Oreobates barituensis, Vaira & Ferrari, 2008

Vaira, Marcos & Ferrari, Liliana, 2008, A new species of Oreobates (Anura: Strabomantidae) from the Andes of northern Argentina, Zootaxa 1908 (1), pp. 41-50 : 43-47

Oreobates barituensis sp. nov.

Figs 1–2

Holotype. FML 21079 (field number MV 268 ), adult male, calling when captured, collected at Baritú , Departamento Santa Victoria, Provincia Salta, Argentina (22º 29’ 58,53’’S 64º; 45’ 40,83’’W, 1100 m above sea level), on 25 October 2001 by M. Vaira.

Paratypes. FML 21077-21078 (field numbers MV 255-256 ), adult males, and FML 21080 (field number MV 269 ), adult female, same data as the holotype . MV 238-240 (to be catalogued at FML), adult males, same locality as the holotype , collected on 2 December 2000 by M. Vaira. MV 410-413 , adult males, collected at Arazay , Departamento Santa Victoria, Provincia Salta, Argentina (22º 19’ 0’’S 64º 42’ 59,9’’W, 1300 m above sea level), on 21 November 2007 by M. Vaira . MV 414-421 , adult males, collected at Lipeo , Departamento Santa Victoria, Provincia Salta, Argentina (22º 25’ 52.56’’S 64º 44’ 7.17’’W, 1300 m above sea level), on 23 November 2007 by M. Vaira .

Etymology. The species is named after the village of “Baritú” where the holotype specimen was collected.

Diagnosis. A species of the genus Oreobates (as reviewed by Hedges et al. 2008) characterized by (1) head wider than long, snout long, subacuminate in dorsal and lateral views, canthus rostralis straight in dorsal view, rounded in profile; (2) tympanic membrane and annulus distinct, tympanum length half of the eye length; supratympanic fold present; (3) cranial crests absent, upper eyelid with small tubercles; (4) dentigerous processes of vomers ovoid, prominent, posteromedial to choanae; (5) condition “S” of adductor muscle (sensu Lynch 1986); (6) males with vocal slits and a single faint nonspinous nuptial pad on thumb; (7) terminal discs of fingers I and II rounded not enlarged, terminal discs of fingers III and IV truncated and enlarged, circumferential grooves incomplete, ungual flap poorly defined, terminal phalanges knob-shaped, lateral fringes and keels on fingers absent, ulnar tubercles absent, prominent subarticular tubercles, enlarged and conical in profile, supernumerary tubercles conical, smaller than subarticular tubercles; (8) first finger slightly longer than second; (9) toes long, lacking lateral fringes, webbing absent; fifth toe slightly shorter than third; (10) no tubercles on heel and tarsus, prominent subarticular tubercles, enlarged and conical in profile, inner metatarsal tubercle ovoid; (11) skin of dorsum scattered with soft tubercles, scapular and sacral glands present; (12) skin of venter smooth, discoidal fold present; (13) dorsal coloration of body and head in preservative brownish-gray with black marks; limbs brownish and striped with darker bands; venter whitish cream, throat finely mottled in gray.

Oreobates barituensis differs from other Oreobates species as follows (characters of the other species in parentheses): from O. choristolemma by the absence of occipital or mid-dorsal folds (occipital W-shaped fold and/or x-shaped mid-dorsal fold), lack of axillary gland (small axillary gland), and no indented ungual flap on finger discs (notched ungual flap); from O. cruralis by head wider than long (longer than wide), and a single faint nuptial pad on thumb (no nuptial pads); from O. discoidalis by having head wider than long (longer than wide), tympanum size about half of eye length (longer than half of eye length), and a single faint nuptial pad on thumb (no nuptial pads); from O. granulosus by the skin of dorsum scattered with soft tubercles (low keratinized granules and warts); from O. heterodactylus by tympanum about half of eye length (two-thirds of the eye length), dentigerous process posteromedial to choane (medial to choane), and no ulnar tubercles (two to four ulnar tubercles); from O. ibischi by the distinct supratympanic fold (weak tympanic fold), tympanum length about half of eye length (more than two-thirds of eye length); and terminal discs of fingers III and IV enlarged and truncated (markedly enlarged and ovate); from O. lehri by skin of dorsum exhibiting low tubercles not keratinized (enlarged keratinized granules), supratympanic fold distinct and long (weak and short), fingers I and II shorter than finger IV (fingers I, II and IV of approximately the same length), and by its foot length about 50% of SVL (foot length = 60% of SVL); from O. madidi by exhibiting soft scattered tubercles on dorsum (heavily warty), and head wider than long (longer than wide); from O. pereger by the presence of discoidal fold (no discoidal fold), palmar tubercle oval (bifid), and enlarged discs on fingers (no enlarged discs on fingers); from O. quixensis by a smaller size (SVL of adults 35–63 mm), and ventral surfaces smooth (heavily mottled); from O. sanctaecrucis by its predominantly bronze brown dorsal colouration (blackish brown with red to scarlet spots in axiles); from O. sanderi by having no occipital and/or mid-dorsal fold (Wshaped occipital fold and/or x-shaped mid-dorsal fold), and the lack of supernumerary tubercles (conspicuous supernumerary tubercles); from O. saxatilis by a smaller size (SVL of adults 44.5–50 mm) and the lack of an ulnar tubercle (a single, round ulnar tubercle); from O. simmonsi by its dorsum and extremities with soft scattered tubercles (dorsum and extremities homogeneously granular), and a smooth venter (granular); and from O. zongoensis by dorsal skin with soft scattered tubercles (strongly granular), dorsum bronze brown and venter whitish cream (dorsal and ventral surfaces dark brown), and a golden iris in life (orange).

Description of the holotype. Adult male ( Figs 1–2 ); snout-vent length 27.9 mm; head slightly wider than body, head length about 30% of SVL, wider than long (head width/head length 1.1); snout subacuminate in dorsal view, and rounded in profile, tip of snout overlaps border of lower lip in lateral view, nostrils slightly protuberant, directed laterally; canthus rostralis straight in dorsal view, rounded in profile, loreal region slightly concave and moderately sloping; upper eyelid with small tubercles, eyes in lateral position, no cranial crests; supratympanic fold distinct, tympanic membrane and tympanic annulus distinct, tympanum nearly round, its length half of eye length, a large postrictal gland. Choanae rounded partially concealed by palatal shelf when roof of mouth is viewed from below; dentigerous process of vomers ovate, posteriormedial to choanae, about the size of a choanae, tongue subcircular, vocal slits present, posterolateral to tongue. Skin of dorsum scattered with soft tubercles, almost of the same size, with two larger glands on shoulders and two larger glands in sacral region surrounded by a kidney-shaped dark blotch; ventral surfaces smooth, dorsolateral folds composed by small warts, interrupted anteriorly; discoidal fold distinct.

No ulnar tubercles; palmar tubercle moderately large, outer oval larger than inner rounded tubercle; subarticular tubercles single, conical, and prominent; supernumerary tubercles conical, smaller than subarticular tubercles; a single faint nonspinous nuptial pad on thumb; disc of fingers I and II rounded not enlarged, disc of fingers III and IV truncated and enlarged; fingers lacking lateral fringes and keels; relative length of fingers III>IV>I>II.

Heel and tarsus lacking tubercles or folds; inner metatarsal tubercle ovoid, longer than wide; toes lacking lateral fringes and keels, webbing absent; fifth toe slightly shorter than third; terminal discs of toes I, II and V rounded not enlarged, discs of toes III and IV truncated and moderately enlarged; relative length of toes IV>III>V>II>I.

Coloration: In life, dorsum bronze brown, marbled with dark brown, black and cream dots. Irregular interocular dark stripe; interscapular region with yellowish oval blotch. Iris golden, marbled with black; black supratympanic stripe; lips with diffuse brown and white perpendicular bars. A black irregular stripe departs from the tip of the snout and continues to the midpart of the flanks. Dorsal surfaces of forelimbs and hindlimbs with diffuse blackish and brown bars. Venter uniformly whitish, finely mottled with light brown. Throat mottled dark brown. In preservative, dorsal coloration of body and head brownish-gray with black marks; limbs brownish, stripped with darker bands; venter whitish cream, throat finely mottled in gray.

Mean measurements (in mm) and proportions of holotype: SVL 26.2; head length 8.7; head width 8.8; eye length 2.9; eye to nostril distance 4.3; internarial distance 2.2; eye-eye distance 4.8; tympanic membrane height 1.5; tympanic membrane length 1.4; arm length 6.0; thigh length 13.4; tibia length 12.6; foot length 13.7. Tibia length/SVL 0.5; foot length/SVL 0.5; head length/SVL 0.3; head width/SVL 0.3; head width/head length 1.1; eye to nostril/eye length 1.7; tympanic membrane length/tympanic membrane height 0.9.

Variation: Range measurements (in mm) and proportions of male and female paratypes; female paratype in bold: SVL 21.2–29.9; 34.1; head length 7.6–10.5; 10.3; head width 7.7–10.1; 12.5; eye length 2.0–3.0; 3.1; eye to nostril distance 3.0–5.4; 4.8; internarial distance 1.9–2.4; 2.5; eye-eye distance 3.8–5.8; 6.2; tympanic membrane height 1.1–2.1; 2.0; tympanic membrane length 0.9–2.1; 2.0; arm length 4.7–7.0; 7.5; thigh length 10.5–15.8; 18.1; tibia length 10.5–14.5; 18.3; foot length 9.8–15.6; 16.6. Tibia length/SVL 0.4–0.5; 0.5; foot length/SVL 0.4–0.6; 0.5; head length/SVL 0.3–0.4; 0.5; head width/SVL 0.3–0.4; 0.3; head width/head length 0.9–1.2; 1.3; eye to nostril/eye length 1.5–2.0; 1.5; tympanic membrane length/tympanic membrane height 0.8–1.3; 0.9.

Most noticeable morphological differences compared to the holotype are as follows:

a – Skin of dorsum less warty (MV 255, 269, 415, 417, 418, 419) to almost smooth (MV 256, 416, 420, 421).

b – Supratympanic fold less noticeable (MV 255, 416).

c – Upper eyelid with few small tubercles (MV, 420, 421) or smooth (MV 416).

d – Discoidal fold less noticeable (MV 415, 417, 419, 421)

Distribution and natural history. Oreobates barituensis is know from three localities (Arazay, Lipeo and Baritú, Fig. 3 ), all small villages bordering the Parque Nacional Baritú, in a subtropical humid montane forest of north-western Argentina (ecoregion of Southern Andean Yungas). The area consists of a mosaic of agriculture, secondary shrub, and both primary and secondary forest. The individuals were collected while calling at dusk and night. Males were calling from the bare ground or from small rocks. The single gravid female was collected at Baritú together with calling males. The species occurred in syntopy with Oreobates discoidalis .

Advertisement call. The call of Oreobates barituensis ( Fig. 4 ) consists of a short trill formed by 5 to 6 short notes (mean 5.3 ± 0.5), with a call duration of 168 to 211 milliseconds (mean 185.3 ± 18.9). The dominant frequency peak is between 2916 and 3449 Hz (mean 3226 ± 121.26). The note duration ranged from 2 to 6 milliseconds (mean 4.3 ± 1.0) with a note repetition rate within calls ranging from 29.5 to 32.05 notes per second (mean 30.6 ± 1.01).

Comparisons with published calls descriptions: The call of O. barituensis is shorter than the call of O. cruralis (179–620 ms), O. discoidalis (379–632 ms), and O. madidi (926–1075 ms); it is similar in duration to the call of O. heterodactylus (126–245 ms), O. ibischi (89–264 ms), and O. quixensis (120–170 ms) and longer compared to that of O. sanctaecrucis (91– 97 ms). It consists of fewer notes per call than the call of O. cruralis (13–27 notes), O. discoidalis (8–11 notes), and O. madidi (28–32 notes); it is similar to O. heterodactylus (5–9 notes) and O. ibischi (4–9 notes); but longer than O. quixensis (1–5 notes) and O. sanctaecrucis (1 note per call). The note repetition rate is similar to O. madidi (29.3–30.3 notes/sec); smaller than O. cruralis (37.5–72.6 notes/sec) and larger than O. discoidalis (16.8–23.7 notes/sec) and O. sanctaecrucis (mean 10.8 notes/sec). The dominant frequency is higher compared to calls of O. ibischi (2000–2981 Hz), O. discoidalis (2114–2472 Hz), O. madidi (2412–2584 Hz), O. quixensis (720–1620 Hz) and O. sanctaecrucis (1400–2200 Hz), but slightly lower when compared to O. cruralis (2900–3800 Hz) and O. heterodactylus (2876–4134 Hz).

Comparison with the advertisement call of O. discoidalis from Abra de Cañas, Argentina ( Fig. 5 ): The 10 call recordings of two individuals of this population consist of a long melodious call formed by 10 to 13 notes, with a call duration of 550 to 720 milliseconds (mean 634 ± 57.13). The note duration ranged from 24 to 40 milliseconds (mean 31.6 ± 3.3) with a note repetition rate within calls ranging from 18 to 18.7 notes per second (mean 18.2 ± 0.27). The dominant frequency peak is between 1902 and 2164 Hz (mean 2068 ± 63.5). In comparison, the call of O. barituensis is very distinctive with a notably shorter call length and fewer notes per call. The note duration is shorter, but with a longer repetition rate. The dominant frequency is considerably higher.

Comparison with the advertisement calls of O. cf. cruralis from Bolivia: The calls of O. cf. cruralis from the Bellavista Mountains reported by Reichle et al. (2001) and Padial et al. (2008b) are notably similar to the calls emitted by O. barituensis (see spectogram of Fig. 2B in Padial et al. 2008b). Despite some disparity in the number of notes per call (4 to 13 notes in O. cf. cruralis ) the call length (107–392 ms), note repetition rate (33.65–37.4 ms), and dominant frequency (2880–3400 Hz) are very similar. In comparing the calls of O. cf. cruralis from la Hoyada with O. barituensis , we found noticeable differences in call length (326–338 ms), number of notes per call (9–10 notes), and dominant frequency (2680–2831 Hz).

Figures

FIGURE 1. Holotype of Oreobates barituensis sp. nov. in life (FML 21079).

FIGURE 2. Dorsal and lateral view of head, palm and plantar of holotype of Oreobates barituensis sp. nov. (FML 21079). Scale = 1 cm.

FIGURE 3. Distribution of Oreobates barituensis sp. nov. in the montane forests of Northwestern Argentina. The square represents the type locality and stars denote the other localities of collection.

FIGURE 4. Oscillogram and sound spectrogram of advertisement call of holotype of Oreobates barituensis sp. nov. (FML 21079, SVL 27.9 mm), recorded on 25 October 2001 at type locality. Air temperature during recording 17.5 °C.

FIGURE 5. Oscillogram and sound spectrogram of advertisement call of Oreobates discoidalis from Abra de Cañas, northern Argentina (MCN 361, SVL 27.7 mm), recorded on 08 November 1996. Air temperature during recording 20.2 °C.