Aromobates tokuko Rojas-Runjaic, Infante-Rivero & Barrio-Amorós, 2011, sp. nov.
Creators: name: Rojas-Runjaic, Fernando J. M.
name: Infante-Rivero, Edwin E.
name: Barrio-Amorós, César L.
Publisher: name: Zenodo
Year: 2011
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Amphibia
Anura
Aromobatidae
Aromobates
Aromobates tokuko

description: Aromobates tokuko sp. nov.
English name: Perija’s Nurse Frog Spanish name: Sapito Niñera de Perijá (Figures 1–3, Table 2)
Holotype. Adult male, MHNLS 18479, from the surroundings of Ipika, Yukpa indigenous community, Río Tokuko basin, Municipio Machiques de Perijá, Sierra de Perijá, Estado Zulia, Venezuela (09°52’ N, 72°51’ W; elevation 595 m), collected on 26 November 2006, by F. Rojas-Runjaic and E. Infante.
Paratypes. Twenty-one specimens: four adult females (MHNL 18471, 18474, 18478, 18480) and two adult males (MHNLS 18473, 18476) with the same collection data as the holotype; four adult females (MHNLS 18490– 91, 18493, 18495) collected on 27 December 2006, at the holotype locality; two adult males (MHNLS 18498–99) from Kusare waterfall, near Ipika, Río Tukuko basin, Municipio Machiques de Perijá, Sierra de Perijá, Estado Zulia, Venezuela (09°52’ N, 72°50’ W; elevation 579 m), collected on 28 December 2006 by F. Rojas-Runjaic and E. Infante; three adult females (MHNLS 18521–23) and one adult male (MHNLS 18520) collected on 11 April 2007, with the same collection data as the holotype; one adult female (MHNLS 18568) and three adult males (MHNLS 18566–67, 18569), from Kiriponsa, Yukpa indigenous community, Río Tokuko basin, Municipio Machiques de Perijá, Sierra de Perijá, Estado Zulia, Venezuela (09º52’ N, 72º52’ W; elevation 1005 m), collected on 12 April 2007 by F. Rojas-Runjaic and E. Infante; one adult female (MHNLS 19748) from near Terakibu, Yukpa indigenous community, Río Tokuko, Municipio Machiques de Perijá, Sierra de Perijá, Estado Zulia, Venezuela (09º52’ N, 72º49’ W; elevation 419 m), collected on 16 September 2008 by F. Rojas-Runjaic and P. Cabello.
Referred specimens. Eight specimens: four juveniles (MHNLS 18477, 18481–83), with the same collection data as the holotype; three juveniles (MHNLS 18492, 18494, 18496) and one premetamorph (MHNL 18497), collected on 27 December 2006, with the same collection data as the holotype.
Diagnosis. (1) Skin of posterior third of dorsum, flanks, prehumeral area, dorsum of thighs and shanks granular; (2) Paired dorsal digital scutes conspicuous and protuberant on all toes; (3) Distal subarticular tubercle under FIV circular and conspicuous; (4) FIV extending past distal subarticular tubercle of FIII; (5) FI shorter than FII; (6) Digital discs present; (7) Finger discs moderately expanded; (8) Lateral fringes absent on FI and FIV, preaxials on FII and FIII, present and conspicuous on all toes; (9) Metacarpal ridge absent or, if present, very weak and almost indistinct; (10) FIII of adult males not swollen; (11) Carpal pad absent; (12) Male excrescences on thumb absent; (13) Thenar tubercle small (approximately 1/3 of the palmar tubercle and equal in size and shape to the proximal subarticular tubercle of FII) elliptical and conspicuous; (14) Black arm gland in adult males absent; (15) Tarsal keel present, well-defined and slightly curved from proximal edge of inner metatarsal tubercle, transverse across tarsus, and reaching almost the mid-tarsus where it becomes slightly wider; (16) Toe discs slightly expanded, disc of TI barely wider than distal end of adjacent phalanx (including fringes), discs of TII–TV about 1.5 times wider than distal end of adjacent phalanx; (17) Toe webbing basal between TI–TIV; (18) Metatarsal fold flat and very weak, almost indistinct; (19) dorsum uniformly dark brown or with a pale brown background and irregularly-spaced dark brown spots; (20) Dorsolateral stripe present, pale golden to cream, from tip of snout to midbody or to upper level of the groin, eventually continual with paracloacal horizontal stripes; (21) Oblique lateral stripe present but diffuse, formed by small whitish spots coincident with small non-keratinized tubercles, extending from groin to midbody; (22) Paracloacal horizontal stripe present, diffuse to very well defined; (23) Ventrolateral stripe absent; (24) Throat grayish ivory (with profusion of evenly spaced melanophores when seen under magnification) on almost all males and some females, immaculate ivory on almost all females and some males; (25) Throat collar absent; (26) Chest and belly white to ivory, rarely with pale gray or pale brown spots on chest and anterior third of belly; (27) Ventral surface of arms, thighs, shanks and tarsi pale orange; (28) Palms and soles pale gray; (29) Axillae, groins and hidden parts of hind limbs weakly yellowish; (30) Iris golden and finely dotted with black, with a transversal wide blackish band and a bright golden pupil ring; (31) Large intestine unpigmented, creamish white; (32) Adult testis whitish; (33) Median lingual process absent; (34) Tympanum ill-defined, about 1/4 concealed posterodorsally; (35) Vocal sac structure not distinct; (36) Teeth present on the maxillary arch; (37) Small size, with males up to 23.2 mm of SVL and females up to 29.2 mm.
Comparison with other species. Aromobates tokuko (characters in parentheses) differs by its small size from large species of the genus, such as A. alboguttatus (Boulenger, 1903), A. leopardalis (Rivero, 1978), A. meridensis (Dole & Durant, 1973), A. nocturnus (Myers, Paolillo & Daly, 1991), and A. capurinensis (Péfaur, 1993), all with maximum SVL> 31 mm (up to 29.2 mm). Aromobates alboguttatus has smooth dorsal skin (granular) and its venter is brown spotted with white (ivory white). Aromobates leopardalis has toes 1/3 webbed (basally webbed between TI–TIV), dorsal skin smooth with a few tubercles posteriorly (granular), a strongly spotted dorsum (without consistent pattern). Aromobates meridensis has FI slightly longer than FII (FI shorter than FII), subarticular distal tubercle of FIV indistinct (conspicuous), fringes absent on fingers (preaxial fringes on FII and FIII), tarsal keel straight and indistinct (slightly curved and well defined), dorsolateral stripes absent or, if present, very ill-defined (dorsolateral stripes always present, generally well-defined), and belly bright yellow with diffuse dark reticulation (belly immaculate ivory, occasionally with diffuse pale brown or grayish spots on anterior half, never reticulated). Aromobates nocturnus is the most peculiar and largest congener, with SVL reaching 62 mm (29.2 mm), fully webbed toes (basally webbed), belly coloration mottled with grayish white in life (immaculate ivory, occasionally with diffuse pale brown or grayish spots on anterior third), and unique nocturnal (diurnal), aquatic (riparian), and releasing a mercaptanlike odor when molested (absent). Aromobates capurinensis is a larger frog, mean SVL of females 33.4 mm (25.5 mm), with dorsal skin smooth (granular), dorsolateral stripes present but indistinct (distinct), oblique lateral stripe absent (formed by small whitish spots).
The seven other species of Aromobates (A. duranti [Péfaur, 1985], A. haydeeae [Rivero, 1978], A. mayorgai [Rivero, 1980], A. molinarii [La Marca, 1985], A. orostoma [Rivero, 1978], A. saltuensis [Rivero, 1980], and A. serranus [Péfaur, 1985]), are similar in size to Aromobates tokuko. Aromobates duranti has smooth dorsal skin (granular), FI longer than FII (FI shorter than FII), finger discs not expanded (expanded), and a gray venter with white spots (unicolor ivory without spots). Aromobates haydeeae has no fringes on fingers (fringes on FII and FIII), FI longer than FII (FI shorter than FII), tarsal fold ill-defined (well defined), dorsal color reddish copper (dark to light brown), and ventral parts orange (ivory white). Aromobates mayorgai has smooth dorsal skin with a few tubercles posteriorly (granular), ventral parts yellow (ivory white), and the oblique lateral stripe absent (formed by small whitish spots). Aromobates molinarii has FI and II equal in length (FI shorter than FII), fringes absent on fingers (preaxial fringes on FII and FIII), tarsal fold slight (well defined), toes moderately webbed (basally webbed), and the oblique lateral stripe absent (formed by small whitish spots). Aromobates orostoma has no fringes on fingers (fringes on FII and FIII), dorsal skin smooth (granular), and venter yellow (ivory white). Aromobates saltuensis has FI and FII equal in length (FI shorter than FII), dorsal skin smooth with a few tubercles posteriorly (granular), supratympanic bulge absent (present), and no tympanum (present). Aromobates serranus has a distinct tympanum (ill-defined), dorsum brown with blotches or reticulum (usually uniform, but not reticulated), and ventral parts creamy white with brown reticulation (immaculate ivory).
Description of the holotype. The holotype is an adult male of 22.6 mm SVL. Body robust, short and slightly wider than head (Fig. 1 a). Head almost as long as wide; head length 38.1% SVL; greatest head width between angles of jaws 38.7% SVL. Snout short and subacuminate in profile (Fig. 2 c), nearly rounded in dorsal and ventral view (Figs. 2 a–b). Distance eye-naris slightly shorter than eye diameter (EN/ED = 0.8). Nares are situated laterally to the tip of the snout; nares visible from the front, not visible dorsally; barely visible ventrally. Canthus rostralis faintly angular; loreal region flat. Interorbital region wider than upper eyelid; snout longer than eye length (ETS/ ED = 1.8). Tympanum ill-defined, about 1/4 of the tympanum concealed posterodorsally by low supratympanic fold formed by superficial slip of m. depressor mandibulae; tympanum is positioned closely behind eye and low, nearly touching angle of jaws. Teeth are present on maxillary arch. Vocal slits large and long, from mid-level of tongue to near angles of jaws. Tongue is slightly cordiform, 2/3 free posteriorly, without median lingual process. Dorsal skin, including dorsal surfaces of hind limbs, granular, moderately granular on upper eyelids, and smooth on forelimbs. Skin of the flanks moderately granular; tuberculate on the prehumeral area (inferoposteriorly to angle of mouth), on ventral portion of the flanks, external sides of shanks and tarsi. Ventral skin smooth on throat, chest and lower portion of belly, moderately granular on low chest, and upper belly; ventral skin smooth on ventral surface of the arms, and slightly granular on undersurface of thighs.
Hand (Fig. 2 d) is moderate in size (26.8% SVL). Relative lengths of adpressed fingers are III> IV> II> I; FIV reaches past the distal subarticular tubercle of FIII; discs of all fingers moderately expanded, round; disc on FIII 1.5 times wider than distal end of adjacent phalanx. FIII not swollen. Base of palm has a large, rounded palmar tubercle; small (approximately 1/3 of the palmar tubercle and equal in size and form to the proximal subarticular tubercle of FII), well-defined, and elliptical thenar tubercle on base of FI; one elliptical subarticular tubercle each on FI and FII, and two circular each on FIII and FIV; all tubercles very conspicuous and swollen; without supernumerary tubercles. Fringes on fingers absent on FI and FIV; preaxial fringes present on FII and FIII. Metacarpal ridge and carpal pad absent. Paired dorsal digital scutes conspicuous and protuberant in all fingers. Nuptial excrescences on thumb absent.
Hind limbs of moderate length, shank 49.8% SVL. Relative lengths of adpressed toes are IV> III> V> II> I; TI short, the tip reaching the anterior third of subarticular tubercle of TII. Toe discs slightly expanded, about 1.5 times wider than distal end of adjacent phalanx. Paired dorsal digital scutes conspicuous and protuberant in all toes. Feet (Fig. 2 e) with basal web from TI–TIV, absent between TIV and TV. One to three non-protuberant, small subarticular tubercles present (one on TI and TII, two on TIII and TV, three on TIV, the proximal one almost indistinct). Conspicuous fringes on all toes. Two metatarsal tubercles are present, including a small round outer, and an oval and protuberant inner tarsal tubercle, the latter twice the size of the former. Metatarsal fold flat and very weak, almost indistinct. With a well-defined and slightly curved tarsal keel from proximal edge of inner metatarsal tubercle, transverse across tarsus, and almost to the mid-tarsus, where it becomes slightly wider. Anal opening at upper quarter level of thighs, with a slight flap above vent.
Color in life (based on field notes of FR, 11/26/2006). The dorsal background color is pale brown, with some irregular dark brown spots extending from the interorbital region to the posterior third of the dorsum; two conspicuous paravertebral dark brown stripes present, beginning in the sacral area and joining distally above the vent. A dorsolateral pale golden stripe present on each side of dorsum, starting from tip of snout and continuing through the canthus rostralis, external edge of the upper eyelid and dorsolaterally to reach the upper level of the groin; this stripe is solid and conspicuous, iridescent when seen under magnification. Sides of body with a well-defined blackish brown lateral band from tip of snout to upper level of groin, covering the naris, the two superior thirds of the eye, and the superior third of the tympanum; the upper border of this band is almost straight and in touch with the dorsolateral pale golden stripe, while the lower border becomes broader and diffuse posterior to the tympanum. A diffuse and inconspicuous oblique lateral stripe is present from groin to midbody; it is formed by small whitish spots, coincident with small non-keratinized tubercles. Ventrolateral stripe absent. Tubercles on prehumeral area and ventral portion of the flanks whitish. Paracloacal marks whitish and diffused, forming horizontal stripes from base to middle of thighs.
Dorsal background of forelimbs pale brown. Shoulder and axilla slightly yellowish; anterior side of upper arm with a diffuse dark brown longitudinal stripe, posteriorly without marks. Forearm dorsally dotted with small and diffuse brown spots; with a ventrolateral row of irregular blackish brown spots extending from elbow to wrist. Fingers with alternating whitish and blackish brown bands; discs blackish brown with bluish digital scutes. Dorsal surfaces of hind limbs pale brown in background color; cross-barred with four to five well-defined blackish brown bars on thighs, shanks and tarsi; a longitudinal blackish brown stripe on anterior side of thigh, from groin to knee. Groin and hidden parts of hind limbs slightly yellowish. Toes banded as the fingers; discs blackish brown with bluish digital scutes.
Ventrally the throat is grayish ivory; the chest and belly ivory (with profusion of evenly spaced melanophores when seen under magnification); ventral surfaces of arms, thighs, shanks and tarsi are pale orange. Palms and soles gray. Iris is golden and finely dotted of black, with a transversal wide blackish band and a bright golden pupil ring.
Color in preservative (after three years, January 2010). Dorsal background pale brown faded to pale beige; dorsal dark brown spots and stripes turned pale brown. The golden color of dorsolateral stripe faded to pale cream (Figs. 1 a, 2b). Blackish brown lateral band, spots of the flanks, inner longitudinal stripe of the upper arm, spots of the forearms and cross-bands of the thighs, shanks, fingers and toes turned dark brown (Figs. 1 a, 2c–d). The ventral side pale ivory with a profusion of melanophores on the throat conferring a dirty aspect to this region (Fig. 1 b, 2a). Palms and soles are dirty ivory, fingers and toes spotted with pale gray (Figs. 1 b, 2d–e).
Measurements of holotype (in mm). SVL: 22.6; SL: 11.3; ThL: 11.3; FL: 10.7; HaL: 6.1; HeL: 8.6; HW: 8.8; InD: 2.8; EN: 2.1; ED: 2.6; TD: 1.1; ETS: 4.5; F3D: 0.8; T4D: 1.0; 1FiL: 3.3: 2FiL: 3.9. See Table 2 for measurements of the type series.
Variation. Aromobates tokuko is quite variable in color pattern in both sexes and it is difficult to differentiate males and females at first glance. Except by size no other sexually dimorphic characters are noticeable (Figs. 1 a– d). Males and females of similar size could only be identified by dissection or inspection of presence/absence of vocal slits. Adult females reach larger sizes than adult males; the nine adult males of the type series range in SVL from 21.7–23.2 mm (22.6 ± 0.5), while the thirteen adult females range from 21.9–29.2 mm (25.5 ± 1.8). Variation of general morphometric characters of the type series is shown in Table 2. The head length ranges from 35.0%– 39.8% SVL (37.3 ± 1.3; n = 23), and maximum head width from 35.1%–39.1% SVL (37.0 ± 1.1; n = 23). The ratio of width/length of head is somewhat variable, with the head sligthly longer than wide in 57% of the type series, slightly wider than long in 30%, and as wide as long in the remaining 13%. The ratio EN/ED is also variable but every distance eye-naris is slightly shorter than eye diameter (0.7–0.9 [0.8 ± 1.1; n = 23]). The snout in males is slightly longer than the eye (ratio ETS/ED) and more variable than in females (males: 1.3–1.8 [1.4 ± 0.2; n = 10], vs. females: 1.2–1.5 [1.4 ± 0.1; n = 13]). Hand length ranges from 23.3%–29.4% SVL (26.4 ± 1.3; n = 23). The male paratype MHNLS 18473 has FI slightly longer than FII, while the norm is that FI is shorter than FII. A metacarpal ridge is present but very inconspicuous in MHNLS 18498 (male) and MHNLS 18522 (female), and it is absent in all other specimens of the type series. A metatarsal fold is present but very weak and almost indistinct in MHNLS 18471, 18480, and 18490 (all females). Protuberant tubercles on the posterior third of dorsum, flanks, thighs and shanks are more evident in females (Figs. 1 a, c), very conspicuous in MHNLS 18478, 18490–91 and 18495.
Dorsal color patterns vary from uniform dark brown (males MHNLS 18520, 18498–99; females MHNLS 18480, 18490–91, 18523) (Fig. 3 b), to pale brown with irregularly-spaced dark brown spots (Fig. 3 a), as in the holotype (Fig. 1 a). Dorsolateral stripes yellowish cream to pale golden, generally well-defined and extending to upper level of the groin (Fig. 3 a), eventually comming into contact or continuing with paracloacal light stripes (males MHNLS 18473, 18498, 18567, 18569; females MHNLS 18478, 18480); or ill-defined and ending at level of mid-dorsum (males MHNLS 18476, 18520, 18566; females MHNLS 18471, 18490–91, 18495) (Figs. 1 c, 3b). Cross-bands on hind limbs range from four to seven, generally blackish brown and well-defined (Fig. 3 a); diffuse pale brown in MHNLS 18491, 18523 (females), and 18476 (male); hind limbs irregularly spotted with blackish brown (not cross-banded) in MHNLS 18566. Light paracloacal stripes ill-defined or absent in specimens whose dorslateral stripe is also ill-defined (males MHNLS 18476, 18566; females MHNLS 18490–91), and very welldefined in specimens with conspicuous dorsolateral stripe (males MHNLS 18498–99, 18569; females MHNLS 18478, 18480). Oblique lateral stripe almost indistinct in MHNLS 18476 (lateral background uniformly pale brown), and MHNLS 18490 (lateral background uniformly dark brown); well-defined on males MHNLS 18473, 18498–99, and 18569. Ventrally the throat, chest and belly generally are immaculate ivory in females (Fig. 1 d), and the throat is grayish ivory in males (Fig. 1 b), with a profusion of melanophores when seen under magnification (Fig. 2 a); even grayish ivory on chest in MHNLS 18499. In the males MHNLS 18473 and 18476 the throat is barely pigmented, and immaculate ivory in the male MHNLS 18499. Two females have the throat dirty ivory (MHNLS 18491 and 18495), and one female (MHNLS 18490) have weakly spotted of pale brown the throat, chest and anterior half of belly.
Distribution, habitat and natural history. Aromobates tokuko is only known from four localities in the Río Tokuko basin (Kiriponsa, near Ipika, upstream of the Kusare waterfall, and Terakibu) on the eastern versant of the Sierra de Perijá, northwestern Venezuela, between elevations of 419 and 1005 m (Fig. 4). The vegetation of this altitudinal belt was described by Huber & Alarcón (1988) as seasonal semideciduous ombrofilous basimontane forest (from 100–800 m asl), and ombrofilous submontane/montane evergreen forest (from 800–2500 m asl). The region has a biseasonal climatic regime, with a dry period from December–April, and a rainy period from May– November, with maximum rain peaks in May and October, and minimum rain in January and July (Masciangioli & Febres 2000).
Aromobates tokuko is a diurnal and cryptic riparian frog. Even though its presence in the streams can be readily detected by its vocalization, it is very hard to detect visually because males call from underneath rocks or logs, or from hollows and shelters, and exhibit a cryptic dorsal color pattern. The eleven specimens (three males, four females and four juveniles) collected near Ipika on November 2006 were found under rocks and rotten logs around a small quiet pool, in an area of about 4 m 2, along a small intermittent stream permanently shaded by dense canopy in the gallery forest. During the collecting effort (1400–1500 h), several males were heard calling from hidden sites along the stream, but we failed to record the vocalizations. Several tadpoles of A. tokuko in different larval stages were found in the pool but no adult specimen carrying tadpoles were observed. Several tadpoles, and two adults of Leptodactylus cf. wagneri were also found in syntopy with the tadpoles of A. tokuko.
On December 2006, two males (MHNLS 18498 and 18499) were collected while vocalizing at 1140 h, hidden under rocks along a shaded section of a fast moving stream, upstream from Kusare waterfall (Fig. 5). Both males were about 1.5 m apart while calling. At this locality, A. tokuko is syntopic with Rhaebo haematiticus and Leptodactylus cf. wagneri.
Finally, the specimens found at Kiriponsa (a female and three males) were collected at about 1600 h under rocks and in crevices of a large stone along a fast-moving stream. Numerous males were heard calling at this hour. The stream of Kiriponsa runs alongside an indigenous community and is surrounded by a shady coffee plantation.
Etymology. The specific epithet “ tokuko ” is a noun in apposition and refers to the river drainage where the species occurs.
description: Published as part of Rojas-Runjaic, Fernando J. M., Infante-Rivero, Edwin E. & Barrio-Amorós, César L., 2011, A new frog of the genus Aromobates (Anura, Dendrobatidae) from Sierra de Perijá, Venezuela, pp. 37-50 in Zootaxa 2919 on pages 39-48, DOI: 10.5281/zenodo.277908