Centrolene kutuku Ron, García, Brito-Zapata, Reyes-Puig, Figueroa-Coronel, & Cisneros-Heredia, 2024

Ron, Santiago R., García, Dominike, Brito-Zapata, David, Reyes-Puig, Carolina, Figueroa-Coronel, Elías & Cisneros-Heredia, Diego F., 2024, A new glassfrog of the genus Centrolene (Amphibia, Centrolenidae) from the Subandean Kutukú Cordillera, eastern Ecuador, Zoosystematics and Evolution 100 (3), pp. 923-939 : 923-939

Centrolene kutuku Ron, García, Brito-Zapata, Reyes-Puig, Figueroa-Coronel, & Cisneros-Heredia sp. nov.

Proposed Spanish common name.

Rana de Cristal de Kutukú.

Proposed English common name.

Kutukú Glassfrog.

Type material.

Holotype. (Figs 6 – 9 ) QCAZ - A 71386 (field number PUCE SC 61758), collected at República del Ecuador, provincia de Morona Santiago, cantón Santiago de Mendez, parroquia San Francisco de Chinimbimi, Cordillera del Kutukú, sector Puchimi , 22 km ESE Santiago de Mendez (2.7901 ° S, 78.1266 ° W, 2264 m elevation), by Diego Almeida, Diego Paucar, Darwin Núñez, Kunam Nusirquia, and Ricardo Gavilanes on 25 January 2018.

Paratypes. (1 specimen) QCAZ - A 71400 , adult male, collected near the type locality (2.7903 ° S, 78.1265 ° W, 2255 m elevation) on 27 January 2018, same collectors as holotype .

Definition.

Centrolene kutuku sp. nov. is distinguished from all other Centrolenidae by the following combination of characters: (1) dentigerous process of vomer present, without vomerine teeth; (2) snout slightly subacuminate to round in dorsal view and sloping in lateral view; (3) tympanic annulus evident, almost completely visible except for upper most border, tympanic membrane coloured as surrounding skin, supratympanic fold present; (4) dorsal skin microspiculate with abundant tubercles on head and body; (5) ventral skin granular, subcloacal area with two large subcloacal warts; elevated, abundant, enamelled, pericloacal warts, other cloacal ornamentation absent; (6) parietal peritoneum white — iridophores covering ½ of ventral parietal peritoneum (condition P 2), pericardium covered by iridophores and all other visceral peritonea translucent (condition V 1); (7) liver lobed and hepatic peritoneum translucent (condition H 0); (8) adult males with short humeral spines, barely protruding through skin (Fig. 9 ); (9) absent webbing between fingers I and II, II (2 - – 2 +) – 3 - III (2 +) – (2 ½ — 2 ⅓) IV; (10) toe webbing I (1–1 ½) – (2–2 +) II (1 - – 1 + – 2 -) III (1 + – 1 ½) IV (1 ½ – 1) V; (11) dermal fringe along postaxial edge of Finger IV and hand, slightly enamelled ulnar fold; dermal fringe along postaxial edge of Toe V, slightly enamelled metatarsal and tarsal folds, warts on heel absent; (12) unpigmented nuptial pad Type I; prepollex concealed; (13) Finger II slightly longer than Finger I, (14) eye diameter larger than width of disc on Finger III; (15) colour in life, all dorsal surfaces green with light green dots, bones green; (16) colour in preservative, dorsal surfaces lavender with lighter tubercles, white supralabial stripe, flanks with contrasting dorsal-ventral transition in colour, dorsal surfaces of limbs lavender clearer than body with slightly lighter dots; two white spots on arm near shoulder; (17) in life, iris cream with grey reticulations; (18) melanophores on Finger IV absent; scattered melanophores along toes IV and V; (19) calling site of males unknown; call undescribed; (20, 21, 22) fighting behaviour, egg clutches, and tadpoles unknown; (23) SVL in adult males 21.5–21.9 mm (n = 2); females unknown.

Diagnosis.

Centrolene kutuku sp. nov. differs from all other glassfrogs, except C. heloderma , by having humeral spines in males, dorsum green with light dots and without dark marks, dorsum with abundant tubercles, and visceral peritonea translucent (except for pericardium). Centrolene kutuku sp. nov. is similar to C. camposi , C. ericsmithi , C. heloderma , and C. zarza in having humeral spines in males and elevated dermal ornamentations (i. e., dorsal tubercles or warts) and lacking dorsal dark-coloured marks. Centrolene camposi differs from C. kutuku sp. nov. by having (characters of C. kutuku sp. nov. in parentheses) sloping snout in lateral view (rounded), tympanic annulus barely visible (completely visible), colouration in life green dorsum with thick yellowish-white labial stripe continuing into a faint yellowish lateral line and yellowish green flanks (green dorsum with light green dots), and larger body size in males (SVL 29.1–31.2 mm in C. camposi vs. 21.5–21.9 mm in C. kutuku sp. nov.). Centrolene ericsmithi differs from C. kutuku sp. nov. by having tympanic annulus barely visible (almost completely visible), dorsal skin with dispersed spicules (with abundant tubercles), colouration in life green dorsum with thin yellowish labial stripe continuing into a row of white lateral tubercles and yellowish lateral line (green dorsum with light green dots), and larger body size in males (SVL 27.3 mm in C. ericsmithi vs. 21.5–21.9 mm in C. kutuku sp. nov.). Centrolene heloderma differs by having pustular dorsal skin (with abundant tubercles), grey lavender dorsum in preservative (lavender), and outer tarsal fold with low white tubercles (enamelled fold without tubercles). Centrolene zarza differs by having snout rounded with elevated warts at the tip in dorsal view and sloping in lateral view (round, without elevated warts at the tip in dorsal view and rounded in lateral view), dorsal skin shagreen with scattered warts of varying size and abundant, elevated, enamelled warts on head and flanks (abundant tubercles, lacking enamelled warts), dorsum green with yellowish-green dots and enamelled warts (green dorsum with light green dots), and larger body size in males (SVL 23.2–26.2 mm in C. zarza vs. 21.5–21.9 mm in C. kutuku sp. nov.).

Description of the holotype.

(Figs 6 – 9 ) SVL = 21.9 mm, HW = 9.0, HL = 7.2, IOD = 4.1, ED = 2.8, EN = 1.4, IN = 1.9, TYD = 1.0, HAL = 8.6, FL = 10.8, TL = 13.2, F 3 DW = 1.5.

Adult male. Snout rounded in dorsal view, sloping in lateral view, EN / HL = 0.22; nostrils slightly elevated, producing a low depression in the internarial area, loreal region concave; canthus rostralis indistinct. Small-sized eyes, ED / HL = 0.38, directed anterolaterally at about 45 ° from midline, interorbital area wider than eye diameter, IOD / ED = 1.46, EN / ED = 0.59, EN / IOD = 0.34. Tympanic annulus evident and slightly oriented dorsolaterally, supratympanic fold above upper portion of tympanum and extending down to shoulder. Dentigerous processes of vomers present but vomerine teeth absent; choanae rounded, separated; tongue rounded; vocal slits present, extending from mid tongue to near jaw angle.

Skin of dorsal surfaces of body and limbs shagreen with scattered tubercles of varying size on head, dorsum and limbs. Skin of ventral surfaces of body granular. Cloacal opening directed posteriorly at upper level of thighs, no distinct cloacal sheath; subcloacal area coarsely granular with a pair of large, round, flat subcloacal warts on ventral surfaces of thighs below vent; pericloacal area with enamelled warts of similar size; other cloacal ornamentation absent.

Upper arm thinner than moderately robust forearm. Humeral spine present, short, and barely visible externally, not piercing the skin. Relative lengths of fingers III > IV> II > I; webbing formula between fingers absent between I and II, II basal III 2 — 2 1 / 3 IV; finger discs wider than the adjacent phalanx, nearly truncate; disc on third finger slightly larger than those on toes, ED / F 3 DW = 1.86; subarticular tubercles rounded and slightly elevated, supernumerary tubercles abundant and distinct; palmar tubercle prominent, rounded, elevated; thenar tubercle elliptic. Concealed prepollex, unpigmented nuptial excrescences present, Type I on dorsolateral side of thumbs.

Hind limbs slender; TL / SVL = 0.60, FL / SVL = 0.49. Inner metatarsal tubercle large and elliptical; outer metatarsal tubercle small and round. Subarticular tubercles rounded and low, supernumerary tubercles distinct but low. Webbing on feet I 1 ½ – 2 II 1–2 III 1–2 IV 2–1 ½ V; toe discs bluntly truncate. Papilla on tip of discs absent.

Colour of holotype.

Colour in preservative is shown in Figs 7 , 8 . Pale dots on dorsum are of varying sizes. Iris silver with dark, fine reticulations. Parietal peritoneum white, iridophores covering 1 / 3 of ventral parietal peritoneum. Pericardium white (i. e., covered by iridophores), all other visceral peritonea translucent. Colour in life is shown in Fig. 6 .

Variation.

Measurements of QCAZ 71400 in mm: SVL = 21.5, HW = 8.5, HL = 7.0, IOD = 4.0, ED = 2.4, EN = 1.7, IN = 2.0, TYD = 0.9, HAL = 7.5, FL = 10.6, TL = 13.0, F 3 DW = 1.5. The single paratype differs from the holotype by having lower dorsal tubercles (wart-like), a dorsal lavender colour that is lighter, and more contrasting enamelled colouration on limbs.

Etymology.

The specific name of this new taxon is a noun in apposition and refers to the Kutukú Cordillera, the Subandean Cordillera where the new species was discovered. The name originates from the Shuar language, meaning “ paramo with stunted vegetation ” ( Pérez 1984).

Distribution and natural history.

Centrolene kutuku sp. nov. is known from a single locality in southeastern Ecuador, on the western slope of the Kutukú Subandean cordillera, between 2255–2264 m elevation (Fig. 2 ). The species inhabits Montane Evergreen Forest over the Sandstone Plateaus of the Cóndor-Kutukú Cordillera (sensu MAE et al. 2013). Sandstone plateaus in the Subandean Cordilleras have forest ground covered by mosses and roots, forming a false floor with large spaces between roots. The holotype was calling over a leaf 200 cm above the ground, on the edge of a small spring flowing into a black water ravine in a primary forest. The paratype was on a leaf, 300 cm above the ground, next to a black water stream. Both individuals were found in primary forest ( QCAZ specimen database).

Conservation status.

Centrolene kutuku sp. nov. is known from a single locality in the Kutukú cordillera, southeastern Ecuador. The locality is not in a protected area, and by 2020, there were agricultural lands at a distance of 2.7 km ( MAATE 2022). Because collections in Kutukú have been limited, the distribution of the species is likely to be larger. The population status of this new species is unknown, and we recommend assigning it to the Data Deficient Red List category.

Figures

Figure 2. Map of Ecuador (left) and expanded area (right) showing known localities for Centrolene camposi (black square), C. condor (white square), C. kutuku sp. nov. (white triangle), and C. zarza (black circle) in southern Ecuador. Localities are based on specimens deposited at the DHMECN, QCAZ, and ZSFQ collections (see Materials and Methods for a list), Sze ́ kely et al. (2023), and Cisneros-Heredia et al. (2023).

Figure 6. Centrolene kutuku sp. nov. and C. camposi in life. A, B, and E are dorsolateral views, and C, D, and F are ventral views. A – C. Centrolene kutuku sp. nov., holotype, male, QCAZ 71386, SVL = 21.9 mm; B – D. C. kutuku sp. nov., paratype, male, QCAZ 71400, SVL = 21.5 mm. E – F. C. camposi, holotype, DHMECN 11407, SVL = 29.1 mm. Photographs of C. camposi by Juan C. Sánchez-Nivicela.

Figure 7. Centrolene kutuku sp. nov. in preservative. Upper row: dorsal view; lower row: ventral view. A. Holotype, male, QCAZ 71386, SVL = 21.9 mm; B. Paratype, male, QCAZ 71400, SVL = 21.5 mm.

Figure 8. Centrolene kutuku sp. nov. head, hand, and foot in preservative. Upper row: lateral view of the head; lower row: ventral view of hand (left) and foot (right) of the holotype. A. Holotype, male, QCAZ 71386, SVL = 21.9 mm, head length = 7.2 mm; B. Paratype, male, QCAZ 71400, SVL = 21.5 mm, head length = 7.0 mm.

Figure 9. Dorsal X-ray views of Centrolene zarza and Centrolene kutuku sp. nov. A. Centrolene zarza QCAZ 58686, adult male, SVL = 23.9 mm; B. Centrolene kutuku sp. nov. QCAZ 71386, adult male (holotype), SVL = 21.9 mm. Black arrows point to humeral spines; notice the difference in angle orientation, curvature, and size.