Phyllodytes megatympanum, Marciano-Jr, Euvaldo, Lantyer-Silva, Amanda Santiago F. & Solé, Mirco, 2017

Marciano-Jr, Euvaldo, Lantyer-Silva, Amanda Santiago F. & Solé, Mirco, 2017, A new species of Phyllodytes Wagler, 1830 (Anura, Hylidae) from the Atlantic Forest of southern Bahia, Brazil, Zootaxa 4238 (1), pp. 135-142 : 136-141

Phyllodytes megatympanum sp. nov.

( Figs. 1 , 3 )

Holotype. MZUFBA 14088, adult male collected in an epiphytic bromeliad in an arboreal restinga habitat of the Boa União Reserve (15°04’S, 39°03’W; 95 m above sea level), municipality of Ilhéus, state of Bahia, August 0 8th 2013 by E. Marciano-Jr and M. Solé.

Paratopotypes. MZUESC 11671–11672, adult males collected on July 17th 2013, by E. Marciano-Jr, I. Jaloretto, M. Solé and H.R. Silva; MZUESC 16056, collected on April 0 7th 2015, by M. Solé and MZUESC 16061, collected on March 14th 2016 in an epiphytic bromeliad at ~ 5m height by I.R. Dias.

Paratype. MZUESC 10336 , adult male collected in an epiphytic bromeliad in the municipality of Uruçuca (14°35’S, 39°17’W; 90 m above sea level), state of Bahia on January 28th 2011, by M. Solé, I.R. Dias and C.V.M. Mendes.

Diagnosis. A small sized species (SVL 21.3–23.7 mm in males) characterized by: (1) dorsum of body, arms, and legs uniformly light brown; (2) a dark brown stripe extending from the posterior corner of the eyes, upper contour of the tympanum, and reaching the inguinal region; (3) groin yellow; (4) snout pointed in dorsal view, protruding in profile; (5) tympanum large with round distinct tympanic annulus; (6) supratympanic fold well marked extending to shoulder; (7) vomerine teeth in two dense patches almost unified, horizontally positioned, behind the choanae; (8) two anterior large odontoids followed by a series of indistinct, smaller odontoids on each side of the mandible of adult; (9) dorsal skin slightly rough; (10) venter cream with two paramedial rows of developed tubercles parallel to which run additional rows of indistinct tubercles; (11) well-developed tubercle near tibio-tarsal joint.

Comparisons with other species. The dorsal color pattern (immaculate brown) distinguishes Phyllodytes megatympanum from P. gyrinaethes , P. melanomystax , P. punctatus , P. tuberculosus , P. wuchereri and P. maculosus (all have some kind of dorsal pattern). The absence of distinct lateral dark stripes distinguishes P. megatympanum from P. kautskyi and P. luteolus . The yellow groin distinguishes P. megatympanum from all species of Phyllodytes (red groin in P. gyrinaethes and with no highlighted color in all remaining species). The small size (<24 mm in males) separates P. megatympanum from P. kautskyi (> 39 mm) and P. maculosus (> 39 mm). The large tympanum, corresponding to 7.73 % of SVL, distinguishes P. megatympanum from all congeners, in which this ratio is less than 7 %. Only P. acuminatus presents a higher value for this same ratio (8.16 %). However, the latter presents a highly granulated venter (only two marked rows of tubercles in P. megatympanum ). Two large anterior odontoids on each side of the mandible distinguish P. megatympanum from P. edelmoi , P. kautskyi , and P. punctatus which possess only one large odontoid, and from P. brevirostris and P. melanomystax which have no large odontoid.

Description of holotype. Body robust. Head wider than long, its width exceeding the body width; snout pointed in dorsal view, protruding in profile. Nostril small, elliptical, slightly directed posterodorsally; canthus rostralis distinct, mainly near the eyes; loreal region oblique, not concave; eyes large, directed anterolaterally. Eye diameter 30.7 % (29.1–32.7 % in the paratypes) of head length; interorbital space and dorsum of snout flat; tympanum large, with tympanic annulus distinct and round; its diameter is 18.7 % of head length and 61.1 % of eye diameter; supratympanic fold distinct, covering upper quarter of tympanum. Vocal sac subgular, poorly developed; vocal slits near angle of jaws, at posterior border of tongue; tongue large, almost cordiform, fixed behind; two groups of vomerine teeth, almost uninterrupted in straight line behind and between choanae; each side of mandible with two large odontoids, remaining odontoids small, discrete; horizontal pupil divides the iris into dorsal and ventral parts.

Forearms slightly more robust than upper arms; fingers slender, relative lengths I <II = IV <III; subarticular tubercles discrete, round; supernumerary tubercles few, small, low; palmar and thenar tubercles well developed, the first one spatulate, projecting laterally, triangular; the latter elongate, elliptical; discs of fingers well developed, diameter of third finger disc 44.4 % (44.4–46 % in the paratypes) of eye diameter; webbing absent between fingers I and II, very reduced between fingers II–III–IV.

Legs slender; tibia longer than thigh; sum of thigh and tibia lengths 98.6 % (98.6–109.4 % in the paratypes) of SVL. Foot with distinct, round subarticular tubercles; supernumerary tubercles few, round, low; inner metatarsal tubercle ovoid, spatulate, projecting laterally; outer metatarsal tubercle round; a row of distinct tubercles on the outer margins of tarsus; toes slender, relative lengths I <V <II <III <IV; discs on toes almost equal in size to discs of fingers; webbing absent between toes I–II; webbing formula I – II 2 + – 3- III 2+ – 3+ IV 3 – 2 + V.

Dorsal surfaces of body shagreen, less so on limbs, venter, throat, and ventral surface of thighs; two medial indistinct series of round tubercles, accompanied by a few others, dispersed over venter; two distinct round tubercles at insertion of thigh. Ventral surface of forelimbs smooth.

Measurements of holotype (mm). SVL 21.3; HL 8.8; HW 9.4; UEW 2.0; END 2.3; ED 2.7; TD 1.65; THL 9.7; TBL 11.3; FL 14.22.

Color in preservative. Dorsum and dorsal surface of limbs brown. Brown stripe present behind the eyes, passing over the supratympanic fold and reaching the flanks. The color fades until it reaches the flanks. Ventral body and limb surfaces cream.

Color in life. Dorsum uniformly brown; laterally, a dark brown stripe crossing the eye, tympanum, and reaching the inguinal region; venter white; upper half of the iris yellow or reddish and lower half yellow. Groin and concealed parts of the thigh are yellow.

Variation. The type specimens present little variation in morphological aspects and color pattern. The measurements of the specimens from the type series are summarized in Table 1 .

Etymology. The specific epithet refers to the prominent tympanum, one of the largest in relation to SVL among the other species of the genus. Megatympanum is a Latin vernacular name meaning “big tympanum”.

Natural History. We found Phyllodytes megatympanum in syntopy with other Phyllodytes spp. ( P. maculosus , P. melanomystax , and two other undescribed species) at the type locality. Yet, the former could be heard calling from bromeliads at heights of two to more than 10 meters, while the remaining species (except P. maculosus ) call from bromeliads at ground level or in lower heights.

Advertisement call. The advertisement call of Phyllodytes megatympanum is composed of a series of 10 to 19 unpulsed notes (n = 19 calls analyzed) with harmonic structure. Each note has seven visible harmonics and crescent modulation frequency. The first notes are shorter than the following ones, which are more intense. Notes show amplitude modulation from the beginning to the middle, when it decreases. The mean duration of each call is 5.913 ± 4.556 s (3.206– 23.633 s; n = 19 calls) emitted in intervals of 30.904 ± 10.313 s (6.960– 47.580 s; n = 15 intervals). The notes present mean duration of 0.092 ± 0.080 s (0.009– 0.245 s; n = 254 notes) and are emitted at intervals of 0.305 ± 0.100 s (0.105–0.619; n = 235 intervals). The mean dominant frequency is 3.985 ± 0.136 kHz (3.562–4.125 kHz; n = 113 notes analyzed) and corresponds to the second harmonic. Due to its ascendant modulation, the frequency at the beginning of the second harmonic is lower than the frequency towards the end of it, raising a mean bandwidth of 0.8 kHz.

Advertisement call comparisons. Phyllodytes megatympanum , as the majority of the species within the genus Phyllodytes , has calls with more than one note. Out of the nine species whose advertisement call is available, only P. acuminatus and P. melanomystax have calls with one note. Based on its unpulsed structure, the call of P. megatympanum is readily distinguished from the pulsed calls of P. luteolus , P. edelmoi , P. tuberculosus , P. gyrinaethes and P. wuchereri ( Weygoldt 1981; Lima et al. 2008; Juncá et al. 2012; Roberto & Ávila 2013; Cruz et al. 2014). Among the other species of Phyllodytes with unpulsed structure, P. megatympanum can be distinguished from P. kautskyi by the higher mean dominant frequency: 3.985 ± 0.136 kHz (3.562–4.125) in P. megatympanum vs. 1.37 kHz (0.87–1.81) in P. kautskyi , according to the first description of the latter. After the original description of the advertisement call from P. kautskyi by Simon & Gasparini (2003), Simon & Peres (2012) presented additional bioacoustic details from populations of P. kautskyi from southern Bahia. However, there is evidence that leads us to conclude that the studied populations could be actually assigned to P. maculosus (Marciano-Jr et al. in prep). Thus, the differences assigned to polymorphisms in the Bahian populations of P. kautskyi would represent diagnostic features of P. maculosus .

The lower number of notes per call in Phyllodytes megatympanum (10–19) distinguishes it from P. kautskyi (21–22; Simon & Gasparini 2003; Simon & Peres 2012), P. tuberculosus (14–23; Juncá et al. 2012) and P. edelmoi (22–29; Lima et al. 2008). The higher number of notes can distinguish P. megatympanum from P. gyrinaethes (4–6; Roberto & Ávila 2013) and P. luteolus (8–15; Weygoldt 1981). The longer call duration in P. megatympanum 5.91 ± 4.56 s (3.20– 23.63 s) distinguishes it from P. acuminatus (0.03– 0.17 s; Campos et al. 2014), P. melanomystax (0.07 ± 0.04 s; Nunes et al. 2007), P. kautskyi (3.55 ± 0.19 s; Simon & Gasparini 2003; 3.48– 3.90 s in Simon & Peres 2012), P. gyrinaethes (1.7 ± 0.3 s; Roberto & Ávila 2013) and P. edelmoi (5.2 ± 0.44 s; Lima et al. 2008). The mean interval between notes of P. megatympanum 0.350 ± 0.10 s is longer than between notes of P. tuberculosus (0.214 ± 0.048 s; Juncá et al. 2012), P. kautskyi (0.060– 0.120 s; Simon & Gasparini 2003) and P. wuchereri (0.120 ± 0.019 s; Magalhães et al. 2015), but not longer than in P. gyrinaethes (0.400 ± 0.030 s; Roberto & Ávila 2013). Calls from P. maculosus , P. brevirostris and P. punctatus remain undescribed.

Figures

FIGURE 1. Phyllodytes megatympanum sp. nov., holotype (MZUFBA 14088; SVL 21.30 mm), (A) dorsal and (B) ventral views, (C) hand, (D) foot and, (E) lateral view of head. White bars equal 1 mm. Photo: Lucas Menezes.

FIGURE 3. Holotype of Phyllodytes megatympanum sp. nov. in life. Note the yellow coloration in the groin region (black arrow).

Tables

TABLE 1. Range, mean, and standard deviation (SD) of the measurements (mm) of the type specimens of Phyllodytes megatympanum sp. nov. (n = 6 adult males).

Characters	Range	Mean	SD
SVL	21.3–23.7	22.3	0.9
HL	8.4–9.0	8.6	0.2
HW	9.2–9.7	9.4	0.2
UEW	1.5–2.0	1.8	0.2
END	2.0–2.5	2.3	0.2
ED	2.5–2.8	2.6	0.1
TD	1.6–1.8	1.7	0.06
THL	9.7–11.5	10.7	0.6
TBL	11.3–12.9	12.1	0.5
FL	14.2–16.3	15.5	0.7