal surfaces brown. Head slightly darker than dorsum. Sacral lateral patches dark brown, with slightly lighter border. Cloacal triangle, spots on knees, and elbows dark brown with lighter margins. Ventral surfaces brown, becoming darker towards the throat. Scattered cream spots on ventral surfaces, more marked posteriorly and on hindlimbs. Variation ( Fig. 24 ): This section refers to preserved individuals, unless otherwise mentioned. The only paratype , QCAZ 58821 (adult female), differs from the holotype in having a truncate snout in dorsal view and darker coloration. Morphometric variation is detailed in Table 4 . Distribution, natural history, and conservation status ( Fig. 3 ): Phyllonastes sardinayacu is known from a single locality in Sangay National Park, near Sardinayacu, 1700 m a.s.l. Individuals were collected in Eastern Montane Forest at night (22:00–23:00 h) on leaf litter in primary and terra firme forest. Because of the lack of information on population size and geographical range, we suggest assigning P. sardinayacu to the Data Deficient IUCN Red List Category (based on IUCN Standards and Petitions Committee 2023 ). Etymology: The specific name sardinayacu is a toponym used in apposition and it refers to a river at the species type locality. Sardinayacu is a compound word of Kichua origin, ‘sardina’ meaning sardine and ‘yaku’ meaning water.