Cochranella puyoensis

Cisneros-Heredia, Diego F. & Mcdiarmid, Roy W., 2006, Review of the taxonomy and conservation status of the Ecuadorian Glassfrog Centrolenella puyoensis Flores & McDiarmid (Amphibia: Anura: Centrolenidae), Zootaxa 1361, pp. 21-31 : 26-29

Cochranella puyoensis ( Flores & McDiarmid, 1989) n. comb.

Centrolenella puyoensis Flores and McDiarmid, 1989 : Herpetologica, 45 (4), 406 [original description].

Holotype: MCZ 91187 , type locality: " 1.0 km W Puyo, Provincia de Pastaza, Ecuador, between 1000–1050 m elevation". Coloma, 1991: 13 [list of Ecuadorian amphibians]. Almendáriz, 1991: Politécnica, XVI (3), 96 [list of Ecuadorian herpetofauna] .

Cochranella puyoensis — Ruiz-Carranza and Lynch, 1991: Lozania, 57: 23 [new combination under Cochranella ].

Centrolene puyoensis — Duellman and Schulte, 1993: Occas. Pap. Mus. Nat. Hist. Univ. Kansas, 155, 1 – 33 [new combination under Centrolene ]. Cisneros-Heredia and McDiarmid (2006): Zootaxa, 1244, 1 – 32 [analysis of Glassfrogs from eastern Ecuador].

Centrolene puyoense — Frost, 2004: Amphibian Species of the World: Online [changed for gender agreement]. Coloma and Ron, 2004: IUCN Red List of Threatened Species: online [threatened status]. Coloma, 2005–2006: Anfibios de Ecuador: online [list of Ecuadorian amphibians].

In order to provide future workers with data useful in characterizing Cochranella puyoensis , a numbered diagnosis is provided: (1) vomerine teeth present; (2) bones green in life; white or whitish green in preservative; (3) parietal peritoneum covered by guanophores (white), extending posteriorly to the level of the liver and covering the upper half of the stomach; visceral peritoneum clear; (4) coloration in life dark to light green dorsally with small yellow to cream spots/specks, venter bluish-green; in preservative dark to pale purplish-grey with light spots; (5) webbing formula of hand: webbing absent between I and II and vestigal between II and III, III (3 -– 3) – (2 1 / 2 – 2 2 / 3) IV; (6) webbing formula of foot: I (2 – 2 -) – (2 1 / 3 – 2 1 / 2) II 1 1 / 2 – 2 – III (1 1 / 2 – 1 2 / 3) – 2 2 / 3 IV (2 +– 2 2 / 3) – (1 2 / 3 – 2 -) V; (7) snout truncate in dorsal view and truncate to rounded in profile; nostrils slightly elevated and separated by a shallow depression; loreal region concave; (8) all skin surfaces with minute granulations, dorsal skin with scattered low warts or spicules; (9) low nonenameled ridge on forearms and hand; unscaloped fold on tarsus; (10) humeral spine absent in males; (11) tympanum evident ventrally, upper 1 / 4 to 1 / 3 concealed, directed dorsolaterally with slight posterior inclination; supratympanic fold moderately developed to barely evident; (12) 21.2–25.4 mm SVL in males, 27.2–30.0 mm SVL in females; (13) prepollical spine not protruding externally; unpigmented nuptial pad Type I; (14) anal ornamentation with at least two paired tubercles below vent and some additional tubercles and folds; (15) first finger longer than second; (16) lobate liver without guanophores; (17) eye diameter larger than width of disc on finger III; (18) iris in life light blue-green with a transverse green-brown bar (holotype, DFCH-USFQ D 285, QCAZ 7104) or white with grey-green fine reticulations and a transverse gray bar ( QCAZ 7499), iris in preservative grey with some fine dark reticulations, minute dark punctuations, and a transverse dark grey bar; (19) some melanophores on fingers and toes; (20) advertisement call unknown.

The absence of a humeral spine in C. puyoensis would present a contradiction for the hypothesized relationships with C. mariae ( Flores & McDiarmid 1989), because C. mariae was reported to have humeral spines (M. Hensel, pers. comm., in Duellman and Schulte 1993: 31). Unfortunately, no voucher specimens of males of mariae have been studied or reported to be deposited in collections, and the state of the humeral crista ventralis (either with or without a humeral spine) has not been corroborated. The coloration patterns of puyoensis , mariae and azulae are similar and, to the best of our knownledge, unique among glassfrogs (only C. ocellata has a similar coloration pattern, and we think that it is probably related to C. puyoensis ), but without a phylogeny of Centrolenidae any conclusion about their relationships is speculative at best and dependent on the collection and examination of male specimens of mariae and azulae . If mariae and puyoensis are closely related, their placement in different genera would be a consequence of the non-monophyly nature of the centrolenid genera Cochranella and Centrolene (and the non-informative nature of the character used to separate them: humeral spines) or to C. mariae actually lacking humeral spines, and Hensel's comments based on a male of a different species.

The conclusions by Flores and McDiarmid (1989) on the relationships between puyoensis , mariae and azulae (= mariae species group) were based on several characters considered synapomorphies (e.g., microgranulations on the skin surfaces, reduced interdigital webbing). Most subsequent authors have followed their hypothesis ( Ruiz-Carranza & Lynch 1991; Duellman & Schulte 1993). Ruiz-Carranza and Lynch (1995 a) were the first authors to suggest that the proposed mariae group was based on phenetic rather than derived characters, and we concur. The skin microgranulations were considered a unique character uniting C. azulae , C. mariae , and C. puyoensis , but we have subsequently found them present also in C. cochranae ( Goin, 1961) , C. posadae ( Ruiz-Carranza & Lynch, 1995 a), C. luminosa ( Ruiz-Carranza & Lynch, 1995 b), C. luteopunctata ( Ruiz-Carranza & Lynch, 1996) , and C. chami ( Ruiz-Carranza & Lynch, 1995 b)—and they probably occur in more centrolenid species. Reduced webbing between the outer fingers is a condition present in several species of Cochranella . The particular combination of reduced hand webbing and presence of vomerine teeth is present in Cochranella chami , C. cochranae (some specimens), C. cristinae ( Ruiz-Carranza & Lynch, 1995 b), C. luminosa , C. luteopunctata , C. prasina ( Duellman, 1981) , C. puyoensis , and C. spilota ( Ruiz-Carranza & Lynch, 1997) .

Conservation status

New data presented herein extend the distributional range of Cochranella puyoensis . All records from the provinces of Napo and Orellana are located in the Huataracu River Basin, ca. 100 km NE from the type locality (1 km W of Puyo). We think that the locality of the specimen reported from “Río Pucayacu” ( USNM 291298) corresponds to some place in the Andean foothills in the Upper Bobonaza River Basin, province of Pastaza, and not to the mouth of the Pucayacu River near Montalvo (c. 315 m elevation) mentioned in the Ecuadorian gazetteer of Paynter (1993). The Pucayacu River near Montalvo is located in the Amazonian lowlands region of the province of Pastaza (Paynter 1993), while Cochranella puyoensis is a species from foothill regions. The highest elevational record of Cochranella puyoensis is about 1,000 m elevation at the type locality (1 km W of Puyo, province of Pastaza); and the lowest point is around 400 m elevation. in the Huataracu River Basin. All records of C. puyoensis are localities within the provinces of Napo, Orellana, and Pastaza, Ecuador, and this taxon is apparently restricted (endemic) to the Foothill Evergreen forests of the central section of the eastern Andean slopes of E cuador, in the Eastern Subtropical zoogeographic zone ( Fig. 1 ).

Cochranella puyoensis was classified as “Critically Endangered” by Coloma and Ron (2004) because “its extent of occurrence is less than 100 km ², all individuals are in a single location, and there is continuing decline in the extent and quality of its habitat around the city of Puyo [city incorrectly cited as “Douala” in Coloma & Ron 2004]”. However, new data presented herein led us to reconsider its conservation status. Cochranella puyoensis is more widely distributed than previously thought and now it is known to occur in two separate areas: the region around Puyo and two localities on the southeastern slope of Volcan Sumaco in the Huataracu River drainage ( Fig. 1 ). This species is still restricted to just one vegetation formation, the Foothill Evergreen forests of eastern Ecuador. This vegetation formation had a historical area of ca. 13,200 km 2. Today ca. 38 % has been severely affected by anthropogenic activities with ca. 8,200 km 2 remaining (Sierra et al., 1999 with data from 1996). Moreover, ca. 55 % (ca. 4,500 km 2) of the remaining forest is less than 3 km from zones of high human pressure (e.g. deforestation, uncontrolled extension of the agricultural frontier, water pollution), and only ca. 10 % of the remaining Foothill Evergreen forests is protected inside the Ecuadorian Protected Areas System ( SNAP) (Sierra et al., 1999). As with nearly all species of centrolenid frogs, Cochranella puyoensis presumably reproduces along rivulets in primary or secondary forests, it does not persist in heavily impacted areas such as pastures. Thus, its occupancy area is probably even less than the 8,200 km 2 of remaining potentially habitat (extension of presence), and closer to 3,700 km 2 (remaining suitable habitat, at more than 3 km from zones of high human pressure).

Because the current extension of presence of Cochranella puyoensis is less than 5,000 km 2 but larger than 100 km 2 (criteria B 1), its occupancy area is probably less than 500 km 2 but larger than 100 km 2 (B 2), it is known from fewer than five localities (criteria B 1 a, B 2 a), population declines have been reported in several centrolenid species from the eastern slopes of Ecuador (criteria B 1 b, B 2 b) ( Cisneros-Heredia & McDiarmid, 2005, Cisneros-Heredia et al. 2006); and, important considerations relative to its conservation status (extension of presence, occupancy area, and habitat quality) continue to decline (both observed and projected), we recommend that Cochranella puyoensis be treated as an “Endangered” species on both a national and global level under the IUCN (2001) system with the following criteria and sub-criteria: EN B 1 ab(i,ii,iii)+ 2 ab(i,ii,iii).

Figures

FIGURE 1. Distribution of the Glassfrog Cochranella puyoensis (Flores and McDiarmid) in Ecuador. Circle corresponds to the type locality, 1. 0 km W Puyo (province of Pastaza = 3), and dots to new localities reported herein: ca. 45 km E of Narupa (province of Napo = 1), Río Huataracu (province of Orellana = 2), “ Río Pucayacu ” (province of Pastaza = 3).