Bioacoustics of Pristimantis rivasi

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 .