Bioacoustics of Fritziana izecksohni

Diagnosis. —The radiograph ( Fig. 2A–D ) shows two diagnostic features for the genus Fritziana : large nasals, narrowly separated from the maxillae and premaxillae (see Duellman and Gray 1983 ), and quadratojugal not articulating with maxilla (see Castroviejo-Fisher et al. 2015 ). In addition to the osteological characters, the dorsolateral folds of the brood pouch of females of F. izecksohni (ZUFRJ 13978) matches the described pattern of the species of Fritziana (see Duellman and Gray 1983 ). The new species differs from the other species in the genus by the following combination of traits: (1) nostrils narrowly separated with 0.5 0.7 mm of IND/IOD ( ¯X ¼ 0.56 ± 0.07 mm ); (2) diameter of tympanum equal to or larger than diameter of disc on third finger; (3) subarticular tubercles divided; (4) venter uniformly beige; (5) advertisement call with pulse groups composed of more than two pulses each; (6) advertisement call with longer first pulse group absent. Literature Acoustic structures Duellman and Gray (1983) Advertisement call/call group* Note Pulse — Heyer et al. (1990) Advertisement call Note Pulse — Weygoldt and Carvalho-e-Silva (1991) — Overlapped notes* Note Advertisement call Sinsch and Juraske (2006) Advertisement call Pulse group Pulse Call series Franz and de Mello (2015) Advertisement call Note Pulse — Comparisons with the other species. — Fritziana izecksohni differs from all other species of Fritziana by its dorsal coloration pattern, which is characterized by an interorbital triangle-shaped mark ( Figs. 3A , 4A ). Among the species that might have an interorbital triangle, F. ohausi has a marbled pattern on the dorsal and lateral surfaces, an interorbital brown triangle-shaped mark. Two stripes extend posteriorly from this interorbital mark; the stripes can be long and divergent, extending to the sacral region, short and divergent, or short and convergent (V-shaped mark). Fritziana goeldii has a brown interorbital hourglass-shaped mark extending to the middle of the body, and F. tonimi has, more commonly, an interorbital triangle and a posteriorly opened ‘‘V’’ or a bilobated mark reaching the insertion of the arm, or two dorsolateral lines originating on the snout, extending to the eye and tympanum, continuing posteriorly, and converging in the cloacal region, thereby forming a triangular shape (see fig. 4A,B of Walker et al. 2016 ). Fritziana ulei has an interorbital bronze pentagon-/hexagonshaped mark bordered by black ( Folly et al. 2014 ) and F. fissilis has a dorsal pattern consisting of beige with some small dark dots with patchy distribution ( Fig. 4C–E ). The new species has divided subarticular tubercles on fingers IV and V and toes IV and V, differing from F. goeldii , F. ohausi , F. tonimi , and F. ulei (undivided subarticular tubercles on fingers and toes in these species). The new species has an average head width larger than the head length (HW/HL: ¯X ¼ 1.09 ± 0.004, n ¼ 5) differing from F. tonimi , which has a narrower head (HW/HL: ¯X ¼ 0.83 ± 0.08, n ¼ 3). Fritziana izecksohni differs from F. ohausi in its reproductive behavior of releasing tadpoles into water accumulated in bromeliads (tadpoles deposited in water accumulated in bamboo holes in F. ohausi ; Duellman and Gray 1983 ) and by having the nostrils more narrowly separated than in F. ohausi (IND/IOD ¼ 0.56 in F. izecksohni , and 0.82 in F. ohausi ). Fritziana izecksohni differs from F. fissilis by the tip of the snout being mucronate (snout outline rounded to nearly rounded, not mucronate in F. fissilis ) and by having larger females (SVL 33.5 mm in F. izecksohni and 27.4–28.0 mm in F. fissilis ). The new species has an average tympanum diameter larger than that of the disc on the third finger (TYD/DD3: ¯X ¼ 1.1 ± 0.13, n ¼ 5), differing from F. fissilis (TYD/DD3 0.80 ± 0.08, n ¼ 2) and F. ohausi (TYD/DD3: ¯X ¼ 0.70 ± 0.11, n ¼ 38), which have small tympanum diameters.

Description of holotype . —Dorsolateral folds of dorsal pouch partially developed ( Fig. 4A,B ). Skin on dorsal surfaces mostly smooth, head well tuberculated. SVL 33.5 mm , head slightly longer than wide (HL/HW ¼ 1.03). Snout mucronate in dorsal view, rounded in lateral view ( Fig. 3D ). Nostrils oval, lateral, closer to the tip of snout (NSD ¼ 1.3 mm ) than to anterior corner of orbit; internarial distance equivalent to around 50% of interorbital distance (IND/IOD ¼ 0.45) and 21% of head width (IND/HW ¼ 0.21). Eye diameter (ED ¼ 3.7 mm ) equivalent to 31% of the head length (ED/HL ¼ 0.31). Canthus rostralis distinct, rounded; loreal region concave. Tongue oval. Vomerine teeth between choanal openings. Tympanum distinct, large (TYD ¼ 1.6 mm ), 43% of the diameter of the eye and equal to the diameter of disc on third finger (TYD/DD3 ¼ 1). Supratympanic fold well developed, extending from eye to insertion of arm. Outer margins of hand, arm, thigh, shank, knee, and tarsus crenulated. Arms long and thick; lengths of fingers II <III <V <IV; discs on fingers well developed; fingers not webbed; subarticular tubercles large, divided ( Fig. 3B,C ); six large palmar tubercles; number of tubercles on fingers II, III, IV, and V are 8, 4, 4, and 2, respectively. Relative toe lengths: I <II <V <III <IV; vestigial webbing between toes I and II; webbing formula, I 2–3 1/3 II 2 2/3–3 III 2–3 1/2 IV 4 1/2–3 2/3 V. Number of tubercles on toes I, II, III, IV, and V are 3, 4, 4, 6, and 2, respectively; five palmar tubercles. Venter granular. Measurements of holotype (mm). —SVL 33.5; HL 11.9; HW 11.5; IND 2.4; IOD 5.1; ED 3.7; END 3.4; NSD 1.3; TYD 1.6; ARL 9.1; FRL 7.8; HNL 10.8; FIL 7.5; DD3 1.6; THL 16.4; SL 18.4; FL 25.4; TL 9.5. Color of holotype in life. —Dorsal surface yellow to green, marked with dark brown dots ( Fig. 4A ); white interorbital triangle-shaped mark. Golden iris with narrow black lines forming a complex net. Forelimbs beige, with small brown spots. Thigh and shank beige with brown spots. Hind limbs beige, with narrow brown transverse bars. Ventral surface beige ( Fig. 4B ). Color of holotype in preservative. —The coloration pattern was maintained with the white interorbital triangleshaped mark clear. Color of the dorsal surface became paler and color of the ventral surface remained beige, but lighter. Thigh and shank became a lighter beige but still with brown spots. Variation. —Head longer than wide (HL/HW: 1.2 1.3, n ¼ 5); snout rounded ( n ¼ 1) or semicircular ( n ¼ 4) in dorsal view; internarial distance 54% of interorbital distance (IND/ IOD ¼ 0.5 0.6, n ¼ 5) and 19% of head width (IND/HW ¼ 0.17 0.20, n ¼ 5); eyes large (ED: ¯X ¼ 4.0 ± 1.0 mm, n ¼ 5), 52% of head length (ED/HL ¼ 0.44 0.74, n ¼ 5); tympanum distinct and small (TYD: ¯X ¼ 1.6 ± 0.3 mm , n ¼ 5), corresponding to 32% of eye diameter, and the diameter can be equal to or larger than the diameter of digit on third finger; female ( holotype ) is slightly larger than males ( Table 2 ). Male SVL ranges from 21.5 to 29.4 mm ( n ¼ 5); males with single, median, and subgular vocal sac. Variation in the dorsal pattern occurs in the direction, width, and continuity of the stripes of the dorsal pattern ( Fig. 5 ). The gray and white stripes from the dorsal pattern may be slightly curved at some parts, may have wider sections, may have short interruptions ( Fig. 5A ; MNRJ 48613 and 48606), or even be so interrupted that the dark stripe is divided into irregular brown spots bordered by white inverted-triangle shape ( Fig. 5B ; ZUFRJ 14528). Regarding the 16S mitochondrial gene, we found a relatively high intraspecific divergence for F. izecksohni ( Fig. 1 ). This molecular divergence was even higher than interspecific divergences. Advertisement call. —We classified all analyzed calls as advertisement calls because we found little variation among sampled calls ( Fig. 6 ). Each call ( Figs. 7 , 8 , 9G–I ) is composed of a sequence of pulse groups. Usually, the first pulse group has the lowest amplitude and thenceforth the amplitude gradually increases group by group until the amplitude peak. The amplitude peak often occurs with the last pulse group; however, it can be between the middle and the end of the call (i.e., with a decreasing amplitude period at the end of the call). The pulse-group period varies from 0.027 to 0.455 s ( ¯X ¼ 0.169 ± 0.057 s , mode ¼ 0.158 s , n ¼ 281). The pulse groups are composed of 1 to 35 pulses per group ( ¯X ¼ 4.6 ± 3.7, mode ¼ 3, n ¼ 331). The number of pulses per call varies from 10 to 47 ( ¯X ¼ 30.3 ± 8.3, mode ¼ 23, n ¼ 50). The pulse duration varies from 0.003 to 0.019 s ( ¯X ¼ 0.007 ± 0.001 s , mode ¼ 0.006 s , n ¼ 1517). The pulse interval varies from 0.001 to 0.048 s ( ¯X ¼ 0.007 ± 0.003 s , mode ¼ 0.005 s , n ¼ 1186). The pulse period varies from 0.006 to 0.054 s ( ¯X ¼ 0.013 ± 0.002 s , mode ¼ 0.012 s , n ¼ 1186). In the first one or two pulse groups, the relative amplitude between the pulses is similar to the common amplitude pattern of the call (i.e., with amplitude peak at the end). The rest of the pulse groups show an inverse pattern, with the first pulse having the peak amplitude, which decreases gradually pulse by pulse until the end of the group. Some calls are emitted with short intervals in between, resulting in call series. The call rate with calls regularly emitted was 0.5 calls per second ( n ¼ 1). Although the pulses have a wide frequency band (1500–14,000 Hz), a harmonic series is notable (frequency bands more energetic in spectrogram), with up to six harmonics. The dominant frequency of the call corresponds to the fundamental one. Each pulse group sounds like a rattle. Occasionally a longer single pulse is emitted at the end of the call, resembling a short whistle ( Fig. 7 ).

Comparison with advertisement calls of species of Fritziana ( Table 1 ). —The advertisement call of F. izecksohni resembles that of F. goeldii in the typically quite regular pulse-group durations and many pulses (often more than two) per pulse group. The call of F. izecksohni can be distinguished from that of F . aff. fissilis sp. 1 (sensu Franz and de Mello 2015 ) by having a dominant frequency up to 2500 Hz (vs. higher than 3000 Hz in F . aff. fissilis sp. 1; Table 1 , Fig. 9 ); from that of F. fissilis by absence of a longer first pulse group followed by very short pulse groups (vs. present in F. fissilis ; Fig. 9 ; cf. Duellman and Gray 1983 ); and from that of F. ohausi by the presence of more than two pulses per pulse group (vs. pulse groups with up to two pulses in F. ohausi ; Fig. 9 ). The advertisement call of F. ulei is unknown ( Folly et al. 2014 ).