Rhinella lescuri, Fouquet, Antoine, Gaucher, Philippe, Blanc, Michel & Velez-, Claudia M., 2007

Fouquet, Antoine, Gaucher, Philippe, Blanc, Michel & Velez-, Claudia M., 2007, Description of two new species of Rhinella (Anura: Bufonidae) from the lowlands of the Guiana shield, Zootaxa 1663, pp. 17-32 : 24-27

Rhinella lescuri sp. nov.

Holotype. MNHN 2006.2608, an adult male collected 16 April 2004 by Philippe Gaucher from "Saut wanapi", Haute Wanapi, French Guiana (02°30'694"N/53°494'153"W), 170m above sea level (see Fig. 1 : 18).

Paratypes. MNHN 2006.2609, MNHN 2006.2610, MNHN 2006.2612, MNHN 2006.2613, four males collected in the same time and place. MNHN 2006.2611, a female collected by Corine Sarthou at "layon savane Ouest", a very close site from the above one.

PG 103, PG 104, (Philippe Gaucher personal collection) two males collected 12 December, 2002 by Philippe Gaucher from "Crique Limonade", Saül, French Guiana (03º37’N / 53º12’W, 100 m above sea level). T3027 (Universite Montpellier-2), collected 10 March, 2001 by Philippe Gaucher from "Mitaraka-Sud", French Guiana (02°16'N / 54°31'W, 170 m above sea level). 112BM (Michel Blanc personal collection), a male collected by Michel Blanc from "Litany", French Guiana (02°26'195"N/54°25'184"W, 30 m above sea level). 121BM (Michel Blanc personal collection), a male collected by Michel Blanc from Saül, French Guiana (03º37’N / 53º12’W, 100 m above sea level). 5MC, 5'MC (Christian Marty personal collection) a female and a male collected in amplexus by Christian Marty from "camp sisam", French Guiana (04°11'N / 52°22'W, 100 m above sea level).

Diagnosis. A medium sized species of the R. margaritifera species group as defined genetically by Fouquet et al. (2007) and morphologically by Hoogmoed (1990) and Vélez-Rodriguez (2004). It is distinguished from all other species of this complex by the following combination of characters ( Fig. 5 ): (1) SVL of two females 43.7 ± 0.8 mm, of eight males 34.6 ± 4.3 mm; (2) bony knob at angle of jaws absent, corner of mouth angular; (3) canthus rostralis smooth, concave laterally, without crests; (4) heel not reaching posterior margin of eye when hindlimbs adpressed; (5) cephalic crests low; (6) neural spines indistinct; (7) tympanum large but smaller than eye diameter, round in males, ovoid in females; (8) paratoid glands relatively small, elongated posteriorly; (9) upper eyelid without projections; (10) toes about three-quarters webbed, three phalanges free on toe 4; (11) tarsal fold absent; (12) skin densely tuberculate, particularly on limbs, less between eyes and center of back in females; tubercules conical with small keratinized spicules; (13) oblique row of tubercules present from posterior corner of pratoid glands to groin; (14) snout pointed with fleshy soft ridge extending to tip of snout; (15) iris golden.

Rhinella lescurei can be distinguished from R. margaritifera (A), R. hoogmoedi , R. martyi (C), R. stanlaii , R. sclerocephala , R. roqueana ; R. alata and all the unnamed Rhinella species from Colombia identified by Vélez-Rodriguez (2004) by its smaller SVL, the absence of prominent cranial crests, and the very pointed snout due to the presence of a distinct fleshy ridge ( Table 1 and see Fig. 5 ). It can be distinguished from R. proboscidea (after Hoogmoed 1986) by its smaller SVL, densely tuberculate skin (smooth skin in R. proboscidea although see Zimmerman & Bogart, 1988) and distinct paratoids (indistinct in R. proboscidea ). Rhinella lescurei can be distinguished from R. dapsilis , by its tuberculate skin and smaller size and from R. acutirostris by its smaller SVL, more pointed snout, angular corner of the jaws, and its small supratympanic ridges (in males and females). From Rhinella scitula , it can be mostly distinguished by the poorly distinct cephalic crests, a more pointed snout, and less distinct paratoids. From R. sp. E (in sympatry in French Guiana and with which it can be easily confused) and R. castaneotica , it can be distinguished by its larger size, the color of the iris (golden vs blue to green in R. sp. E and greenish yellow in R. castaneotica ), the presence of a fleshy ridge at the tip of the snout, larger eyelids (UEW), longer tibia (TIBL), by having its nostrils closer to each other ( IND), by having a clearly distinct tympanum, the presence of a lateral row of tubercules, and the outer metatarsal tubercule only two times smaller than the inner one (three times in R. sp. (E) and R. castaneotica ). R. lescurei is distinguishable from R. magnussoni by its slightly smaller size and by the tuberculated margins of the external part of the feet and the toes.

Description of holotype. MNHN 2006.2608 ( Fig. 5 ). SVL 38.3 mm; HW 14.6 mm at angle of jaws; head shorter than wide, HL 12.8 mm. In dorsal view, snout acuminate, protruding and rounded in lateral view, with pointed vertical fleshy ridge from tip of snout to mouth; canthus rostralis strongly concave, smooth, without crests; top of head flat; cephalic crests poorly developed; paratoid poorly developed, elongated posteriously; eyelid thick, wide, densely tuberculate; nares slightly protuberant, directed dorsolaterally; corner of mouth very angular; tympanum clearly visible, ovoid.

Skin of dorsum and limbs covered with high spicules, more numerous on outer edges of limbs, eyelids, and jaws; sides with a lateral row of large tubercules. Forelimbs slender, relatively long, digits long; tips of digits slightly bulbous; lengths of fingers 4<1=2<3; webbing basal; edge of webbing spinulous; thenar (metacarpal) tubercule ovoid, subarticular and supernumerary tubercules present ( Fig. 5 ). Hindlimbs slender, inner metatarsal tubercle ovoid, approximately two times as large as outer; plantar surface with conical subarticular and many supernumerary tubercles. Length of toes 1<2<3<5<4, webbing well developed, edges of webbing very spinulose ( Fig. 5 ).

Coloration: The dorsum has a leaf like pattern with successive shades of dark to light brown ( Fig. 5 ). Dark brown triangular area are present on the head and lighter patches begin occur between the eyes and the middle of the flanks. Another dark brown mark begins at the middle of the flank and ends before the junction with legs; darker marks are also present across suface the limbs and the fingers. A large dorsal cream stripe extends from the tip of the snout to the end of the body. The flanks are dark brown except for a lighter mark under the eye. The throat is black with very smal white dots, and the belly is cream with large black spots.

Va r ia ti o n. This species is also highly polymorphic. The coloration of the back can be uniformly brown to light gray or with a variety of leaf-like patterns ( Fig. 3 a,f) with successive shades of dark to light brown or gray. A whitish mid-dorsal stripe can occur and can be very thin to 5 mm wide. Flanks are generally darker than the back.

Vo c al iz a ti on. The calls are long (several seconds) and composed of very short pulse groups that last for 30 ms ( Fig. 6 , Table 2 ). Pulse groups are spaced out by 97.2 ms and comprise 4.8 pulses / group on average. The peak frequency is 1.16 kHz and the pulses last 3.45 ms on average.

Distribution and Ecology. Rhinella lescurei is only known from French Guiana, i.e. the southwestern (Haute Wanapi and Mitaraka), central (Saül), western (Litany) and northeastern portions (Cisame camp on Approuague river, Pararé station on Aratai river). Localities range from 20 to 170 m above sea level. During the rainy season (from November to January and from March to May), males call during day time within 10 meters of slowly running water. Calling males are usually isolated from each other and perched between 0.3 and 1 m high on a vine, dead trunk or root. Amplexus is axillary.

Rhinella lescurei probably occurs in southeastern Suriname and Brazilian areas adjacent to French Guiana and Suriname. Preliminary results of an analysis of genetic data spanning the distribution of the R. margaritifera group suggest that this taxon could be endemic to the Guiana Shield ( Fouquet et al., 2007; authors’ unpubl. data).

Etymology. The name of the species honors the herpetologist Jean Lescure who has worked in French Guina for decades and is considered the most important founder of French Guianan herpetology.

Figures

FIGURE 1: Map of sampled areas adapted from Fouquet et al. (2007) and additional unpublished data. Black circles: Rhinella margaritifera (clade A), white star: R. margaritifera (clade B), white circles: R. martyi (clade C), white triangles: R. lescurei (clade D), white squares: Rhinella sp. (clade E).

FIGURE 3 A-F: Holotype of R. martyi (MNHN 2006.2601): a. dorsal view, b. profile of head, c. ventral view of left foot, d. ventral view of left hand; e: Rhinella margaritifera (clade A) (138 bm), female, in dorsal view, f. living specimen MNHN 2006.2602. Arrows indicate one of the main character to differenciate the two species.

FIGURE 6: Rhinella lescurei fragment of vocalization (two pulse-groups). (1) pulse-goup; (2) pulse.

FIGURE 5 A – F: Holotype of R. lescurei (MNHN 2006.2608): a. dorsal view, b. profile of head, c. ventral view of left foot, d. ventral view of left hand; e: Rhinella sp. E (198 bm), male, in dorsal view, f. living specimen, a male calling while perched on a vine. Arrows indicate one of the main character to differenciate the two species.