Bioacoustics of Hyloscirtus maycu

Diagnosis. Characters in this section pertain to preserved specimens unless otherwise noticed. Coloration refers to life specimens. The most similar species to H. maycu sp. nov. living in the Amazon basin are Hyloscirtus albopunctulatus , H. elbakyanae sp. nov. , H. dispersus sp. nov. , H. phyllognathus , and H. torrenticola . Hyloscirtus maycu sp. nov. differs by the absence of a supratympanic fold (present in H. albopunctulatus and H. dispersus sp. nov. ), an inconspicuous tarsal fold (present and thick in H. albopunctulatus , H. phyllognathus , and H. torrenticola ), conspicuous subarticular tubercles in hands and feet (small to inconspicuous in hands and feet in H. albopunctulatus ; Fig. 11 ), inconspicuous supernumerary tubercles in hands and feet (conspicuous in hands in H. dispersus sp. nov. ), pericloacal spots ill-defined or absent (well-defined in H. albopunctulatus and H. phyllognathus ), an absent calcar tubercle (present in H. dispersus sp. nov. and H. phyllognathus ), and a clam iris with dark pinkish or leather reticulations (a clam shell iris with black or sand dune reticulations in H. albopunctulatus and a bronze iris in H. torrenticola , Fig. 12 ). Although our sample size is small, the available evidence indicates that H. maycu sp. nov. differs from H. elbakyanae sp. nov. by its smaller size (Fig. 7 ). The advertisement call of H. maycu sp. nov. has a rise time of 0.8 s (longer in H. albopunctulatus with 2.28 ± 0.80 s and shorter in H. elbakyanae sp. nov. with 0.57 ± 0.05 s and in H. torrenticola with 0.16 ± 0.017 s ), a dominant frequency of 2343.8 Hz and a fundamental frequency of 1171.9 Hz (higher dominant frequency in H. dispersus sp. nov. of 2795.41 ± 138.68 Hz and fundamental frequency of 2700.63 ± 195.66 Hz). Hyloscirtus torrenticola also has a higher dominant frequency of 2743.79 ± 48.22 Hz and a fundamental frequency of 2743.75 ± 48.16 Hz. Hyloscirtus maycu sp. nov. has a call duration of 0.053 s (longer in H. dispersus sp. nov. of 0.11 ± 0.015 s ) (Table 4 , Fig. 9 ; Melin 1941 ; Duellman and Altig 1978 ; Rivera-Correa 2016 ). Additionally, H. maycu sp. nov. inhabits elevations between 882 and 1183 m , while H. elbakyanae sp. nov. lives lower between 214 and 622 m and in wetter and warmer environments (Figs 5 , 10 ).

Distribution and natural history. Hyloscirtus maycu sp. nov. is known only from its type locality in Provincia Morona Santiago and one locality in Provincia Zamora Chinchipe (airline distance 32 km ), at elevations between 882 and 1183 m , on the foothills of Cordillera del Cóndor, in Ecuador (Fig. 5 ). Biogeographic region is Eastern Lower Montane Forest ( Ron et al. 2022 ). This species lives in primary and secondary forests. They are nocturnal and associated with ravines and streams. Males call from vegetation up to 2 m high, on the edge of the streams. One individual was recorded calling under a rock, and another on a rock in a ravine with low flow. A metamorph was found (in March) on an island of rock in the middle of a stream, suggesting that its tadpoles develop in streams, like other Hyloscirtus . A tadpole ( QCAZ 67083 ) was found on a pool next to a stream in February.

Definition. In this section, coloration and characters refer to preserved specimens unless otherwise mentioned. The definition and diagnosis are based on two adult females and three adult males . Hyloscirtus maycu sp. nov. can be diagnosed by the combination of the following characters: (1) mean SVL 33.4 mm in adult males (range 31.9–34.2; n = 3) and mean SVL 42.7 mm in adult females (range 41.7–43.7; n = 2; Suppl. material 1 : table S 5; Fig. 7 ); (2) white supralabial stripe present or absent; (3) tympanum round, inconspicuous in males and distinct in females; supratympanic fold inconspicuous and unpigmented; (4) white ulnar and tarsal folds inconspicuous or conspicuous; (5) subarticular tubercles conspicuous, round and single, in hands and feet; (6) supernumerary tubercles inconspicuous in hands and feet; (7) calcar tubercle absent; (8) pericloacal spots well-defined; (9) all surfaces plain cream with a combination of black and white spots in the dorsum; (10) in life, dorsal surfaces and flanks olive green to crete with white spots and minute or thick black spots scattered over the body; axillar and inguinal regions blueish or mongoose; venter and posterior surfaces of thighs yellow; other ventral surfaces silver or greenish; bones and articulations blue; unpigmented pericloacal spots; webbing yellow orange; iris clam shell with thick dark pinkish to leather reticulations; (11) the advertisement call consists of a single note, with duration of 0.053 s ( n = 1) and a dominant frequency of 2343.8 Hz and fundamental frequency of 1171.90 Hz. The call can be repeated consecutively from 10–13 times in a series of calls.