A member of the genus Hypsiboas characterized by: (1) mean SVL 35.40 mm in males (range 32.65–37.74; n = 19), 51.89 mm in females (range 47.16–54.84; n = 5); (2) basal webbing on fingers; (3) calcar small and conical; (4) dorsal coloration varying from cream to grayish brown, pinkish white or brown, with dark marks in some individuals (e.g., broad transversal bands); (5) middorsal brown stripe often present; (6) flanks pale cream or gray (in life, blue in large females and light blue or white in males) with dark brown vertical bars; (7) hidden surfaces of thighs pale cream or gray (in life, blue in large females and light blue or white in males) with dark brown transversal bars; (8) ventral surfaces of thighs creamy white, yellowish white or brown; (9) venter creamy white or yellowish white; (10) webbing on feet; (11) in life, iris creamy silver or bronze with upper red to reddish brown band; (12) prepollical spine present in males.

Hypsiboas fasciatus is most similar to Hypsiboas almendarizae sp. n. and Hypsiboas calcaratus. Hypsiboas calcaratus can be distinguished from Hypsiboas fasciatus by the shape of the calcar (large and triangular in Hypsiboas calcaratus vs. small and conical in Hypsiboas fasciatus), structure of the advertisement calls (Fig. 12A–B and 12E–F), and by the yellow to orange color of the upper band in the iris (red to reddish brown in Hypsiboas fasciatus). Hypsiboas almendarizae sp. n. differs from Hypsiboas fasciatus in having narrower transversal dark bars on the flanks and thighs (mean width of bars on thighs = 5.05% of femur length, SD = 0.61, in Hypsiboas almendarizae sp. n.vs. 8.58%, SD = 1.56, in Hypsiboas fasciatus). The color of the upper band in the iris also distinguishes both species (red to reddish brown in Hypsiboas fasciatus vs. yellow to orange in Hypsiboas almendarizae sp. n.; Fig. 14A–B).

Hypsiboas fasciatus differs from Hypsiboas maculateralis sp. n. in advertisement call (Figs 12A–B and 13A–B) and in the presence of transversal bars on the flanks and hidden surfaces of the thighs (dark blotches instead of bars in Hypsiboas maculateralis sp. n.) Hypsiboas fasciatus can easily be distinguished from Hypsiboas alfaroi sp. n. and Hypsiboas tetete sp. n. by the presence of a calcar (instead of a small tubercle on the heel) and by the absence of dark flecks on the gular region and chest (present in Hypsiboas alfaroi sp. n. and Hypsiboas tetete sp. n.) Morphological characters useful to differentiate Hypsiboas fasciatus from other species are shown in Table 6.

Variation in dorsal and ventral coloration of preserved specimens is shown in Figure 5. Background dorsal coloration varies from cream (e.g., QCAZ 41488, 48584) to pale grayish brown (e.g., QCAZ 18271), grayish brown (e.g., QCAZ 27258), pinkish white (e.g., QCAZ 41575), pale brown (e.g., QCAZ 23148) or brown (e.g., QCAZ 26497). Irregular dorsal marks can be present in diverse patterns. A dark middorsal stripe extends from the tip of the snout to the mid-sacrum (e.g., QCAZ 26497) or to the vent (QCAZ 23144). In a few individuals, the middorsal line is absent (QCAZ 17123, 31040). In some individuals (e.g., QCAZ 41575) broad transversal bands are present on the dorsum; narrower brown transversal bars are present on the dorsal surfaces of the limbs (one or two on the upper arm and forearm and three to five on the thigh, shank, and foot). In some individuals, scattered minute brown dots may be present on dorsum (e.g., QCAZ 48584). The coloration of flanks and hidden surfaces of thighs vary from pale cream to creamy white, brown or gray, with dark brown vertical bars (4 to 12 on each flank and 6 to 12 on each thigh). The area with vertical bars extends from the groin to the axilla (e.g., QCAZ 41575) or to the mid flank (e.g., QCAZ 41576, 18271). In some individuals, similar transversal bars can be present on the hidden surfaces of the shanks, ventral surfaces of the forelimbs, and dorsal surfaces of the feet (e.g., QCAZ 41575). The shape of the calcar is small and conical and shows little variation among individuals.

Ventral areas vary from creamy white (e.g., QCAZ 48584) to yellowish white (e.g., QCAZ 41576, 41488). A narrow to wide brown stripe can be present on the outer edge of the hands, forearms, thighs, feet, and tarsal folds (e.g., QCAZ 48584, 41576, 41575, 26497). In some specimens, scattered minute pale brown blotches can be present on the lips (e.g., QCAZ 26497, 24866). Coloration of webbing and discs vary from yellowish white to brown or gray. Bones are white.

In the examined series of adults, the largest male has a SVL of 37.74 mm, and the largest female 54.84 mm; mean male SVL = 35.40 mm (n = 19; SD = 1.65), mean female SVL = 51.89 mm (n = 5; SD = 3.18). Females are significantly larger than males (t = -16.24, df = 22, P < 0.001). Inter-population variation in size and other morphometric variables is shown in Tables 1 and 2.

(based on digital photographs; Figs 4A and 8A). Dorsal surfaces vary from pale yellowish tan (e.g., QCAZ 47070) to brown (e.g., QCAZ 48611) with a middorsal dark brown line (e.g., QCAZ 48585) and scattered minute black dots (e.g., QCAZ 47051); some individuals have diffuse broad pale brown transversal bands on the dorsum (e.g., QCAZ 48583); pale brown transversal bars are present on the dorsal surfaces of the limbs; flanks and hidden surfaces of thighs are white, light blue or blue with dark brown vertical bars (e.g., QCAZ 47070, 47051); in some specimens, dark brown vertical bars are present on the hidden surfaces of the shanks, ventral surfaces of the upper arms and dorsal surfaces of the feet (e.g., QCAZ 48671); venter creamy white, sometimes with yellowish white on its posterior half (e.g., QCAZ 48670); ventral surfaces of hindlimbs and forelimbs translucent pinkish white (e.g., QCAZ 47051) or brown (e.g., QCAZ 48611); in some specimens, ventral surfaces of the thighs creamy white (e.g., QCAZ 47070); discs and webbing pale yellowish tan (e.g., QCAZ 48584) or brown (e.g., QCAZ 48611); a narrow to wide brown stripe is present on the outer edge of the hands, forearms, thighs, feet, and tarsal folds (e.g., QCAZ 48611); iris creamy silver (e.g., QCAZ 48584) or bronze (e.g., QCAZ 48611) with upper red to reddish brown band (e.g., QCAZ 48628); bones vary from green (e.g., QCAZ 48671) to white (e.g., QCAZ 48628).

We recorded calls of one male at Bombuscaro (Provincia Zamora Chinchipe) on 9 June 2010, three males at La Pradera (Provincia Morona Santiago) on 10 June 2010, and one male at Comunidad San Luis (Provincia Morona Santiago) on 13 June 2010. The advertisement call consists of three to five quack notes (Fig. 12A–B). Mean call duration is 0.52 s (SD = 0.24) and mean rise time is 0.24 s (SD = 0.06). Sound frequency increases from the beginning to the end of the note; mean dominant frequency is 1855.81 Hz (SD = 148.08) and mean fundamental frequency is 884.89 Hz (SD = 105.52). Other call parameters are listed in Table 7.

Hypsiboas fasciatus has been recorded in the Ecuadorian and Peruvian Amazon basin (Morona Santiago and Zamora-Chinchipe provinces in Ecuador and Región Amazonas in Peru) (Fig. 15). Localities with known elevation range from 730 to 1593 m above sea level. The elevation at Romerillos Alto (1593 m) is the highest known locality for Hypsiboas fasciatus, while Tink (730 m) is the lowest.

Specimens from Comunidad San Luis, La Pradera, La Pituca, Limón, Miazi Alto, Nueva Principal, and Tiink were found in primary and secondary forest, perching on vegetation 30 to 200 cm above the ground, in flooded areas, ponds, swamps, and near streams. Individuals in Zamora were found in grassy swamps roosting in shrubs between 30 and 110 cm above ground.

Vegetation types for Ecuadorian localities are: (1) Amazonian Evergreen Foothill Forest, characterized by a mixture of Amazonian and Andean vegetation with a canopy of 30 m, (2) Evergreen Lower Montane Forest of the Amazonian Range, characterized by trees reaching 20–30 m of height and abundant epiphytes and hemiepiphytes, with Dictyocaryum lamarckianum (Arecaceae) as dominant species, and (3) Evergreen Lower Montane Forest of the East of the Southern Andes, characterized by abundant epiphytes, trees reaching 30 m of height with Podocarpus as dominant species.

Its distribution polygon has 8,572 km² of which 2,198 km² (25.6%) have been degraded by human activities, especially agriculture and cattle raising (estimated from Ministerio de Ambiente del Ecuador 2013). Because habitat degradation is increasing, we assign Hypsiboas fasciatus to the Red List category Near Threatened. Its distribution polygon overlaps with three protected areas: Parque Nacional Podocarpus, Reserva Biológica el Quimi and Refugio de Vida Silvestre el Zarza. Its distribution polygon does not overlap with the polygon reported in the Red List assessment for this species by Icochea et al. (2004). The new range represents < 1% of the range reported in the IUCN Red List.