Cochranella wileyi, Guayasamin & Bustamante & Almeida-Reinoso & Funk, 2006

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 : 504-507

COCHRANELLA WILEYI SP. NOV.

Holotype: QCAZ 26028 ( Fig. 11 ), adult female, YBS (0°41′S, 77°53′W; 2100 m), Provincia de Napo, Ecuador, collected by M. R. Bustamante on 5 January 2001.

Paratopotypes: Adult males. QCAZ 26024 , collected by D. Almeida-Reinoso on 13 June 2003 . QCAZ 26029 and 30, collected by M. R. Bustamante on 11 May 2002 . QCAZ 26057 , collected by D. Almeida-Reinoso on 14 December 2003 . QCAZ 27435 , collected by M. R. Bustamante on 30 April 2004 .

Diagnosis: Cochranella wileyi sp. nov. ( Fig. 4G, H ) differs from other species in the family by the following combination of characters: (1) vomerine teeth absent; (2) in life, bones pale green; (3) in preservative, dorsum lavender; parietal peritoneum and pericardium white, hepatic peritoneum clear, visceral peritoneum cream, peritoneum around kidneys white with small, unpigmented spots; (4) in life, dorsum uniform pale green; in preservative, dorsum lavender; (5) webbing absent between inner fingers; webbing reduced between outer fingers, III 3 – −2 2/3 IV; (6) webbing formula on foot usually I 2–2 1/3 II (1 1/3 −1 2/3)–(2 1/2 −3 –) III (1 ± 1 2/3)–(2 2/3 −3 –) IV (3 – −3 +)–(2 – −2 +) V; (7) snout truncate in dorsal aspect, truncate to protruding in lateral profile; (8) dorsal skin finely shagreen in males and females, with numerous spinules in males; (9) low and thin ulnar fold; tarsal fold absent; (10) humeral spine absent; (11) tympanum orientated almost vertically, with slight posterior and lateral inclinations, tympanic annulus visible anteroventrally, tympanic membrane clearly differentiated; (12) SVL in males 24.0– 26.2 mm (mean = 24.6, n = 5); 27.1 mm in one female; (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 ( Lynch & Duellman, 1973: fig. 2 A); (15) when adpressed, Finger II slightly longer than Finger I; (16) liver tetralobed; (17) diameter of eye about twice width of disc of Finger III.

Cochranella wileyi is assigned to the Cochranella ocellata species group (as defined by Ruiz-Carranza & Lynch, 1991a, 1995a) based on the absence of white pigment in the visceral peritoneum (white visceral peritoneum in the Cochranella granulosa group) and the presence of reduced webbing between Fingers III and IV (extensive webbing between Fingers III and IV in the Cochranella spinosa group). Characters used to distinguish among species in the Cochranella ocellata group are presented in Table 4. Cocharella wileyi is likely to be confused with C. cariticommata and C. griffithsi , but the kidneys ( Fig. 12 ) in C. wileyi are covered with a white peritoneum (kidneys cream in C. cariticommata ); additional differences between these two species are summarized in Table 4. Although no discrete characters separate Cochranella wileyi and C. griffithsi ( Table 4), we argue that they represent evolutionary independent lineages. The two species have allopatric distributions: C. wileyi is found on the Amazonian slopes of the Ecuadorian Andes, whereas C. griffithsi inhabits the Pacific slopes of the Andes in southern Colombia and adjacent Ecuador. Additionally, the two species have differences in the frequencies of at least two characters. In preservative, all the specimens of C. wileyi have a thin white border on the upper lip (white border on upper lip absent in 65% of C. griffithsi , n = 60) and a dorsum without dark flecks (dorsum with dark purple or black flecks in 90% of C. griffithsi , n = 60). Based on the distribution of the species and the morphological differences mentioned above, and using the evolutionary species concept ( Wiley, 1978; modified from Simpson, 1961), we hypothesize that C. wileyi and C. griffithsi are distinct species.

Description of holotype: Adult female, SVL 27.1 mm ( Fig. 11 ). Head slightly wider than body; head length 88.8% of head width, 29.5% of SVL; snout truncate in dorsal and lateral profiles; canthus weakly defined; loreal region concave; lips slightly flared; nostrils closer to tip of snout than to eye, not protuberant, directed anterolaterally; internarial area barely depressed; eye large, directed anterolaterally; transverse diameter of disc of Finger III 45% of eye diameter; supratympanic fold low, obscuring posterodorsal portion of tympanic annulus; tympanum orientated almost vertically, with slight posterior and lateral inclination; tympanic membrane translucent, with pigments only on its upper half; vomers lacking teeth; choanae large, longitudinally rectangular; tongue ovoid, with ventral posterior fifth not attached to mouth floor and posterior margin notched.

Humeral spine absent; low ulnar fold evident; relative length of fingers: III> IV> II> I; no webbing between inner fingers; webbing formula for outer fingers III 3 – −2 2/3 IV ( Fig. 6E ); fingers with narrow lateral fringes; discs expanded, nearly round; disc pads elliptical; subarticular tubercles round, simple; supernumerary tubercles small; palmar tubercle elliptical, simple. Length of tibia 60.9% of SVL; no tarsal fold evident; webbing formula on foot I 2–2 1/3 II 1 2/3 −3 – III 2 – −2 2/3 IV 3–2 – V ( Fig. 6F ); toes with narrow lateral fringes; discs on toes round; disc on Toe IV narrower that disc on Finger III; disc pads round; inner metatarsal tubercle large, ovoid; outer metatarsal tubercle absent; subarticular tubercles small, round; supernumerary tubercles absent.

Skin on dorsal surfaces of head, body, and lateral surface of head and flanks shagreen without spinules; throat smooth, cream; belly and lower flanks slightly areolate; cloacal opening directed posteriorly at upper level of thighs, surrounded by low, white tubercles; pair of large, round tubercles posteroventral to vent.

Colour in life: (based on QCAZ 27441, adult male; M. R. Bustamente field notes; Fig. 4G, H ). Dorsum pale green; lower flanks and venter transparent; parietal peritoneum white, covering anterior part of abdomen (heart not visible); iris white-copper with black reticulation; bones green.

Colour in preservative: Dorsum of head, body and limbs pale lavender; thin white border on the upper lip; dorsally, all fingers, Toes I–III and most of Toe IV unpigmented; cloacal region mostly unpigmented, except for a few minute white pigmented flecks. Males with cream nuptial pad on Finger I. Two males (QCAZ 26029 and 30) were dissected to observe coloration of internal organs: parietal peritoneum white, pericardium white, hepatic peritoneum clear, visceral peritoneum cream, peritoneum around kidneys white with small, unpigmented spots ( Fig. 12 ).

Measurements (in mm): Measurements of the holotype and paratypes of Cochranella wileyi sp. nov. are given in Table 7.

Variation: All males have the following characteristics: (1) dorsal skin shagreen, but with numerous small spinules; (2) long vocal slits, extending posterolaterally from the posterolateral base of tongue to angle of jaws; (3) nuptial pad large, ovoid, granular, extending from ventrolateral base to dorsal surface of Finger I, covering the proximal half of the length of Finger I (Type I of Flores, 1985); and (4) low tarsal fold on the inner edge of foot. In lateral view, head protruding ( QCAZ 26030 , 26057 , 27435 ). Variation of webbing formula on feet is presented in Table 8 .

Etymology: The specific name is a noun in the genitive case and a patronym for E. O. Wiley, one of the most influential persons in the development of phylogenetic systematics and use of the evolutionary species concept.

Distribution, ecology and natural history: Cochranella wileyi is known only from the cloud forests surrounding YBS (0°41′S, 77°53′W; 2100 m). Six individuals were collected during 3 years of inventory work at Yanayacu, suggesting that Cochranella wileyi is a rare species. Frogs were found in primary forest at night on leaves 120–220 cm above streams (five males) or above the ground (one female). Three males were found near egg clutches, which were on the tip of leaves ( Fig. 13 ); as in Centrolene bacatum , males were never found in the same leaf as the egg clutches, suggesting that males do not guard the eggs. Distance between egg clutches varies, but can be as close as 20 cm; the number of eggs per clutch varies from 19 to 28 (mean = 22, n = 17); eggs are whitish as well as embryos in early developmental stages (QCAZ 28497– 500). One male (QCAZ 26024) was found guarding two clutches and two other males (QCAZ 26029 and 30) were found together near four clutches ( Fig. 13 ). It is unknown which of the two males was guarding which of these four clutches. Males call from the upper side of leaves.

Remarks: In Ecuador, we are aware of only two species in which egg clutches are deposited on the tip of leaves, Cochranella griffithsi and C. wileyi .

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 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 11. Dorsal (top) and ventral (bottom) views of the holotype of Cochranella wileyi sp. nov., adult female, SVL = 27.1 mm, QCAZ 26028.

Figure 12. Kidneys of Cochranella wileyi sp. nov., male, QCAZ 26030, ventral view. Note that kidneys are covered with a white peritoneum and small, unpigmented spots. Length of kidneys = 4.7 mm.

Figure 13. Egg clutches of Cochranella wileyi sp. nov. Note that egg clutches are hanging on the tip of leaves. Each egg mass contains between 19 and 28 eggs.