Phyllodytes gravata sp. nov.

urn:lsid:zoobank.org:act: FF6D0BDA-3533-4340-BC19-2BFE9069F75E

Figs 1–2; Table 1

Phyllodytes sp. 6 – Blotto et al. 2021: 7–9, table 1, fig. 5.

Diagnosis

The new species is assigned to the genus Phyllodytes based on the occurrence of odontoids in the lower jaw and molecular data supporting the placement of Phyllodytes gravata sp. nov. (as Phyllodytes sp. 6) as sister taxon of P. amadoi + Phyllodytes sp. 7 (Blotto et al. 2021). The new species is distinguished from its congeners by a combination of the following characters: small-sized adults, SVL = 19.5–22.0 mm in males (n = 15) and SVL = 23.5 mm in the female (n = 1); slender body; head slightly wider than long (HL 90.5% of HW); snout rounded in dorsal view and lateral profile with a small apical tubercle; canthus rostralis rounded; loreal region concave; tympanum and tympanic annulus distinct; supratympanic fold extending from the posterior region of the eye to near the arm insertion; single subgular vocal sac; two large anterior odontoids followed by three to six smaller ones on each side of the mandible in adults; lateral margin of the forearms with three to four discrete outer tubercles, with either fused or unfused bases; a discrete row of tubercles along the tarsus, ending with a prominent tubercle near the tibio-tarsal junction; light brown coloration on the snout, gradually becoming lighter along the dorsum until turning cream, usually with small light brown blotches on the dorsum; a brown stripe extending from the snout to slightly beyond the arm or midbody; venter with two to four central rows of tubercles flanked by smaller irregularly arranged tubercles; and advertisement call consisting of a series of 22–34 pulsed notes, with a duration of 5.2– 7.3 s and a dominant frequency ranging from 2.75 to 3.83 kHz.

Etymology

The specific epithet gravata is a popular name used in Brazil for plants of the family Bromeliaceae. This name is used as an invariable noun in apposition and derived from the Tupi language, Karawatá, largely used by native people before the colonization. As an oxytone, its pronunciation follows [gra-va- TAH], with stress on the final syllable. The first and second ‘a’ sounds resemble the ‘a’ in ‘apple’. This new species name is a reference to the habits of species of Phyllodytes that characteristically live and reproduce in tank-bromeliads of the Atlantic Forest.

Type material

Holotype

BRAZIL – Bahia State • ♂; Porto Seguro, Trancoso, RPPN Rio do Brasil; -16.557547, -39.120899; 54 m a.s.l.; I.R. Dias and L. Santos leg.; 27 Jan. 2024; MZUESC 23891.

Paratypes

BRAZIL – Bahia State • 1 ♀; same collection data as for holotype; MZUESC 23889 • 5 ♂♂; same collection data as for preceding; MZUESC 23887, 23890, 23892 and 23922; UFBA 17656 (ex-MZUESC 23888) • 4 ♂♂; same collection data as for holotype; 26 Jan. 2024; MZUESC 23884 – 85, 23915; UFBA 17657 (ex-MZUESC 23886) • 5 ♂♂; Porto Seguro, Trancoso, Fazenda Nova Alegria; -16.606111, -39.144833; 50 m a.s.l.; M.T. Rodrigues, P.M.S. Nunes, M. Teixeira Jr., T. Mott, and J.M. Guellere leg.; 26–27 Mar. 2007; MZUSP-A 149538, 149539, 149540, 149541, 149542.

Description of holotype

Adult male in good state of preservation. Measurements are given in Table 1. Body slender; head wider than long (HL 91.5% of HW; HW 35.5% of SVL; HL 32.5% of SVL); snout rounded in dorsal view, with a small apical tubercle; rounded in profile; nostrils small, round, directed anterolaterally; canthus rostralis rounded; loreal region concave; internarial distance smaller than eye-nostril distance (IND 52.6% of END); eyes large, prominent, and directed anterolaterally (ED 33.8% of HL; 31.0% of HW; 115.8% of END; tympanum medium-sized (TD 19.7% of HW; 7.0% of SVL), distinct, and nearly circular, diameter larger than internarial distance (TD 140.0% of IND), more than half of the eye-to-nostril distance (TD 73.7% of END) and eye diameter (TD 63.6% of ED); tympanic diameter greater than the third finger disc width (TD 116.7% DF3) and the fourth toe disc diameter (TD 107.7% of 4TD); tympanic annulus evident; supratympanic fold evident, extending from the posterior corner of the orbit, covering the dorsal edge of the tympanum, to near the insertion of the arm; vocal sac subgular; vocal slits present; oval, flat tongue; vomerine teeth arranged in two slightly spaced, horizontal rows, positioned between and behind the choanae; each side of the mandible with two large anterior odontoids, followed by three small ones; horizontal pupil.

Forearms slightly wider (in cross-section) than arms, with three or four small tubercles along the lateral edge; one tubercle on the lateral side of the fourth finger; hands large (HAL 90.8% of HL); subarticular tubercles round, largest on the fourth finger; supernumerary tubercles indistinct; palmar tubercle oval, smaller than the thenar tubercle; thenar tubercle elongated; relative finger lengths: I <IV <II <III; light-coloured nuptial pad on the internal base of the finger I, unspotted and lacking dark excrescences, contrasting with the surrounding skin, which bears dark spots; finger webbing formula I 2 ½ – 1- II 1+ – 2+ III 2+ – 1- IV.

Hind limbs long (THL + TBL + TAL + FL equals 169.5% of SVL); thigh length shorter than tibia length (THL 93.3% of TBL; THL 48.5% of SVL; TBL 52.0% of SVL); sum of thigh and tibia lengths equal to SVL (THL + TBL 100.5% of SVL); one prominent tubercle at the insertion of each leg; a discrete row of tubercles on the tarsus, with a single large tubercle on posteroventral internal margin of tarsus, near to tibiotarsal junction; tarsal length smaller than foot length (TAL 70.4% of FL); foot length smaller than thigh and tibia lengths (FL 83.5% of THL; FL 77.9% of TBL); subarticular tubercles rounded; supernumerary tubercles indistinct; inner metatarsal tubercle is large and elongated; outer metatarsal tubercle small and round; toe webbing formula I 1 – 2+ II 2- – 3- III 1 – 3- IV 3+ – 1+ V.

Supracloacal crest absent; skin smooth, except for chest, belly and ventral of thighs that rugose; ventral tubercles arranged in two central rows, bordered by smaller tubercles not arranged in rows.

In preservative, the snout is light brown, with dark brown markings extending to the middle of the body and the tibia region, while the rest of the body is pale yellow. A light brown stripe extends from the snout to just beyond the forelimbs. The ventral surfaces are pale yellow.

Variation

Most specimens of the type series are morphologically consistent with the holotype. Variation in measurements is presented in Table 1. MZUSP-A 149539 has a truncate snout in dorsal view, MZUSP 149538-A has a truncate snout in lateral view, and specimen MZUSP-A 149542 has a protruding snout in lateral view. UFBA 17657 exhibits three tubercles at the tip of the snout, one central and two lateral. MZUESC 23915 presents a distinct crest between the nares. In MZUESC 23889 (female), both the tympanum and the tympanic annulus are poorly defined. MZUESC 23885, MZUESC 23890 and UFBA 17657 display a single tubercle on the lateral margin of finger IV. MZUESC 23887 exhibits a second prominent tubercle at the left tibio-tarsal articulation. MZUESC 23884, MZUESC 23891 and UFBA 17657 lack the light brown speckling typically observed along the dorsum. MZUESC 23922, MZUSP-A 149538 and MZUSP-A 149540 have a stripe that starts at the snout and extends to the middle of the body.

In life (Fig. 3), individuals exhibit a predominantly yellowish dorsal colouration, with dark brown speckling reaching the mid-dorsum in most specimens and extending to the posterior limbs in some. Brown dorsolateral stripes originate at the tip of the snout, pass through the ocular and tympanic regions, and become progressively diffuse, terminating just beyond the forelimbs or near the midbody. Some individuals lack a defined dorsal pattern, while in others the lateral stripes are faint or nearly imperceptible. The ventral surfaces are predominantly yellowish.

Comparison with congeners (character states for the other species are shown in parenthesis)

Phyllodytes gravata sp. nov. is distinguished by its smaller adult size (19.5–23.5 mm SVL) when compared to P. kautskyi Peixoto & Cruz, 1988 (36.5–43.5 mm SVL), P. maculosus Cruz, Feio & Cardoso, 2007 (39.5–43.5 mm SVL), and P. magnus Dias et al. 2020 (36.4–41.1 mm SVL); from P. acuminatus Bokermann, 1966 and P. iuna Santos, Roseno, Solé & Dias, 2023 by its wider-than-long head (head as long as wide); and by its rounded snout in dorsal view, differing from P. acuminatus, P. kautskyi, P. megatympanum Marciano, Lantyer-Silva & Solé, 2017, and P. wuchereri (Peters, 1873) (pointed snout). It further differs from P. melanomystax, and P. praeceptor by usually possessing a small apical tubercle on the snout (absent).

Phyllodytes gravata sp. nov. lacks conspicuous groin colouration, a diagnostic feature distinguishing it from P. gyrinaethes Peixoto, Caramaschi & Freire, 2003 (red groin) and P. megatympanum (yellow groin). Additionally, the tympanum of P. gravata is distinct and proportionally smaller (TD 3.8–7.2% of SVL), which contrasts with P. acuminatus and P. megatympanum (TD 7.73–8.16% of SVL), as well as with P. gyrinaethes (tympanum hidden) and P. melanomystax (tympanum barely visible). Phyllodytes gravata differs from P. tuberculosus Bokermann, 1966 by lacking the pair of evident lateral tubercles on the hand (two evident lateral tubercles).

Phyllodytes gravata sp. nov. has an inconspicuous row of tubercles along the tarsus, with a single prominent tubercle at the tibiotarsal articulation, differing from P. iuna and P. praeceptor (a single prominent tibiotarsal tubercle), and from P. kautskyi, P. luteolus, P. maculosus, P. magnus, P. megatympanum, P. melanomystax, P. tuberculosus, and P. wuchereri (a row of evident tubercles, which may or may not exhibit a prominent tubercle at the tibiotarsal articulation). Additionally, P. luteolus, P. maculosus and P. tuberculosus may also exhibit a double crenulated row of tubercles along the tarsus. Phyllodytes gravata differs from P. punctatus by the presence of two large anterior odontoids on each side of the mandible (one large odontoid), and by the absence of supernumerary tubercles on the plantar surface (present) (Caramaschi & Peixoto 2004).

Phyllodytes gravata sp. nov. typically exhibits a dark brown stripe extending from the snout, passing through the eye, and terminating either just posterior to the arm insertion or at midbody (Fig. 4). Between the snout tip and the eye, this stripe is usually paler and may be less distinct or even absent in some individuals (e.g., MZUESC 23922, MZUSP 149538-A, MZUSP 149540-A). Most specimens show dark spots or blotches on the dorsum between the dorsolateral stripes, except for MZUESC 23884, MZUESC 23891 and UFBA 17657. When present, the pale stripe between the snout and the eye distinguishes P. gravata from P. acuminatus, P. brevirostris (Peixoto & Cruz 1988), P. edelmoi Peixoto, Caramaschi & Freire, 2003, P. gyrinaethes, P. kautskyi, P. maculosus, and P. magnus (absence of an evident stripe between the nostril and the eye) and from P. melanomystax (which exhibits a dark stripe). Phyllodytes gravata is distinguished from P. wuchereri by the presence of a single dorsolateral stripe (two dorsolateral white stripes bordered by dark brown to black lines). Additionally, the new species differs from P. brevirostris (Peixoto & Cruz 1988), P. edelmoi, P. kautskyi, P. megatympanum, and P. magnus by usually having spots and blotches on the dorsum (immaculate dorsum).

Morphologically, Phyllodytes gravata sp. nov. is most similar to P. amadoi. However, it differs from P. amadoi by having a rounded snout in lateral view (vertical), inconspicuous tubercles along the tarsus with a single prominent tubercle near the tibiotarsal articulation (only one tibiotarsal tubercle in most cases, although some specimens [MZUESC 14941, 14943, 14952, 14959, 24028] present a subtle and barely visible row of tubercles along the tarsus, usually on only one side of the body), and exhibit a dorsal coloration with less contrasting spots and blotches when compared to P. amadoi (see Fig. 7). Additionally, P. gravata is larger in body size, as evidenced by non-overlapping morphospace in PCA of uncorrected data (PC1+PC2 = 80.75% variance; PC1 driven by SVL, PC2 by FL; Fig. 5, Table 2). This separation disappears when size-adjusted (PC1+PC2 = 54.5% variance; PC1 influenced by FL and THL, PC2 by HW and HL; Fig. 5, Table 2). Under these conditions, individuals of both species showed substantial overlap in morphospace, indicating that the morphological differences observed are largely due to variation in body size. Nevertheless, the new species differs from P. amadoi by an divergence of 8.5% in the 16S rRNA gene (Blotto et al. 2021), and by differences in the characteristics of the advertisement call (see Bioacustics comparisons with congeners). In addition, P. gravata can be distinguished from P. sp. 7, a phylogenetically proximate lineage (sensu Blotto et al. 2021), by its dorsal colour pattern (see Fig. 7), by a divergence of 7.4–7.7% in the 16S rRNA gene (Blotto et al. 2021), and by differences in the advertisement call (see Discussion).

Advertisement call

The advertisement call (Fig. 6) of Phyllodytes gravata sp. nov. has a mean duration of 6.1 ± 0.6 s (5.2– 7.3 s; n = 40), with inter-call intervals averaging 67.1 ± 18.7 s (range: 42.7– 110.9 s; n = 40). Calls consist of 27.0 ± 3.8 notes (22–34; n = 40), each with a duration of 0.02 ± 0.002 s (0.004 – 0.094 s; n = 1079) and inter-note intervals of 0.19 ± 0.015 s (0.06– 0.39 s; n = 1040). The note emission rate is 4.3 ± 0.2 notes/s (4.0–4.9 notes/s), each note has a mean of 15.5 ± 2.4 pulses (range 1–37), which are emitted at a rate of 403.36 ± 69.58 (117.6–952.3) pulses/s. The first five notes typically contain fewer pulses (1–13) than the following ones. The advertisement call of P. gravata exhibits an ascending pattern of amplitude modulation, with the initial intensity being low and generally increasing gradually over the first eight notes, after which the amplitude tends to stabilise. However, the individual notes themselves display an inverse structure, each beginning with high intensity and decreasing in amplitude to form a distinct descending pattern (Fig. 6)

The mean dominant frequency of calls is 3.31 ± 0.28 kHz (2.75–3.83 kHz; n = 40), while notes exhibit a mean dominant frequency of 3.2 ± 0.3 kHz (1.33–4.17 kHz; n = 1079). In 37.5% of calls (n = 15), the first two notes displayed dominant frequencies below the mean (1.33–2.5 kHz). The 90% bandwidth averages 1.5 ± 0.1 kHz (1.4–1.7 kHz; n = 40). The 5% and 95% frequency limits are 2.4 ± 0.3 kHz (1.7–2.9 kHz) and 4.0 ± 0.2 kHz (3.4–4.7 kHz), respectively (n = 40 for both).

Bioacoustic comparisons with congeners

The number of notes per call in Phyllodytes gravata sp. nov. (27 ± 3.8; 22–34; n = 40) is greater than in P. amadoi (14.5 ± 1.0; 13–17; n = 17, Vörös et al. 2017), P. acuminatus (1–4, Campos et al. 2014), P. gyrinaethes (4.9 ± 0.6; 4–6, Roberto & Ávila 2013), P. luteolus (8–15, Weygoldt 1981), P. megatympanum (13.37 ± 2.56; 10–19; n = 19, Marciano et al. 2017), P. melanomystax (1, Nunes et al. 2007), P. praeceptor (8.3 ± 1.5, 6–12; n = 28, Orrico et al. 2018), and P. wuchereri (10–21, Cruz et al. 2014; Magalhães et al. 2015). However, there is overlap with the upper range of P. tuberculosus (18.6 ± 3.3; 14–23; n = 5, Juncá et al. 2012).

The call duration of P. gravata sp. nov. (6.1 ± 0.6 s; 5.2–7.3; n = 40) is longer than that of P. amadoi (3.41 ± 0.28 s; 2.99–4.11; n = 17, Vörös et al. 2017), P. gyrinaethes (1.3– 2.3 s; n = 13, Roberto & Ávila 2013), and P. melanomystax (0.07 ± 0.04 s, Nunes et al. 2007). The note duration in P. gravata (0.02 ± 0.002 s; 0.004 –0.094; n = 1079) is shorter than that of P. edelmoi (0.1 ± 0.003 s; 0.044 –0.163, Lima et al. 2008), P. luteolus (0.125 s, Weygoldt 1981) and P. praeceptor (0.295 ± 0.075 s; 0.141 –0.538; n = 235, Orrico et al. 2018).

Phyllodytes gravata sp. nov. has a lower mean number of pulses (15.5 ± 2.4; 1–37; n = 1079) than P. praeceptor (28.7 ± 9.4; n = 89), P. tuberculosus (24.55 ± 4.36; n = 40), and P. wuchereri (16.18 ± 3.2; n = 11). In contrast, its mean pulse repetition rate is higher (403.3 ± 69.58; 117.6–952. 3; n = 1079) than that of the aforementioned species (P. praeceptor: 98.9 ± 15.8 pulses/s; P. tuberculosus: 169.1 ± 28.1 pulses/s; P. wuchereri: 204.6 ± 41.4 pulses/s). Moreover, P. gravata also exhibits a higher mean pulse repetition rate than P. amadoi (368.4 ± 86.6 pulses/s).

Additionally, the pulsed call structure of P. gravata distinguishes it from species with harmonic calls such as P. acuminatus, P. kautskyi, P. megatympanum, and P. melanomystax (Simon & Gasparini 2003; Nunes et al. 2007; Campos et al. 2014; Marciano et al. 2017), and P. magnus (pulsed and harmonic, Dias et al. 2020).

Natural history and geographic distribution

Specimens of Phyllodytes gravata sp. nov. were recorded vocalizing shortly after sunset in mussununga formations in the district of Trancoso, Porto Seguro, southern Bahia, Brazil (Fig. 7). Individuals were observed in both terrestrial (Aechmea lamarchei Mez and Vriesea sp. Lindl - Bromeliaceae; Fig. 3E–F) and epiphytic bromeliads, the latter located approximately 50 cm above ground level. Some males were observed with the posterior part of their body submerged in water while vocalizing. The species was recorded at two nearby localities: (1) the Private Natural Heritage Reserve (RPPN) Rio do Brasil, encompassing an area of approximately 9 km ², and (2) Fazenda Nova Alegria. Both sites are situated within the Central Corridor of the Atlantic Forest (Fig. 7). Mussunungas are often mistaken for restinga formations; however, they occur inland as enclaves of sandy soil within Florestas de Tabuleiro (tableland forests) and are not associated with the shoreline. These ecosystems remain understudied, but existing research indicates that they harbour distinctive assemblages of flora and fauna, including several endemic and understudied species (Simonelli et al. 2008; Borges et al. 2020; Godoy & Piratelli 2020; Lima et al. 2021). Although P. gravata has so far only been recorded in mussununga, our field sampling was geographically restricted. Further research is needed to determine whether this species also occurs in adjacent vegetation types.