Ranitomeya yavaricola, Perez-Peña, Pedro E., Chavez, German, Twomey, Evan & Brown, Jason L., 2010

Perez-Peña, Pedro E., Chavez, German, Twomey, Evan & Brown, Jason L., 2010, Two new species of Ranitomeya (Anura: Dendrobatidae) from eastern Amazonian Peru, Zootaxa 2439, pp. 1-23 : 4-12

Ranitomeya yavaricola sp. nov.

Figures 2–5 , 11

Holotype. MZUNAP-01-520 ( Fig 3 .), an adult male collected by Pedro Perez-Peña nearby Lago Preto, 17 km W of Estiron de Ecuador, Provincia Ramon Castilla, Departamento Loreto, Peru; 4° 27' 35.0" S, 71° 45’ 3.5"W, 120 m elevation; August 2009; found foraging in leaf litter within terra firme forest.

Paratypes. All from same locality as holotype (MZUNAP-01-518, 519) an adult female and male (respectively) collected by P. Pérez-Peña in August 2009.

Etymology. The specific epithet is noun in apposition that means “inhabitant of the Yavarí” and is formed from the Latin suffix “ -icola ” for “dweller” or “inhabitant” and Río Yavarí, the watershed where this species occurs.

Definition and diagnosis. Assigned to the genus Ranitomeya due to the combination of the following characteristics: small size (<18 mm SVL), first finger distinctly shorter than second, dorsal coloration conspicuous and bright, dorsal skin smooth, toe webbing absent, maxillary and premaxillary teeth absent.

Ranitomeya yavaricola can be distinguished from other species of Ranitomeya by the combination of irregular, pale turquoise spots and stripes on the dorsum, solid-bronze limbs, and irregular sky-blue spots on the ventral surface of the upper thighs. Ranitomeya flavovittata possesses irregular, bright yellow spots and stripes (often broken) on the dorsum (vs. pale turquoise in R. yavaricola ). Additionally, the limbs of R. flavovittata are black with light blue reticulation (vs. limbs solid bronze in R. yavaricola ), and R. flavovittata typically possesses a complete (to nearly complete) yellow median dorsal stripe and lacks conspicuous spots on the ventral surface of the upper thighs (vs. median dorsal stripe absent and ventral thigh spots present in R. yavaricola ). Ranitomeya vanzolinii possesses bright yellow dorsal spotting, light blue reticulation on a ground color of black on limbs, and lacks conspicuous spots on the ventral surface of the upper thighs. Ranitomeya yavaricola is similar in appearance to the nominal morph of Excidobates captivus and Adelphobates castaneoticus . The nominal morph of Excidobates captivus has dull brown limbs (vs. bronze in R. yavaricola ), bears yellow spots on the flanks (vs. flank spots absent in R. yavaricola ), and has paired reddishorange dorsolateral dashes (vs. dorsolateral spots and stripes pale turquoise to spring green in R. yavaricola ). Adelphobates castaneoticus is larger in size (SVL up 23 mm), lacks the inner metacarpal tubercle, and lacks distinct bronze limbs. Furthermore, it has conspicuous red flash-marks on the upper surface of the forearms, thighs, and calves.

Measurements (in mm) of holotype. The male holotype ( Fig. 3 ) has SVL 15.2; FL 7.1; TL 7.2; KK 13.1; FoL 4.9; HaL3.4; HL 5.5; HW 5.0; BW 4.3; UEW 2.3; IOD 2.2; IND 1.8; TD 0.9; ED 1.9; DET 0.5; L1F 1.9; L2F 2.2; W3D 0.9; W3F 0.3. For paratype measurements see Table 1 .

Description of holotype. Widest part of head at jaw articulations. Head width slightly wider than body. Tongue ovoid; teeth absent. Snout sloping and rounded in lateral profile, slightly blunted in dorsal profile. Nares situated at tip of snout and directed laterally; both nares visible from ventral and anterior view but not from dorsal view. Canthus rostralis rounded, loreal region flat and nearly vertical. Upper eyelid approximately equal in width to interorbital distance; internarial distance roughly equal to horizontal eye diameter. Tympanum round, partially concealed posterodorsally.

In life, skin texture nearly smooth on dorsal surfaces of body and head; limbs and rump weakly granular. Venter weakly granular on limbs and body, ventral surface of head nearly smooth.

Hands ( Fig. 4 ) relatively large, length 22 % of SVL. Relative length of appressed fingers III> IV> II> I; first finger 90 % length of second; finger discs greatly expanded, width of disc on finger III 2.6 times width of adjacent phalanx. Unpigmented median metacarpal tubercle present on base of palm; inner metacarpal tubercle present near base of finger I; unpigmented proximal subarticular tubercles present on base of each digit, except on finger I, where tubercle is part-way up the digit; distal subarticular tubercle visible only on finger III. All tubercles raised above level of hands; scutes present on dorsal surface of fingers.

Hind limbs moderate length, with heel of appressed hind limbs reaching level of eye. Femur and tibia roughly equal in length, femur 99 % length of tibia; knee–knee distance 86% of SVL. Relative lengths of appressed toes IV> III> V> II> I ( Fig. 4 ); first toe short with unexpanded disc; second toe with slightly expanded disc, discs on toes III–V moderately expanded. Two unpigmented metatarsal tubercles on base of foot, one situated medially near base of toe I, the other situated laterally at the base of the fifth metatarsal. Proximal subarticular tubercles present at base of each toe but most notable on toes I, II, III due to lack of pigmentation. Toes III and V with two large subarticular tubercles, toe IV with three subarticular tubercles. Tarsal keel extends from below knee to medial metatarsal tubercle at foot. Tarsal tubercle absent; feet and hands lack webbing and lateral fringing.

Color in life. In life, body black with metallic sage-green dashes anterior and posterior to each eye, a single spot between eyes; metallic-sage dorsolateral stripes extend from upper thighs to shoulders where they each form a single dash. Broad sage oblique-lateral lines extend from the axillae to groin, where they fuse with a large spot on upper surfaces of each thigh. Broad labial stripe present, continues posteriorly to upper surfaces of arms. Limbs and digits solid bronze. Paired sage dashes on underside of thighs. Underside of head sage with two pairs of gular spots, creating appearance of an hourglass. Venter black with coarse, irregular sage marbling. Iris black.

Color in preservative. In preservative, turquoise/sky-blue coloration turns grey and bronze limb coloration turns brown.

Variation (based on 15 adults). Adults 15.2–17.7 mm SVL (mean 16.4 mm). Head about as wide as body except in single gravid female whose body was wider than the head. Head width 98 % of body width (range 81–109 %). Head width 30–36 % of SVL in adults. No apparent sexual dimorphism in external morphology except that males possess faint vocal slits on the floor of the mouth and have a slightly expanded subgular pouch.

The completeness of dorsolateral and medial lateral stripes varies considerably between individuals ( Fig. 5 ). Line/dash/spot coloration varies subtly between a sky-blue to a very light bluish-yellow to pale sage-green, with a majority of individuals being light turquoise.

Venter coloration is typically darker than dorsal coloration and is less variable, being predominantly skyblue. Ventral ground coloration varies from dark brown to black. Venter reticulation is largely symmetrical and often forms a broad, irregular, black medial-stripe in half of the specimens ( Fig. 5 ). Most individuals possess a large gular spot in the center of the throat (80 %). In all individuals, sky-blue dashes are present on the ventral surface of the upper thighs, though their size varies considerably between individuals.

Hands relatively large, length 22–26 % of SVL. First finger 65–95 % length of second; finger discs moderately expanded in both males and females, width of disc on finger III 2 –3.6 times width of adjacent phalanx. Tibia 86–107 % length of femur (mean 99 %); knee–knee distance 82–92 % of SVL (mean 87 %).

Tadpole measurements (in mm). A stage 25 tadpole (MZUNAP-01-521) was used for the description ( Fig. 6 ). Total length 12.5; body length 4.7; internarial distance 0.9; eye to nares distance 0.8; eye diameter 0.5; interorbital distance 0.7; tail length 7.8.

Tadpole description. Snout rounded when viewed from above; body ovoid in dorsal view. Eyes dorsal, angled laterally, pupils white in preservative. Nares not forming tube, situated half-way between eye and tip of snout, directed dorsolaterally. Spiracle sinistral; vent dextral. Ventral tail fin begins at tail base, dorsal tail fin begins just posterior to plane of vent opening, ventral and dorsal fins relatively uniform in thickness throughout tail, tapering towards tip. Musculature depth uniform throughout, tapering toward tip.

Mouth directed anteroventrally. Oral disc emarginate, anterior and posterior labia forming flaps free from body wall, 1.4 mm in width. Marginal papillae absent on anterior labium, present in one complete row on posterior labium. Papillae rounded; submarginal papillae absent. Jaw sheaths deep in longitudinal width, serrate, lacking indentations. Lateral processes short, extending barely past lower jaw. Labial tooth row formula is 2(2)/3[1]. A-1 complete (62 teeth), A-2 with medial gap (34 teeth), same width as A-1. P-1 with medial gap (46 teeth), P-2 (44 teeth), and P-3 complete (44 teeth); P-1 and P-2 equal width, P-3 slightly shorter.

Color in Life. In life, the head appears light grey. Pigmentation on dorsum mottled brown, ground color weakly transparent. Eyes black, papillae white. Ventral coloration is transparent (most internal organs are visible) with irregular faint red flecking that is dense around mouth and nares. Tail musculature white with abundant brown mottling, fins almost transparent.

Color in Preservative. In preservative, coloration is identical, though red pigmentation turns to brown.

Vocalizations. The following values are presented as: min-max (average ± SD, number of individuals). The advertisement call is a short trilled note ( Fig. 7 ) with duration between 630–880 ms (760 ± 140 ms, 7) and is repeated at irregular intervals of 2–7 notes per minute (3.14 ± 1.80 notes per minute, 6). Each note consists of 20–27 pulses (mean = 24). Calling activity is sporadic and continues throughout daylight, but peaks in the early morning and late afternoon. Dominant frequency is 5400–6000 Hz (5600 ± 2000 Hz, 5) at temperatures between 24.5–26 °C.

The call of R. yavaricola sounds similar to the calls of other species in the vanzolinii group, although there are some slight differences within this group. Ranitomeya flavovittata has slightly longer notes (1 sec vs. 760 ms in R. yavaricola ). Ranitomeya imitator (n = 25) has a call that is slightly shorter in duration (686 ms vs. 760 ms in R. yavaricola ) and has a slightly lower dominant frequency (5200 Hz vs 5600 Hz in R. yavaricola ).

Distribution and natural history. Ranitomeya yavaricola occurs in primary forests in a small area of northeastern Peru. This species likely occurs more widely within the broad interfluvium bordered by the Ucayali, Amazon, Yavarí, and Blanco rivers ( Fig. 1 ). Much of the area bordering these rivers is seasonally or permanently flooded and it is possible that these large expanses impose limits to this species’ distribution ( Fig. 8 ).

Ranitomeya yavaricola is only known from forests near Lago Preto (but see discussion). Lago Preto is a large oxbow lake at the confluence of Yavarí and Yavari-Mirin rivers. Near Lago Preto, several forest types are present: seasonally flooded forests, swamp forests that are saturated year-round, and upland terra firme forests. At Lago Preto, R. yavaricola occurs in upland forests and very low lying forests, just above the flood zone of seasonally flooded forests (i.e. várzea forests) and swamps. These sites contained many large trees and a relatively sparse understory. The upland forests in this region are some of the most diverse in the Amazon basin, with estimates of tree diversity exceeding 300 species per hectare in some areas ( Pitman et al. 2003, Fine et al. 2006) These forests are dominated by trees of the families Fabaceae (legumes), Bombacaceae (“mallows” such as kapoks), and Moraceae (figs) ( Fine et al. 2006). This species is sympatric with three other dendrobatids: Ranitomeya uakarii , Ameerega hahneli , and A. trivittata . This species potentially also co-occurs with R. flavovittata and R. ventrimaculata , both of which have been observed less than 90 km from Lago Preto ( Fig. 8 ).

Ranitomeya yavaricola was typically observed foraging throughout the leaf litter or calling from the leaves of terrestrial palms (Genoma spp.), epiphytes (primarily bromeliads), and on the branches of fallen trees (between 0.2–3 m above the ground). Ranitomeya yavaricola is an extremely shy species and when encountered dives to the ground and hides within the leaf litter or within the roots of plants. A single tadpole was observed in the phytotelm of a small bromeliad that was ca. 1.5 m above the ground. Prior to the discovery of the tadpole, a male was observed calling near the bromeliad (<0.3 m). The pool of water housing the tadpole was small, containing less than 30 ml of water. The most abundant species of bromeliad in the area typically grows in small clumps of 2–6 plants ( Fig. 9 ). Ranitomeya yavaricola is the most abundant species of Ranitomeya at Lago Preto. Using visual encounters, we observed 3 individuals in 30 man-hours of observation (0.1 encounters per man-hour) and using acoustic estimates, we recorded 20 different individuals in 3.7 man-hours of observation (5.6 encounters per man-hour). Lastly, as the result of casual observations, over a two week period in June 2009, 20 people encountered 6 individuals. During this study 12 individuals of R. uakarii were observed at Lago Preto (as the result of both casual observation and surveys).

Conservation status. Following the IUCN Red List criteria ( IUCN 2001), this species should be listed as Data Deficient (DD). It is currently known from only a single locality but probably occurs more widely.

Figures

FIGURE 1. Map of study areas. Lago Preto, the type locality of R. yavaricola sp. nov., is depicted by a yellow dot. Nueva Capanahua community, the type locality of R. cyanovittata sp. nov., is depicted by a blue dot.

FIGURE 2. Dorsal and ventral views of Ranitomeya yavaricola sp. nov. from Lago Preto, Loreto, Peru.

FIGURE 3. Type series of Ranitomeya yavaricola with corresponding ventral photos. Left to right: MZUNAP- 01 - 519, MZUNAP- 01 - 518, MZUNAP- 01 - 520. Bar equals 10 mm.

FIGURE 4. Right hand and right foot of Ranitomeya yavaricola.

FIGURE 5. Intrapopulation variation of Ranitomeya yavaricola. Each row shows the dorsum and venter of an individual. The first three rows are adult males and the last row is an adult female.

FIGURE 6. Tadpole of Ranitomeya yavaricola. Top: lateral and dorsal views of a Gosner Stage 25 tadpole. Bottom left: ventral view of tadpole. Bottom right: mouthparts of the tadpole of R. yavaricola.

FIGURE 7. Advertisement calls of members of the vanzolinii group that occur in close geographic proximity to Lago Preto. Space between notes was reduced so that two notes would fit into spectrogram. A) R. imitator from San Gabriel de Varadero, Loreto, Peru recorded at 23.5 ° C. Dominant frequency: 4900 Hz. Mean note length: 1.1 sec. Actual space between notes (not as pictured): 8.2 sec. Note: the note length in this spectrogram is longer than the average for this species (which is 0.7 sec, see Vocalization section), however, as mentioned above, we used this population given its close proximity to Lago Preto. B) R. flavovittata from Quebrada Blanco, Loreto, Peru recorded at 24.5 ° C. Dominant frequency: 5500 Hz. Mean note length: 1.0 sec. Space between notes (as pictured): 4.3 sec. C) R. yavaricola from Lago Preto recorded at 24 ° C. Dominant frequency: 5950 Hz. Mean note length: 0.8 sec. Actual space between notes (not as picture): 16.3 sec.

FIGURE 8. Distributions of Ranitomeya that occur within the forests bordered by the Ucayali, Amazon, Yavarí, and Blanco rivers. The blue color depicts areas that are prone to flooding or that are permanently flooded. These areas likely act as barriers to gene flow for most Ranitomeya species. Each colored circle represents the corresponding species at each site. The white dot depicts the only known locality of the R. cyanovittata. The area that becomes seasonally flooded was calculated from two data sources: areas classified as Várzea by the World Wildlife Foundation (Olson et al. 2001) and spatial calculations in Environmental Systems Research Institute’s GIS ArcView 9.2 that estimated the seasonally flooded areas. The latter was done by calculating the feet above sea-level of major streams that seasonally flooded throughout the area. These values were kriged to create a raster that accounted for elevation changes relative to level of the major rivers. The resulting raster was subtracted from a digital elevation model, and areas below 10 meters were classified as “ seasonally flooded ”.) Both the Varzea and “ floodable ” areas were summed to create the blue layer area depicted here. Ten meters is an average the annual fluctuation in river levels for the lower Ucayali, upper Amazon, and lower Yavari rivers (Goulding et al. 2003).

FIGURE 9. The photo depicts habitat where several R. yavaricola were observed. The inset is a photo of a bromeliad where a tadpole was observed.

FIGURE 11. View of the Rio Blanco basin near the type locality of R. cyanovittata, Loreto, Peru. Photograph by Diego Vasquez.

Tables

TABLE 1. Measurements of type series of R. yavaricola (MZUNAP- 01 - 518 - MZUNAP- 01 - 520) and additional specimens that were not collected. * Sexing based upon calling activity ** observed courting with male number 8

	MZUNAP -01-518	MZUNAP -01-520	MZUNAP -01-519	1	2	3	4	5	6	7	8	9	10	11	12	Mean (Max-Min)
SVL FL TL	17.2 7.0 7.5	15.2 7.1 7.2	16.8 7.0 7.3	15.5 7.2 6.8	16.0 7.7 7.5	16.2 7.4 7.1	16.2 7.5 7.2	15.9 7.0 7.4	17.1 8.0 6.9	16.7 7.6 7.6	16.6 7.5 7.6	17.7 7.9 7.5	16.7 8.0 7.2	15.9 7.2 7.2	16.7 7.0 7.3	16.4 (17.7 15.2) 7.4 (8.0 7.0) 7.3 (7.6 6.8)
KK FoL HaL HL HW	14.8 6.1 3.8 6.1 5.3	13.1 4.9 3.4 5.5 5.0	14.0 5.5 3.8 5.9 5.1	13.8 5.7 3.8 5.8 5.4	14.8 6.2 4.0 6.2 5.4	14.2 6.4 4.0 6.6 5.9	13.7 5.9 3.9 6.2 5.4	14.3 5.6 4.1 6.2 5.5	14.2 6.0 4.0 6.4 5.6	14.4 6.4 4.0 5.9 5.4	14.9 5.9 4.2 5.8 5.6	14.7 6.0 4.2 5.9 5.7	14.5 6.6 3.9 6.3 5.7	14.0 6.0 4.0 6.2 5.5	14.1 6.5 4.2 6.5 5.4	14.2 (14.9 13.1) 6.0 (6.6 4.9) 4.0 (4.2 3.4) 6.1 (6.6 5.5) 5.5 (5.9 5.0)
BW UEW IOD IND TD ED DET	4.3 2.6 2.3 1.9 0.9 1.9 0.3	4.3 2.3 2.2 1.8 0.9 1.9 0.5	5.4 2.4 2.3 2.1 0.9 2.2 0.4	5.2 2.5 2.2 2.0 0.7 2.0 0.5	5.9 2.7 2.5 2.3 0.5 2.0 0.7	4.9 2.9 2.3 2.2 1.1 2.0 0.6	5.5 2.6 2.2 2.2 0.8 2.0 0.3	5.3 2.8 2.2 2.2 0.7 2.1 0.4	5.7 2.6 2.2 2.3 0.7 1.9 0.6	5.4 2.6 2.5 2.3 0.5 2.1 0.7	5.6 2.4 2.0 2.2 0.7 1.9 0.5	6.1 2.4 2.1 2.4 0.9 2.0 0.6	5.6 2.8 2.3 2.0 0.9 2.1 0.8	5.1 2.7 2.6 2.3 0.9 1.8 0.6	5.8 2.0 2.6 2.2 1.3 2.0 0.3	5.3 (6.1 4.3) 2.6 (2.9 2.0) 2.3 (2.6 2.0) 2.2 (2.4 1.8) 0.8 (1.3 0.5) 2.0 (2.2 1.8) 0.5 (0.8 0.3)
L1F L2F W3D W3F	1.8 2.5 0.8 0.4	1.9 2.2 0.9 0.3	2.1 2.2 0.9 0.3	2.0 2.6 1.0 0.4	2.1 2.8 1.0 0.3	2.0 2.8 1.1 0.3	2.0 2.6 1.0 0.4	1.9 2.9 1.0 0.4	2.2 3.0 1.1 0.4	2.0 2.5 1.0 0.4	2.1 2.9 1.0 0.5	2.1 2.9 1.0 0.3	2.0 2.8 1.1 0.4	2.0 2.5 1.1 0.3	2.1 2.8 1.1 0.5	2.0 (2.2 1.8) 2.7 (3.0 2.2) 1.1 (2.0 0.8) 0.4 (0.5 0.3)
BM SEX	- 3	- Ƥ	- 3	0.3 *	0.3 3*	0.4 3*	0.3 3*	0.3 3*	0.4 3*	0.4 3*	0.5 3*	0.5 Ƥ **	0.4 3*	0.3 _	0.4 _	0.4 (0.5 0.3) _