Bioacoustics of Sphaenorhynchus caramaschii

Diagnosis. Sphaenorhynchus caramaschii is an intermediate size species for the genus ( Figure 5 ) and is characterized by the following combination of characters: (1) absence of external tympanum; (2) snout from truncate to slightly mucronate in dorsal view and protruding in lateral view; (3) presence of a dark line from the snout to the eye; and (4) a long advertisement call, generally with more than 5 seconds of duration and more than 20 notes per call. Comparison with other species. Sphaenorhynchus caramaschii is distinguished from S. planicola and S. dorisae by presenting a dark line from the snout to the eyes (absent in these former species). From S. carneus it is distinguished by having vomerian teeth and a SVL greater than 20 mm . From S. lacteus and S. pauloalvini it is distinguished by having a concealed tympanum. From S. prasinus it is distinguished by having a dorsolateral white line. From S. bromelicola it is distinguished by having vocal sac well developed, with longitudinal folds in the pectoral region; in S. bromelicola the vocal sac is small without longitudinal folds in the pectoral region. From S. palustris and S. orophilus it is distinguished by lacking dark nuptial asperities in males and by having the tympanum invisible from skin transparency. Finally, from S. surdus it is distinguished by having the snout generally truncate, sometimes slightly mucronate (mucronate in S. surdus ) and, mainly, by having a long advertisement call, generally with more than 5 seconds of duration (usually below 2 seconds in S. surdus ), and by having larger interval between notes, greater than 0.1 seconds (below 0.09 seconds in S. surdus ) (see also Table 1 ).

Description of Holotype . Body elliptic and slender. Head triangular, longer than broad. Snout slightly mucronate in dorsal view and protruding in lateral view ( Figure 6 ). Mouth opening ventral. Internarial distance narrow, shorter than the eye to nostril distance. Canthus rostralis rounded. Choanae rounded. Interorbital distance larger than eye diameter. Tympanum indistinct and concealed, but perceptible beneath skin. Vocal sac single, externally expanded, and large with evident transversal folds. There is one large vocal slit on each side of the tongue. Vomerine teeth in two distinct, short transverse, series, with three teeth each, lying between and just posterior to choanae. Tongue narrow, longer than wide. Thigh slightly longer than tibia; foot shorter than thigh and tibia. Finger length I<IV<II<III. Toe length I<II<V<III<IV. Finger and toes tips with rounded adhesive disks ( Figure 6 ). Thumb with keratinized nuptial pad. Finger webbing reduced and toe webbing moderately developed. Finger and toe subarticular tubercles rounded and single. There are several rounded supernumerary tubercles in the hand between the first subarticular tubercle and the elliptical internal metacarpal tubercle and the heart-shaped external metacarpal tubercle. In the feet there are 13 supernumerary tubercles mostly between the rounded external metacarpal tubercle and the oval internal metacarpal tubercle. Inner metatarsal tubercle large and ovoid. Ventral skin granular and dorsal skin slightly granular, almost smooth. Cloacal region granular and cloacal flap absent. Measurements of the holotype are presented in table 2. Measurement S. surdus S. caramaschii Holotype Males (n = 17) Holotype Males (n = 11) Females (n = 2) Color in life . Dorsum and limbs are bright green with brownish dots. Venter smooth green, but lighter than dorsum. Presence of a white dorsolateral line from the snout to the groin; under this line there is a dark line from the snout to the flanks. Dark line from the eye to the snout present. Cloacal region with white spots. Snout-vent-length 28 25.78 ± 2.29 24.33 (22.85 – 29.32) 24.67 ± 0.98 26.45 – 28.89 (23.25 – 25.94) Head length 7.5 7.59 ± 0.74 8.01 (6.17 – 9.14) 7.48 ± 0.35 8.18 – 8.51 (6.91 – 8.10) Head width 7.5 7.75 ± 0.53 7.55 (6.80 – 8.41) 7.54 ± 0.38 8.20 – 8.55 (6.66 – 7.95) Eye diameter Not provided 2.13 ± 0.21 2.06 (1.74 – 2.67) 2.13 ± 0.16 2.20 – 2.38 (1.93 – 2.52) Interorbital distance Twice the width of upper eyelid 3.53 ± 0.36 3.59 (2.97 – 4.19) 3.52 ± 0.33 4.11 – 4.38 (3.05 – 4.15) Eye-nostril distance Not provided 2.37 ± 0.18 2.54 (2.10 – 2.68) 2.46 ± 0.19 2.84 – 2.88 (2.23 – 2.83) Internostril distance Not provided 1.77 ± 0.23 1.88 (1.40 – 2.19) 1.72 ± 0.15 1.72 – 2.17 (1.52 – 1.98) Thigh length 12 12.43 ± 0.99 12.02 (10.97 – 14.11) 12.02 ± 0.58 NM – 13.12 (11.33 – 13.35) Tibia length 13.5 12.53 ± 0.86 11.71 (11.07 – 13.86) 12.51 ± 0.56 NM – 13.00 (11.52 – 13.33) Foot length 11.5 11.37 ± 0.91 10.85 (10.17 – 12.85) 11.64 ± 0.87 NM – 12.53 (10.34 – 13.36) Color in preservative (70% ethanol) . Dorsum and limbs of whitish beige with brownish dots. Ventral region whitish yellow. Limbs in ventral view darker than belly. The dark line from the eyes to the snout is present. Clocacal region with white spots. Nuptial pad brown. Variation. Females larger than males and lacking nuptial pad that is present in males. There is little variation in external morphology within the sexes (see also Table 2 ). Differently from the holotype , some paratypes have the head broader than long, or as broad as long, and the thigh shorter than the tibia, or as long as the tibia. The snout shape varies from truncate to slightly mucronate. In most individuals the dark line from the snout extends to the flanks, in some individuals ends in the edge of the eyes. Dorsal pigmentation varies considerably among individuals, since from totally uniform green to strongly brownish spotted dorsum. Advertisement call. The advertisement call of the S. caramaschii described here was recorded in the municipality of Piraquara, state of Paraná. It has 22 to 43 notes, frequency ranging from 0.94 ± 0.45 kHz (range: 0.11 – 1.57; n = 30 notes; 1 male ) to 4.24 ± 0.40 kHz (range: 3.70 – 5.43; n = 30 notes; 1 male ). Mean dominant frequency is 2.62 ± 0.09 kHz (range: 2.50 – 2.76; n = 30 notes; 1 male ). The mean duration of the call is 8.49 ± 2.83 seconds (range: 5.23 – 10.21; n = 5 calls; 1 male ), but it depends on the number of notes in the call. The mean duration of an individual note is 0.06 ± 0.01 s (range: 0.04 – 0.07; n = 30 notes; 1 male ). The notes are pulsed and the mean interval between them is 0.22 ± 0.04 s (range: 0.18 – 0.37; n = 30 notes; 1 male ) ( Table 1 ; Figure 7 ). Two adjacent males may call in antiphony. Tadpole. Unknown. Natural history. Males breed in the hot and rainy season of the year (September-March) and call from the floating vegetation in temporary or permanent ponds. The reproductive mode is number 1 ( sensu Haddad and Prado, 2005 ): eggs and exotrophic tadpoles in lentic water. The eggs are attached individually to submerged vegetation. Geographic distribution. Besides the type locality, the species occurs also in the municipalities of Pilar do Sul, Iporanga, Apiaí, and Ribeirão Grande, all in the state of São Paulo, in the municipality of Piraí do Sul and Piraquara, state of Paraná, and in the municipality of Treviso and São Bento do Sul (based on recordings), state of Santa Catarina ( Figure 8 ).