Pristimantis ventristellatus, Zumel & Buckley & Ron, 2022

Zumel, Daniel, Buckley, David & Ron, Santiago R, 2022, The Pristimantis trachyblepharis species group, a clade of miniaturized frogs: description of four new species and insights into the evolution of body size in the genus, Zoological Journal of the Linnean Society 195 (1), pp. 315-354 : 344-348

PRISTIMANTIS VENTRISTELLATUS SP. NOV.

( FIGS 20–24 ; TABLES 2 AND 3 )

Z o o b a n k r e g i s t r a t i o n: u r n: l s i d: z o o b a n k. org:act: AB88F2AD-924D-4739-B841-561C 09292737

Holotype ( Figs 20 , 21 ): QCAZ 69240 (field no. SC-PUCE 59773 ), adult male from Ecuador, Provincia Morona Santiago, Cantón Santiago de Méndez, Parroquia San Francisco de Chinimbimi, Puchimi (2.7843º S, 78.1426º W), 1905 m a.s.l., collected by Diego Almeida, Darwin Núñez, Eloy Nusirquia and Jefferson Mora on 10 September 2017 .

Paratypes (26: 12 males, 13 females, one juvenile): Ecuador: Provincia Morona Santiago: Puchimi , QCAZ 69263 , adult female (2.7845º S, 78.1400º W), 1930 m a.s.l. ; QCAZ 69318 , adult female (2.7880º S, 78.1299º W), 2283 m a.s.l. ; QCAZ 69209 , adult female (2.7844º S, 78.1409º W), 1915 m a.s.l. ; QCAZ 69211 , adult male (2.7845º S, 78.1400º W), 1930 m a.s.l. ; QCAZ 69243 , adult male (2.7844º S, 78.1419º W), 1908 m a.s.l. ; QCAZ 69245 , adult male (2.7843º S, 78.1412º W), 1926 m a.s.l. ; QCAZ 69264 , adult female (2.7857º S, 78.1388º W), 1979 m a.s.l. ; QCAZ 69265 , adult male (2.7857º S, 78.1376º W), 1919 m a.s.l. ; QCAZ 69267 , QCAZ 69273 , adult males (2.7858º S, 78.1372º W), 2032 m a.s.l. ; QCAZ 69291 , adult male (2.7848º S, 78.1391º W), 1969 m a.s.l. ; QCAZ 69296 , adult female (2.7843º S, 78.1403º W), 1938 m a.s.l. ; QCAZ 69319 , adult female, and QCAZ 69320 , adult male (2.7880º S, 78.1299º W), 2283 m a.s.l. ; QCAZ 69338 , adult female (2.7866º S, 78.1336º W), 2125 m a.s.l. ; QCAZ 69348 , juvenile, and QCAZ 69349 , adult male (2.7870º S, 78.1320º W), 2180 m a.s.l. ; QCAZ 69351 , adult male (2.7871º S, 78.1319º W), 2193 m a.s.l. ; QCAZ 69357–69359 , adult females, and QCAZ 69362 , adult male (2.7873º S, 78.1317º W), 2203 m a.s.l. ; QCAZ 69365 , adult female (2.7874º S, 78.1314º W), 2211 m a.s.l. ; QCAZ 69368 , adult male (2.7875º S, 78.1312º W), 2218 m a.s.l. ; QCAZ 69395 , adult female (2.7858º S, 78.1340º W), 2043 m a.s.l. ; QCAZ 69397 , adult female (2.7860º S, 78.1338º W), 2029 m a.s.l. Collected by D. Almeida, D. Núñez, E. Nusirquia and J. Mora on 9–13 September 2017 .

Suggested common name: English: stellated venter rain frog. Spanish: cutín de vientre estrellado.

Diagnosis ( Figs 20–24 ): A species of Pristimantis characterized by the following combination of characters: (1) dorsal skin shagreen with scattered tuberclesandpustules; scapularregionwithW-shaped scapular folds and two pairs of anterolateral and posteromedial conical or subconical tubercles along them; low interocular fold, usually with one or two low subconical interocular tubercles; dorsolateral folds usually absent; ventral skin weakly areolate on throat and chest, and coarsely areolate on belly and posteroventral surface of thighs; discoidal fold distinct; (2) tympanic annulus present, its upper margin covered by low supratympanic fold; tympanic membrane present but hidden by skin; one or two postrictal conical or subconical tubercles; (3) snout short to moderate in length with a rostral papilla at tip, subacuminate in dorsal view and rounded to protruding in profile; (4) upper eyelid with one distinct conical tubercle on the posterolateral quadrant, and several subconical tubercles spread over all its surface; (5) cranial crests absent; (6) vocal slits and nuptial pads absent; (7) Finger I shorter than Finger II; discs of digits expanded, rounded to truncate; (8) fingers without lateral fringes; (9) low and subconical ulnar tubercles; (10) heel bearing one to few low subconical tubercles; inner tarsal fold illdefined; low and subconical outer tarsal tubercles; (12) toes with narrow lateral fringes; basal toe webbing, most distinctive between Toe IV and Toe V; Toe V slightly longer than Toe III; discs expanded and rounded, nearly as large as those on fingers; (13) in life, dorsum brown to dark brown with a darker W-shaped scapular mark posterior to the scapular fold; dark brown interorbital bar; sides of head brown bearing darker labial bars; flanks showing the same colour of the dorsum, with or without several diffuse dark brown diagonal stripes; venter dark brown to brown with white spots, which may reach the lower halves of flanks and head; anterior surface of thighs and inner surface of shanks usually bearing some inconspicuous pale red blotches; brown groins with or without inconspicuous red blotches; iris bronze to reddish copper; and (14) SVL range in adult females from 18.62 to 22.97 mm (mean = 20.67; N = 13), in adult males 14.51 to 16.69 mm (mean = 15.87, N = 13; Tables 2 and 3 ).

Comparisons with other species: In this section, coloration refers to live individuals unless otherwise mentioned. Pristimantis ventristellatus can be confounded with P. pramukae by having a dark brown dorsal coloration and a dark venter with scattered clear spots and pale flecks ( Figs 13 , 23 ). However, dorsal surfaces of P. ventristellatus are usually more tuberculate, the clear ventral spots are more numerous and its venter is darker. They also differ in the snout shape, which is subacuminate in dorsal view and protruding in profile in P. ventristellatus ( Fig. 20A, B ), and usually rounded in both views in P. pramukae ( Fig. 10A, B ). The shape of the snout does not allow to clearly distinguish P. ventristellatus from P. trachyblepharis . However, they differ in dorsal and ventral coloration, lighter and generally creamy-yellow in P. trachyblepharis , whose venter is also slightly translucent (unlike in P. ventristellatus ). Finally, the most tuberculate individuals of P. ventristellatus could be mistakenly identified as P. albujai , since both species are small, dark brown dorsally and ventrally, have a subacuminate snout in dorsal view and have prominent scapular folds. They can be easily differentiated by looking at their groins and hidden surfaces of the hindlimbs, which are usually red in P. albujai and brown with or without inconspicuous red blotches in P. ventristellatus ( Fig. 23 ). Pristimantis ventristellatus also differs from P. albujai in lacking distinct dorsolateral folds, which are prominent in P. albujai .

Description of the holotype: Adult male (QCAZ 69240). Measurements (in mm): SVL 15.67; tibia length 9.02; foot length 7.75; head length 6.03; head width 5.41; interorbital distance 2.03; width of upper eyelid 2.06; internarial distance 0.9; eye–nostril distance 1.78; eye diameter 2.53; tympanum diameter 0.97. Colour of the holotype in life and preservative is shown in Figures 20 and 21 , respectively.

Head ( Figs 20 , 21A, B ): Longer than wide, wide as body; snout moderate in length with a rostral papilla at the tip, subacuminate in dorsal view, protruding in profile; canthus rostralis distinct, concave in dorsal view, slightly rounded in profile; loreal region concave; tympanic annulus distinct, its upper margin covered by low supratympanic fold; tympanic membrane present but hidden by skin; two postrictal tubercles, one conical and one smaller and subconical; low interocular fold with a subconical interocular tubercle; upper eyelid with several subconical tubercles and three conical tubercles, of which the largest is posterolateral; many pustules on the occipital region surround a pair of subconical tubercles; skin on throat weakly areolate; dentigerous processes of vomer indistinct; choanae concealed by palatal shelf of maxilla; tongue as wide as long, posteriorly notched, posterior half not adherent to the mouth floor.

Dorsum and venter ( Figs 20 , 21A, B ): Dorsal skin shagreen bearing numerous pustules, spicules and tubercles; W-shaped scapular folds; two pairs of conical scapular tubercles, anterolateral and posteromedial along the scapular fold; several subconical cloacal tubercles; low lateral folds formed by rows of pustules on flanks; skin on chest weakly areolate, belly coarsely areolate; discoidal fold ill-defined.

Forelimbs ( Fig. 21C ): Low and subconical ulnar tubercles; Finger I shorter than Finger II; discs narrowly expanded, rounded; all fingers having ventral pads surrounded by circumferential grooves; palmar tubercles not well defined, barely visible; fingers lacking lateral fringes; basal webbing smaller than that on toes, slightly noticeable between Fingers III and IV.

Hindlimbs ( Fig. 21D ): Heel bearing several pustules and one low subconical tubercle; distinct subconical tubercles on outer surface of tarsus; inner tarsal fold diffuse; Toe V slightly longer than Toe III; discs expanded, rounded, nearly as large as those on fingers; all toes having ventral pads surrounded by circumferential grooves; inner metatarsal tubercle enlarged, approximately three times the size of the outer metatarsal tubercle; hyperdistal subarticular tubercle of Toe IV distinct; narrow lateral fringes; basal webbing more noticeable between Toe IV and V; skin on posteroventral surfaces of thighs coarsely areolate.

Variation: Four individuals have available DNA sequences; mean intraspecific uncorrected genetic p- distance is 0.6% for the 16S gene. In the type series, adult males (SVL range 14.51–16.69 mm) are between 10.37 and 36.84% smaller than adult females (SVL range 18.62–22.97 mm). Below we list character states distinct from those described in the holotype, followed by an example. Colour variation in life and in preservative is shown in Figures 22 to 24.

Head ( Figs 22–24 ): Snout short (QCAZ 69395). Snout rounded in profile (QCAZ 69264). Canthus rostralis angular in profile (QCAZ 69359). Three postrictal tubercles, one conical and two subconical (QCAZ 69263); one conical tubercle (QCAZ 69243); two subconical tubercles (QCAZ 69245). Interocular region without interocular fold or interocular tubercles (QCAZ 69368); two subconical interocular tubercles (QCAZ 69319). Upper eyelid with one elongate tubercle, two conical tubercles and several subconical tubercles (QCAZ 69319); several subconical tubercles (QCAZ 69211); one conical tubercle and several subconical tubercles (QCAZ 69243). Dentigerous processes of vomer posterior to the choana, oblique and widely separated, each vomer bearing two or three teeth (QCAZ 69357).

Dorsum and venter ( Figs 22–24 ): Dorsal skin finely shagreen with scattered pustules and tubercles specially in the posterior half (QCAZ 69357); shagreen, highly tuberculate (QCAZ 69267). Low scapular folds (QCAZ 69362). Two pairs of subconical scapular tubercles (QCAZ 69358); conical scapular tubercles (QCAZ 69338). Inconspicuous dorsolateral folds (QCAZ 69245). Two lateral folds on each flank (QCAZ 69245). Forelimbs ( Fig. 24 ): Supernumerary tubercles at base of fingers (QCAZ 69318). Subarticular tubercles distinct, well defined (QCAZ 69318). Low hyperdistal tubercles (QCAZ 69318). Outer palmar tubercle lower than thenar tubercle (QCAZ 69357). Outer palmar tubercle bifid, approximately 1.5 times the size of the thenar tubercle (QCAZ 69209). Narrow lateral fringes (QCAZ 69623). Basal webbing distinct (QCAZ 69209). Discs truncate (QCAZ 69368).

Hindlimbs ( Fig. 24 ): Two conical tubercles and a few subconical tubercles on outer surface of tarsus (QCAZ 69267). Inner tarsal fold distinct (QCAZ 69273) or absent (QCAZ 69351). Low hyperdistal tubercles (QCAZ 69318). Outer metatarsal tubercle lower than inner metatarsal tubercle, approximately twice its size (QCAZ 69349). Discs truncate (QCAZ 69264).

Distribution, natural history and conservation status: This species is only known from the type locality, Puchimi, in the Cutucú Mountain Range, in Morona Santiago Province, Ecuador, between 1908 and 2283 m a.s.l. ( Fig. 3 ). The natural region is Eastern Montane Forest. Individuals were found from 10 to 100 cm above the ground level on leaves in forest ( Fig. 4 ) characterized by low shrubs and abundant mosses and terrestrial bromeliads. All observations were made at night. Individuals were collected down to 1 km from the nearest disturbed area (pastureland), suggesting that P. ventristellatus can persist at least under moderate anthropogenic habitat disturbances. The type locality is within a protected area, the Kutukú-Shaimi Protection Forest. According to the available data, this species has a restricted distribution (Extent of Occurrence 0.122 km 2, Area of Occupancy 12 km 2). However, adjacent areas remain unexplored, so we assign P. ventristellatus to the Data Deficient Red List Category ( IUCN 2021).

Etymology: The specific name ventristellatus refers to the dark colour with white spots on the venter of this species, which resembles a starred (stellate) night sky.

Figures

Figure 3. Distribution of Pristimantis trachyblepharis species group. Locality information for examined specimens is shown in Supporting Information, Table S2. UCS: Unconfirmed Candidate Species. Elevations are indicated in metres above sea level.

Figure 4. Land coverage in the Ecuadorian localities where individuals of the eight described species of the Pristimantis trachyblepharis species group were found. Land coverage shapefile was downloaded from Ministerio del Ambiente y Agua of Ecuador, at http://ide.ambiente.gob.ec/mapainteractivo. Locality information for examined specimens is shown in Supporting Information, Table S2.

Figure 10. Photographs in live of the holotype of Pristimantis pramukae (QCAZ 68549; adult female, SVL 20.15 mm). A, dorsal view; B, lateral view; C, frontal view; D, ventral view.

Figure 13. Colour variation in life individuals of Pristimantis pramukae in ventral view. A, QCAZ 72591 (adult female, SVL 19.91 mm); B, QCAZ 72608 (adult female, SVL 18.47 mm); C, QCAZ 72588 (juvenile, SVL 9.59 mm); D, QCAZ 68591 (subadult male, SVL 13.18 mm); E, QCAZ 72617 (subadult male, SVL 13.14 mm); F, QCAZ 68547 (adult male, SVL 14.78 mm).

Figure 20. Photographs of the holotype of Pristimantis ventristellatus (QCAZ 69240; adult male, SVL 15.67 mm) in life. A, dorsal view; B, lateral view; C, frontal view; D, ventral view.

Figure 21. Photographs of the holotype of Pristimantis ventristellatus (QCAZ 69240; adult male, SVL 15.67 mm) in preservative. A, dorsal view; B, ventral view; C, ventral view of the right hand; D, ventral view of the right foot.

Figure 22. Colour variation in life individuals of Pristimantis ventristellatus in dorsolateral view.A, QCAZ 69245 (adult male, SVL 16.46 mm); B, QCAZ 69263 (adult female, SVL 18.62 mm); C, QCAZ 69273 (adult male, SVL 15.41 mm); D, QCAZ 69319 (adult female, SVL 18.62 mm); E, QCAZ 69365 (adult female, SVL 20.85 mm); F, QCAZ 69368 (adult male, SVL 15.16 mm).

Figure 23. Colour variation in life individuals of Pristimantis ventristellatus in ventral view.A, QCAZ 69245 (adult male, SVL 16.46 mm); B, QCAZ 69263 (adult female, SVL 18.62 mm); C, QCAZ 69273 (adult male, SVL 15.41 mm); D, QCAZ 69318 (adult female, SVL 22.02 mm); E, QCAZ 69365 (adult female, SVL 20.85 mm); F, QCAZ 69368 (adult male, SVL 15.16 mm).

Figure 24. Colour variation in preserved individuals of Pristimantis ventristellatus: 1, dorsal views; 2, ventral views. A, QCAZ 69264 (adult female, SVL 19.82 mm); B, QCAZ 69357 (adult female, SVL 20.6 mm); C, QCAZ 69318 (adult female, SVL 22.02 mm); D, QCAZ 69319 (adult female, SVL 18.62 mm); E, QCAZ 69320 (adult male, SVL 16.69 mm); F, QCAZ 69368 (adult male, SVL 15.16 mm); G, QCAZ 69265 (subadult male, SVL 14.51 mm).