Two new species of terrestrial frogs of the Pristimantis gladiator complex (Anura, Strabomantidae) from the Ecuadorian Andes, with insights on their biogeography and skull morphology Author Reyes-Puig, Juan Pablo https://orcid.org/0000-0002-0730-9356 Unidad de Investigacion, Instituto Nacional de Biodiversidad (INABIO), Quito, Ecuador & Fundacion EcoMinga; Fundacion Oscar Efren Reyes, Departamento de Ambiente, Banos, Ecuador juanpabloecominga@gmail.com Author Urgiles-Merchan, Miguel https://orcid.org/0000-0002-4606-2237 Unidad de Investigacion, Instituto Nacional de Biodiversidad (INABIO), Quito, Ecuador Author Franco-Mena, Daniela https://orcid.org/0000-0003-3655-2678 Laboratorio de Biologia Evolutiva, Colegio de Ciencias Biologicas y Ambientales COCIBA, Universidad San Francisco de Quito USFQ, Quito, Cumbaya, Ecuador Author Guayasamin, Juan M. https://orcid.org/0000-0003-0098-978X Laboratorio de Biologia Evolutiva, Colegio de Ciencias Biologicas y Ambientales COCIBA, Universidad San Francisco de Quito USFQ, Quito, Cumbaya, Ecuador Author Batallas, Diego https://orcid.org/0000-0002-0068-8146 Laboratorio de Biologia Evolutiva, Colegio de Ciencias Biologicas y Ambientales COCIBA, Universidad San Francisco de Quito USFQ, Quito, Cumbaya, Ecuador & Universidad Complutense de Madrid, Madrid, Spain Author Reyes-Puig, Carolina https://orcid.org/0000-0001-7828-8698 Unidad de Investigacion, Instituto Nacional de Biodiversidad (INABIO), Quito, Ecuador & Laboratorio de Biologia Evolutiva, Colegio de Ciencias Biologicas y Ambientales COCIBA, Universidad San Francisco de Quito USFQ, Quito, Cumbaya, Ecuador text ZooKeys 2023 2023-09-26 1180 257 293 http://dx.doi.org/10.3897/zookeys.1180.107333 journal article http://dx.doi.org/10.3897/zookeys.1180.107333 1313-2970-1180-257 912793FF3FCF46248CCBB42A9FD2BD73 D3C115F72BB351AB89F7AF46AF0A7E43 Pristimantis donnelsoni Juan Pablo Reyes-Puig, Miguel Urgiles-Merchan , Carolina Reyes-Puig, Daniela Franco-Mena, Diego Batallas & Juan M. Guayasamin sp. nov. Figs 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 Type material. Holotype . DHMECN 14701, adult female (Figs 2 - 7 ), collected by CRP, JPRP, and DFM from Reserva Chamana, eastern slopes of Tungurahua Volcano, Ulba, Banos , Tungurahua, Ecuador ( 1.4272°S , 78.3967°W ; 3,028 m alt.) on 13 August 2018. Figure 2. Pristimantis donnelsoni sp. nov. in ethanol. Adult female, holotype, DHMECN 14701, in dorsal, ventral and lateral views. Photographs by JPRP. Figure 3. Ventral view of left hand and foot of Pristimantis donnelsoni sp. nov. Adult female, holotype, DHMECN 14701. Photographs by JPRP. Figure 4. Lateral views of Pristimantis donnelsoni sp. nov. in life. Adult female, holotype DHMECN 14701. LRC: 15.42 mm. Photographs by Frank Pichardo. Figure 5. Dorsolateral and ventral views in life of Pristimantis gladiator species complex and related species A Pristimantis donnelsoni sp. nov. female, DHMECN 14701, holotype, LRC: 15.42 mm B Pristimantis donnelsoni sp. nov. male, DHMECN 18854, LRC: 13.66 mm from Cerro Candelaria C Pristimantis kayi sp. nov. female, ZSFQ 0775, holotype, LRC: 19.7 mm D Pristimantis kayi sp. nov. male, DHMECN 14450 LRC: 13.58 mm, from Reserva Machay E Pristimantis gladiator sensu stricto female, DHMECN 12463, LRC: 20.38 mm F Pristimantis gladiator sensu stricto, male DHMECN 12474, LRC: 16.87 mm; from Rio Quijos drainage G Pristimantis festae female, DHMECN 16280, LRC: 20.19 mm H Pristimantis festae , male (left), DHMECN 16837, LRC: 16.50 mm; female (right), DHMECN 16836, LRC: 19.80 mm; Photographers: JPRP ( A, B ), MYM ( D, E, F, H ); Patricia Bejarano ( G ); Jose Vieira ( C ). Figure 6. Pristimantis donnelsoni sp. nov. dorsal and ventral views of the preserved types series A DHMECN 4779, female B DHMECN 4782, female C female, ZSFQ 1097 D holotype, 14701, female E DHMECN 4781, male F DHMECN 16613, male G DHMECN 16610, male H ZSFQ 1098, male I DHMECN 4778, male. Photographs by JPRP and David Brito Zapata. Figure 7. Life dorsal and ventral views of Pristimantis donnelsoni sp. nov., in situ A, B holotype male DHMECN 14701, LRC: 15.42 mm, from Chamana Reserve C, D paratype female DHMECN 13321, LRC: 15.47 mm, from Cerro Candelaria E, F paratype female DHMECN 16175, LRC:13.71 mm, from Cerro Candelaria G, H paratype female DHMECN 18159, LRC:18.72 mm, from Hacienda Guamag I, J adult male DHMECN 18185, LRC:14.26 mm, from Finca Palmonte. Photographs by JPRP. Paratypes . (22, 13 ♂ / 9 ♀, Fig. 6 ): ZSFQ 1087, adult female collected by CRP, JPRP and DFM from Reserva Chamana, Ulba, Banos , Tungurahua, Ecuador ( 1.421°S , 78.3866°W ; 2909 m alt.) on 11 August 2018. ZSFQ 1090 and 1096, adult females collected by CRP, JPRP, and DFM from Reserva Chamana, Ulba, Banos , Tungurahua, Ecuador ( 1.4256°S , 78.3854°W ; 2977 m alt.) on 12 August 2018. ZSFQ 1100, adult male collected by CRP, JPRP, and DFM from Reserva Chamana, Ulba, Banos , Tungurahua, Ecuador ( 1.4273°S , 78.3853°W ; 3000 m alt.) on 12 August 2018. ZSFQ 1103 and 1105, adult males collected with the same data as ZSFQ 1090. DHMECN 16606, adult male collected by JPRP from Reserva Chamana, Ulba, Banos de Agua Santa, Tungurahua, Ecuador ( 1.4343°S , 78.3942°W ; 3125 m alt.) on 14 August 2018. DHMECN 16608, 16610 and 16613, adult males with the same data as DHMECN 16606. DHMECN 4772, 4777 and 4782 adult females collected by JPRP from Nahuazo-Runtun , Banos , Banos de Agua Santa, Tungurahua, Ecuador ( 1.4258°S , 78.4257°W ; 3100 m alt.) on 28 March 2008 DHMECN 4778, adult male and DHMECN 4779, adult female, collected by JPRP and Nelson Palacios from San Antonio, Banos , Banos de Agua Santa, Tungurahua, Ecuador ( 1.4572°S , 78.3016°W ; 2850 m alt.) on 30 April 2007. DHMECN 4769, adult male collected by JPRP and Salomon Ramirez from Pondoa, Banos , Banos de Agua Santa, Tungurahua, Ecuador ( 1.4370°S , 78.4426°W ; 3000 m alt.) on 31 March 2007. DHMECN 4774 and DHMECN 4781 adult males collected by JPRP from Pondoa, Banos , Banos de Agua Santa, Tungurahua, Ecuador ( 1.4370°S , - 78.4426°W ; 3240 m alt.) on 21 March 2007. DHMECN 4807, adult male collected by JPRP, Salomon Ramirez , and Stalin Caceres , and Luis Recalde from Bosque Protector Cerro Candelaria, Rio Verde, Banos de Agua Santa, Tungurahua, Ecuador ( 1.4572° S , 78.3016°W ; 2850 m alt.) on 11 May 2008. DHMECN 18159 and 18160, adult females collected by JPRP, Patricio Vinueza, Paulete Benavidez, and Nantar Kuja in Bosque Protector Guamag, Ulba, Banos de Agua Santa, Tungurahua, Ecuador ( 1.4194°S , 78.3648°W ; 2800 m alt.) on 28 May 2022. DHMECN 18185, adult male collected by JPRP, Patricio Vinueza and Eduardo Pena in Finca Palmonte, Rio Negro, Banos de Agua Santa, Tungurahua, Ecuador ( 1.4349°S , 78.2629°W ; 2485 m alt.) on 14 May 2022. Generic placement. As defined by Lynch and Duellman (1997) , Hedges et al. (2008) and Franco-Mena et al. (2023) , the Pristimantis myersi group (subgenus Pristimantis Trachyphrynus ) contains species with the following combination of traits: (1) small body size (SVL in females <34.6 mm; in males <20.5 mm); (2) short snout; (3) robust body; (4) Toe V longer than Toe III, Finger I shorter than II; (5) digital discs narrow or slightly expanded (expanded in P. floridus ); and (6) cranial crests absent. In addition, all species in the group are found on low vegetation or at ground level or even underground. The morphology of the new species agrees with all the aforementioned diagnostic traits; therefore, we place it in the genus Pristimantis , subgenus Pristimantis Trachyphrynus . Diagnosis. (1) Skin of dorsum shagreen, occipital fold evident, dorsolateral folds low in banded individuals or weakly defined in uniform or irregular dorsal colour patterns, skin on venter coarsely areolate (Fig. 2 ); (2) tympanic annulus and tympanic membrane present, tympanum prominent, sexually dimorphic, tympanum in males 7% SVL, tympanum in females 6% SVL; (3) snout subacuminate in dorsal view (tip of snout pointed), rounded in lateral view (Fig. 2 ); (4) upper eyelid with several small rounded to subconical tubercles; upper eyelid in males 56% IOD (in females 59%) IOD; cranial crests absent; (5) odontophore processes of the vomer partially concealed, oblique in outline, each processes bearing several small, poorly defined teeth; (6) sphenethmoides with acuminated anterior border dorsally, ventrally present an anteriorly rounded acuminated projected border, posterior border horizontal articulated with frontoparietals; posterior border of frontoparietal present enlarged quadrangular process posteriorly in dorsal view; zygomatic ramus of squamosal short and rounded in dorsal view; procesus cultriform of the parasphenoides reaching posterior level of the vomers, acuminated anterior border (Fig. 8 ); (7) males with vocal slits and subgular vocal sac; lacking nuptial pads; (8) finger I shorter than II, discs on fingers II-IV rounded (Fig. 3 ); (9) fingers with slightly visible lateral fringes; (10) ulnar tubercles small, low; (11) heel with small tubercles; outer edge of tarsus with small tubercles, more accentuated in males; (12) inner metatarsal tubercle oval elongated, about twice the size of outer metatarsal tubercle that is rounded; (13) toes lacking lateral fringes, webbing absent; Toe V slightly longer than III, discs slightly expanded (Fig. 3 ); (14) dorsum brown in several shades, with dark extreme yellow or green tones, females generally darker than males that have usually a banded pattern; banded limbs; venter light brown with dark brown flecks; hidden surfaces of the groin, thighs and armpits pinkish to reddish (in life), chest and throat present light brown tones (Figs 4 - 7 ); (15) SVL in males, 14.9-16.4 mm (mean = 13.8, SD = 3.9, n = 32), in females, 13.5-19.7 mm (mean = 17.1, SD = 4.41, n = 18); (16) advertisement call with two notes, duration note of 236-293 ms, with intervals of 522-620 ms; call is comprised by tonal sounds of constant frequency, with a slight upward modulation at end of call; (17) dominant frequency at 2.93 kHz, with two partial harmonics, first one with a range of 5.86-5.94 kHz and the second one with a range of 8.79-8.96 kHz; (18) call duration ranging from 1052-1136 ms. Comparison with other species (Figs 5 , 8 , 9 ). Pristimantis donnelsoni sp. nov. is smaller than its closer congeners, externally is most similar to P. gladiator (Lynch, 1976) and P. festae (Peracca, 1904), (Kruskal-Wallis Chi2 = 25.39, p = <0.001, Table 2 , Fig. 9 ), males in P. gladiator 15.8 mm vs. P. donnelsoni sp. nov. 13.8 mm; females in P. gladiator 20.2 vs. P. donnelsoni sp. nov. 17.1 mm; males in P. festae 16.4 mm vs. P. donnelsoni sp. nov. 13.8 mm; females in P. festae 20.7 vs. P. donnelsoni sp. nov. 17.1 mm. Additionally, the new species differs in having reddish and pinkish marks on the groin and ventral surfaces in several tones of brown, unlike P. gladiator which features dark orange marks on a dark brown venter. Pristimantis donnelsoni sp. nov. has a subacuminated snout in comparison to P. gladiator which is acuminate. On the other hand, the snout of P. festae is rounded in dorsal view and subacuminated in P. donnelsoni sp. nov. Another species, closely related and morphologically similar to P. donnelsoni , is P. kayi sp. nov. Although the two new species are extremely similar, differences in the tympanum diameter are evident, TD in P. donnelsoni sp. nov. 0.9 mm vs. P. kayi sp. nov. 1.0 mm (Kruskal-Wallis Chi2 = 10.28, p = <0.05*, Table 2 , Fig. 8 .). Pristimantis leoni and P. sirnigeli are found at the Western Andean Cordillera, but they lack distinctive concealed reddish flash marks on the groin that are characteristic of P. donnelsoni sp. nov. Figure 8. Skull morphology diagram in dorsal (left column) and ventral (right column) views in four species of the Pristimantis myersi species group: A, B P. donnelsoni sp. nov., DHMECN 4808 C, D P. kayi sp. nov., DHMECN 14447 E, F P. gladiator DHMECN 12465 G, H P. festae DHMECN 9294. Detail of the skull bones abbreviations: pmax = premaxilla; max = maxilla; spheth = sphenethmoides; fpar = frontoparietal; pter = pterigoides; pro = prootic; q = quadratojugal; sp = squamosal; exo = exoccipital; prph = parasphenoides. Frontoparietal fontanelle not coloured. Figure 9. Boxplot of body size (SVL) and tympanic diameter (TD) in four closely-related species of the Pristimantis myersi species group. *Asterisks represent species with significant differences. Table 2. Measurements of four closely-related species of Pristimantis from the eastern Ecuadorian Andes.
- Pristimantis donnelsoni sp. nov. Pristimantis kayi sp. nov. Pristimantis festae Pristimantis gladiator
Females n = 18 Males n = 32 Females n = 30 Males n = 13 Females n = 10 Males n = 13 Females n = 6 Males n = 14
SVL 13.48-19.71 (16.60 +/- 4.41) 10.87-16.35 (13.61 +/- 3.87) 12.33-20.16 (16.25 +/- 5.54) 11.77-15.58 (13.68 +/- 2.69) 18.77-23.67 (20.75 +/- 1.4) 13.24-18.35 (16.36 +/- 1.49) 18.92-20.94 (19.93 +/- 1.43) 13.43-18.83 (16.13 +/- 3.82)
HW 5.42-7.5 (6.46 +/- 1.74) 4.3-6.45 (5.38 +/- 1.52) 5.16-7.45 (6.31 +/- 1.62) 4.37-5.44 (4.91 +/- 0.76) 7.09-9.69 (88.22 +/- 0.88) 5.04-7.09 (6.44 +/- 0.61) 6.85-8.02 (7.44 +/- 0.83) 4.97-6.69 (5.83 +/- 1.22)
HL 5.32-7.54 (6.43 +/- 1.57) 4.86-6.58 (5.72 +/- 1.22) 5.25-8.11 (6.68 +/- 2.02) 4.85-6.28 (5.57 +/- 1.01) 6.25-9.34 (7.59 +/- 0.89) 5.23-7.54 (6.52 +/- 0.62) 7.25-8.21 (7.73 +/- 0.68) 5.37-7.11 (6.24 +/- 1.23)
EN 1.15-1.7 (1.43 +/- 0.39) 0.9-1.57 (1.24 +/- 0.47) 1.04-2.03 (1.54 +/- 0.7) 0.89-1.6 (1.25 +/- 0.5) 1.3-2.01 (1.61 +/- 0.21) 0.97-1.47 (1.25 +/- 0.15) 1.87-2.04 (1.96 +/- 0.12) 1.15-1.75 (1.45 +/- 0.42)
IND 1.39-1.93 (1.66 +/- 0.38) 1.13-1.71 (1.42 +/- 0.41) 1.32-2.18 (1.75 +/- 0.61) 1.27-1.82 (1.55 +/- 0.39) 1.75-2.2 (1.98 +/- 0.16) 1.4-2.05 (1.73 +/- 0.19) 2.06-2.27 (2.17 +/- 0.15) 1.52-2.03 (1.78 +/- 0.36)
IOD 1.66-2.69 (2.18 +/- 0.73) 1.61-2.4 (2.01 +/- 0.56) 1.67-2.97 (2.32 +/- 0.92) 1.54-2.08 (1.81 +/- 0.38) 2.23-2.89 (2.58 +/- 0.23) 1.85-2.51 (2.19 +/- 0.2) 2.3-2.84 (2.57 +/- 0.38) 1.71-2.54 (2.13 +/- 0.59)
EW 1-1.58 (1.29 +/- 0.41) 0.8-1.45 (1.13 +/- 0.46) 0.85-1.91 (1.38 +/- 0.75) 0.76-1.51 (1.14 +/- 0.53) 1.13-1.77 (1.51 +/- 0.2) 1.05-1.57 (1.31 +/- 0.15) 1.22-1.77 (1.5 +/- 0.39) 1.01-1.66 (1.34 +/- 0.46)
TD 0.72-1.17 (0.95 +/- 0.32) 0.58-1.34 (0.96 +/- 0.54) 0.47-1.49 (0.98 +/- 0.72) 0.82-1.19 (1.01 +/- 0.36) 0.6-1.23 (0.95 +/- 0.18) 0.51-0.96 (0.77 +/- 0.12) 1.08-1.6 (1.34 +/- 0.37) 0.72-1.59 (1.16 +/- 0.62)
ED 1.68-2.55 (2.12 +/- 0.62) 1.41-1.97 (1.69 +/- 0.4) 1.65-2.62 (2.14 +/- 0.69) 1.38-2.09 (1.74 +/- 0.5) 1.95-2.65 (2.26 +/- 0.26) 1.58-2.15 (1.85 +/- 0.17) 2.05-2.4 (2.23 +/- 0.25) 1.65-2.24 (1.95 +/- 0.42)
TL 6.19-7.98 (7.09 +/- 1.27) 4.95-7.74 (6.35 +/- 1.97) 5.89-9.98 (7.94 +/- 2.89) 5.32-7.23 (6.28 +/- 1.35) 6.89-8.61 (7.76 +/- 0.56) 5.56-7.32 (6.42 +/- 0.51) 9.63-10.54 (10.09 +/- 0.64) 6.88-9.21 (8.05 +/- 1.65)
HaL 3.09-4.55 (3.82 +/- 1.03) 2.71-4.4 (3.56 +/- 1.2) 3-5.2 (4.1 +/- 1.56) 2.73-3.74 (3.24 +/- 0.71) 3.89-5.44 (4.76 +/- 0.46) 3.38-4.26 (3.85 +/- 0.29) 5.09-5.7 (5.4 +/- 0.43) 3.34-4.63 (3.99 +/- 0.91)
FL 5.62-8.31 (6.97 +/- 1.9) 4.72-7.58 (6.15 +/- 1.02) 4.9-8.96 (6.93 +/- 2.87) 4.69-6.32 (5.51 +/- 1.15) 7.1-9.5 (8.28 +/- 0.75) 5.87-7.35 (6.63 +/- 0.45) 9.21-9.94 (9.58 +/- 0.52) 5.78-8.62 (7.2 +/- 2.01)
FW 0.37-0.64 (0.51 +/- 0.19) 0.33-0.63 (0.48 +/- 0.21) 0.33-0.89 (0.61 +/- 0.4) 0.33-0.55 (0.44 +/- 0.16) 0.32-0.61 (0.53 +/- 0.09) 0.41-0.51 (0.43 +/- 0.03) 0.73-1.04 (0.89 +/- 0.22) 0.53-0.79 (0.66 +/- 0.18)
TW 0.39-0.7 (0.55 +/- 0.22) 0.3-0.6 (0.45 +/- 0.21) 0.38-0.95 (0.67 +/- 0.4) 0.38-0.65 (0.52 +/- 0.19) 0.3-0.64 (0.51 +/- 0.09) 0.38-0.51 (0.46 +/- 0.04) 0.72-1.09 (0.91 +/- 0.26) 0.41-0.81 (0.61 +/- 0.28)
Legend: SVL (snout-vent length), HW (head width), HL (head length), EN (eye-nostril distance), IND (internarial distance), IOD (interorbital distance), EW (upper eyelid width), TD (tympanum diameter) eye-nostril, ED (eye diameter), TL (tibia length), HaL (Hand length), FL (foot length), FW (Finger III width), TW (Toe IV length). Differences in the skull morphology amongst closely-related species are summarised in Table 3 as follows: Pristimantis donnelsoni sp. nov. has the posterior border of the frontoparietal with an elongated quadrangular crested process projected posteriorly; while in P. gladiator , it is irregular and slightly projected posteriorly; in P. kayi sp. nov. posterior border of frontoparietal, it is irregular and not projected; finally, P. festae exhibit frontoparietal with rounded posterior border not projected. Table 3. Skull diagnostic characters between four related species of Pristimantis gladiator complex.
Species Sphenethmoides in ventral view Frontoparietals Squamosal Parasphenoides
Pristimantis donnelsoni sp. nov. The anterior border is triangular and the posterior border presents horizontal articulations with frontoparietals Posterior border with elongated quadrangular crested process posteriorly Short and rounded zygomatic ramus The cultriform process reaches the posterior level of vomers and ends in a sharp anterior border; does not reach the posterior border of the skull, lateral ala of parasphenoid short does not reach the level of the maxilla
P. kayi sp. nov. The anterior border is truncated or blunt and not projected and the posterior present oblique articulation with frontoparietals The posterior border is irregular and not projected Elongated and sharp zygomatic ramus, reaching maxillae The cultriform process reaches the posterior level of vomers and ends in a blunt anterior border
P. gladiator The anterior border is rounded and projected anteriorly, posterior border presents a pair of suboval processes posterior, articulated with frontoparietals The posterior border is irregular and slightly projected posteriorly Short and blunt zygomatic ramus The cultriform process does not reach the posterior region of vomers with a subacuminated anterior border
P. festae The anterior border is not projected and the posterior is serrated Round posterior border not projected Very short and blunt zygomatic ramus not extending to the maxillae The cultriform process is short and does not reach vomers, present and anterior short blunt border and posterior serrated border its anterior border is short and very acute
The length and shape of the zygomatic ramus in the squamosal, are short and rounded in Pristimantis donnelsoni sp. nov.; P. gladiator presents a short and blunt zygomatic ramus; P. kayi sp. nov. shows an elongated and sharp zygomatic ramus, reaching level of the maxillae; whereas in P. festae , zygomatic ramus is very short and blunt, not extending to the level of the maxillae (Fig. 8 ). In ventral view of the skull, differences are evident in P. donnelsoni sp. nov., the anterior border of sphenethmoides is triangular and posterior border presents horizontal articulations with frontoparietals; in P. gladiator , anterior border of sphenethmoides is rounded and projected anteriorly, posterior border presents a pair of posterior suboval processes, articulated with frontoparietals; in P. kayi sp. nov., the anterior border of sphenethmoides is blunt and not projected and the posterior border presents oblique articulation with frontoparietals. In P. donnelsoni sp. nov., the parasphenoid does not reach posterior border of the skull, lateral alary process of parasphenoid is short and does not reach level of maxilla, the cultriform process of the parasphenoid reaches posterior level of vomers and ends in a sharp anterior border, differing from P. gladiator , in which parasphenoid does not reach the posterior region of vomers with a subacuminated anterior border; in P. kayi sp. nov., the cultriform process of the parasphenoid reaches the posterior level of vomers and ends in a blunt anterior border, in P. festae , the sphenethmoides presents an anterior border of cultriform process and does not reach vomers, its anterior border is short and very acute (Table 3 , Fig. 8 ). Description of the holotype (Figs 2 , 3 , 4 ). Adult female (DHMECN 14701) with robust body and short limbs; head slightly longer than wide, not as wide as body, head width 40% of SVL (15.4 mm); head length 41% of SVL; snout short, with a fleshly terminal rounded tip, subacuminated in dorsal view and rounded in lateral view; eye-nostril distance 9.9% of SVL; nostrils narrow higher than long, laterally directed; canthus rostralis angular in dorsal and lateral view; loreal region slightly concave; lips rounded; upper eyelid bearing small low rounded tubercles; snout and interorbital region with scattered small low rounded tubercles; upper eyelid width 49.3% of IOD; tympanic annulus visible on its 3⁄4 part, with the dorsal margins obscured by supratympanic fold; tympanic membrane present, distinct; tympanum diameter 43.6% of eye diameter, one subconic postrictal tubercle surrounded by little low tubercles; rounded tubercles along the supratympanic fold and 2-3 rounded tubercles surrounded by small tubercles on the temporal region; Choanae small, rounded, not concealed by palatal shelf of maxilla; dentigerous processes of vomers low, distinct, oblique in outline, widely separated, positioned posteromedial to choanae; each vomer bearing 2 or 3 teeth; tongue twice as long as wide, free posteriorly on two-thirds of its length. Temporal folds are formed by a row of small low tubercles, extending from the posterior margin of the upper eyelid to the suprascapular region. Skin on the dorsum with scattered, low-rounded tubercles, small folds formed by little rounded tubercles on upper areas of flanks; lower flanks finely granular; skin on the upper surfaces of forelimbs and hind limbs with indistinct rows of low rounded tubercles. Skin of the throat, chest, and ventral surfaces and limbs is weakly areolate, venter coarsely areolate; discoidal fold weakly defined; cloacal sheath short; skin in the cloacal region smooth. Row of 2 or 3 rounded ulnar tubercles; palmar tubercles low, outer palmar tubercle bifid, V-shaped, approximately twice as large as elongate ovoid thenar tubercle; subarticular tubercles low, well-defined, rounded in ventral view and flattened in lateral view; supernumerary tubercle at the base of fingers present, indistinct; fingers bearing lateral fringes; Finger I shorter than Finger II; discs on Fingers I and II, rounded and slightly expanded; discs more expanded on Fingers III and IV; ventral pads on fingers well-defined by circumferential grooves on Fingers II, III and IV, not evident on Finger I (Fig. 3 ). Hind limbs robust, tibia length 47.54% of SVL; foot length 47.67% of SVL; upper surfaces of hind limbs with low rounded tubercles; heel bearing one to four low rounded tubercles; the outer surface of tarsus bearing a row of four low rounded tubercles; inner tarsal fold present; inner metatarsal tubercle evident, oval, elongate elliptical, three times size of outer metatarsal tubercle; inner plantar surface smooth; subarticular tubercles poorly defined, rounded in ventral view and flattened in lateral view; toes lacking lateral fringes; webbing between toes absent; discs on toes rounded, slightly expanded; all toes with ventral pads defined by circumferential grooves, less distinct on Toe I; relative lengths of toes: I <II <III <V <IV (Fig. 3 ); Toe V slightly longer than III, disc of Toe III not reaching medial subarticular tubercle of Toe IV; the distal end of the disc on Toe V reaches the medial subarticular tubercle of Toe IV. Measurements of the holotype (in mm). Adult female, DHMECN 14701, SVL = 15.4; Tibia Length = 7.3; Foot Length = 7.4; Hand Length = 3.8; Head Length = 6.3; Head Width = 6.2; Eye Diameter = 1.9; Tympanum Diameter = 0.8; Forearm Length = 4.2; Snout Length = 5.3; Tarsus Length = 4.2; Thigh Length = 5.5; Upper Arm Length = 3.4; Interorbital Distance = 2.1; upper Eyelid Width = 1.0; Internarial Distance = 1.5; Eye-Nostril distance = 1.5; Wide Finger III = 0.4; Toe IV Width = 0.4. Colour of holotype in life (Figs 4 , 5 , 7 ). Head, sides of the head, dorsum, flanks and limbs brown, with a large rounded white blotch on the middle of dorsum; light and dark brown banded lips, the broad dark brown supratympanic band extends from the tympanum to level of insertion of arm; flanks darker than dorsum with oblique, pale and diffuse bands; several pinkish-whitish markings scattered near the groin and axilla; limbs banded in light and dark brown tones. Throat and venter dark brown covered with scattered tiny white spots; ventral surfaces of limbs lighter brown with grey tones. Iris silver with a dark copper-coloured horizontal bar. Colour of holotype in ethanol (Figs 2 , 3 , 6 ). Dorsum dark brown with a mid-dorsal white spot; limbs banded with light brown; lips banded; dark supratympanic band delineated below with thin pale line; flanks dark brown to black with pale oblique bands; several white markings near groin and axilla; chin with brown marking outlined with pale shades; throat brown with pale spots; belly dark brown covered with minute white spots; ventral surfaces of limbs and palms light brown with pale spots. Osteology of the skull. The skull of the adult female paratype DHMECN 4808, is illustrated on its dorsal and ventral surfaces in Fig. 8 . We describe main skull bones with diagnostic characters and the key differences are summarised in Table 3 . Skull is slightly longer than wide. Dorsally paired nasals overlap the sphenethmoid, the sphenethmoid articulates posteriorly with the frontoparietal, posterior border of frontoparietal present quadrangular projected process posteriorly. A large frontoparietal fontanelle, connected to two parietal fontanelles, is delimited by the sphenethmoid and the frontoparietals. In ventral view, anterior margin of the sphenethmoid is acuminated. Palatines overlap with the sphenethmoid and vomers. The vomer is narrowly separated medially; each vomer has three distinctive rami dentigerous process of the vomer reaches the level of the palatine. The parasphenoid present an inverted cross shape; cultriform process with an acute anterior border that reaches level of vomers, the alary processes are directed transversely, partially covering the otic area; the posterior process of the parasphenoid does not reach the foramen magnum. In dorsal view, zygomatic ramus of squamosal presents a short and rounded anterior border extending backwards to the level of the maxilla (Fig. 8 ). Variation (Figs 5 , 6 , 7 , 9 ). Pristimantis donnelsoni is highly polymorphic and sexually dimorphic species (Suppl. material 1). Females show dark brown dorsal colouration with black to brown banded flanks and tiny white spots; brown with white spots on dorsum; white interorbital line from snout to cloaca, whitish interorbital band, broad brown dorsal mid-dorsal band delineated towards flanks with dark brown to yellowish to black. Some individuals with shades of green. Venter brown in various shades with small whitish spots; some individuals dark brown-grey with a cross pattern along the mid-line and shoulder girdle, white line delineating the outer edge of the tarsus, leg and cloaca. Males are smaller than females and characterised by dorsal banding patterns in shades of grey, brown, cream and yellowish, some individuals with pale dorsolateral lines along the dorsolateral folds; white interorbital bar; hidden groin surfaces and armpits with white or pale markings mottled with shades of grey or brown. Some individuals with shades of green on the dorsum and flanks. Call description (Fig. 10 ). The call description of Pristimantis donnelsoni sp. nov. is based on recordings of a male paratype DHMECN 4774, on 21 March 2007, 19:00 h, made by JPRP, on the northern flank of Tungurahua Volcano, no environmental parameters were obtained. The calling male was sitting on herbaceous plants on the forest floor. The call is comprised by tonal sounds of constant frequency, with a slight upward modulation at the end of the song. It presents a dominant frequency at 2.93 kHz, with two partial harmonics, first one with a range of 5.86-5.94 kHz and the second one with a range of 8.79-8.96 kHz. It has a duration ranging from 1052-1136 ms, with intervals ranging from 4531-5985 ms, emitting at a rate ranging from 8.43-10.60 calls/minute. The calls are composed of two notes. The notes have a duration ranging from 236-293 ms, with intervals ranging from 522-620 ms. Figure 10. Oscillogram and spectrogram of the advertisement call of Pristimantis donnelsoni sp. nov., adult male, paratype DHMECN 4774. Distribution and natural history observations. Pristimantis donnelsoni sp. nov. is known from seven localities on the southern mountains of the Pastaza drainage, Tungurahua Province, Ecuador (Fig. 11 ). Three localities are located on the Tungurahua Volcano, whereas the others correspond to nearby protected areas (Chamana Reserve and Cerro Candelaria Reserve, Finca Palmonte and Bosque Protector Hacienda Guamag), all at elevations of 2950-3800 m. The collection localities range from high Andean montane forest, with trees of the genera Ceroxylum , Clusia , Weinmannia , and others, between 10-20 m high, with abundant epiphytes, bromeliads orchids, and mosses, to paramo habitat which is mainly grassland with shrubs in the higher part (Fig. 12 ). Most of the individuals were found sitting on herbs or on leaf litter on the forest floor, with dense ferns and small herbaceous plants, always near ground level (<30 cm above ground). Calling males are active during the day and sporadically call at night. Sympatric species include Pristimantis aff. devillei , P. modipeplus in Tungurahua Volcano, P. puruscafeum and. P. marcoreyesi and P. lacrimosus group sp. nov., in Cerro Candelaria and Chamana. Figure 11. Distribution of four closely-related species of the Pristimantis myersi species group in the Andes of Ecuador. Figure 12. Habitat vegetation at type localities and etymology of the two new frogs described herein. Photographs by JPRP and Zane Libke A panoramic view of the upper Pastaza Valley and its adjacent mountains, main geographic barriers promoting speciation at a regional scale, at back Tungurahua Volcano and mountains south of the Pastaza River habitat of Pristimantis donnelsoni sp. nov., image from the slopes of Cerro Mayordomo type locality of Pristimantis kayi sp. nov., in the northern mountains to the Pastaza River B Tungurahua Volcano eruption, from Chamana Reserve C Montane forest in Candelaria Reserve D Don Nelson Palacios (+) during an expedition; we tribute his work with the naming of Pristimantis donnelsoni sp. nov. E Sumaco Volcano seen from Wawa Sumaku, habitat of P. kayi sp. nov. F Montane forest and subparamo in Leito, Patate G Andreas Kay (+); we honour his devotion to nature photography and research in the upper Pastaza Valley and through Ecuador by naming Pristimantis kayi sp. nov. Etymology. The specific epithet " Pristimantis donnelsoni " is a noun in the genitive case and a patronym for Don Nelson Palacios (Fig. 12D ). We named this new species after him as a tribute to his friendship and collaboration in the first collections of new species described during the last decade and several additional important localities within the upper basin of the Pastaza River. This is a special recognition to him for eternity.