Bioacoustics of Boana platanera

Diagnosis. Character states of compared species are given in parentheses. Boana platanera is sister of B. xerophylla ( Fig. 1 ) and it can be diagnosed from the latter by the following combination of adult male characters: a pale orange-yellow or light brown coloration on dorsum (dark brown to green tones; Fig. 8I, J ); presence of black or dark brown speckles in the anterior half of the palpebral membrane (absent; Fig. 9 ); pericloacal region dark brown (cream); advertisement call with shorter, 28−71 ms, first note length (79–124 ms in call type I and 85−110 ms in call type II), composed of five notes (one note in call type I). Although not diagnostic, the following characters may help to differentiate both species: the new species has a statistically significant larger body ( 46.57–63.34 mm ) than B. xerophylla ( 45.13–56.71 mm ) ( Table 2 in Escalona et al . 2019a ); in preservative, the gular region is cream with dark brown or black flecks near to the jaw border (cream and sometimes with few dark brown speckles on the border of the jaw; Fig. 9 ); advertisement call with statistically significant longer pulse interval (11−23 ms) than B. xerophylla (12–14 ms in call type I and 11−14 ms in call type II); statistically significant longer second phase length (137−312 ms) than B. xerophylla (73−150 ms in call type II). Boana platanera is sympatric with B. pugnax in lowland western and central Venezuela , as well as some regions in Colombia and Panama . The new species is distinguished from B. pugnax by having a pale orange-yellow or light brown coloration on dorsum (dark-brown to dark-grey tones; Fig. 8G, J ); the anterior half of the palpebral membrane densely pigmented (poorly pigmented); dorsal surfaces of finger and toe discs usually cream, when pigmented, pale gray (dark); calcar absent (poorly developed); a complex advertisement call composed of five notes (simple call of one note). Although not diagnostic, B. platanera is distinguished from B. pugnax by having a statistically significant smaller body (males: B. platanera : 46.57–63.34 mm ; B. pugnax : 55.85–74.80 mm [sample from western Venezuela ]; Table 4 ); and a statistically significant longer advertisement call ( B. platanera : 200−451 ms; B. pugnax : 156–258 ms). The new species differs from Boana crepitans by having a pale orange-yellow or light brown coloration on dorsum (gray-cream tones to dark brown; Fig. 8H, J ); advertisement call composed of five notes (two notes). Although not diagnostic, the new species has a statistically significant shorter ETD (eye to tympanum distance; B. platanera : 0.96–2.78 mm ) than B. crepitans ( 1.99–3.29 mm ) ( Tables 1–2 in Escalona et al . 2019a ); statistically significant shorter advertisement call ( B. platanera : 200−451 ms; B. crepitans : 368−473 ms), with a statistically significant shorter second phase ( B. platanera : 137−312 ms; B. crepitans : 278−367 ms) ( Tables 2 , 3 in Escalona et al . 2019a ). Boana platanera differs from B. rosenbergi by having a smooth dorsum, thighs, and flanks (rough or with tubercles in at least one of these regions; Fig. 8F, J ); smaller body size (males: B. platanera : 46.57–63.34 mm ; B. rosenbergi : 75.55–83.98 mm ); presence of black dots on anterior half of the palpebral membrane (absent); ulnar fold smooth (slightly crenulated); and a complex advertisement call (simple in B. rosenbergi ) with shorter duration ( B. platanera : 200−451 ms; B. rosenbergi : 551–759 ms) ( Table 2 ). The new species differs from Boana exastis by having a smooth dorsum, thighs, and flanks (rough or with tubercles in at least one of these regions; Fig. 8D, J ); smaller body size (males: B. platanera : 46.57–63.34 mm ; B. exastis : 81.1–99.0 mm); presence of black dots on anterior half of the palpebral membrane (absent); poorly-defined dermal fringes on limbs (crenulated dermal fringes), less webbing in hands and feet (more extensive webbing in hands and feet), absence of cloacal plate (presence); absence of calcars (presence); complex advertisement call (simple in B. exastis ), with shorter duration ( B. platanera : 200−451 ms; B. exastis : 807–1229 ms) ( Table 2 ). Boana platanera differs from B. lundii by having a smooth dorsum, thighs, and flanks (rough or with tubercles in at least one of these regions; Fig. 8E, J ); presence of black dots on anterior half of the palpebral membrane (absence); poorly-defined dermal fringes on limbs (well defined); less webbing in hands and feet (more webbing in hands and feet); absence of calcars (presence); complex advertisement call (simple), with shorter duration ( B. platanera : 200−451 ms; B. lundii : 834–1228 ms) ( Table 2 ). The new species differs from Boana pardalis by having a smooth dorsum, thighs, and flanks (rough or with tubercles in at least one these regions; Fig. 8C, J ); presence of black dots on first half of the palpebral membrane (absence); poorly-defined dermal fringes on limbs (crenulated); less webbing in hands and feet (more webbing in hands and feet); absence of cloacal plate (presence); absence of calcars (presence); complex advertisement call (simple), with longer duration ( B. platanera : 200−451 ms; B. pardalis : 117–143 ms), composed of 4–6 notes (one) ( Table 2 ). Boana platanera differs from B. faber by having a smaller body size (males: B. platanera : 46.57–63.34 mm ; B. faber : 77.90–97.08 mm ); presence of black dots on anterior half of the palpebral membrane (absence); ulnar fold present (absent); cream gular coloration with dark-brown flecks near to the jaw border (dark); complex advertisement call (simple), longer advertisement call ( B. platanera : 200−451 ms; B. faber : 75–121 ms), composed of 4–6 notes (one note), with higher fundamental frequency ( B. platanera : 542.7−1125.0 Hz; B. faber : 344.5–447.9 Hz) ( Table 2 ). Boana platanera is readily distinguishable from B. albomarginata by having a smooth dorsal skin (slightly granular in B. albomarginata ), a pale orange-yellow coloration with dark-brown marks, irregular or broad X-shaped on the dorsum and dark-brown bars on flanks and thighs (green with some white spots on the dorsum; Fig. 8A, J ); supratympanic fold slopes downward to a point above arm insertion (supratympanic extends posteriorly until half of the laterodorsal region); absence of calcar (presence); complex advertisement call (simple), with longer duration ( B. platanera : 200−451 ms; B. albomarginata : 166–185 ms), with 4–6 notes (one note), and lower fundamental frequency ( B. platanera : 542.7−1125.0 Hz; B. albomarginata : 1136.9–1231.7 Hz) ( Table 2 ).Although not diagnostic, the new species is larger bodied (males: B. platanera : 51.97–59.08 mm ; B. albomarginata : 44.68–53.6 mm ).

Variation in morphology. The variation of external measurements, as well as hand and foot webbing formula of some type specimens and from all the specimens examined is shown in Table 5 . There is sexual dimorphism in body size, with males generally smaller than females (males: 46.57–63.34 mm ; females: 54.33–74.74 mm ), and by the presence of a prominent prepollical spine in males ( Figs. 5 , 6 ). Color variation in life. When active at night, adult specimens have a yellow, tan, to light brown coloration, with brown patterns (irregular in shape or with a broad X-shaped blotch near the head; some specimens have a brown vertebral line) on dorsum ( Figs. 6A , 7C ). Brown dots are spread on the flanks, above the upper lip, on the limbs, and on the webbings. Some specimens have a brown line delimiting the supratympanic fold. Some specimens have apparent scars on the dorsum. There is a brown blotch with a white line on the upper margin on heels and cloacal region. There are several vertical brown bars on flanks and transversal brown bars on the thighs. White coloration predominates along all the ventral surfaces, with strong orange or pinkish tones on the belly, arms, and thighs. In some specimens, the dorsal brown bars of the thighs are projected on the internal portion. The tarsus has two colorations delimited by the tarsal fold. The outer portion of the tarsus has a brown coloration with orange tones, while the internal portion has orange coloration. Some specimens have some brown spots around the mandible, on the upper portion of the thigh, and/or the webbing at the hands and foots. During the day, when normally are inactive, they have a pale cream coloration ( Fig. 6E ). The brown patterns and spots, when visible, are pale gray, and the bars on the flanks and thighs are dark brown almost black. Juvenile specimens have a pale green coloration with black diffuse dots on the dorsum ( Fig. 6F ). During the night, the iris around the pupil is metallic gray color and the outer area is pale emerald ( Fig. 6A, C, D ). Color variation in preservative. Coloration pattern of paratopotypes in preservative is depicted in Fig. 5 . Specimens from localities other than the type locality show some color variation, as follows: dorsum occasionally may be uniformly pale-brown ( e.g ., ULABG 2950 , 2951 , 7755 , 7803 ) , sometimes bearing two scapular dark brown spots ( e.g. , ULABG 5338 ) , or few scattered small dots on sacral region ( e.g. , ULABG 5337 , 5338 ) or dorsum ( e.g. , ULABG 7745 ) . Some specimens tend to have an ashy background with irregular markings ( e.g. , ULABG 5060 , 6902 , 7753 ) and, very rarely, have a lichen aspect ( e.g. , ULABG 7756 , 7757 ) . More often, dorsum bears large blotches that may be irregular in shape ( e.g. , ULABG 1416 , 3725 ) , or sometimes with a broad X-shaped brown blotch ( e.g. , ULABG 2544 , 4749 , 4754 ) that could tend to be diffuse ( e.g. , ULAB 2949 ) . Specimen ULABG 7744 has a white supratympanic line from posterior border of eye to posterior part of tympanum, and a white line along border of upper lip. Specimen ULABG 1417 has a dark brown line on middle of dorsum, from almost tip-of-snout to sacral region. Forearms and wrists may have brown bands ( e.g. , ULABG 2544 ) . Shanks and thighs may have bands with ill-defined borders ( e.g. , ULABG 2544 ) . Natural history. All specimens from the type series were collected after dusk (around 20:00 h) in a sewage system alongside a paved road, in steep terrain, 947 m asl. These were found active on the floor, many of them vocalizing. Surrounding vegetation was disturbed second-growth forest, with primary humid forest surrounding it ( Fig. 7B ). No other anuran species was heard or seen at this site. The additional museum specimens reviewed came from the Tropical and Premontane altitudinal belts of the Holdridge’s system as applied to Venezuela ( Ewel et al . 1976 ), within the life zones of Tropical dry forest and Tropical humid forest, as well as Premontane dry forest and Premontane humid forest. The associated vegetation is usually that of open disturbed areas, with abundance of grasses and few trees. Field records of ELM for some of the referred specimens indicate that the species lives in places with annual mean temperatures higher than 17 ºC and mean annual precipitation roughly between 600 and 1,500 mm . Two precipitation regimes are associated with the distribution of this species. One is the bi-seasonal pluviometry regime, with a single wet season around the middle of the year (June and July). The other is the tetra-seasonal regime with two wet seasons separated by a short midyear period of less precipitation ( Monasterio & Reyes 1980 ). Males vocalize on vegetation up to 5 m ( Fig. 6G ), but generally from the ground, on rocks, or partially submerged or floating in the water, although the latter behavior is usually observed in artificial and temporary pools ( Fig. 6H ). Field observations indicate that the amplexus in Boana platanera is axillary ( sensu CarvajalCastro et al . 2020), with the toes projected above the female shoulders ( Fig. 10 ). Scars on the dorsum of several individuals suggest the existence of male to male combat in this species. This species can form choruses and males are separated from each other by at least one meter. In addition, this treefrog usually lays eggs in rafts in lentic aquatic systems. The following species were detected sharing the same breeding sites as B. platanera : B. lanciformis , B. pugnax , Dendropsophus microcephalus , Engystomops pustulosus , Leptodactylus fuscus , Pleurodema brachyops , Pseudis paradoxa , Rhinella horribilis , R. marina , Scarthyla vigilans , and Scinax rostratus .