Pristimantis rivasi, Barrio-Amorós, César L., Rojas-Runjaic, Fernando & Barros, Tito R., 2010

Barrio-Amorós, César L., Rojas-Runjaic, Fernando & Barros, Tito R., 2010, Two new Pristimantis (Anura: Terrarana: Strabomantidae) from the Sierra de Perijá, Venezuela, Zootaxa 2329, pp. 1-21 : 11-17

Pristimantis rivasi sp. nov.

Figures 6 , 9

Holotype: MHNLS 18445, field number WES (Walter Schargel) 3029; an adult female with convoluted oviducts, collected by Walter Schargel, Gilson Rivas and Tito Barros on 11 August 2006, from Cerro Las Antenas, elevation 1670 m, 10°20’ N- 72°35' W, Sierra de Perijá, Municipio Rosario de Perijá, estado Zulia, Venezuela.

Paratypes: two adult males ( MHNLS 18797, 18872) from the summit of Cerro Las Antenas, elevation 1933 m, 10º19’31.0”N- 72º35’29.0”W, Sierra de Perijá, Municipio Rosario de Perijá, estado Zulia, Venezuela, collected on 26 March 2008, by F. Rojas-Runjaic and Pablo Velozo; one adult male ( MHNLS 18459) from the path to Antenas Héctor Dario Socorro, elevation 1600 m, 10º20’N- 72º34’W, collected on 31 March 2007, by T. Barros and G. Rivas; four adult males ( MHNLS 18835-36,18865-66), from the creek behind the house at Cerro Las Antenas, elevation 1449 m, 10º20’37.0”N- 72º33’41.0”W,Sierra de Perijá, Municipio Rosario de Perijá, estado Zulia, Venezuela, collected on 27 March 2008, by Fernando Rojas-Runjaic and Edwin Infante; one adult male ( MHNLS 18860), from the path between the first and second antennas, Cerro Las Antenas, elevation 1480 m, 10º19’34.2”N- 72º35’28.4”W, Sierra de Perijá, Municipio Rosario de Perijá, estado Zulia, Venezuela, collected on 27 March 2008, by Pablo Velozo and Paul Granado; three adult males ( MHNLS 19010-12), from coffee plantation near Yurumuto ( Yukpa indigenuos village), elevation 1640 m, 09º54’11.1”N- 72º54’17.0”W, Río Tokuko basin, Sierra de Perijá, Municipio Machiques de Perijá, estado Zulia, Venezuela, collected on 14 September 2008, by F. Rojas-Runjaic and Pedro Cabello.

Diagnosis. Pristimantis rivasi is a medium sized (males with SVL 25–30.8 mm, mean= 27.4 mm; one female SVL 41 mm) member of the P. unistrigatus species group. (1) Dorsal skin smooth anteriorly, having ill-defined occipital ridges, shagreen posteriorly posteriorly with conspicuous and scattered small granules; ventral skin areolate; (2) tympanum distinct, with a tympanic annulus, 43% of ED; (3) snout subovoid with truncate tip in dorsal view, truncate in profile; canthus rostralis rounded; (4) upper eyelid with small granules; (5) choanae small, round; dentigerous processes of the vomers small, slightly oblique, each with five odontophores; tongue large, cordiform; (6) males with vocal slits, subgular vocal sac, and single white nuptial pads; (7) Finger I shorter than II; (8) fingers with lateral keels; outer pads enlarged; (9) ulnar tubercles absent; (10) tarsal tubercles and calcars absent; (11) two metatarsal tubercles, inner oval, large; outer conical, very small, almost indistinct; (12) toes with well marked lateral keels; webbing basal; toes III, IV and V with relatively broad disks, slightly smaller than those on fingers III and IV; (13) in life dorsal colour creamy brown, with an ill-defined to contrasting X, W and V-shaped marks over pale brown or gray on dorsum; incomplete canthal stripe dark brown to dark olive; supratympanic stripe black; ill-defined to very contrasting transverse bars are present on legs; iris orange bronze with fine black reticulations. In preservative, female dorsal colour bluish brown with no pattern; some small dark grey spots irregularly spread; flanks with a dark brown reticulation on whitish background; cross bars on legs ill-defined; ventral colouration whitish with small irregularly spread dark brown spots, more profuse on throat, with an ill defined mid-gular line, better defined mid-ventrally; lip bars dark brown, ill-defined, more like spots; iris grey with black reticulation; males with a contrasting pattern.

Pristimantis rivasi is unique among other Pristimantis from the northern Andes of Colombia and Venezuela in the following combination of characters: tympanum with a distinct tympanic annulus, absence of calcars, all tubercles on hands and feet distinct and protuberant, except outer metatarsal tubercle, preserved dorsal skin smooth, fringes on fingers and toes; basal webbing on feet; cranial crests present.

Pristimantis rivasi (characters in parentheses) is here compared with cloud forest, subparamo and paramo inhabitants from Venezuela and nearby Colombia. The only two paramo dwellers in Perijá are known from the Colombian side. Pristimantis cuentasi can be distinguished by its flat tubercles on dorsal skin and dorsolateral folds (absent), rounded dorsal profile (truncate), no cranial crests (present), and fingers without distinct disks (large). Pristimantis reclusus has flat tubercles on dorsum (absent), no cranial crests (present), disks on fingers slightly expanded (very expanded), and a row of low ulnar tubercles (absent). Other species from the Sierra Nevada de Santa Marta in Colombia can be easily separated by not having cranial crests (present): P. carmelitae , P. insignitus , P. megalops , P. sanctamartae , P. tayrona ( Lynch & Ruíz Carranza, 1985), and P. w - nigrum (Boettger, 1892). The following three species share with P. r i v a s i the presence of cranial crests, but can be differentiated by additional characters. Pristimantis cristinae ( Lynch & Ruíz Carranza, 1985) has dorsolateral folds reaching the sacrum (absent), a rounded dorsal snout profile (truncate), one tubercle on each eyelid (absent), and tubercles on heel and outer edge of tarsus (absent). Pristimantis delicatus (Ruthven, 1917) , has a middorsal raphe (absent), a rounded dorsal snout profile (truncate), one prominent conical tubercle on eyelid (absent), and toe disks that are small and barely expanded (large, expanded). Pristimantis ruthveni ( Lynch & Ruíz Carranza, 1985) , has a middorsal raphe and paravertebral and dorsolateral folds (absent), a rounded dorsal snout profile (truncate), and disks on fingers and toes not as enlarged and expanded as in P. r i v a s i. The following three species are known from the Cordillera Oriental de Colombia, and also live in or near the Venezuelan paramo de Tamá. Pristimantis nervicus ( Lynch, 1994) , has small digital disks (large, expanded), skin with warts (absent), no cranial crests (present); P. nicefori (Cochran & Goin, 1970) , has no enlarged finger disks (present, large) ( Lynch 1994). Pristimantis anolirex ( Lynch, 1983) has flat warts on dorsum (absent), dorsolateral folds (absent), a rounded dorsal snout profile (truncate), and possess both ulnar tubercles and a calcar (absent) ( Lynch 1983). Pristimantis douglasi is a member of the P.galdi species group ( P. unistrigatus species group), with an acuminate dorsal view of the snout (subacuminate with truncate tip), ulnar and tarsal tubercles present (absent), inner tarsal fold (absent), short dorsolateral folds (absent), toe V slightly longer than III, surpassing penultimate tubercle on TIV (much longer, reaching anterior edge of distal subarticular tubercle on TIV), a labial white stripe (absent), usually a narrow white vertebral stripe (absent in the type series of P. rivasi ), cream lines on canthus, eyelids and back of scapula (absent), Pristimantis turik is the only other species of the genus with cranial crests inhabiting the Sierra de Perijá. It has a Toe V slightly longer than III, thus not falling in the unistrigatus group (Toe V considerably longer than III, with the disk on Toe V reaching the anterior edge of the distal subarticular tubercle of Toe IV); a small tympanum, 1/3 of the ED (1/2); and lacks supernumerary tubercles on palms and soles (present).

Description of the holotype. The female holotype has 41 mm of SVL ( Fig. 6 ). Head roughly as wide as long: head width 41.4% of SVL. Snout subovoid in dorsal view with the tip truncate ( Fig. 7a ), round in profile ( Fig. 7 b); EN longer than ED; nostrils not protuberant, directed dorsolaterally; canthus rostralis rounded and distinct, loreal region slightly concave. Upper eyelid with small granules. Cranial crests present, low, along postero-exterior half of the frontoparietals ( Fig. 7 c). Tympanum distinct, 43% of ED, surrounded by a tympanic annulus, with a supratympanic fold hiding little less than half of its posterodorsal section. Choanae small, rounded, not concealed by palatal shelf of maxillary arch; vomerine dentigerous processes small, slightly oblique, bearing 5 teeth each, posterior and medial to choanae. Tongue cordiform, posterior one third free.

Dorsal skin smooth anteriorly, shagreen posteriorly in preserved holotype ( Fig 8a ), with scattered tubercles and two tubercles at mid level of the nasals only notable in life ( Fig. 6 ); some small post tympanic tubercles also present (seen only in life); ill-defined occipital ridges; middorsal raphe absent; dorsolateral folds absent. Ventrally ( Fig 8 b), throat and chest smooth, belly and inferior part of thighs areolate. Ulnar, tarsal tubercles and calcars absent.

Relative length of adpressed fingers III>IV>II>I; first finger reaching first third of disk on finger II. Finger disks much broader than long, disk on finger III of right hand three times wider than adjacent phalanx; truncate except on Finger II of left hand, which looks smaller; disk on thumb distinctly expanded but smaller than those on the other fingers. Finger II disk on right hand double wide than adjacent phalanx; Finger II disk on left hand only 1.3 times wider than adjacent phalanx. Single white nuptial pads on thumbs. Lateral fringes along all fingers, weaker on thumb; giving the appearance of ill-developed basal webbing. Palmar and thenar tubercles distinct, bifid and larger the first, ovoid the last. Subarticular tubercles protuberant, single, round. Supernumerary tubercles protuberant, in rows under each finger ( Fig. 8 c).

Hind limbs relatively short; shank 53.6% of SVL. Relative lengths of appressed toes IV>V>III>II>I. IV toe disk slightly smaller than III finger disk. Toes with prominent lateral fringes; toes with basal webbing.

Disks wider than long, wider than phalanges, truncate. Inner metatarsal tubercle large, oval; outer almost indistinct, conical; subarticular tubercles protuberant, single, round; supernumerary tubercles small ( Fig 8 d).

Colour in life ( Fig.6 ). The dorsal colour is creamy brown, with an ill-defined black interorbital bar. There is a poorly defined X-shaped pattern over pale brown on the dorsum. The canthal stripe is black and cut in two on both sides; the supratympanic stripe is black. Ill-defined pale brown transverse bars are present on the legs. The iris is a bronze orange with fine black reticulations. Gilson Rivas noted that the undersides of the legs were red (GR, field notes).

Colour in preservative. Dorsal colour pattern bluish brown, with irregular darker spots spread, without any particular pattern ( Fig. 8a ). A narrow interorbital bar is almost indistinct. There are two symmetrical spots anterior to each eye, the superior one apparently forming part of a poorly defined canthal stripe, and an inferior one similar to a lip bar. Tympanic membrane dark brown; tympanic annulus bluish grey; supratympanic fold black. Three transversal bars on shanks ill-defined. Posterior part of flanks, inguinal region, and hidden surfaces of posterior extremities with a black reticulation on whitish background. Ventrally ( Fig 8 b), throat and chest dirty white with a profusion of small dark brown spots, more evident on the edges; belly whitish with less profusion of dark brown spots; a mid gular and mid ventral line is evident especially on belly. Iris grey with black reticulation.

Measurements of holotype (in mm): SVL: 41; ShL 22; HeL: 17; HW: 17.1; InD: 3.3; EN: 7; ED: 5.1; TD: 2.2; ETS: 8.3; FD: 2.4; T4D: 2.2; 1FiL: 7; 2FiL: 7.6.

Variation: Eight male paratypes have subgular sac, well-developed vocal slits, and ill defined single white nuptial pads. Their size is smaller (SVL 25–30.8 mm, mean= 27.4 mm, n = 8) than the only available female. The shape of the snout seen from above vary from truncate (holotype, MHNLS 18459, 18836, 18865, 18872) to subovoid (MHNLS 18797, 18860, 18866). The disk on fingers III and IV can be oval, round, or heart-shaped, although not notched. Dorsal pattern of males is much more contrasting (Appendix III top), usually consisting of an occipital W mark, an inverted and discontinuous V formed by dark brown spots, diagonal dark bars on flanks, and transverse vertical bars on hind limbs (from the less contrasting to the most MHNLS 18866, 18835, 18836, 18459, 18860, 18797, 18872 and 18865). Ventrally (Appendix III bottom) all are whitish, with a profusion of melanophores on the throat (from the less contrasting to the most MHNLS 18865, 18860, 18872, 18866, 18835, 18836, 18459 and 18797). The colour in life of MHNLS 18459 ( Fig 9a ) was dorsally light brown with the W and inverted V made by black spots; other marks were dark reddish brown, and forearm and hind limbs transverse bars were dark brown. A more contrasting individual (MHNLS 18860; Fig. 9 b) was whitish dorsally with the same but much defined greenish marks. The iris was in all individuals constantly golden orange with a fine black reticulation.

Natural history: Pristimantis rivasi is known from two localities: Cerro Las Antenas, between 1438 and 1945 m, and the Río Tokuko basin, between 1389 and 1640 m. At each locality, the species was collected at three different sites (see Distribution). One of the sites at Cerro Las Antenas corresponds to a section of a narrow rocky creek at 1450 m elevation, surrounded by a dense primary cloud forest. Here P. rivasi was found in sympatry with Cryptobatrachus remotus , Cochranella sp., Hyalinobatrachium tatayoi and Rhinella marina (Linnaeus, 1758) . During March 2008 (end of the dry season), several individuals were observed on leaves of bushes and palms, from the forest litter level to four meters over the ground. The second site at Cerro Las Antenas is a section of a dirt road surrounded by cloud forest between 1548 and 1620 m in elevation, and P.

rivasi was found in sympatry with P. yukpa , Hypsiboas cf. crepitans (Wied-Neuwied, 1824) and Rhinella marina . The last site at Cerro Las Antenas is a secondary and short forest at the summit of Cerro Las Antenas, at an elevation of 1933 m, with dominant tree ferns, abundant vines and Cecropia . In this last site, Pristimantis rivasi was found in sympatry with P. lassoalcalai sp. nov. The holotype was collected in this last locality, after a heavy but short rain. Male paratypes were calling from bush leaves on the talus of the road, on leaves, tree branches, shrubs and bamboo sticks.

During March and July 2008, many males of P. rivasi were vocalizing intensely in choruses, between 1800 and 2000 h., some from short plants and higher bushes and other hidden in the forest litter; afterwards, some males called sporadically to 0 130 h. The vocalization of P. rivasi is a series of clicks similar of what we could produce with the tongue against the palate. Onomatopoeically those notes can be described as “cloc, cloc, cloc,” emitted in series from a few to many, lasting for at most one minute.

During the September 2008 expedition to the Río Tokuko basin, many P. rivasi were heard vocalizing actively and also in choruses after a short rain about 2030h in a shadow coffee field. Pristimantis yukpa and another new species of Pristimantis (F. Rojas.Runjaic et al. unpubl.) were sympatric at that site. We confirmed the presence of P. r i v a s i in two more places of this same basin: surroundings of the Yupka indigenous village named Pishikakao at an elevation of 1603 m, 09º54’28.4”N- 72º54’59.3”W; and around the other Yukpa village called Yurumuto, at 1389 m, 09º53’51.2”N- 72º54’06.4”W; there we only could heard the distinctive call of the species around 1830h. In both last localities P. rivasi was sympatric with P. y u k p a.

Etymology: The name of this species is a patronym for Gilson Rivas Fuenmayor, one of the original collectors of the new species, a good friend and enthusiastic Venezuelan herpetologist, for his many contributions to Venezuelan herpetology.

Distribution: ( Fig 5 ) The species is known from six sites in two localities: 1—creek behind the house of Cerro Las Antenas, 2—section of the path between the first and second antennas (type locality), and 3— second antenna, in the summit of Cerro Las Antenas, Municipio Rosario de Perijá (these three sites are comprehended in a lineal transect of 6.2 km and appear as a single circle on the map of Fig 5 ); 4— surroundings of the Yukpa village Yurumuto, 5—the hill between Yurumuto and Pishikakao, and 6— surroundings of the Yukpa village Pishikakao, in the río Tukuko basin, Municipio Machiques de Perijá (all three sites are in within 2 km and appear as a single circle on the map of Fig 5 ). The northernmost locality is separated from the southernmost by an air distance of ca. 62 km; the elevational range is from 1438–1933 m. It is expected to occur throughout similar environments in the Sierra de Perijá.

Comment: Pristimantis rivasi is clearly a member of the unistrigatus group sensu Lynch and Duellman (1997) and Hedges et al. (2008), as it has areolate belly skin, Finger I shorter than II, and Toe V considerably longer than III, with the disk on Toe V reaching the anterior edge of the distal subarticular tubercle of Toe IV. However, as noted before, this group is phenetic, and must be tested genetically.

Remarks. The area where the two species described here reside is in permanent danger of habitat loss. In addition to the activities of Yukpa indigenous people, there exist persistent deforestation activities by criollo inhabitants, who cultivate malanga using a highly destructive procedure. Only the southernmost locality of P. rivasi lies inside the Parque Nacional Sierra de Perijá. Cerro Las Antenas is unprotected. Despite we have punctually explored other areas of the Sierra, the two new species have been observed in only two localities. Although nothing is known about the population status of these two new species, or the real distribution, we recommend listing these species under category VU D2 of the IUCN (vulnerable with very small distributional area of 20 km ² or 5 localities), following Stuart et al. (2008), due to its apparent very restricted distribution and the dangers that the area is facing (named above).

The Pristimantis fauna of Perijá must be rich, as revealed by recent work ( Lynch 2003; Barrio-Amorós et al. 2007), but exploring the area is a dangerous activity due to problems of civil unrest as presence of guerrillas, paramilitares and narco-dealers.

Figures

FIGURE 5. Map of NW Venezuela, showing major physiographic elements: Maracaibo Lake, Sierra de Perijá to the west, and Cordillera de Mérida to the south east. Type locality and known distribution of Pristimantis lassoalcalai sp. nov. is shown by a white rhomb. Pristimantis rivasi sp. nov. distribution is shown by white circles; that to the north correspond to the type locality.

FIGURE 6. Pristimantis rivasi sp. nov. in life, female holotype. Photo by T. R. Barros.

FIGURE 9. A: male paratype MHNLS 18459. Photo by T. R. Barros. B: Male paratype in life MHNLS 18860, showing extreme pattern. Photo by P. Velozo.

FIGURE 7. A: Dorsal and B: Lateral view of the head of the holotype of Pristimantis rivasi sp. nov. Scale equal to 5 mm. C: Frontoparietal crests apparent on female holotype.

FIGURE 8. A: Dorsal and B: Ventral view of the female holotype of Pristimantis rivasi sp. nov. Scale equal to 5 mm. C: Palmar view of the right hand and D: Plantar view of the right feet of the holotype of Pristimantis rivasi sp. nov. Scale equal to 2 mm.