Atelopus pastuso, Coloma, Luis A., Duellman, William E., C, Ana Almendáriz, Ron, Santiago R., Terán-Valdez, Andrea & Guayasamin, Juan M., 2010

Coloma, Luis A., Duellman, William E., C, Ana Almendáriz, Ron, Santiago R., Terán-Valdez, Andrea & Guayasamin, Juan M., 2010, Five new (extinct?) species of Atelopus (Anura: Bufonidae) from Andean Colombia, Ecuador, and Peru, Zootaxa 2574, pp. 1-54 : 20-28

Atelopus pastuso sp. nov.

Holotype. QCAZ 15013, adult gravid female, from near a lake in Voladero, Páramo de El Ángel (approx. 0˚41' N, 77˚53' W; ca 3750 m), Provincia Carchi, Ecuador, obtained on 12 January 1980 by Jaime Jaramillo.

Paratypes. QCAZ 15009–12, 15014–15 (2 females, 1 male, 3 juveniles), same data as holotype; EPN 3238 (1 juvenile) from Chiles, 5 km W from Lagunas Verdes on road from Tufiño to Maldonado, 3840m, Provincia Carchi, Ecuador, obtained on 8 February 1986 by Ana Almendáriz and Patricio Ponce; KU 117840–41 (juveniles) from Volcán Chiles, 10 km W Tufiño, obtained on 23 February 1968 by John D. Lynch; QCAZ 15018 (female) from San Gabriel, Provincia Carchi, obtained on 1 January 1980 by Rafael Narváez; KU 164754–57 (4 females), from 4.5 km E San Gabriel, obtained on 4 October 1974 by William E. Duellman and John E. Simmons; EPN 3239–55 (11 adult females, 2 adult males, 4 juveniles), from Espejo, Hacienda La Esperanza (NW of El Ángel), 3400 m, obtained on 12 February 1986 by Ana Almendáriz and Patricio Ponce; QCAZ 1051, 1053, 1908–15 (9 juveniles) from 26.6 km W of Tulcán, near the Volcán Chiles (on road from Tulcán to Maldonado), 3690 m, obtained on 8 June 1989 by Felipe Campos Y., Stella de la Torre, Diego Lombeida and Luis A. Coloma; KU 164759–164837, 164841–48, 166296–166300 from 20 km SW Tulcán, Páramo de El Ángel, 3350 m, obtained on 18 May 1975 by William E. Duellman, Linda Trueb, John E. Simmons, and Dana T. Duellman; KU 117842–73 from Quebrada de Piedras, 20 km SW Tulcán, obtained on 24 February 1968 by John D. Lynch; QCAZ 3742 (female) from 42 km W of Tulcán, Provincia Carchi, Ecuador, 3645 m, obtained on 3 March 1993 by Diego Lombeida and Luis A. Coloma; KU 202255–66 (2 females, 10 males) from 30 km SW Tulcán, obtained on 26 February 1984 by David M. Hillis and John E. Simmons; KU 202267 (female) from 38 km SW Tulcán, obtained on 2 April 1984 by John E. Simmons; KU 117799–839, 178338 (30 females, 2 males, 3 juveniles) from Tulcán, Provincia Carchi, Ecuador, obtained on 22 and 23 February 1968 by John D. Lynch, except KU 178338 that was collected on 26 May 1977 by John D. Lynch; MHNG 2258.64–74, 2271.39–40, QCAZ 57–58 (12 females, 3 males) from Tulcán, Provincia Carchi, Ecuador, obtained on 5 April 1985 by Luis A. Coloma; KU 202254 (female) from 12 km E of junction Pan-American highway and El Carmelo road, obtained on 24 February 1984, by David M. Hillis.

Referred specimens. From Departamento Nariño, Colombia: ICN 26549, 26558, 26560 from Hacienda Alsacia, Tuquerres, km 10 (by road, Tuquerres-Guachucal), obtained on 16 November 1982 by María C. Ardila and Pedro M. Ruiz; ICN 26570 26574, 26580 from Cumbal, km 8 (by road Cumbal to El Volcán), 3470 m, obtained on 16 November 1982 by María C. Ardila and Pedro M. Ruiz; ICN 26585–86 from Cumbal, km 10–11, (by road Cumbal to El Volcán), 3470–3500 m, obtained on 16 November 1982 by María C. Ardila and Pedro M. Ruiz; ICN 2807, 2817–19 from Cumbal, Vereda El Salado-Pueblo Viejo, obtained on February 1976 by Mario Fajardo; ICN 2822–24 from Cumbal, Laguna de Cumbal, obtained on February 1976 by Mario Fajardo; ICN 2835 from San José, Pueblo Viejo, Vereda El Salado, obtained on February 1976 by Mario Fajardo. From Ecuador: EPN 2195–2211, from Cordillera Troya (on the road to Tulcán), Provincia Carchi, obtained on October 1959 by Manuel Olalla; QCAZ 2678, from Monte Olivo, Provincia Carchi, 3000 m, obtained on 1 March 1991 by Giovanni Onore; MHNG 2385.12–13, 2385.15–30, 2385.32–43, from Pimampiro, Provincia de Imbabura, approx. 2100 m, obtained on August 1986 by Giovanni Onore; QCAZ 15019– 22, from Pimampiro, Provincia de Imbabura, approximately 2100 m, obtained on 13 November 1976 by Fernando Ortiz-Crespo and Luis Rodríguez; EPN 3312–13, from Laguna Cuicocha, Provincia de Imbabura, 3590 m, obtained on 26 January 1988 by Ana Almendáriz and Jhanira Regalado. See additional specimens under Remarks.

Diagnosis. (1) A medium-sized species with SVL in adult females 38.7 (29.6–50.7, SD = 3.89, n = 153) and in adult males 31.8 (26.1–38.9, SD = 2.42, n = 128); (2) hind limbs short, tibia length/SVL 0.29–0.41 (n = 281); (3) phalangeal formula of hand 2-2-3-3, basal webbing absent; (4) foot webbing formula I (½)—(1-– 1) II (½–1)—(1–2+) III (1–2-)—(2–3½) IV (2–3+)—(½–1½) V; (5) snout rounded to acuminate, slightly protruding beyond lower jaw; (6) tympanic membrane, tympanic annulus and stapes absent; (7) dorsal surfaces of body usually smooth, bearing few warts in sacral region, (8) warts and spiculae (black in life) present on forearm, flanks and dorsal surfaces of thighs and shanks; (9) vertebral neural processes inconspicuous; (10) dorsum black to grayish green and bright green (black to dark gray to cream, some specimens bearing either a marbled dorsum with diffuse dark and clear marks or a dark brown dorsum with cream marks in preservative); (11) minute gray stippling present on dorsum of body, (12) venter green to yellowish green, bright yellow, and dull creamy white (uniform cream in preservative); (13) gular region without warts, spiculae or coni.

In having a black and blackish gray dorsum in preservative, Atelopus pastuso sp. nov. is most similar to A. ardila , A. bomolochos , A. boulengeri Peracca, A. carrikeri , A. ebenoides , A. ignescens , A. nanay , A. petersi Coloma, Lötters, Duellman and Miranda-Leiva , A. podocarpus sp. nov., and A. spp. (populations from Río Tililag, Corazón Chupa and Atillo, in Chimborazo province). Atelopus pastuso differs from A. bomolochos , A. spp. A. peruensis , and A. podocarpus by having gray spiculae (yellow in A. bomolochos , red in A. podocarpus , white in A. nanay and A. spp.). Atelopus pastuso differs from A. carrikeri , A. ignescens and A. ardila by lacking a patch of spiculae and coni on the gular and pectoral regions (present in A. carrikeri , A. ignescens and A. ardila ) and by having green pigments on dorsum and flanks (absent in A. carrikeri , A. ignescens and A. ardila ). Atelopus pastuso differs from A. boulengeri by being smaller. It differs from A. petersi by having green coloration and lacking dorsal and ventral color patterns (dorsum with yellow orange pattern to almost entirely black, venter yellow with or without black marks, or uniform orange to reddish orange in A. petersi ). Atelopus pastuso differs from A. ebenoides by having green coloration (black with yellow and white marks in A. ebenoides ). It differs from A. nanay (from the Cordillera Occidental in the southern Andes of Ecuador) by having numerous black spiculae on flanks (scattered white spiculae in A. nanay ).

Description of holotype. ( Figs. 9 A–C, virtual animation). Gravid female with eggs visible through ventral skin. Head slightly longer than wide, HLSQ and HDWD less than one third SVL (HLSQ/SVL = 0.277, HDWD/SVL = 0.253); snout acuminate in dorsal view; in lateral view, profile of tip of snout to the anterior margin of jaw nearly straight and slightly protuberant; swollen gland on tip of snout absent; nostrils slightly protuberant, directed laterally, situated at level slightly posterior to apex of lower jaw; canthus rostralis distinct, flared, nearly straight from eye to nostril; loreal region concave; lips not flared; interorbital region and occiput flat, smooth; eyelid flared without distinct tubercles; postorbital region glandular; pretympanic and tympanic areas bearing spiculae; tympanic membrane and tympanic annulus absent; postmandibular and temporal area with spiculae; choanae small, rounded, widely separated; tongue twice as long as wide, about equal width along its length, free along its posterior third.

Forearm relatively short (RDUL/SVL = 0.268); palmar tubercle round, well defined; supernumerary palmar tubercles distinct; thenar and subarticular tubercles distinct, raised; digital tips with round pads; thumb relatively long (THBL/HAND = 0.702), apparently having two phalanges; webbing on hands absent, fingers lacking lateral fringes or keels; relative length of fingers II<III<V<IV. Tibia relatively short (TIBL/SVL = 0.332); fold on distal half of inner edge of tarsus absent; inner metatarsal tubercle oval and slightly raised; outer metatarsal tubercle round, slightly raised, about two-thirds length of inner metatarsal tubercle; supernumerary plantar tubercles conspicuous; subarticular tubercles flat, barely conspicuous; digital pads distinct; webbing formula of foot I (½)—(½) II (½)—(1½-) III (1+)—(3-) IV (2)—(1) V; relative length of toes I<II<III>V<IV.

Dorsal surfaces of head and shoulders smooth; flanks, dorsum of sacral region, thighs, and proximal surfaces of forelimbs bearing numerous spiculae; spiculae occur singly or in groups of up to six; throat rugose; chest, belly, undersides of limbs nearly smooth, except arm warty and ventral surfaces of thighs rugose; cloacal opening inconspicuous tube at upper level of thighs, directed posteriorly; round warts surrounding rugose cloacal opening.

Color in preservative (70–75 % ethanol): dorsal surfaces of head, body and limbs blackish gray, darker at limbs and margin of head; creamy white area at lower margin of eye; flanks paler than dorsal surfaces; margin of cloacal opening blackish gray; irregular gray mark on pelvic patch. Minute gray stippling on dorsum of body (viewed at 8x magnification); dark gray spots at base of gray spiculae; throat, chest, belly, and ventral surfaces of arms and thighs uniform cream; other ventral surfaces of limbs gray; palmar surfaces gray except for cream palmar, thenar and some subarticular and supernumerary tubercles; inner and outer metatarsal tubercles cream in contrast to adjacent dark gray areas; proximal end of tongue lacking black pigment; lower lip entirely creamy white.

Color in life (from a color transparency of holotype QCAZ 15013 in posterodorsal view): Dorsum of body and limbs dark green, flanks yellowish green; spiculae black.

Holotype measurements (mm): SVL 41.8, TIBL 13.9, FOOT 14.5, HLSQ 11.6, HDWD 10.6, ITNR 3.9, EYDM 3.2, EYNO 2.8, RDUL 11.2, HAND 10.4, THBL 7.3, SW 11.4.

Variation. Meristic variation is given in Table 4 . A female paratopotype (QCAZ 15014) resembles the holotype except that it has a slightly darker dorsum; the inner and outer palmar and plantar tubercles show more contrast to adjacent areas, and the outer plantar tubercle is more swollen. Other paratypes from the same general area of the holotype (EPN 3238–3255; QCAZ 1051, 1053, 3742), from Tulcán (MNHG 2258.64– 2258.74, QCAZ 57–58, 1908–1915), from San Gabriel (QCAZ 15018), and from 20–38 km SW of Tulcán (KU 164759–164837, 164841–48, 166296–166300, 202255–67) are similar to that above described with the following noteworthy exceptions. Color of the dorsum in preservative varies from plain greenish gray (EPN 3242) to plain dark brownish gray (EPN 3251) and plain black (KU 164759–164837, 164841–48, 166296– 166300); a male (EPN 3248) has dark brown marks on a pale gray background, forming a marbled pattern on dorsum of head and body. A narrow middorsal brown line from the tip of the snout to the cloacal region is conspicuous in nine specimens, whereas it is barely visible or absent in others. In all specimens, the flanks are paler than the dorsum and vary from cream in contrast to a dark brown dorsum (EPN 3247) to only slightly paler than a greenish gray dorsum (EPN 3242). A juvenile (QCAZ 1914) possesses few, creamy white spiculae on the lower flanks. The throat, chest and belly are uniform yellowish cream. One female from the type locality (QCAZ 15011) has a patch of white warts with scattered dark pigments on the chest. A brown or gray mark at the pelvic patch region varies from absent to barely conspicuous. The ventral surfaces of limbs mostly vary in the degree of contrast between the palmar and plantar tubercles with the adjacent areas; for example, in EPN 3245 the palmar surfaces are nearly entirely yellowish cream, whereas in EPN 3239 there is a high color contrast between the palmar tubercles and the adjacent areas. In females, there is variation in size, abundance and distribution of spiculae; for example EPN 3244 has abundant and large spiculae, whereas EPN 3242 has few spiculae on the dorsum of body. Juveniles possess spiculae and warts about equally abundant as in adults.

Atelopus pastuso

In specimens from a population west of the type locality, from Cordillera Troya (EPN 2195–2211), the dorsum varies from plain dark gray to pale brown; the venter is cream.

South of the type locality, specimens from populations at Provincia de Imbabura (QCAZ 2678 from Monte Olivo, MNHG 2385.12–13, 2385.15–30 2385.32–43 from Pimampiro, and QCAZ 15019–22 from Volcán Cotacachi) are more variable in dorsal color. In addition to having a plain dark gray to plain cream dorsum, some specimens have either a marbled dorsum with diffuse dark and pale marks or a dark brown dorsum with cream marks. All are uniform creamy yellow ventrally, but some specimens from Pimampiro have ventral dark marks. A female (MNHG 2385.29) has a brown band across the throat at a level posterior to the mandible, whereas other specimens (MNHG 2385.19, 20, 24, 28, 30, 39, 40, 44, 48, 1 female, 6 males, 2 juveniles) have diffuse brown marks on the chest-gular region. Farther south, two specimens from Laguna Cuicocha (EPN 3312–13, female and male) are similar to the type specimens, except they have a more rugose ventral skin.

Sexual dimorphism is evident in that females are larger than males ( Table 4 ). Males have vocal slits and keratinized nuptial pads on the dorsal and inner surfaces of the thumb (except at terminal phalanx) and on Finger III, on which they are most numerous on the proximal phalanx. The forelimbs are relatively long and slen- der in females, but they are short with a stout muscular area in males ( Table 4 ); there are significant differences in RDUL between males and females (RDUL Student’s t -test, t = 12.6718, df = 263, P <0.0001). Males nearly lack spiculae but bear abundant warts homogeneously distributed on the flanks and dorsum.

Color in life. ( Figs. 4 C–F). Gómez Castillo (1982) described the color in life of populations from Túquerres, El Espino, Guachucal and Cumbal at about 3000 m, in Departamento Nariño, Colombia, the frogs had a pale green dorsum with black spiculae, and the venters were very pale green to nearly white. Cepeda Quilindo and Rueda Almonacid (2005:135) published color pictures of an amplectant pair and of an individual in dorsal and ventral view (locality not stated). Almendáriz and Cisneros (2005:153) described individuals (including a photo) from Lagunas Verdes, Provincia del Carchi; EPN 3238 has a black dorsum and a lemon green venter with a black anal pelvic patch bordered by orange (AA field notes of 26 January 1988). The following are taken from color photographs and/or descriptions of coloration in life in field notes. Adult male from the type locality, QCAZ 15009 (color slide in anterolateral view, taken by Eugenia del Pino): flanks and dorsal surfaces of limbs green; suborbital region and throat yellow; spiculae on arms black; iris black.

Páramo de El Ángel, 20 km SW Tulcán, 3350 m (KU 164759–848; WED field notes, 18 May 1975, photo of 164759): dorsum black with grayish green flanks in some individuals; venter yellowish green (predominantly yellow on throat and ventral surfaces of hind limbs; predominantly green on belly) or venter uniformly green (throat in some dull creamy white); soles greenish gray; ventral border of orbit pale yellow; iris dark brown.

Two adult females from Tulcán, MHNG 2258.68 (two color slides in dorsal view taken by LAC), MNHG 2258.65 (two color slides in dorsolateral view taken by LAC): In MHNG 2258.68, dorsum nearly uniform greenish cream, except spiculae nearly black; gray suffusion in supraorbital region, forearm, dorsal surfaces of hands and feet; gray bands across fingers and toes; outer palmar tubercle cream; outer plantar tubercle white. MNHG 2258.65 similar to above, except for having four large, diffuse, round, gray marks on dorsum of head and body; flanks greenish-cream with a pale yellowish-cream suborbital area. The iris is black.

QCAZ 3742, female from 42 W of Tulcán (LAC field notes, 2 March 1993): dorsum greenish black with a reticulate pattern; venter yellowish-cream.

QCAZ 1908–15, 1051, 1053, from 26.6 km W of Tulcán, near Volcán Chiles (LAC field notes of 8 June 1989): dorsum greenish black; flanks and venter pale green to yellow; spiculae black; palmar and plantar tubercles creamy yellow; suborbital region yellowish green; iris black. QCAZ 1911 (juvenile, two color slides of venter taken by LAC): throat, chest and belly pale yellow; lower lip with whitish-cream margin; black pelvic mark; limbs gray ventrally, except tips of fingers and toes black; black stripe extends along mid-length of fingers; black marks on plantar surfaces; palmar and plantar tubercles whitish-cream; outer metatarsal tubercle white.

EPN 3239–55, from Hacienda La Esperanza (AA field notes, 12 February 1986): dorsum plain black to pale gray, olive green, or green; venter yellow to sulfur-yellow and green-yellow with a black pelvic mark. EPN 3253 with black cephalic region extending to middorsum and changing to olive-green posteriorly; gular region bright yellow; abdominal region yellow; extremities olive-green; anal mark orange.

QCAZ 15018, female from San Gabriel (color slide in dorsolateral view taken by Eugenia del Pino): dorsum of head, body, and limbs bright green; flanks yellowish green; spiculae black, canthus, eyelid, and postorbital ridge dark gray.

QCAZ 15019–22, two females and two males from Volcán Cotacachi (Eugenia del Pino Lab notes, November 1976): dorsum grayish green; coni black; throat, venter and undersides of forearms yellow; brown or gray mark surrounding anal region. In life, female (QCAZ 15019) from Volcán Cotacachi had a grayish green dorsum with black pointed spiculae; the cloacal region was brown to gray, and the gular region and ventral surfaces of the hind limbs and forearm were yellow, but with a patch of white warts on chest–gular region (Eugenia del Pino, Lab notes, 13 November 1976).

Tadpoles. Unknown.

Distribution, ecology, natural history, and conservation status. Atelopus pastuso is known only from paramo and subparamo habitats from Departamento Nariño in southern Colombia to Provincia Imbabura in northern Ecuador. It occurs in the following natural formations (according to the classification proposed by Va le n ci a et al. 1999): Páramo de Frailejones, Páramo Herbáceo, Bosque Siempre Verde Montano Alto and Bosque de Neblina Montano. These habitats lie between 2800–3900 m in the high massif of the Nudo de Pasto (as defined by Duellman 1979) and in the northern extreme of the Cordillera Occidental del Ecuador ( Fig. 5 ). The area of its extent of occurrence is of about 3127 km 2. One locality of A. pastuso at the western versant of Cordillera Occidental is in close proximity to the Ecuadorian localities of A. angelito ( Fig. 5 ); thus, they might have occurred in parapatry or sympatry at these localities. At the type locality, Páramo de El Ángel, annual mean rainfall is 1275 mm and the annual mean temperature is 6.9 °C ( Hijmans et al. 2005). KU 164759–848 (WED field notes, 18 May 1975) from Páramo de El Ángel, 20 km SW Tulcán, 3350 m above sea level were found at wet paramo, grazed, with bunch grass and few cushion plants. At the time of collection, one individual was under rock by day; others were crawling on ground and amid vegetation (some ± 20 cm above ground on sunny side of bunch grass). Temperature data (˚C) were taken for KU 164761–164779 and are shown in Table 5 . As reported by Duellman and Trueb (1986:216 as A. ignescens ), these black frogs are able to raise their body temperatures rapidly by climbing onto sunny sides of bunch grass; within half an hour after emergence, 20 individuals had body temperatures of 0.5 to 4.6˚C (mean = 1.45˚C) above the adjacent substrate. EPN 3239–55 from Hacienda La Esperanza were found between 8:30 to 10:30 hours under stones and trunks in a cypress forest surrounded by cultivated fields (AA field notes, 12 February 1983).

Frog Temperature Substrate Temperature Air Temperature Adult gravid females were collected on 18 May 1975, 13 November 1976, 12 January 1980, 5 April 1985, 13 March 1986, August 1986, 2 March 1993; the smallest juvenile (MHNG 2385.51, SVL 12.8 mm) was collected on August 1986. An amplectant pair (QCAZ 15021, male; 15019, female) was collected on 13 November 1976; the female had white eggs and a reddish-white oviduct; the male had pink fat bodies, large testes with the Bidder´s organs (few oocites) over the ventral surfaces of the gonads; in female QCAZ 15022 oocites were mononucleate (Eugenia M. del Pino Lab notes, November 1976). Female QCAZ 15019 contains 201 ovarian eggs about 1.85 mm of diameter (1.62–2.14 mm, SD = 0.139523, n = 15).

The stomach contents of four females (MHNG 2258.66-67 from Tulcán, EPN 3244–45 from Espejo) and one male (MHNG 2258.71 from Tulcán) are shown in Table 6 . In a female (MHNG 2258.66), approximately 80 % of stomach contents were unidentifiable digested vegetal and animal material; the largest prey item was a Lampyridae larva with a length of 6.27 mm; a wing of an undetermined Hymenoptera was 5.29 long; the most common items, the Acari, were 0.42–1.02 mm long. In a female (MHNG 2258.67), seeds were also observed; approximately 70 % of stomach contents were unidentifiable digested vegetal and animal material; the largest prey item was an unidentified Coleoptera , with elytron 4 mm long; the most common items, the Acari, were 0.83–0.97 mm long. In a male (MHNG 2258.71), approximately 75 % of stomach contents were unidentifiable vegetal and animal digested material; the largest prey item was a Lampyridae larva 4 mm long; the most common items, the Acari, were 0.73–1.30 mm long.

Ecuador. An asterisc (*) indicates larva.

Atelopus pastuso is considered to be Critically Endangered (Possibly Extinct) (A2ace, IUCN Red List categories and criteria). The species is tagged as Possibly Extinct until further surveys confirm otherwise. The population has declined dramatically (more than 80 %) in the last two decades probably because of climate change and the impact of pathogens, which have affected many other montane species of Atelopus .

This species was abundant at least at some localities. On 18 May 1975, a field party from the University of Kansas recorded 90 individuals (0.50 ind/pers/min) at Páramo El Angel (Carchi Province; 3350 m; WED field notes). Alméndariz and Orcés (2004) reported, in 1986, densities of 10 individuals per square meter in Páramo de El Ángel. The last living individuals were seen in 1993, in spite of many collecting efforts at several localities throughout the entire range of its distribution. In Colombia, although this species previously was abundant at several localities, no individuals have been found after 16 November 1982, despite intensive search efforts since the mid-1990´s ( Cepeda-Quilindo and Rueda-Almonacid 2005).

In Ecuador, several dead or unhealthy individuals were found throughout its range before its disappearance: QCAZ 3742 was collected in an unhealthy condition at 42 km W of Tulcán; it was active at 15:35h, close to the road and at about 5 m from a stream in natural forest; the animal died the next day after capture (LAC field notes, 2 March 1993). The last living individuals were observed (but not collected) on 29 June 1993, when six additional individuals were found dead between 13:00h and 14:00h at Quebrada Chumaví, 9 km N of Cuicocha, Imbabura Province (putative hybrid zone, see under Remarks). Merino-Viteri (2001) examined three of these specimens (QCAZ 3691, 3699, 3742) and reported them as positive for chytrid infection.

Etymology. The specific name pastuso is used as a noun in apposition. Pastuso is a Spanish word, which refers to the inhabitants of the Pasto region in southern Colombia and northern Ecuador.

Remarks. Twenty-one specimens from an area of about 26.4 km 2 ( Fig. 5 )—La Joya-Huagsi (SW of Otavalo) (QCAZ 15016–17), Hacienda Curubí (Páramos de Mojanda) (EPN 3299–301), and Quebrada Chumaví, 9 km N of Cuicocha (QCAZ 3691–92, 3695–700, 4050, 4798–802; EPN 3312–13)—are similar in coloration to either A. pastuso or A. ignescens . However, among them, eight of 15 females that are similar in coloration to A. pastuso , bear a patch of brown pustules and spiculae in chest-throat region. The latter is characteristic of A. ignescens , A. ardila , and A. carrikeri . The presence and absence of this feature in specimens from these localities and the occurrence of individuals that have coloration of either A. ignescens or A. pastuso is intriguing. This polymorphism and mixture of characters suggests the possibility of hybridization at the contact zone between A. ignescens and A. pastuso (see discussion below).

Figures

FIGURE 4. — (A, B) Atelopus ardila from 12 km E of Pasto, Departamento Nariño, Colombia (KU 169287 – 88, photos: WED); (C – D) Atelopus pastuso from Tulcán and 26, 6 km W Tulcán, Provincia Carchi, Ecuador (MNHG 2258.68, QCAZ 1911, photos: LAC); (E – F) Atelopus pastuso from Tulcán and Cerro Cotacachi (MNHG 2258.65, QCAZ 15021 adult male, photos: LAC, Eugenia M. del Pino, respectively); (G) Atelopus pastuso from Hacienda La Esperanza (EPN 3244 adult female, photo: AA); (H) Atelopus angelito from NE Maldonado (KU 3244 adult female, photo: John D. Lynch).

FIGURE 5. — Map of southern Colombia and northern Ecuador showing localities of Atelopus angelito, A. ardila, A. gigas, A. orcesi, A. pastuso and a population of hypothetical hybrids between A. pastuso and A. ignescens. Symbols for A. ardila indicate one or several close localities.

FIGURE 9. — Holotype of Atelopus pastuso (QCAZ 15013): (A) adult female, SVL = 41.8 mm; molt visible in lateral view (B) ventral view of right hand, enlarged 3.9 times of A; (C) ventral view of left foot; enlarged 3.9 times of A.

Tables

TABLE 4. Meristic variation of Atelopus pastuso. Mean ± one SD, and range are given. Abbreviations follow Gray and Cannatella (1985) and Coloma et al. (2000). They are: SVL = snout – vent length; TIBL = tibia length; FOOT = footh length; HLSQ = head length; HDWD = head width; EYDM = eye diameter; EYNO = eye – nostril distance; ITNA = internarial distance; RDUL = radio-ulna length; THBL = thumb length; SW = sacrum width. All measurements are in mm.

	Males (n = 128)	Females (n = 153)
SVL	31.82 ± 2.42 (26.1–38.9)	38.68 ± 3.89 (29.6–50.7)
TIBL	11.75 ± 1.14 (8.5–14.2)	13.04 ± 1.23 (11.2–16.7)
FOOT	12,82 ± 1,30 (9.3–16.0) (n = 123)	14.8 ± 1.55 (12.0–20.3) (n = 146)
HLSQ	9.83 ± 0.69 (7.8–11.5)	10.60 ± 0.85 (9.2–13.5)
HDWD	9.64 ± 0.63 (7.5–11)	10.48 ± 0.84 (9.0–13.3)
ITNA	3.35 ± 0.32 (2.7–4.3) (n = 121)	3.72 ± 1.22 (2.7–13.7) (n = 144)
RDUL	9.38 ± 0.81 (7.3–11.6) (n = 121)	10.76 ± 0.94 (8.9–13.4) (n = 144)
THBL	5.38 ± 0.69 (4.2–8.8) (n = 121)	6.64 ± 0.79 (5.1–9.3) (n = 144)
SW	8.86 ± 0.83 (6.5–11.3) (n = 121)	10.89 ± 1.32 (8.2–14.8) (n = 144)
RDUL/SVL	(0.25–0.36) (n = 121)	(0.25–0.32) (n = 144)
TIBL/SVL	(0.30–0.41)	(0.29–0.40)
HLSQ/SVL	(0.25–0.35)	(0.24–0.31)
HDWD/SVL	(0.25–0.34)	(0.23–0.31)

TABLE 5. Temperature variation (° C) of Atelopus pastuso (KU 164761 – 14779).

14.4	13.0	10.2
15.0	14.2	10.2
14.8	13.0	10.2
18.4	17.6	10.2
15.6	14.6	10.2
17.6	17.6	12.4
19.2	17.6	12.4
17.6	14.8	12.4
19.8	15.2	12.4
17.0	14.4	12.4
15.6	14.5	12.4
15.2	13.4	12.4
13.4	12.0	12.4
16.2	15.0	12.4
16.8	15.8	12.4
22.5	20.8	12.4
17.0	15.5	12.4
17.5	16.8	12.4
17.5	17.0	13.0
18.2	17.5	13.0

TABLE 6. Number of prey items in the stomach contents of Atelopus pastuso from Tulcán and Espejo, Provincia Carchi,

Taxa	Female	Female Female Female	Male
	MHNG 2258.66	MHNG 2258.67 EPN 3244 EPN 3245	MHNG 2258.71
Acari	11	25 – –	12
Acari (Oribatei)	–	– – 5	–
Aracnida	2	– – 7	–
Apterigota	2*	– –	–
Coleoptera	1	5 – –	1
Coleoptera (Curculionidae)	–	2 – –	–
Coleoptera (Lampyridae)	1*	– – –	1*
Coleoptera (Scolytidae)	–	– 4 –	–
Coleoptera (Staphylinidae)	–	– – 1	–
Collembola	–	1 – –	–
Diptera	2	2 24 1*	–
Formicidae	7	11 – –	11
Hemiptera	–	1 – –	1
Hemiptera (Ligaeidae) Homoptera ( Aphidae )	– –	– – 1 – 5 –	– –
Homoptera ( Delphacidae )	–	– – 1	–
Hymenoptera	–	– 17 –	–
Hymenoptera (Eulophidae)	–	– – 7	–
Lepidoptera	–	– – 1*	–
Total	26	47 45 29	26