Centrolene buckleyi, (BOULENGER, 1882)

Guayasamin, Juan M., Bustamante, Martín R., Almeida-Reinoso, Diego & Funk, W. Chris, 2006, Glass frogs (Centrolenidae) of Yanayacu Biological Station, Ecuador, with the description of a new species and comments on centrolenid systematics, Zoological Journal of the Linnean Society 147 (4), pp. 489-513 : 497-499

CENTROLENE BUCKLEYI (BOULENGER, 1882)

Diagnosis: Centrolene buckleyi differs from other species in the family by the following combination of characters: (1) vomerine teeth absent; (2) in life, bones green; (3) in preservative, parietal peritoneum and pericardium white, hepatic peritoneum clear, visceral peritoneum cream, peritoneum around kidneys cream; (4) in life, dorsum uniform green with or without spinules and scattered, whitish warts; in preservative, dorsum lavender with or without whitish warts; (5) webbing absent between Fingers I and II, basal webbing between Fingers II and III; webbing between outer fingers usually III (2 1/2 −3 –)–(2 1/3 −2) IV; (6) webbing formula on foot usually I (1 1/2 −2 –)–(2 ± 2 1/4) II (1 – − 1 +)–(2 1/4 −2 1/2) III (1 ± 1 1/2)–(2 1/3 −2 2/3) IV (2 2/3 −3 –)−1 2/3 V; (7) snout round in dorsal aspect, slightly sloping to sloping in lateral profile ( Fig. 5A, B ); (8) dorsal skin finely shagreen, with or without spinules; (9) ulnar and tarsal tubercles absent; outer ulnar and tarsal folds low or absent; (10) humeral spine present; (11) tympanum orientated almost vertically, with slight lateral and posterior inclinations, tympanic annulus visible except for its dorsal border, which is covered by a low supratympanic fold; tympanic membrane not differentiated from skin around tympanum; (12) SVL in males 27.9–30.5 mm (mean = 28.9; n = 20); in females 29.8–34.4 mm (mean = 31.7; n = 5); (13) prepollical spine not protruding externally; nuptial pad large (Type I of Flores, 1985); nuptial excrescences cream, finely granular; (14) pair of large, round tubercles posteroventral to vent (as illustrated by Lynch & Duellman, 1973: fig. 2A); (15) when adpressed, Finger II longer than Finger I ( Fig. 6A ); (16) liver with four lobes; (17) diameter of eye almost twice width of disc of Finger III.

Centrolene buckleyi is in the Centrolene prosoblepon species group based on the possession of humeral spines, green bones, eye larger than disc of Finger III, and white pericardium and parietal peritoneum (but see Remarks). Most species in the Centrolene prosoblepon group differ from those in the Centrolene peristictum group by lacking white pigment on the digestive tract (white pigment present in the Centrolene peristictum group) and from species in the Centrolene geckoideum group by having an eye that is larger than the disc of Finger III (diameter of eye <disc of Finger III in the Centrolene geckoideum group).

Centrolene buckleyi is easily distinguished from other species in the region by having a humeral spine (in males), white upper lip, a moderate size (SVL in males 27.9–30.5 mm; in females 29.8–34.4 mm) and a sloping snout in lateral profile. Additional characters distinguishing species in the Centrolene prosoblepon group (as defined by Ruiz-Carranza & Lynch, 1991a) are presented in Table 1.

Colour in life: Dorsal surfaces bright to dark green, sharply demarcated laterally from white lower flanks; throat and most of venter pale green; parietal peritoneum yellowish white; heart not visible; edge of upper lip, outer edge of tarsus and cloacal stripe white; bones green; iris pale copper flecked with black ( Lynch & Duellman, 1973; Fig. 4A–C ). Additionally, specimens from YBS have white warts on dorsum ( Fig. 4A ).

Colour in preservative: Dorsum of head and body lavender with or without small, unpigmented spots; limbs cream with slight lavender tonality; conspicuous white border on the upper lip, lower lip lacks white pigmentation; dorsally, all fingers, Toes I–III and most of Toe IV unpigmented; outer edge of forearm faintly marked with white pigment; cloacal region mostly unpigmented, except for few minute white spots. Males with cream nuptial pad on Finger I. Ulnar and tarsal folds whitish; venter cream. Two males (QCAZ 26031 and 32) were dissected to observe coloration of internal organs: parietal peritoneum white covering the anterior two-thirds to three-quarters of the belly, pericardium white, hepatic peritoneum transparent, visceral peritoneum cream, kidneys cream.

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Measurements (in mm): Measurements of the specimens collected at YBS are shown in Table 2.

Distribution, ecology, and natural history: Centrolene buckleyi is found between 2100 and 3300 m in the Andes of Venezuela through Colombia to southern Ecuador ( Frost, 2004) and northern Peru ( Duellman & Wild, 1993). Although we have inventoried Yanayacu intensively for 3 years, only three individuals of C. buckleyi have been found, suggesting that this species is quite rare. One male (QCAZ 22388) was found on a leaf approximately 160 cm above a stream in secondary cloud forest at night. This male was found close to a clutch of eggs. A second male (QCAZ 26031) was found calling from a bamboo leaf 300 cm above a stream in primary forest, also at night.

Call: We recorded nine calls of one male Centrolene buckleyi (QCAZ 26032; SVL = 25.9 mm) in the laboratory of QCAZ (air temperature = 22.7 °C; cassette number QCAZ-CC-154). The male began calling from a cooler, escaped the cooler, and then continued calling in a dark room. Each call consisted of 1–5 notes, each note with two distinct metallic, high-pitched pulses ( Fig. 7 ). These calls presumably represent advertisement calls, although recordings of other males in the field will be necessary to confirm this presumption. A detailed summary of call parameters is given in Table 3. The call of the specimen collected at YBS differs remarkably from previous reports. According to Bolívar et al. (1999), the fundamental frequency of a C. buckleyi in Colombia (4°44′39′N, 76°18′16′W; 2220 m) was 5200 Hz (highest frequency in the YBS specimen = 4139 Hz; Table 3). The differences between these calls may represent geographical variation within a single species, different type of call and/or measurement errors, but it is also possible that the two populations represent distinct lineages (discussed below).

Remarks: The validity of the Centrolene prosoblepon group as a monophyletic group remains to be tested; it is important to emphasize that phenetic groups (if not supported by unambiguous synapomorphies) are convenient only for some taxonomic activities such as identifying and naming species. Specimens of Centrolene buckleyi collected in YBS (QCAZ 22388, 26031 and 32) differ from the description presented by Lynch & Duellman (1973) in the following (characters in parentheses are from Lynch & Duellman, 1973): (1) dorsum with scattered whitish warts (no warts); (2) when adpressed, Finger II longer than Finger I (first and second fingers equal in length); (3) outer edge of forearm with lightly white dermal ridge (ulnar ridge absent); (4) inner edge of tarsus with low fold (tarsal fold absent); and (5) SVL in males, 25.3–26.5 mm (28.4–29.5 mm). Examination of a larger series of C. buckleyi (Appendix 1) reveals that most of the differences mentioned above are artefacts of a small sample size or mistaken observations. Additionally, Lynch & Renjifo (2001) mentioned that males of C. buckleyi have tubercles in the reproductive season. Myers & Donnelly (1997) elevated the Venezuelan populations of Centrolene buckleyi ( Centrolenella buckleyi venezuelensis Rivero, 1968 ) to the species level, Centrolene venezuelense ( Rivero, 1968) , but they did not provide evidence supporting this taxonomic change. Although it is possible that the populations in Venezuela form a distinct lineage ( Señaris, 2001), taxonomic changes need to be justified with studies across the distribution range of ‘ Centrolene buckleyi ’.

Figures

Figure 4. Photographs of glass frogs. A, B, Centrolene buckleyi from Yanayacu Biological Station, male, dorsolateral and ventral views, QCAZ 26032 (WCF); C, Centrolene buckleyi from Carchi, male, dorsolateral view, MECN 1246 (MRB); D, E, Cochranella posadae, male, dorsolateral and ventral views, QCAZ 25090 (WCF); F, Centrolene bacatum, dorsolateral view, male, QCAZ 26056 (MRB); G, H, Cochranella wileyi sp. nov., males, dorsolateral and ventral views, QCAZ 26029 and 27441, respectively (MRB); I, Cochranella griffithsi, dorsolateral view, QCAZ 29525 (JMG).

Figure 5. Lateral and dorsal views of heads. A, B, Centrolene buckleyi, male, QCAZ 22388; C, D, Cochranella posadae, male, QCAZ 26023; E, Cochranella wileyi sp. nov., female, QCAZ 26028; F, Cochranella wileyi sp. nov., male, QCAZ 26029. Scale bar = 2 mm.

Figure 6. Ventral view of hands and feet. A, B, Centrolene buckleyi, male, QCAZ 22388; C, D, Cochranella posadae, males, QCAZ 25090 and 26023, respectively; E, F, Cochranella wileyi sp. nov., female, QCAZ 26028. Scale bar = 2 mm.

Figure 7. A, power spectrum; B, sonagram; and C, oscillogram of the advertisement call of Centrolene buckleyi (QCAZ 26032). The call shown here consists of four notes, each note with two distinct pulses. The power spectrum was measured along the duration of the first note.