Oreophrynella seegobini, Kok, Philippe J. R., 2009

Kok, Philippe J. R., 2009, A new species of Oreophrynella (Anura: Bufonidae) from the Pantepui region of Guyana, with notes on O. macconnelli Boulenger, 1900, Zootaxa 2071, pp. 35-49 : 36-40

Oreophrynella seegobini sp. nov.

Figs. 1–3

Holotype. IRSNB 1979 (field number PK 2052), an adult male collected by Philippe J. R. Kok, Paul Benjamin and Claudius Perry, 29 November 2007 at 16h45, summit plateau of Mount Maringma, Cuyuni- Mazaruni District, Guyana (05° 12’ 59”N, 060° 35’ 05”W, 2088 m elevation).

Paratype. IRSNB 1980 (field number PK 2053), an adult male with same data as holotype.

Etymology. It is my pleasure to name this species in honour of my friend Giuliano “Kinky” Seegobin to acknowledge him for his friendship, hospitality, and always enthusiastic help during field work in Kaieteur National Park, Guyana. Kinky (as nicknamed by his friends and diamond miner colleagues) developed a keen interest in amphibians and reptiles and is continuously ready for a collecting trip, even in the middle of the night. He unfortunately cancelled the Maringma expedition due to a health issue.

Diagnosis. The new species is assigned to the genus Oreophrynella because of the following suite of characters: habitus bufoniform, parotoid glands absent, adult size less than 38 mm, Toes I–II opposed to III–V, thick skin between digits, skin tuberculate, tympanum absent. No other anuran in northern South America shares this combination of characters.

In addition to the aforementioned diagnostic characters, the following features characterize the new species: (1) small size (up to 20.6 mm SVL in male, female unknown); (2) frontoparietal crests indistinct; (3) postorbital crests prominent; (4) prominent short suborbital crests; (5) dorsal skin minutely spiculate with scattered medium to large, elevated, oval and round tubercles; (6) ventral skin anteriorly rugose with few large, flat, round granules, posteriorly tuberculate; (7) webbing on hand and foot well-developed; (8) adult dorsal colour in life blackish brown; (9) adult ventral colour in life dark brownish orange; (10) one vocal slit present on the left or on the right side of the floor of the buccal cavity.

Oreophrynella seegobini is immediately distinguished from all its known congeners, except O. weiassipuensis Señaris, DoNascimiento and Villarreal, 2005 by indistinct frontoparietal crests and prominent postorbital crests.

In addition to the cephalic crests condition, Oreophrynella seegobini further differs from O. dendronastes Lathrop and MacCulloch, 2007 and O. macconnelli by well-developed webbing (basal in O. dendronastes and O. macconnelli ), blackish brown dorsal colour in life (light brownish orange to olive brown in O. dendronastes and O. macconnelli ) and dark ventral colour in preservative (creamy yellow in O. dendronastes and O. macconnelli ); from O. nigra Señaris, Ayarzagüena and Gorzula, 1994 by well-developed webbing (moderate in O. nigra ), low density of large tubercles (high density of small closely-set tubercles in O. nigra ) and dark brownish orange belly in life (blackish brown in O. nigra ); from O. quelchii by well-developed webbing (moderate in O. quelchii ), low density of large tubercles (high density of tubercles in O. quelchii ) and dark brownish orange belly in life (bright orange with black mottling in O. quelchii ); from O. vasquezi Señaris, Ayarzagüena and Gorzula, 1994 by well-developed webbing (moderate in O. vasquezi ), low density of large tubercles (high density of closely-set tubercles in O. vasquezi ) and dark flanks in life and in preservative (distinctly lighter than dorsum in O. vasquezi ); from O. cryptica Señaris, 1995 by well-developed webbing (basal to moderate in O. cryptica ), blackish brown dorsal colour in life (dark reddish brown in O. cryptica ), and dark ventral colour in preservative (creamy white, often with a dark patch in the centre of the belly in O. cryptica ); and from O. huberi Diego-Aransay and Gorzula, 1990 by well-developed webbing (basal to moderate in O. huberi ), blackish brown dorsal colour in life (rufous-orange in O. huberi ), and dark ventral colour in preservative (creamy white in O. huberi ).

The new species is distinguished from Oreophrynella weiassipuensis by [characters of O. weiassipuensis according to Señaris et al. (2005) are in parentheses] having more prominent postorbital crests that are straight or slightly anteriorly concave (less developed, posteriorly concave), short prominent suborbital crest (indistinct), prominent canthal ridge extending roughly from tip of snout to halfway between nostril and upper eyelid (low), eye-nostril distance 79–86% of eye diameter (59%), larger and more prominent dorsal tubercles, ventral skin anteriorly rugose with large, flat, round granules, posteriorly tuberculate (granular with few small tubercles), a blackish brown dorsal colour without mid-dorsal line (reddish brown with darker marks and a thin dark brown mid-dorsal line), a dark brownish orange ventral colour with a black mid-ventral line (light reddish brown without black mid-ventral line), and orange palm and sole (light brown).

Description of the Holotype. Adult male ( Figs. 1 A–D, 2A, C), head slightly wider than long, HL 34% SVL, EN 86% EYE. Snout with a small fleshy conical projection on the tip, acuminate in profile, projecting beyond the level of the lower jaw, SL 1.4x EYE; loreal region smooth, vertical, slightly concave; canthus rostralis distinct, angular, with a prominent canthal ridge extending roughly from tip of snout to halfway between nostril and upper eyelid; nostrils protuberant directed laterally; internarial area highly concave; IND 117% EN; IOD 0.8x SL, 31% HW, with a few medium-sized tubercles; frontoparietal crests indistinct. Temporal region vertical, postorbital crest well-developed, prominent, very sharp, anteriorly inclined, almost straight, slightly concave anteriorly; tympanum absent; sharp subocular crest well visible, shorter than eye length, not connecting with postorbital crest; tongue lanceolate, wider posteriorly, 35% longer than wide, attached anteriorly, posterior quarter free. One vocal slit on the left side (absent on the right side), short, lateral. Premaxillary and maxillary teeth absent; choanae small, round; odontophores and vomerine teeth absent.

Forelimbs long, slender; axillary membrane absent; hands moderately large, relative finger lengths III>II=IV>I, fingers flattened, tips not expanded; palm, fingers and webbing covered by numerous small, round, supernumerary tubercles; subarticular tubercles larger than surrounding supernumerary tubercles; thenar and palmar tubercles conspicuous, prominent, thenar tubercle at base of first finger, ovoid, subequal to round palmar tubercle; webbing well-developed ( Fig. 3 A).

Hindlimbs long, slender, TIB 39% SVL, femur slightly longer than tibia (FEM 104% TIB), tibiotarsal articulation extending to jaw articulation when hindlimbs adpressed along body; feet moderately large; FOOT 84% TIB; Toes I–II opposed to III–V, relative toe length IV>I>V>II=III, toes flattened, tips not expanded; sole, toes and webbing covered by numerous small, round, supernumerary tubercles; subarticular tubercles larger than surrounding supernumerary tubercles; inner and outer metatarsal tubercles small, of size similar to subarticular tubercles at the base of Toes II–V, inner metatarsal tubercle slightly larger than outer one; webbing well-developed ( Fig. 3 B).

Cloacal opening directed ventrally at mid-level of thighs, covered by a fleshy sheath.

Dorsal skin minutely spiculate with scattered medium to large oval and round, conspicuously elevated tubercles; top of head with a few medium-sized to large tubercles, upper eyelid covered with smaller tubercles, those close to the external margin aligned in a more or less distinct row; limbs densely covered by medium-sized to large round tubercles ( Fig. 1 A–C). Ventral skin anteriorly rugose with few scattered large, flat, round granules, posteriorly tuberculate ( Fig. 1 D).

Measurements of the Holotype (mm). SVL 20.0; HL 6.8; HW 7.8; SL 3.0; EN 1.8; EYE 2.1; IND 2.1; IOD 2.4; HAND 4.7; FEM 8.1; TIB 7.8; FOOT 6.6.

Colour in life. Dorsum, top of head and flanks blackish brown, lower arm, hindlimbs and top of hands and feet slightly lighter than dorsum. A bright yellowish orange spot at arm insertion on the left side, lacking on the right side where the area is dark brownish orange. Upper eyelids and lateral surfaces of snout dark brownish orange ( Fig. 1 A–C). Throat, chest and anterior part of belly dark brownish orange, posterior part of belly and area below vent blackish brown. A black mid-ventral line running from tip of lower jaw to posterior part of belly, slightly curved sinistrally. Ventral surface of limbs brownish orange. Palms and soles orange ( Fig. 1 D). Iris dark greenish brown with inconspicuous dark grey streaks.

Colour in preservative. Dorsal surfaces very dark brown, dorsal surfaces of hands and foot slightly lighter ( Fig. 2 A). Ventral surfaces dark greyish brown, with a black patch below vent. Black mid-ventral line running from tip of lower jaw to posterior part of belly more conspicuous than in life. Palms and soles light grey ( Fig. 2 C).

Variation. The paratype is very similar to the holotype, except as follows: EN 79% EYE; SL 0.8x EYE; IND 105% EN; IOD 1.3x SL, 29 % HW; TIB 38% SVL; FEM 108% TIB; FOOT 86% TIB; inner metatarsal tubercle proportionally larger and more conspicuous, outer indistinct; subocular crest longer and more conspicuous; tongue proportionally wider posteriorly; one vocal slit on the right side (vs. on the left side in the holotype); dorsal colour slightly darker, absence of yellowish orange spot at arm insertion ( Figs. 1 E, 2B); ventral surface of hindlimbs dark brown (instead of brownish orange); mid-ventral line slightly curved dextrally ( Figs. 1 F, 2D).

Measurements of the Paratype (mm). SVL 20.6; HL 7.0; HW 7.9; SL 3.0; EN 1.9; EYE 2.4; IND 2.0; IOD 2.3; HAND 4.6; FEM 8.4; TIB 7.8; FOOT 6.7.

Distribution and ecology. Oreophrynella seegobini is currently known only from the type locality, the summit of Maringma tepui in Guyana ( Figs. 4A –B).

Both specimens were collected on the same day at the same time (16h45), ca. 1.0 m from each other. The holotype was walking slowly on the muddy ground, while the paratype was found hidden under a rotting bromeliad leaf. Habitat consists of tepui scrub ( Fig. 5 , see Kok 2008 for details on the vegetation of the summit of Maringma tepui). Both specimens emitted a soft “peep” when handled, a similar sound that was heard around the camp in early morning and before sunset. It is thus probable that the call of the species is a soft “peep-peep-peep” similar to the call of other high elevation Oreophrynella species ( McDiarmid & Gorzula 1989, D. B. Means, pers. comm.). The species might be more abundant than expected, but difficult to find due to minute size and cryptic colouration. More colour photographs of the habitat of the species are in Kok (2008). The only other amphibian species collected during our stay on the summit of Maringma tepui (25–30 November 2007) are Anomaloglossus cf. roraima , A. sp, and Hypsiboas sibleszi .

Figures

FIGURE 1. Oreophrynella seegobini sp. nov. A – C: Dorsolateral and dorsal views of the holotype in life (IRSNB 1979, 20.0 mm SVL). D: Ventral view of the holotype in life. E: Dorsolateral view of the paratype in life (IRSNB 1980, 20.6 mm SVL). F: Ventral view of the paratype in life.

FIGURE 2. Oreophrynella seegobini sp. nov. A: Dorsal view of the holotype (IRSNB 1979, 20.0 mm SVL) in preservative. B: Dorsal view of the paratype (IRSNB 1980, 20.6 mm SVL) in preservative. C: Ventral view of the holotype in preservative. D: Ventral view of the paratype in preservative. Scale bar is 10 mm.

FIGURE 3. Oreophrynella seegobini sp. nov., preserved holotype (IRSNB 1979, 20.0 mm SVL, ventral view). A: Left hand. B: Left foot. Scale bars are 1 mm.

FIGURE 5. The summit of Maringma tepui, habitat of Oreophrynella seegobini sp. nov. (29 November 2007).

FIGURE 4. A: Map of the Guiana Shield, dark arrow indicates location of Maringma tepui (in red). B: Area map of Maringma tepui showing the type locality of Oreophrynella seegobini sp. nov. (brown dot) and the collecting locality of O. macconnelli (orange dot). Coordinates and boundary with Brazil are approximate and based on the available map (note that there is a substantial difference in the country boundary between this map and that shown in Google Earth). Maps elaborated after “ Roraima Sheet 40 SE ” published by the Survey Department of Guyana, 1972, and a radar image of South America by NASA / JPL / NIMA available at http: // photojournal. jpl. nasa. gov / catalog / PIA 03388.