Pristimantis maryanneae, Reyes-Puig 1 & Reyes-Puig 1 & Franco-Mena 5 & Jost 2 & Yánez-Muñoz 1, 2022

Reyes-Puig 1,2, Juan Pablo, Reyes-Puig 1,3,4, Carolina, Franco-Mena 5,6, Daniela, Jost 2, Lou & Yanez-Munoz 1,2, Mario H., 2022, Strong differentiation between amphibian communities on two adjacent mountains in the Upper Rio Pastaza watershed of Ecuador, with descriptions of two new species of terrestrial frogs, ZooKeys 1081, pp. 35-87 : 35

Pristimantis maryanneae sp. nov

Figures 31 , 32 , 33 Proposed standard English name: Maryanne’s Robber Frog Proposed standard Spanish name: Cutín de Maryanne

Material examined.

Holotype. DHMECN 14454 (adult male Fig. 32 ), collected by Mario Yánez, Juan Pablo Reyes-Puig and Daniela Franco-Mena, in the Naturetrek Vizcaya Reserve , Ulba Parish, Baños township, Tungurahua Province, Republic of Ecuador (-1.357750, -78.393533; 2404 m elev.) on 26 February 2018.

Paratypes (1 female, 3 males). DHMECN 14451 (♂ adult male), DHMECN 14453 (juvenile), with same location data as the holotype; DHMECN 14452 (♂ adult male) with same location data as the holotype, collected on 27 February 2018 and DHMECN 14550 (♀ adult female) with the same location data as the holotype, collected on 15 February 2018 .

Generic placement.

We assign the new species to Pristimantis , based on having head about as wide as body; cranial crests absent; dentigerous process of vomers present; “S” condition of the adductor muscles; terminal discs on digits, bearing well-defined circumferential grooves, supported by T-shaped terminal phalanges; Toe V as long as, or longer than, Toe III; and subarticular tubercles not protruding (Hedges 2008).

Diagnosis.

Pristimantis maryanneae can be distinguished from other Pristimantis by the following character combination: (1) skin on dorsum finely shagreen, with flat and low warts, weak and fine sacral fold, composed of some low warts, two pairs of scapular tubercles diagonal aligned behind the eye; venter areolate with pustules, discoidal fold present; (2) tympanum absent, hidden beneath the skin; tympanic anulus visible under the skin measuring 25% of the eye diameter; (3) snout short, rounded in dorsal and lateral profile; (4) upper eyelid with 2-3 subconical tubercles (rounded in preservative); upper eyelid wider than interorbital distance; cranial crests absent; (5) dentigerous process of vomer present, oblique in outline with 2-3 oval teeth; (6) males without vocal slits, no nuptial pads; (7) Finger I shorter than II; digital pads expanded; (8) fingers with weakly defined laterals fringes; (9) forearms with small ulnar subconical tubercles; (10) heel bearing a small subconical tubercle; outer edge of tarsus bearing small subconical tubercles, inner tarsal fold absent; (11) two metatarsal tubercles, inner oval twice or three times larger than outer oval that is subconical; (12) toes without lateral fringes; supernumerary tubercles present, Toe V larger than III, does not reach distal subarticular tubercle of Toe IV; (13) dorsal colouration dark grey to grey with green marks, with transverse dark brown marks, with a chevron and irregular “H” shaped marks, flanks with cream diagonal bands, shanks with cream diagonal bands and light brown interspaces, hind-limbs with grey transverse bands and dark brown interspaces; ventral colouration dirty cream with a line along middle of the venter, chin and outer mandibula mottled with dark brown marks, iris light brown to grey with black reticulation and horizontal coppery stripe and (14) SVL males 17.61-17.8 mm; female 21.06mm.

Comparisons with other species.

(Fig. 33 ) The condition of the hidden tympanum is a distinctive characteristic that differentiates Pristimantis maryanneae from other Pristimantis within the eastern versant of the Andes in central Ecuador. Only P. ventrimarmoratus shares the condition of the tympanum; however, the ventral colouration of that species is composed of large black and white marks and the hidden surfaces have orange and yellow marks. Pristimantis sp from El Encanto have different iris and ventral colour patterns. Pristimantis maryannaeae does not exhibit flash colours on the venter, groin and hidden surfaces. Externally the new species resembles Pristimantis verecundus ( Lynch and Burrowes 1990) and P. mutabilis ( Guayasamin et al. 2015) from north-western Ecuador; however, these species have extremely opposite distributions, dorsolateral folds, reddish colours on the groin in P. mutabilis and both have a tympanum, in contrast to P. maryaneae .

Description of the holotype.

(Figs 31 , 32 ) Adult male (measurements in mm): SVL 17.86; tibia length 9.07; foot length 9.18; head length 7.34; head width 6.78; upper eyelid width 1.97; interorbital distance 2.5; internarial distance 1.96; eye-nostril distance 1.81; eye diameter 2.35; tympanum diameter 0.79; hand length 5.08. Head longer than wide, length 41.6% SVL, wide 38% SVL; snout rounded in dorsal and lateral view (Fig. 31 ). Eye-nostril distance 10.13% SVL; canthus rostralis concave and loreal region slightly concave; nostril slightly protuberant orientated laterally; interorbital area flat, wider than the upper eyelid, upper eyelid measure 78.8% interorbital distance; cranial crests absent; occipital fold defined by the presence of two pairs of prominent subconical tubercles on the occipital and scapular regions; row of small rounded tubercles from the tip of the snout to the interorbital region; upper eyelid with three subconical tubercles (rounded in preservative); rounded tubercles scattered on the cantus rostralis and loreal region (Fig. 34 ); tympanic membrane undifferentiated from surrounding skin, tympanic annulus visible beneath the skin, rounded, laterally orientated, tympanum diameter 33.61% of the eye diameter, postrictal tubercles present, low; small choanae, rounded in outline, not covered by the palatal floor of maxilla; dentigerous process of vomer present oblique in outline; oval tongue longer than wide, 40% of it fixed to the mouth floor.

Skin on dorsum finely shagreen with rounded tubercles widespread; venter areolate with some pustules, discoidal fold present; anal ornamentation absent, with several rounded tubercles; forearms slender with two subconical ulnar tubercles and a row of subconical tubercles along the anterior edge (reduced or less evident in preservation effects); fingers with fine lateral fringes, palmar tubercle oval, the same size and shape as thenar; subarticular tubercles rounded and defined, with supernumerary tubercles at the base of each digit; digital pads truncated and expanded, twice as wide as the digit in fingers III, IV, on fingers I and II slightly wider than digit; all fingers have digital pads defined by circumferential grooves (Fig. 34 ).

Hind-limbs slender, tibia length 50.78% SVL, two subconical tubercles on the heel, a row of subconical tubercles on the outer edge of tarsus; inner tarsal fold present; toes with fine lateral fringes, without digital webbing, digital pads of the toes expanded, on toes IV and V twice as wide as digits and on toes I, II, III slightly more expanded than digit; low and rounded subarticular tubercles, supernumerary tubercles weakly defined and rounded; metatarsal tubercles present, inner oval three times the width of the outer tubercle that is rounded; toe V longer than III, not reaching to the base of distal subarticular tubercle of toe IV.

Colour of holotype in life (Fig. 34 ). Dorsal surfaces light brown to dark brown with dark marks, delineated by golden reticulations. Limbs banded with light brown and dark brown, delineated by golden tones. Throat light grey with small dark grey marks, an inverted triangle on the throat and chin, other ventral surfaces dark grey with light grey. Iris coppery/yellow with black reticulations.

Colour of holotype in ethanol 70 % (Fig. 31 ). Head grey with an interorbital dark bar, nasal dark marks, a pair of subocular and supratympanic black bands. Dorsal pattern with irregular marks in several dark grey tones, delineated by irregular reticulations, a pair of dark marks forming ocellus on the posterior flanks. Anterior and posterior limbs banded from light grey to dark. Throat and venter with minute black points, ventral surfaces of forelimbs and hind-limbs grey.

Variation (Fig. 34 ). Pristimantis maryanneae shows dorsal variation in colour from light brown to dark brown, with some individuals bearing a head mask predominantly yellow; ventral surfaces can vary from small dense brown marks to grey tones. Variation in iris from coppery to grey coppery. Variation in morphometric measurements presented in Table 3 .

Distribution and natural history.

Pristimantis maryanneae is known only from the type locality, Naturetek Vizcaya Reserve, located at Ulba Parish, Baños township, Tungurahua Province, at 2400 m elevation in the eastern versant on the Andes in central Ecuador (Fig. 2 ), near the southwest limit of Llanganates National Park. This species was found in mature montane cloud forest ( MAE 2012), characterised by a canopy of 25 to 30 m covered by epiphytes, orchids, bromeliads, bryophytes, and ferns. The bambusoid grass genus Chusquea was predominant in the area. The five known specimens of Pristimantis maryanneae were found in the lower stratum of the forest, sitting on leaves from 60 to 160 cm; one individual was found in leaf litter during the day, while all others were found on fern leaves at night.

Etymology.

Specific epithet is in recognition of Maryanne Mills ( née Sawle), a zoologist from Perth, Australia. In 1986, she helped her husband, David Mills, set up the UK’s premier wildlife tour operator, Naturetrek and she has been based in England ever since. Her passion for the environment and its conservation has led Naturetrek to donate widely to this cause, including donations to World Land Trust which allowed EcoMinga Foundation to purchase more than 1,000 acres of Ecuadorian cloud forest, where this new species of terrestrial frog was discovered.

Figures

Figure 2. Sample points in the Naturetrek-Vizcaya Reserve (black triangles) and the Machay Reserve (black circles). The white triangle is the type locality of Pristimantis maryanneae sp. nov. and the white circle is the type locality of Pristimantis burtoniorum sp. nov. The grey shaded areas are the Reserves of the EcoMinga Foundation within the Llanganates-Sangay Corridor and the green shaded areas represent Llanganates National Park (north) and Sangay National Park (south).

Figure 31. Pristimantis maryanneae sp. nov. (DHMECN 14454), adult, male holotype SVL = 17.9 mm A dorsal view B ventral view C lateral view. Photographs by Mario H. Yanez-Munoz.

Figure 32. Pristimantis maryanneae sp. nov. (DHMECN 14454), adult male, holotype A palmar surface detail B plantar surface detail Photographs by Mario H. Yanez-Munoz.

Figure 33. Live photograps of new species and comparison with similar Pristimantis frogs in the region A Pristimantis burtoniorum sp. nov. (DHMECN 16220 from Machay Reserve Cerro Mayordomo.) B P. maryanneae sp. nov. (DHMECN 14454 from Naturetrek Vizcaya Reserve) C P. prolatus (DHMECN 16244 from El Encanto) D P. albujai (DHMECN 12245 from Sardinayacu river) E P. tungurahua (DHMECN 15224 from Naturetrek Vizcaya Reserve) F P. puruscafeum (not collected from Cerro Candelaria Reserve) G P. sacharuna (DHMECN 16723 from Rio Zunag Reserve) H P. ventrimarmoratus not collected from Rio Zunag Reserve I Pristimantis sp (DHMECN 16250 from El Encanto). Photographs Juan Pablo Reyes Puig, Mario Yanez Munoz, Jorge Brito and Lou Jost.

Figure 34. Pristimantis maryanneae, live photographs of Paratypes A lateral view and B dorsal view (DHMECN 14452) C lateral view and D dorsal view (DHMECN 14451). Photographs by Mario H. Yanez-Munoz.