Pristimantis kayi Juan M. Guayasamin, Miguel Urgiles-Merchan , Daniela Franco-Mena, Carolina Reyes-Puig, Diego Batallas & Juan Pablo Reyes-Puig, 2023

Reyes-Puig, Juan Pablo, Urgiles-Merchan, Miguel, Franco-Mena, Daniela, Guayasamin, Juan M., Batallas, Diego & Reyes-Puig, Carolina, 2023, 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, ZooKeys 1180, pp. 257-293 : 257

Pristimantis kayi Juan M. Guayasamin, Miguel Urgiles-Merchan, Daniela Franco-Mena, Carolina Reyes-Puig, Diego Batallas & Juan Pablo Reyes-Puig sp. nov.

Figs 1 , 5 , 8 , 12 , 13 , 14 , 15 , 16 , 17

Type material.

Holotype. ZSFQ 0775, adult female (Figs 5C , 13 , 15 - 17 ) collected by José Vieira, David Brito-Zapata, Jefferson Mora, and Carolina Meneses from Volcán Sumaco, Sumaco National Park, Napo, Ecuador (0.5696°S, 77.5939°W; 2322 m alt.) on 11 September 2018.

Paratypes (13, 4 ♂ / 9 ♀, Figs 14 , 17 ). ZSFQ 0779, adult female. ZSFQ 773, adult male. ZSFQ 782, adult female with the same data as the holotype, ZSFQ 783, adult female collected by José Vieira, David Brito-Zapata, Jefferson Mora, and Carolina Meneses from Sumaco National Park, Napo, Ecuador (0.5696°S, 77.5753°W; 2,476 m alt.) on 1 September 2018; ZSFQ 778, adult male, ZSFQ 780 and 781 with same data as ZSFQ 783. DHMECN 14446, adult female collected by Mario Humberto Yánez Muñoz, JPRP, and DFM from Cerro Mayordomo, Reserva Machay, Río Negro, Baños de Agua Santa, Tungurahua, Ecuador (1.3686°S, 78.2693°W 8; 2972 m alt.) on 2 March 2018. DHMECN 15226 and 15237, adult females collected by Kelsey Huisman and Eduardo Peña from Vizcaya, Reserva Naturetrek, Ulba, Baños de Agua Santa, Tungurahua, Ecuador (1.396°S, 78.3942°W; 3150 m alt.) on 12 December 2019. DHMECN 15231 and 15233, adult females collected by Kelsey Huisman and Eduardo Peña from Cerro Mayordomo, Reserva Ecológica Machay, Río Verde, Baños de Agua Santa, Tungurahua, Ecuador (1.368°S, 78.2692°W; 2969 m alt.) on 24 November 2019. DHMECN 16212, adult female collected by JPRP fromVizcaya, Reserva Naturetrek, Ulba, Baños de Agua Santa, Tungurahua, Ecuador (1.3962°S, 78.3941°W; 3062 m alt.) on May 2021. DHMECN 18440, adult male collected by JPRP, Eduardo Peña, and Edgar Martínez, from Los Mortiños, Leito, Patate, Tungurahua, Ecuador (-1.315235, -78.452793; 3448 m alt.) on 6 July 2022. MZUTI 2209, adult female collected by Juan M. Guayasamin and Lucas Bustamante from Cordillera de los Guacamayos, Napo, Ecuador (0.3769°S, 77.5048°W; 2190-2247 m alt.) in March 2013. MZUTI 2010, 2011, 2013 and 2014 with the same data as MZUTI 2209.

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 frogs 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.

Diagnosis.

(1) Skin on dorsum shagreen with small scattered, rounded warts; upper flanks with numerous low warts; dorsolateral and w-shaped occipital folds present (Figs 13 - 15 ); (2) tympanic membrane and tympanic annulus well differentiated (Fig. 12 ); tympanic annulus not sexually dimorphic; tympanum in males 7% SVL, tympanum in females 7% SVL; (3) snout rounded in dorsal, protruding in lateral view (Fig. 15 ); (4) upper eyelid usually bearing one conical or subconical tubercle and many low tubercles; upper eyelid about in males 63% IOD, in females 59% IOD; cranial crests absent; (5) dentigerous processes of the vomer evident, each process bearing 2-3 teeth; (6) sphenethmoides on its dorsal view with short blunt anterior border, is short and blunt in ventral view, posterior border present oblique articulation with frontoparietals; posterior border of frontoparietal with an irregular border not projected in dorsal view; zygomatic ramus of squamosal elongated anteriorly, in dorsal view; procesus cultriform of the parasphenoides reaching posterior level of the vomers, rounded anterior border (Fig. 8 ); (7) males with vocal slits, nuptial pads absent; (8) finger I shorter than finger II; disc on Finger I not expanded; discs on Finger II-IV slightly expanded (Figs 6 , 15 ); (9) fingers with thin lateral fringes; (10) two or three low ulnar tubercles present; (11) heel with low to conical tubercle; outer edge of tarsus with low conical tubercles; (12) inner metatarsal tubercle oval, about 1.5-2 × the length of round outer metatarsal tubercle; (13) toes with thin lateral fringes; webbing absent; Toe V slightly longer than Toe III; discs slightly expanded (Figs 15 , 16 ); (14) in life, dorsum brown with darker and lighter markings; venter light grey to black, with or without orange to red spots of different sizes; groin with orange to red spots that are more conspicuous in females than males (see Colour variation; Figs 14 , 17 ); (15) SVL in adult males, 11.8-15.6 mm (mean = 13.7, SD = 2.7, n = 30), SVL in adult females 12.3-20.2 mm (mean = 16.3, SD = 5.5, n = 13); (16) call composed of 1 to 7 notes, notes have a mean duration of 36.0 ± 18.3 ms, the mean interval between notes is 43.8 ± 36.2 ms, emitted at a mean rate of 15.7 ± 6.1 notes/second. The notes are composed of 2 to 13 pulses. Pulses have a mean duration of 3.9 ± 1.1 ms, with a mean interval between pulses of 4.2 ± 2.8 ms, emitted at a mean rate of 202.2 ± 119.7 pulses/second; (17) dominant frequency of 3.19 ± 0.05 kHz, with 2-6 partial harmonics in the spectrogram; (18) call duration of 165.1 ± 130.1 ms.

Comparison with other species

(Figs 5 , 8 , 9 ). Pristimantis kayi sp. nov. is most similar to P. gladiator (Lynch, 1976), P. festae (Peracca, 1904), and P. donnelsoni sp. nov. Pristimantis kayi sp. nov. differs from P. gladiator and P. festae by being smaller (Kruskal-Wallis Chi2 = 25.39, p = <0.001, Table 2 , Fig. 9 ). Additionally, P. kayi sp. nov. differs from P. festae by having orange to red spots on the groin (white to reddish large spots in P. festae ; Fig. 5 ) and slightly expanded discs on outer fingers (discs not expanded in P. festae ). Pristimantis kayi sp. nov. is similar to the allopatric P. donnelsoni sp. nov.; however, the diameter of the tympanum in males is larger in P. kayi sp. nov. compared to P. donnelsoni sp. nov. and the other closely-related species (i.e. P. festae and P. gladiator ) (Kruskal-Wallis Chi2 = 10.28, p = <0.05*, Table 2 , Fig. 9 ). The most conspicuous differences in the skull morphology between the two new species are listed below (Fig. 8 ): in P. kayi sp. nov., the parasphenoid is much more developed than in P. donnelsoni sp. nov., with its lateral alary processes almost reaching the squamosal; also, the palatine bones are shorter in P. kayi sp. nov. than in P. donnelsoni sp. nov. Finally, the zygomatic ramus of the squamosal is much longer in P. kayi sp. nov. than in P. donnelsoni sp. nov. (Fig. 8 ).

Description of the holotype

(Figs 13 , 15 , 16 ). Adult female (ZSFQ 0775) robust body; head slightly longer than wide, not as wide as body, head width 35.27% of SVL (19.7); head length 38% of SVL; snout rounded in dorsal view, protruding in lateral view; eye-nostril distance 9% of SVL; with small papilla at tip (Fig. 1 ); in lateral view, distinct rostral ridge; loreal region slightly concave; nostrils protruding, laterally directed; interorbital area flat, wider than upper eyelid (upper eyelid width 62% of OID); cranial ridges absent; upper eyelid with one conical and several non-conical tubercles; tympanic membrane well defined, pigmented like surrounding skin; tympanic ring distinct, round; supratympanic fold present, obscuring anterodorsal and posterodorsal edges of the ring; tympanic diameter 46% of eye length; several low to conical tubercles situated in the area just posterior to tympanum. Choanae are small, with an oval to square shape, not concealed by the palatal shelf of maxillary; the dentigerous process of the vomer oblique, widely separated, posteromedial to choanae, each bearing two small teeth; tongue slightly longer than wide, granular, with a conspicuous notch along the posterior border.

The skin of the head is greyish; the dorsum greyish, with scattered small tubercles, some of which are aligned over a W-shaped occipital marking, forming folds; upper flanks with numerous low warts; venter slightly areolate; discoidal fold absent; the cloacal sheath is absent; fingers with thin lateral bangs; length of fingers I <II <IV <III; palmar tubercle round, thenar tubercle oval (Fig. 16 ); subarticular tubercles round, not prominent; supernumerary palmar tubercles not evident; disc sheath of Finger I not expanded; those of Fingers II-IV slightly expanded; all disc sheaths with nearly elliptical ventral pads defined by grooves (Fig. 16 ).

Hind limbs relatively robust; tibia length 47% SVL; foot length slightly smaller than tibia length (foot length 44% SVL); tarsal tubercles present; small, conical tubercle on heel; toes with narrow lateral fringes (Fig. 16 ); subarticular tubercles round, not prominent; inner metatarsal tubercle oval, two times the size of outer tubercle; few low supernumerary plantar tubercles present (Fig. 16 ); disc covers of Toes slightly expanded; toes with defined pads; disc pads nearly elliptical; toe lengths I <II <III <V <IV (Fig. 16 ); the tip of Toe V reaches the middle level of penultimate subarticular tubercle of Toe IV; the tip of Toe III almost reaches the proximal border of penultimate subarticular tubercle of Toe IV.

Measurements of the holotype

(in mm). Adult female, ZSFQ 0775. SVL = 19.7; Tibia Length = 9.3; Foot Length = 8.6; Hand Length = 5.0; Head Length = 7.5; Head Width = 7.0; Eye Diameter = 2.4; Tympanum Diameter = 1.1; forearm length = 4.4; snout length = 5.6; Tarsus length = 5.3; Thigh Length = 8.3; Upper arm Length = 3.1; Interorbital Distance = 2.6; Upper Eyelid Width = 1.6; Internarial Distance = 2.1; Eye-Nostril distance = 1.8; Finger III Width = 0.8; Toe IV Width = 0.3.

Colour of holotype in life

(Fig. 13 ). Head, sides of the head, dorsum, flanks and limbs brown, with darker interorbital bar, lips banded with light and dark brown; broad dark brown supratympanic band extending from region anterior to tympanum to before arm insertion. Flanks lighter than dorsum with oblique, dark bands, several scattered whitish markings near the groin and a white spot in the axilla; limbs banded in shades of dark brown. The throat and belly are dark brown and covered with scattered small yellowish-white spots; the lower ventral part has orange spots; the ventral surfaces of the forelimbs are lighter brown. Iris golden with dark brown reticulations, with a reddish-copper horizontal bar.

Colouration of holotype in ethanol

(Figs 15 , 16 ). The holotype has the following colour pattern: head pale brown with darker interorbital and labial bars; black supratympanic stripe; dorsum brown with several darker markings. Flanks grey to black with minute white spots and lighter diagonal stripes. Groin black with large white spots. The dorsal surfaces of limbs are pale brown with dark brown bars. Cloacal region pale brown, delimited by supracloacal black stripe. The anterior and posterior surfaces of the thighs are brown with several medium to large cream spots. Throat and chest cream-brown with darker marks on the centre (Fig. 15 ). Venter dark grey, with minute to large white spots. Palms and soles are mostly cream, with some pigmentation of Finger IV and Toe V (Fig. 16 ).

Osteology of the skull.

The skull of the adult female paratype DHMECN 14447 is illustrated on its dorsal and ventral surfaces in Fig. 8 . We describe the main skull bones with diagnostic characters in Table 3 . Skull is slightly longer than wide. Dorsally paired nasals overlap the sphenethmoid; the sphenethmoid articulates posteriorly with the frontoparietals, posterior border of frontoparietal is irregular and not projected. 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 rounded. The palatines are relatively short and overlap the sphenethmoid on its anterior portion. Vomers are narrowly separated medially; each vomer has three distinctive rami; the dentigerous process of the vomer does not reach the level of the palatine and almost contacts the tip of the cultriform process of the parasphenoid. The large parasphenoid presents the shape of an inverted cross; the alary processes are directed transversely, partially covering the otic area and almost reaching the squamosal; the posterior process of the parasphenoid almost reaches the foramen magnum. In the dorsal view, the long zygomatic ramus of the squamosal presents an elongated and acuminated anterior border that extends towards the level of the maxilla (Fig. 8 ).

Variation

(Figs 14 , 17 ). Dorsal surfaces with various shades of brown, with or without darker bands or bars. Darker facial markings such as labial, canthal and interorbital bars are usually present. Dorsal mark is an inverted “V” in the coccygeal region; other patterns include arrangements of thin lines arranged longitudinally. Dorsal surface of hands and feet with irregular brown spots. The fore- and hind limbs are banded with dark brown, separated by light brown interspaces. Flanks with various shades of brown, usually lighter than dorsum. Hind surfaces of thighs with black or dark brown bars and cream interspaces. Groin with orange and sometimes yellowish-white spots on an orange background. Belly brown; sometimes mottled. The belly may have numerous orange to yellowish-white spots. In some specimens, there is a yellowish-white cross on the belly. Iris is golden to bronze with fine black reticulations and a reddish-copper horizontal middle stripe.

Call description

(Fig. 18 ). The description is based on the call of an adult male (MZUTI 852), recorded during the night (21:40 h) by Italo Tapia on 7 June 2012, at the Cordillera de los Guacamayos, Province of Napo, Ecuador. The male was calling from leaf litter at ground level. The air temperature was 12.2 °C. The recording consisted of 21 calls, 37 notes and 856 pulses. The call of Pristimantis kayi sp. nov. is composed of the emission of several elements with different characteristics, ranging from single notes to pulsed notes. The call (Fig. 1 ) has a mean dominant frequency of 3.19 ± 0.05 kHz, with 2-6 partial harmonics in the spectrogram. It has a mean duration of 165.1 ± 130.1 ms. The mean interval between calls is 4565.6 ± 5742.3 ms, emitted at a mean rate of 32.6 ± 23.2 calls/minute. Calls are composed of 1 to 7 notes. Notes have a mean duration of 36.0 ± 18.3 ms. The mean interval between notes is 43.8 ± 36.2 ms, emitted at a mean rate of 15.7 ± 6.1 notes/second. The notes are composed of 2 to 13 pulses. Pulses have a mean duration of 3.9 ± 1.1 ms, with a mean interval between pulses of 4.2 ± 2.8 ms, emitted at a mean rate of 202.2 ± 119.7 pulses/second (Table 4 ). The call of Pristimantis kayi sp. nov. does not present stereotyped notes. Due to their structural elements (i.e. notes-pulses), notes can be classified into three different types: Single note calls (CNS; Fig. 18A ), Pulsed note calls (CNP; Fig. 18B ) and Complex calls (CNP; Fig. 18C ), which contain single (non-pulsed) and pulsed notes in its structure. Temporal and spectral measurements of the different call types are shown in Table 4 .

Distribution and natural history observations.

Pristimantis kayi sp. nov. has been recorded from the Cordillera de Guacamayos, Volcán Sumaco (Napo Province) and Cerro Mayordomo, Machay Reserve, Naturetrek Vizcaya Reserve, Leito Reserve (Tungurahua Province) at an elevational range of 2190-3600 m a.s.l. (Fig. 11 ). Calling males were heard during the day and night. During the night, frogs of Pristimantis kayi sp. nov. were found on the forest floor or perched on low vegetation (always below 60 cm from ground level), including shrubs, grasses ( Neurolepis sp.), ferns and Selaginella . The species has been found in primary and disturbed Andean forests, with trees of the genus Weinmannia , Clusia , Alnus and others, of 10-15 metres (Fig. 12 ).

Etymology.

The specific epithet " Pristimantis kayi " is a noun in the genitive case and a patronym for Andreas Kay, a German physicist, biologist and friend who spent much of his life documenting and exploring biodiversity, contributing substantially to the conservation of Ecuadorian forests (Fig. 12 ). Andreas was part of the team that created Fundación EcoMinga’s Dracula Reserva in north-western Ecuador. Additionally, his work shed light on understanding the diversity and endemism patterns of orchids in the Llanganates-Sangay Ecological Corridor, where he passed away in 2019. Some of his amazing photographs can be seen here: https://www.flickr.com/photos/andreaskay/albums/.

Figures

Figure 1. Evolutionary relationships amongst species in the Pristimantis gladiator complex, under the Maximum Likelihood inference criterion (modified from Franco-Mena et al. (2023)). Red font indicates the new sequence.

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 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.

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.

Figure 13. Holotype of Pristimantis kayi sp. nov. in life, adult female, ZSFQ 0775. LRC: 19.7 mm. Photographs by Jose Vieira.

Figure 14. Colour variation of Pristimantis kayi sp. nov. A MZUTI 2209, adult female, LRC: 20.15 mm, from Cordillera de Guacamayos B MZUTI 2210, adult female, LRC: 19.90 mm, from Cordillera de Guacamayos C MZUTI 2211, adult male, LRC: 14.30 mm, from Cordillera de Guacamayos D MZUTI 2213, adult male, LRC: 15.10 mm, from Cordillera de Guacamayos E MZUTI 2214, adult female, LRC: 18.73 mm, from Cordillera de Guacamayos F ZSFQ 774, adult female, LRC: 18.96 mm from Sumaco Volcano G ZSFQ 782, adult female, LRC: 30.03 mm, from Sumaco Volcano. Photographs by Lucas Bustamante (A, B, C, D, E) and Jose Vieira (F, G).

Figure 15. Preserved holotype of Pristimantis kayi sp. nov. ZSFQ 0775, on its dorsal, ventral and lateral views. Photographs by David Brito-Zapata.

Figure 16. Detailed ventral view of hand and feet of the holotype ZSFQ 0775 of Pristimantis kayi sp. nov. Photographs David Brito-Zapata.

Figure 17. Dorsal and ventral views of preserved type series of Pristimantis kayi sp. nov. A holotype ZSFQ 0775, female; Paratypes B ZSFQ 0779, female C DHMECN 16212, female D MZUTI 5162, female E MZUTI 4657, male F ZSFQ 0773, male G DHMECN 15233, male H DHMECN 18440, male; Photographs by JPRPR and David Brito-Zapata.

Figure 18. Call of Pristimantis kayi sp. nov. (adult male, MZUTI 852). The species has different types of calls, represented as follows: A single note call B pulsed note calls C complex calls (non-pulsed and pulsed notes).