Scinax peixotoi, Brasileiro, Cinthia A., Haddad, Celio F. B., Sawaya, Ricardo J. & Martins, Marcio, 2007

Brasileiro, Cinthia A., Haddad, Celio F. B., Sawaya, Ricardo J. & Martins, Marcio, 2007, A new and threatened species of Scinax (Anura: Hylidae) from Queimada Grande Island, southeastern Brazil, Zootaxa 1391, pp. 47-55 : 48-52

Scinax peixotoi sp. n.

Scinax perpusillus queimadensis Lutz, 1973 Nomen Nudum

Holotype. CFBH 9437 ( Fig. 1 ), adult male, collected at Queimada Grande Island, Municipality of Itanhaém, São Paulo state, Brazil, on 20 January 2002, by C. A. Brasileiro, R. J. Sawaya, and O.V. Marques.

Paratopotypes. Collected with the holotype: CFBH 9440, adult female; CFBH 09438­09439, adult males; ZUEC 13240, adult male; ZUEC 13241, adult female; MNRJ 39757, adult male. Collected at Queimada Grande Island by A. R. Hoge and A. T. Leão on 22 June 1947: MZUSP 31283, 31286­31287, 31291, 31293­31297, 31299, adult males; MZUSP 312884­312885, 312888, adult females. Collected at Queimada Grande Island by R. J. Sawaya on 17 December 2004: MNRJ 39758 adult female.

Diagnosis. Scinax peixotoi is a moderate­sized species (males 18.8–20.7 mm SVL, females 22.4–25.1 mm SVL) relative to other species of the Scinax perpusillus group ( Peixoto 1987, Duellman & Wiens 1992; Faivovich 2002). The species is characterized by (1) snout protruding in lateral view and subacuminate in dorsal view, (2) canthus rostralis distinct and well defined, (3) head slightly longer than wide, (4) loreal region weakly concave, (5) protruding eyes, (6) internostrils distance similar to eye diameter, (7) tibia + tigh size same or greater than SVL; (8) vestigial webbing between toes I and II, II and III, (9) dorsal skin texture slightly rugose, and (10) in preservative, dorsum silvery­colored.

Comparison with other species. Scinax peixotoi differs from S. alcatraz by its smaller size ( S. alcatraz males: 19.7–24.4 mm SVL; females 27.0– 29.8 mm SVL), a wider head (SVL/HW S. peixotoi 2.7–3.2, S.alcatraz 2.6–2.9), loreal region more concave, canthus rostralis more evident, smaller and less pronounced eyes, larger distance between nostrils ( IND /HW S. peixotoi 0.28–0.39; S. alcatraz 0.21–0.25), more rugose dorsal skin texture, and silvery and more ornamented dorsum. Scinax peixotoi differs from S. arduous by its more robust body shape, less protruding eye, more protruding snout, less wider head (SVL/HW males of S. arduous 2.9–3.4;), loreal region less concave; absence of tubercles on the loreal region, and less metallic dorsum color. Scinax peixotoi differs from S. atratus by its larger size (maximum SVL of males of S. atratus 19.2 mm, maximum SVL of females 20.0 mm; Peixoto, 1988), more robust body shape, more evident canthus rostralis, loreal region more concave, and tibia and thigh with the same size (tibia much larger than thigh in S. atratus );. Scinax peixotoi differs from S. littoreus by its more rugose dorsal skin texture, presence of supratympanic folder (absent in S. littoreous ), protrunding snout in lateral view (little truncate in S. littoreous ), and silvery and more ornamented dorsal color pattern. Scinax peixotoi differs from S. melloi by its larger size (SVL of males S. melloi , 15.9–17.00 mm, N = 10), shorter head (SVL/HL S. peixotoi 2.3–2.6; S. melloi 2.5–2.8), larger distance between nostrils ( IND /HW S. peixotoi 0.28–0.39; S. melloi 0.23–0.30), more roguse dorsal skin texture, less variable dorsal pattern, and less keratinized inner metacarpal tubercule. Scinax peixotoi differs from S. perpusillus by its more robust body shape, wider head (SVL/HW S. perpusillus 2.6–3.0; SVL/HW S. peixotoi 2.7–3.2), smaller eye diameter (DO/SVL S. perpusillus 0.12–0.14; S. peixotoi 0.09–0.12), more protrunding snout, presence of supratymapnic folder (absent in S. perpusillus ), and distinct dorsal color pattern. Scinax peixotoi differs from S. v­signatus by its more rounded canthus rostralis, less wider (SVL/HW S. v­signatus : 3.3–3.9; SVL/HW S. peixotoi 2.7–3.2) and less long head (SVL/HL S. v­signatus 2.4–2.6; S. peixotoi 2.3– 2.6); smaller eye diameter (DO/SVL S. v­signatus 0.11–0.14); tibia with the same size as the thigh (tibia larger than thigh in S. v­signatus ); distinct dorsal color pattern, and no evident v­shaped dark mark on dorsum.

The advertisement calls of Scinax peixotoi (see below) differ from those of S. arduous and S. perpusillus recorded at their type­locality (Pombal & Bastos, 2002). The notes in the call of S. peixotoi are considerably shorter and exhibit a lower dominant frequency compared to those of S. arduous (mean note duration 25 ms; mean dominant frequency 4301 Hz). The notes of S. peixotoi are longer and have lower frequency compared to those of S. perpusillus (mean note duration 14 ms; mean dominant frequency 4913 Hz).

Description of holotype. Body robust ( Fig. 1 ); head longer than wide; snout protruding in lateral view and subacuminate in dorsal view ( Fig. 2 A, B); nostrils rounded, canthus rostralis distinct, slightly rounded; loreal region weakly concave; eye protuberant; tympanum distinct, diameter about half of the eye diameter; weak supratympanic fold from tympanic region to shoulder; discrete subgular vocal sac; tongue round and large; vomerine teeth in two arc shape series; medium­sized, elliptical choannae. Arms slender; forearms slightly robust, outer metacarpal tubercle large and bifid, inner metacarpal tubercle elliptic; subarticular tubercles rounded, single; fingers without webbing; finger lengths IV <I <II <III ( Fig. 2 C). Legs robust; tibia longer than thigh; feet with an elliptical inner metatarsal tubercle; round outer metatarsal tubercle; subarticular tubercles rounded, single, toe lengths I <II <V <III <IV ( Fig. 2 D); foot webbing formula I­2 + II 2 + ­3+ III 1 +­2 IV 2 ­ ­1+V. Dorsal and ventral skin texture rugose.

Color in preservative of the holotype. Dorsum light silvery with a dark brown lateral stripe; tibia and thigh with dark brown transverse stripes; throat with black spots; venter white; undersurfaces of throat, arms, hands, fingers, thighs, tibiae, feet, and toes, white with dark spots.

Color in life of the holotype. Dorsum brownish; a dark brown line on the canthus rostralis, upper eyelids, and supratympanic fold; interorbital dark brown line; upper surface of thigh and tibia distinct with dark transversal stripes; hidden portion of shanks with irregular yellow flash color spots. Iris golden with a horizontal black bar.

Measurements of the holotype (mm). SVL 20.3, HL 8.2, HW 6.8, ED 2.3, TD 1.1, IOD 2.3, END 2.4, IND 2.2, THL 9.4, TBL 10.4, FL 7.7, HL 5.5.

Variation in the type series. In preservative, coloration of dorsum varies from light gray to dark gray. Interorbital bar and dorsal bars sometimes not evident in dark gray individuals. Females larger than males. Adhesive disks more developed in females. Females lack vocal sac and vocal slits. Measurements of 15 males and five females are presented in Table 1 .

Males (N = 15) Females (N = 5)

SD Range SD Range Vocalizations. Calls of two males of Scinax peixotoi were recorded on the night of 17 January 2002 just after a storm, at the same locality the holotype was captured. Thirty calls of those two males were analyzed. Air temperature during recordings was 23 °C. Each call is composed by 3–5 notes (= 3.9 ± 0.7 notes, N = 20 calls), with duration of 9–28 ms (= 17 ± 7 ms; N = 15 notes). Notes consisted of 4–9 pulses (= 6.2 ± 1.4 pulses, N = 30 notes) with duration range of 1–3 ms (= 1.6 ± 0.6 ms, N = 55 pulses). Call duration ranged Natural history. We visited Queimada Grande Island six times during the period of 2001–2005. Visits occurred in January, April, May, and December. We observed calling and reproductive behavior only in January 2002. Males called at night from the leaves of ground bromeliads (ca 40–60 cm in diameter) on a rock outcrop, frequently in a head­up vertical posture. Females were also found on bromeliad leaves. As observed in other species of the S. perpusillus species group ( Oliveira and Navas, 2004), S. peixotoi tend to favor clustered bromeliads, as we never observed calling males in isolated plants throughout the island. All type specimens were collected at a single large patch of bromeliads at an altitude of ca. 50 m.

Distribution. Scinax peixotoi is known only from Queimada Grande Island (24 29’S; 46 41’W), a 43 ha island about 33 km from the coast of Itanhaém, in southern coast São Paulo state.

Etymology. The specific name honors Oswaldo L. Peixoto, the first herpetologist to recognize S. peixotoi as a distinct species, and for his contributions to our understanding of the Scinax perpusillus group.

Figures

FIGURE 1. Scinax peixotoi, CFBH 9437 (holotype), adult male in life from Queimada Grande Island, Itanhaém, São Paulo, southeastern Brazil. SVL = 20.3 mm. Photo by O. A. V. Marques.

FIGURE 2. Scinax peixotoi CFBH 9437 (holotype). (A) Dorsal and (B) lateral views of head; ventral views of (C) left hand and (D) foot.

Tables

TABLE 1. Measurements (in mm) of males and females of the type series of Scinax peixotoi. Snout­vent length (SVL), head length (HL), head width (HW), tympanun diameter (TD), eye diameter (ED), interorbital distance (IOD), eye­nostril distance (END), internostril distance (IND), thigh length (THL), tibia length (TBL), foot length (FL), and hand length (HaL).

SVL	19.8	0.8	18.8–20.7	24.1	1.1	22.4–25.1
HL	8.1	0.3	7.7–8.8	9.6	0.4	9.1–10.2
HW	6.8	0.4	6.2–7.3	8.3	0.3	8.1–8.7
TD	1.2	0.1	1.0–1.5	1.3	0.1	1.2–1.5
ED	2.2	0.1	2.0–2.4	2.5	0.3	2.0–2.8
IOD	2.3	0.2	1.9–2.6	3.4	0.1	3.5–4.6
END	2.5	0.1	2.4–2.8	3.2	0.2	2.8–3.4
IND	2.2	0.4	2.0–3.2	2.4	0.1	2.3–2.6
THL	9.0	0.7	8.2–9.9	11.6	0.3	11.3–11.8
TBL	10.7	0.4	9.9–11.1	12.8	0.4	12.4–13.5
FL	7.5	0.6	6.0–8.4	9.5	0.4	8.9–9.6
HaL	5.3	0.3	4.9–6.0	6.5	0.2	6.2–6.7