Bokermannohyla diamantina Napoli and Juncá, 2006

Napoli, Marcelo Felgueiras & Juncá, Flora Acuña, 2006, A new species of the Bokermannohyla circumdata group (Amphibia: Anura: Hylidae) from Chapada Diamantina, State of Bahia, Brazil, Zootaxa 1244, pp. 57-68 : 59-66

Bokermannohyla diamantina Napoli and Juncá , sp. nov.

( Figs. 1–3 )

Holotype. MZUEFS 1784, adult male, from Riacho do Tijuquinha, Serra dos Barbados, District of Catolés de Cima, Municipality of Abaíra (13o16’08’’S; 41o54’39’’W; 1700 m altitude), State of Bahia, Brazil, collected by Flora Acuña Juncá, on 14–15 February 2004.

Paratopotypes. Adult males: MZUEFS 1785 and UFBA 5053, collected with holotype; UFBA 5054, on 12 February 2004; MZUEFS 1781, on 14 February 2004; UFBA 5055, on 15 February 2004. Adult female: MZUEFS 1798, on 14–15 February 2004. All collected by Flora Acuña Juncá.

Diagnosis

Species characterized by the following combination of traits: medium size (SVL 46.7–51.7 mm in adult specimens); head length 2.8–2.9 times smaller than SVL; tympanum medium­sized, its diameter 1.3–1.5 times smaller than eye diameter (TD/SVL 0.07–0.08); thigh and tibia lengths 0.48–0.52 and 0.49–0.51 of SVL, respectively; dorsum medium to blackish brown, with weak transverse dark brown bars; flanks, anterior, and posterior surfaces of thighs with dark transverse brown stripes, without additional thin stripes between them; vocal slits in adult males; advertisement call with 2–4 notes, and dominant frequencies from 0.39–0.56 kHz.

Comparison with other species

Bokermannohyla diamantina (SVL 46.7–51.7 mm) is larger than B. astartea , B. feioi , B. ibitipoca , B. nanuzae , B. sazimai (combined species SVL 30.2–44.1 mm), and B. ravida (SVL 30.1–47.6 mm), but smaller than B. caramaschii , B. carvalhoi , B. circumdata , B. gouveai , B. luctuosa (combined species SVL 55.2–71.6 mm), and B. hylax (SVL 51.4–59.6 mm). The tympanum diameter of B. diamantina (TD/SVL 0.07–0.08) is smaller than in B. caramaschii and B. luctuosa (combined species TD/SVL 0.08–0.10), but larger than in B. astartea , B. sazimai , B. ahenea , B. carvalhoi , B. feioi , B. lucianae (combined species TD/SVL 0.04–0.06), B. nanuzae , B. hylax , and B. ibitipoca (combined species TD/ SVL 0.05–0.07). The shorter head distinguishes B. diamantina (SVL/HL 2.8–2.9) from males of B. astartea , B. hylax , B. izecksohni , B. lucianae , and B. ravida (combined species SVL/HL 2.4–2.7). The narrower head distinguishes B. diamantina (SVL/HW 2.7–2.9) from males of B. ravida (SVL/HW 2.5–2.7). The shorter thigh and tibia lengths distinguish B. diamantina (THL/SVL 0.48–0.52; TL/SVL 0.49–0.51, respectively) from males of B. izecksohni (THL/SVL 0.53–0.55; TL/SVL 0.52–0.55, respectively). Dorsum blackish brown or with weak transverse dark brown stripes in B. diamantina , cream color in B. ibitipoca and B. sazima , the latter with reticulated thin brown stripes and random brown dots over it; also, B. gouveai , B. carvalhoi , B. ahenea , and B. astartea have immaculate dorsa (the two latter with dorsal surfaces golden brown), and B. nanuzae lacks distinct transverse brown bars over it. A dorsolateral blackish brown stripe from tip of snout to inguinal region distinguishes B. feioi from B. diamantina , which lacks such stripe. Flanks, anterior, and posterior surfaces of thighs with dark transverse brown stripes in B. diamantina , they are immaculate in B. nanuzae , B. feioi , and B. lucianae , with thin and fragmented stripes in B. carvalhoi , and with thin brown stripes intercalated with transverse brown bars in B. hylax . The presence of vocal slits in adult males distinguishes B. diamantina from B. caramaschii and B. izecksohni , which lack such structures. The advertisement call distinguishes B. diamantina from all other species of the B. circumdata group for which such data is available (see below).

Description of adult specimens

Descriptive statistics in Table 1 . Medium sized species (SVL 46.7–51.7 mm). Head wider than long, its width and length 2.7–2.9 times smaller than snout­vent length. Internarial distance smaller than eye­nostril distance and eye diameter, the latter larger than eye­nostril distance. Snout slightly truncate in dorsal outline, and rounded in lateral outline. Canthus rostralis rounded. Loreal region slightly concave. Tympanum mediumsized, nearly circular, its width 1.28–1.50 times smaller than eye diameter. Supratympanic fold distinct, covering partially the tympanum. Nostrils directed laterally. Internarial region slightly furrowed. Vomerine teeth present in two angular patches between choanae. Tongue cordiform. Vocal sac single, subgular. Vocal slits distinct. Forearm hypertrophied, with a weak dermal fringe. Third finger disc diameter equal or larger than fourth toe disk. Subarticular tubercles rounded. Distal tubercle of fourth finger bifid. Supernumerary tubercles present. Palmar tubercle divided. Prepollex large, curved, single (not bifid), and with protruding prepollical spine. Modal webbing formulae notation, I 2 3/4–2 3/4 II 2 ­–3 III 2 1/2– 2 IV. Thigh length larger than tibia length, their sum larger than snout­vent length (with exception of the holotype, in which thigh length is smaller than tibia length, and their sum is smaller than snout­vent length). Subarticular tubercles rounded. Supernumerary tubercles distinct. Inner metatarsal tubercle ovoid. Modal webbing formulae notation, I 2 ­ – 2 II 1–2 1/2 III 1 +–2 1/ 2 IV 2– 1 V. Dorsal and ventral surfaces of arms smooth. Belly, throat, chest, and ventral surfaces of thighs glandular.

FIGURE 4. (A) Power spectrum, (B) audiospectrogram, (C) oscillogram of the advertisement call, and (D) oscillogram of the second note figured of the advertisement call of Bokermannohyla diamantina sp. nov. from the Municipality of Abaíra, State of Bahia, Brazil. Air temperature 22o C.

Color in life

Dorsal surfaces dark brown to blackish brown ( Fig. 2 ), with weak transverse dark brown bars on dorsum, flanks, arms, thighs, shanks, tarsus, and feet. Belly and ventral surfaces of chest, throat, and thighs vivid yellow; ventral surfaces of arms, hands, shanks, tarsus, feet, and anterior and posterior surfaces of thighs purple.

Color in preservative

Dorsal surfaces medium to blackish brown, with weak transverse dark brown bars on dorsum, flanks, arms, thighs, shanks, tarsus, and feet. A weak brown vertebral stripe might be present from the tip of snout to the middle of dorsum. Canthus rostralis delimited by a weak subcanthal dark brown stripe. Flanks pale cream with transverse dark brown bars; anterior and posterior faces of thighs medium brown; ventral surfaces pale cream.

nov. from the Municipality of Abaíra, State of Bahia, Brazil. n = number of specimens; X = mean; Min = minimum; Max = maximum; SD = standard deviation. Values in millimeters.

Measurements of holotype

SVL 51.7, HL 17.7, HW 18.7, ED 4.8, END 4.3, TD 3.7, UEW 3.7, IOD 6.0, IND 3.4, NSD 2.8, THL 25.3, TL 25.5, FL 35.8, 3FD 2.5, 4TD 2.2.

Specimens Sexual dimorphism

Adult males of Bokermannohyla diamantina have hypertrophied forearms, enlarged prepollices, and vocal slits, characteristics absent in females.

Advertisement call

The following description is based on advertisement calls from three recorded males. Social interactions among males were not noticed. The call (Fig. 4A–D) is composed of 2–4 pulsed notes, usually three notes, and the first note always with lower intensity than the others. The pulses are very close to each other and present side bands, which prevented the accurate count of the pulse number of each note. Therefore, we counted only the pulses with more intensity in the notes (Fig. 4D). In this sense, the pulse number of one note varied from 21–110 pulses (X = 48.08, n = 59 notes, SD = 23.16). The call duration is 0.63– 1.85 s (X = 1.16, n = 51, SD = 0.29). The interval between calls is 65.45– 3.79 s (X = 8.89, n = 48, SD = 9.81). Note duration between 0.14– 0.40 s, with trend to increase the duration from the first to the last note, and note rate between 2.77–6.13 notes per second ( Table 2 ). Two main energetic bandwidths are clearly distinguishable in the audiospectrogram (Fig. 4B), and two peaks of intensity can be observed on the power spectrum (Fig. 4A). Low frequency is 0.22–0.29 kHz (X = 0.26, n = 51, SD = 0.02) and high frequency 2.08–2.75 kHz (X = 2.45, n = 51 SD = 0.23). The dominant frequency is 0.39–0.56 kHz (X = 0.40, n = 49, SD = 0.03), but in one specimen (MZUEFS 1799), two, of a total of 17 calls analyzed, displayed the dominant frequency in the upper bandwidth (1.59 and 1.63 kHz). This alteration in the dominant frequency may correspond to a change between the two peaks of intensity observed in all calls analyzed.

The advertisement call of Bokermannohyla diamantina is distinguished from the calls of the other species of the B. circumdata group by the general singular structure and by the lowest dominant frequency (0.39–0.56 kHz; 1.25–2.80 kHz; respectively).

Natural history

Bokermannohyla diamantina occurs in gallery forests along creeks surrounded by rocky mountain fields called “Campo Rupestre”, a biome typical in Chapada Diamantina (for description of “Campo Rupestre” see Rizzini 1979). The three males heard were calling from the central axis of an epiphytic bromeliad, a cavity under a rock on the side of a stream, and on the ground in an open field near the stream, respectively. Two individuals were collected in a gallery forest, and four in the “Campo Rupestre” near a stream, all at night. Only one individual was collected during the day, resting inside the gallery forest.

Etymology

The specific name, a noun in apposition, refers to the Chapada Diamantina , the region in the State of Bahia in which is located the type locality of the new species.

Geographic distribution

Bokermannohyla diamantina is only known from the type locality (13o16’08’’S; 41o54’39’’W; 1700 m altitude), Municipality of Abaíra, in Serra dos Barbados. The Serra dos Barbados is a mountain range with altitude varying from 600 to 2033 m, being the highest point of the State of Bahia, and is comprised in the Brazilian semiarid. The mountain scenery contains ecosystems like Caatinga, Cerrado, Campo Rupestre (“rock fields”), Deciduous and Semi­Deciduous Mountain Forests, and gallery forests. This mountain range belongs to the “Área de Proteção Ambiental Serra dos Barbados ”, that is a protected area with sustainable management.

Comments

The species of the Bokermannohyla circumdata group mainly inhabit large forested areas of the Tropical Atlantic Domain near the Brazilian Atlantic coast (see Ab’Sáber 1977 for description of Brazilian morphoclimatic domains). However, species of this group have been encountered far from the Atlantic coast, occurring in Cerrado and Caatinga domains, and also at high elevation fields in the Tropical Atlantic Domain (e.g., B. diamantina , B. circumdata , B. feioi , B. ibitipoca , B. nanuzae , B. ravida , and B. sazimai ), but always associated to gallery forests. This pattern of distribution suggests that the occurrence of species of the B. circumdata group in Cerrado and Caatinga domains is due to the presence of gallery forests, which provide, in some degree, environmental conditions similar to the Atlantic Tropical forests from coastal Brazil, and therefore these species should not be considered as characteristic taxa of Cerrado and Caatinga biomes.

Figures

FIGURE 1. Holotype of Bokermannohyla diamantina sp. nov., MZUEFS 1784, adult male, SVL 51.7 mm.

FIGURE 2. Living specimen of Bokermannohyla diamantina sp. nov., an adult male from the type series (not identified). Photograph by F. A. Juncá.

FIGURE 3. Bokermannohyla diamantina sp. nov., MZUEFS 1784, holotype, adult male. (A) Dorsal and (B) lateral views of head; (C) hand, and (D) foot. Horizontal line equals 5 mm.

Tables

TABLE 1. Descriptive statistics of adult males and a female of Bokermannohyla diamantina sp.

	Males (n = 6)		Female (n = 1)
X	Min Max	SD
SVL 48.28	46.7 51.7	1.95	49.4
HL 17.03	16.6 17.7	0.43	16.9
HW 17.18	16.0 18.7	0.92	17.2
ED 4.97	4.8 5.5	0.29	4.8
END 4.15	3.9 4.3	0.15	3.9
TD 3.77	3.3 4.3	0.33	3.9
UEW 3.80	3.7 4.0	0.12	4.0
IOD 5.55	5.2 6.0	0.36	5.4
IND 3.30	3.1 3.4	0.13	3.3
NSD 2.77	2.4 3.0	0.24	2.7
THL 24.58	23.2 25.3	0.79	24.4
TL 24.31	23.2 25.5	0.78	23.8
FL 35.50	32.4 35.8	1.21	32.6
3FD 2.22	2.1 2.5	0.17	2.2
4TD 2.07	1.9 2.2	0.11	1.8
SVL/HW 2.81	2.72 2.93	0.08	2.87
SVL/HL 2.83	2.78 2.92	0.04	2.92
HL/SVL 0.35	0.34 0.35	0.00	0.34
ED/TD 1.32	1.27 1.50	0.08	1.23
TD/SVL 0.07	0.07 0.08	0.00	0.07
ED/SVL 0.10	0.09 0.11	0.00	0.09
THL/SVL 0.50	0.48 0.52	0.01	0.49
TL/SVL 0.50	0.49 0.51	0.00	0.48
THL+TL 48.90	47.1 50.8	1.43	48.2

TABLE 2. Temporal measurements of the advertisement call of Bokermannohyla diamantina sp. nov. Values are presented as mean ± standard deviation, and minimum­maximum in parentheses. Note duration in milliseconds.

	(not captured)	MZUEFS 1785 (CRC 47.00 mm)	MZUEFS 1799 (CRC 46.80 mm)
Number of calls	21	13	17
Number of notes	3	2.85±0.55 (2–4)	3.41±0.50 (3–4)
Note 1 duration	221.20±34.90 (148.32–296.63)	199.31±38.79 (150.04–262.90)	276.66±37.65 (210.23–322.23)
Note 2 duration	267.57±20.30 (228.83–307.50)	261.26±41.37 (187.55–350.53)	302.52±27.17 (271.09–381.73)
Note 3 duration	277.06±19.56 (235.98–321.80)	262.37±39.89 (175.05–326.71)	360.96±38.19 (309.67–409.40)
Note 4 duration	­	328.62	385.48±17.22
Notes per second	4.16±0.24 (3.70–4.61)	4.25±0.89 (2.77–6.13)	3.28±0.38 (2.77–3.90)