Bioacoustics of Hyloscirtus dispersus

Advertisement call. We analyzed 60 calls from 14 individuals. QCAZ 52006 from Caserío Machay, Provincia Tungurahua , 19 September 2011 , recorded by SRR. QCAZ 59820 from Comunidad Zarentza, Llanganates National Park, Provincia Pastaza , 23 February 2015 , air temperature 18 ° C recorded by D. Rivadeneira. QCAZ 63488 from Cocodrilos, Provincia Napo , 23 June 2016 , recorded by SRR. KU 164338 and one unvouchered specimen from 2 km SW of Río Reventador, Provincia Napo , 19 March 1975 , temperature 18 ° C, recorded by W. E. Duellman. USNM 286338 , Río Reventador, Provincia Napo , recorded by R. McDiarmid. USNM 286349 from Baeza – Lago Agrio Road, Provincia Napo , 22 February 1985 , recorded by R. McDiarmid. USNM 284316 from Cascada San Rafael, Provincia Napo , recorded by M. Foster. Two unvouchered specimens from San Rafael, Provincia Napo , recorded by R. McDiarmid. One unvouchered specimen from Sangay National Park, Provincia Morona Santiago , recorded by D. Batallas. Two unvouchered specimens from Río Azuela, Provincia Napo , 23 October 1971 , temperature 18–19 ° C, and one from Cordillera del Dué, Provincia Sucumbíos , recorded by W. Duellman. The advertisement call consists of a single note, repeated in series of 1–8 calls (Fig. 9 E ). Average call duration is 0.11 ± 0.015 s with an average inter-call interval of 0.33 ± 0.044 s . Mean dominant frequency is 2795.41 ± 138.68 Hz. Other call parameters are listed in Table 4 .

Definition. In this section, coloration and characters refer to preserved specimens unless otherwise mentioned. The Definition and Diagnosis are based on 11 adult females and 36 adult males . Hyloscirtus dispersus sp. nov. can be diagnosed by the combination of the following characters: (1) mean SVL 34.1 mm in adult males (range 31.3–38.7; n = 36) and mean SVL 41.1 mm in adult females (range 35.4–45.2; n = 11; Suppl. material 1 : table S 5, Fig. 7 ); (2) white supralabial stripe present or absent; (3) tympanum rounded, inconspicuous to conspicuous in males and conspicuous in females; supratympanic fold present and unpigmented; (4) white ulnar and tarsal folds; (5) subarticular tubercles conspicuous in hands and feet; (6) supernumerary tubercles inconspicuous in feet and conspicuous in hands: (7) calcar tubercle present; (8) pericloacal spots well-defined; (9) all surfaces plain cream with a combination of scattered large or minute black spots and with white spots or flecks varying from ill-defined to large on the dorsum; (10) in life, dorsal surfaces and flanks yellowish green, olive green, dull green, brownish green or greyish green, with barely visible to thick white spots and minute or thick black spots or flecks, scattered throughout the body; venter yellow, gold, whitish, brownish green, grayish green, or dark pinkish; axillar and inguinal regions and ventral surfaces yellow, blueish, greenish, silver, brownish green or dark pinkish; pericloacal spots yellow, white or unpigmented; webbing yellow, yellow orange, whitish or dark pinkish; iris pearl or pinkish with leather reticulations; (11) the advertisement call consist of a single note, with a mean duration of 0.11 ± 0.015 s and a mean dominant frequency of 2795.4 ± 138.68 Hz and a fundamental frequency of 2700.63 ± 195.66 Hz. The call can be repeated in a series of 1 to 8 calls.

Diagnosis. Characters in this section pertain to preserved specimens unless otherwise noticed. Coloration refers to life specimens. The most similar species to Hyloscirtus dispersus sp. nov. living in the Amazon basin are Hyloscirtus albopunctulatus (sympatrically distributed, Fig. 5 ), H. maycu sp. nov. , H. elbakyanae sp. nov. , H. phyllognathus , and H. torrenticola . Hyloscirtus dispersus sp. nov. differs by having a supratympanic fold (absent in H. maycu sp. nov. , H. elbakyanae sp. nov. , H. phyllognathus , and H. torrenticola ), an inconspicuous tarsal fold (thick in H. albopunctulatus , H. phyllognathus , and H. torrenticola ), conspicuous subarticular tubercles in hands and fee (inconspicuous in hands and feet in H. albopunctulatus , Fig. 11 ), conspicuous supernumerary tubercles in hands (inconspicuous in hands and feet in H. albopunctulatus , H. maycu sp. nov. , and H. elbakyanae sp. nov. ), well-defined pericloacal spots (ill-defined or absent in H. maycu sp. nov. and H. elbakyanae sp. nov. ), a calcar tubercle present (absent in all species except for H. phyllognathus ), and an iris pearl or pinkish with leather-colored reticulations (clam shell with black or sand dune reticulations in H. albopunctulatus and a bronze iris in H. torrenticola , Fig. 12 ). The advertisement call of Hyloscirtus dispersus sp. nov. differs by having a call duration of 0.11 ± 0.015 s (shorter in H. albopunctulatus with 0.051 ± 0.005 s and in H. torrenticola with 0.03 ± 0.001 s ), a dominant frequency of 2743.79 ± 48.22 Hz (lower in H. albopunctulatus with 2149.84 ± 137.36 Hz and in H. elbakyanae sp. nov. with 2321.29 ± 127.86 Hz) and a fundamental frequency of 2700.63 ± 195.66 Hz (lower in H. albopunctulatus with 1214.12 ± 184.71 Hz and in H. elbakyanae sp. nov. with 1184.35 ± 30.48 Hz). Hyloscirtus dispersus sp. nov. has an intercall duration of 0.33 ± 0.044 s (shorter in H. phyllognathus with 0.06 s and in H. torrenticola with 0.07 ± 0.007 s ) (Table 4 , Fig. 9 ; Melin 1941 ; Duellman and Altig 1978 ; Rivera-Correa 2016 ). Moreover, all males of H. dispersus sp. nov. have been found calling while perching on vegetation over streams ( n = 14; Pontificia Universidad Católica del Ecuador 2024 ), while all males of H. albopunctulatus were registered calling from under the rocks next to streams ( n = 5; Pontificia Universidad Católica del Ecuador 2024 ). Finally, H. dispersus sp. nov. inhabits elevations between 879 and 1807 m , while Hyloscirtus elbakyanae sp. nov. lives lower between 214 and 622 m and in warmer and wetter environments (Figs 5 , 10 ).

Distribution and natural history. Hyloscirtus dispersus sp. nov. is known from more than 25 localities from northern to southern Ecuador in the eastern Andean slopes, at elevations between 879–1807 m (Fig. 5 ). From the species analyzed in this study, this is the most widespread and its biogeographic regions are Eastern Lower Montane Forest and Eastern Montane Forest ( Ron et al. 2022 ). This species lives in hillside forests, frequently found in secondary forest and artificial open areas. They are nocturnal and associated with streams of running water and ravines. Males call perched on riparian vegetation up to 2.5 m above the ground. It also occurs close to lagoons and small waterfalls. Perching sites include plants of Araceae , bromeliads, cedars, and ferns ( Pontificia Universidad Católica del Ecuador 2024 ). This species has not been found living or calling under rocks. It is known to live in sympatry with Hyloscirtus albopunctulatus and potentially with H. maycu sp. nov.