(hoc loco): BMNH 1947.2.15.74

BMNH 1947.2.15.75 and BMNH 1947.2.15.76

“El Topo, R. Pastaza, [Provincia Tungurahua,] E. Ecuador, 4200 feet”

The fourth original syntype BMNH 1947.2.15.73 may be conspecific with Pristimantis sinschi sp. nov. but its accurate determination remains open.

Eleutherodactylus ventrivittatus Andersson, 1945; Type locality: “Ambitagua [= Abitagua], Rio Pastaza”, Provincia Tungurahua or Pastaza, Ecuador (according to Frost 2020).

MUSM 32733 (field number IWU 367), GenBank accession numbers MW075408 (16S rRNA) and MW075426 (12S rRNA), an adult male from the Pui Pui Protected Forest (11°12'38.5"S, 74°57'28.9"W; Figs 1, 3), 1800 m a.s.l., Distrito Pichanaqui, Provincia Chanchamayo, Región Junín, Peru, collected on 16 May 2014 by Edgar Lehr and Jiří Moravec.

Two adult males: NMP-P6V 75060 (field number IWU 359), GenBank accession numbers MW075407 (16S rRNA) and MW075425 (12S rRNA), collected at the type locality on 14 May 2014 by Edgar Lehr and Jiří Moravec. MUSM 31165 (field number IWU 123), GenBank accession number KY962801, collected at the entrance of the Pui Pui Protected Forest (11°15'16.1"S, 74°53'30.7"W; Figs 1, 3), 1615 m a.s.l., reached from Nueva Florida in ca. 8 hours walk on 1 May 2012 by Edgar Lehr, and Rudolf von May.

Figure 3. 

Pui Pui Protected Forest (red frame) with collecting sites of Pristimantis sinschi sp. nov. (yellow symbols) and P. albertus and P. sagittulus (blue symbol). Modified after Lehr et al. (2017).

We assign this species to Pristimantis, based on our molecular data (Fig. 2) and general morphological similarity to other members of the genus.

A new species of Pristimantis not assigned to any species group having the following combination of characters: (1) Skin on dorsum shagreen with many small subconical tubercles and a narrow, hairline mid-dorsal fold, skin on ventre areolate; discoidal and thoracic folds present; dorsolateral folds absent; (2) tympanic membrane and tympanic annulus absent; (3) snout short, rounded in dorsal and lateral views; (4) upper eyelid without enlarged tubercles; EW slightly shorter than IOD; cranial crests absent; (5) dentigerous processes of vomers present; (6) males without vocal slits; nuptial pads absent; (7) Finger I shorter than Finger II; discs of digits broadly expanded, elliptical; (8) fingers with lateral fringes; (9) small conical ulnar and tarsal tubercles present; (10) heel without conical tubercles; short inner tarsal fold present; (11) inner metatarsal tubercle ovoid, 3 times as large as outer; outer metatarsal tubercle small, ovoid; low, numerous supernumerary plantar tubercles; (12) toes with lateral fringes; basal toe webbing absent; Toe V longer than Toe III; toe discs slightly smaller than those on fingers; (13) in life, dorsal ground colouration greenish-grey, reddish-brown or brown with or without a hairline mid-dorsal tan stripe; canthal stripe absent, supratympanic stripe greyish-brown; groin black with cream blotches, anterior surfaces of thighs and ventral surface of shanks black; ventral surfaces of thighs salmon and grey mottled; ventre black and cream mottled; iris pale bronze with fine black vermiculation and broad median red band through pupil and a narrow black vertical streak from pupil across lower half of iris; (14) SVL in adult males 25.7–28.8 mm (n = 3), females unknown.

Phylogenetically, Pristimantis sinschi and P. lindae from southern Peru (Región Cusco) are sister taxa. Both species have the dorsum shagreen with subconical tubercles, ventre areolate, dorsolateral folds absent, dentigerous processes of vomers, finger and toe discs expanded, fingers and toes with lateral fringes, tarsal folds, males with vocal slits and groin and ventre cream with black reticulations. However (characters for P. sinschi in parenthesis), P. lindae has a tympanum (absent), the single known male MUSM 26528 has nuptial pads (absent), ventral surfaces of thighs pale brown and grey mottled (salmon and grey mottled) and the iris with a median horizontal dark reddish-brown streak (red) (Duellman 1978).

Pristimantis sinschi is morphologically similar to five other Pristimantis (P. diadematus, P. divnae, P. eurydactylus, P. orcus and P. ventrimarmoratus) from the Amazonian lowlands and lower montane forests which have the ventre and groin contrastingly patterned in black and cream and an inner tarsal fold. However, P. sinschi is readily distinguished from its congeners (except for P. ventrimarmoratus) by lacking a tympanum and having the ventral surfaces of thighs orange brown and grey mottled. Characters for P. sinschi are in parenthesis in the following. Furthermore, P. diadematus has the ventral skin smooth (areolate), males with vocal slits (absent) and nuptial pads (absent) and the iris greenish-bronze with a median horizontal red streak or reddish-copper (pale bronze with fine black vermiculation and broad median horizontal red band) (Duellman and Lehr 2009). Male P. divnae have a much smaller SVL of 22.8–23.4 mm, n = 2 (25.7–28.8 mm, n = 3), scapular region with a W-shaped ridge (hour-glass shaped ridge) and iris golden with black reticulations and fine narrow black bars forming a cross or T (pale bronze with fine black vermiculation and broad median horizontal red band and a vertical streak at its lower half) (Lehr and von May 2009). Male P. eurydactylus lack vocal slits, have nuptial pads (absent), a maximum known SVL of 31.8 mm (28.8 mm, and scapular region with a W-shaped ridge (hour-glass shaped ridge) (Hedges and Schlüter 1992). Male P. orcus have nuptial pads present (absent), have a much smaller SVL of 20.0–25.1, n = 4 (25.7–28.8 mm, n = 3), the groin white or whitish-blue and black (groin black with cream blotches) and the iris gold with a copper tint and fine black reticulations (pale bronze with fine black vermiculation and broad median horizontal red band) (Lehr et al. 2009). Pristimantis ventrimarmoratus and P. sinschi both lack a tympanum and males are without vocal slits. However, male P. ventrimarmoratus have nuptial pads (absent), have a smaller SVL 17.8–25.5 mm, n = 8 (25.7–28.8 mm, n = 3) and the iris pale bronze with fine black flecks (pale bronze with fine black vermiculation and broad median horizontal red band) (Lynch and Duellman 1980).

Head slightly narrower than body, slightly wider than long; head length 42% of SVL; head width 44% of SVL; cranial crests absent; snout moderately long, rounded in dorsal and lateral views (Fig. 4A, B); eye-nostril distance 72% of eye diameter; nostrils slightly protuberant, directed dorsolaterally; canthus rostralis moderately long, broadly rounded in lateral view, weakly concave in dorsal view; loreal region weakly concave; lips rounded; upper eyelid each with several small subconical tubercles; upper eyelid width 86% of IOD; occipital and scapular region with several enlarged conical tubercles and with an hourglass-shaped fold from posterior margin of upper eyelid slightly passing the level of arm insertion; supratympanic fold short and narrow, extending from posterior margin of upper eyelid slightly curved to level of mouth corner; tympanic membrane and annulus absent; one conical postrictal tubercle present bilaterally. Choanae small, ovoid, not concealed by palatal shelf of maxilla; dentigerous processes of vomers oblique, moderately-sized, widely separated, each bearing four teeth; tongue discoidal, not notched posteriorly, covering entire floor of mouth, posterior fifth and lateral parts free.

Figure 4. 

Life holotype (MUSM 32733, adult male, SVL 25.7mm) of Pristimantis sinschi sp. nov. in dorsal (A), dorsolateral (B), ventral (C) and lateral (D) views. Photos by E. Lehr.

Skin on dorsum and flanks shagreen with many small conical tubercles, dorsolateral folds absent, a narrow, hairline mid-dorsal fold present from snout towards cloacal sheath; skin on throat, chest and belly areolate; discoidal and thoracic folds present, weakly defined; cloacal sheath short.

Outer ulnar surface with four (left side) and three (right side) minute low tubercles; palmar tubercle partially divided distally; thenar tubercle ovoid; subarticular tubercles well defined, round in ventral view, conical in lateral view; supernumerary tubercles distinct, ovoid, subconical, approximately half the size of subarticular tubercles; fingers with narrow lateral fringes, much broader at base of fingers; Finger I shorter than Finger II; discs on digits of fingers broadly expanded (about 1.5 times width of digit proximal to disc), elliptical (Fig. 5A).

Figure 5. 

Ventral views of hand (A) and foot (B) of holotype of Pristimantis sinschi sp. nov. Drawings by E. Lehr.

Hind limbs long, slender, tibia length 54% of SVL; foot length 51% of SVL; upper surfaces of hind limbs shagreen with many subconical tubercles; inner surface of thighs smooth, posterior and ventral surfaces of thighs areolate; heels without enlarged conical tubercles; outer surface of tarsus with scattered minute low tubercles; inner tarsal fold present, short and narrow, most distinct at its anterior third; inner metatarsal tubercle prominent, ovoid, three times the size of ovoid outer metatarsal tubercle; subarticular tubercles well defined, round in ventral view, conical in lateral view; plantar supernumerary tubercles distinct, about half the size of subarticular tubercles; toes with narrow lateral fringes; basal webbing absent; discs broadly expanded, elliptical, less expanded than those on fingers; relative length of toes: 1 < 2 < 3 < 5 < 4; disc on Toe III reaching distal subarticular tubercle on Toe IV, disc on Toe V extends distal subarticular tubercle on Toe IV (Fig. 5B).

In life (Fig. 4), dorsum brown with narrow reddish-brown mid-dorsal stripe and weakly-defined reddish-brown interorbital bar; scapular region with widely-separated narrow dark greyish-brown X-shape (Fig. 4B); upper lip with two greyish-brown subocular bars and a greyish-brown supratympanic bar (Fig. 4A); arms and hind legs brown with diagonal black bars, finger and toe discs pale salmon; lower half of flanks cream, upper half of flanks with irregular-shaped dark brown diagonal stripes (Fig. 4A, D), groin and axilla black with cream blotches, posterior surface of thighs black, anterior surface of thighs with diagonal black bars interspaced with pale brown bars; throat greyish-cream with black mottling, chest and belly cream and black mottled, ventral surfaces of thighs salmon and grey mottled, arms and hind legs black and pale grey mottled, with hand and feet surfaces pale grey with palmar and plantar tubercles salmon and discs of fingers I–II and discs of toes I–III salmon, other discs pale grey (Fig. 4C); iris pale bronze with fine black vermiculation and broad median red band through pupil and a narrow black vertical streak from pupil across lower half of iris (Fig. 4A).

In alcohol, general colouration pattern is as described for the holotype in life, except for brown which is pale brown, black which is dark brown, salmon which is cream and pale grey which is brown. Iris is pale grey.

Holotype measurements (in mm): SVL 25.7; TL 13.9; FL 13.0, HL 10.7; HW 11.2; ED 3.9; IOD 3.5; EW 3.0; IND 2.3; E-N 2.8.

All paratypes are similar to the holotype regarding morphology (see Table 3) and colouration pattern (Fig. 6). One specimen has a narrow tan mid-dorsal stripe from snout to cloaca (NMP-P6V 75060, Fig. 6D, E) and all specimens have short and narrow ridges on the anterior flanks (Fig. 6A, B, D, G). One uncollected specimen has a brownish-orange dorsal band (Fig. 6H) and the occipital region with prominent conical tubercles (Fig. 6G).

Figure 6. 

Variation of life male paratypes (A–F) and one uncollected specimen (G–I) of Pristimantis sinschi sp. nov. in dorsolateral, dorsal and ventral views A–C (MUSM 31165, SVL 25.8 mm) D–F (NMP-P6V 75060, SVL 28.8 mm) and G–I (uncollected). Photos by E. Lehr.

Pristimantis sinschi is known from two localities in montane forest of the Pui Pui Protected Forest and its close surroundings in the eastern Andes between 1615 and 1800 m a.s.l. in the Región Junín (Figs 3, 7). The type locality is a primary montane forest with dense vegetation including ferns, tree ferns and epiphytes (bromeliads, mosses). All three frogs were found at night on the vegetation between 80 and 250 cm above ground. The holotype was found on a leaf of a tree fern at 250 cm aboveground, NMP-P6V 75060 was found on a leaf at 150 cm aboveground and MUSM 31165 was found on a leaf at 80 cm aboveground. In the Pui Pui Protected Forest, Pristimantis sinschi occurs syntopically with P. albertus; P. ashaninka Lehr & Moravec, 2017; P. aniptopalmatus (Duellman & Hedges, 2005); P. bipunctatus (Duellman & Hedges, 2005); P. cruciocularis (Lehr, Lundberg, Aguilar & von May, 2006), P. cf. platydactylus (Boulenger, 1903), P. sagittulus and P. cf. stictogaster. According to the sparse data available, we here classify P. sinschi as “Data Deficient” according to the IUCN Red List criteria.

We dedicate this species to our colleague and friend Prof. Dr. Ulrich Sinsch in recognition of his important contributions to the South American and African herpetology. The specific epithet is used as a noun in apposition.

Figure 7. 

Collecting sites in montane forests of Pristimantis sinschi sp. nov. Type locality (A, B) in the close surrounding of the Pui Pui Protected Forest at 1800 m a.s.l. Second known locality (C) at the entrance of the Pui Pui Protected Forest at 1615 m a.s.l. Photos by J. Moravec (A, B) and E. Lehr (C).

Five males: MUSM 31953, 31956, 31959; NMP-P6V 75067, 76021 (NMP-P6V 76021 GenBank accession numbers MW075394 (16S rRNA) and MW075415 (12S rRNA)), from the Pui Pui Protected Forest (Rio Huatziroki valley, 11°07'37.2"S, 75°10'37.0"W; Fig. 3), 1970 m a.s.l., Distrito Pichanaqui, Provincia Chanchamayo, Región Junín, Peru, collected on 13–16 June 2013 by Edgar Lehr, Jiří Moravec, Juan Carlos Cusi and Rudolf von May. Three females: MUSM 31957; NMP-P6V 75068, 76020 (NMP-P6V 76020 GenBank accession numbers MW075393 (16S rRNA) and MW075414 (12S rRNA), same locality and collecting data as the males.

In general, the newly-collected and genetically-determined individuals of Pristimantis albertus correspond to the description of the type specimens. However, they differ in the following features: (1) discoidal fold is present, weakly defined (discoidal fold absent, according to Duellman and Hedges 2007); (2) dentigerous processes of vomers are present (absent, according to Duellman and Hedges 2007); (3) groin is orange in both sexes (Figs 8C, D, H, 9D, F), the orange colouration can continue to posterior parts of flanks and anterior parts of thighs, rarely the orange colouration is present in the axils (MUSM 31959).

Figure 8. 

Life colouration of female (A–D, IWU 237, SVL 24.2 mm) and male (E–H, NMP-P6V 75067, SVL 15.5 mm) Pristimantis albertus in dorsolateral (A, E), dorsal (B, F), ventral C, G) and lateral (D, H) views. Photos by E. Lehr.

(Table 4). The males are relatively small (SVL 12.9–19.5 mm, n = 5). All lack nuptial pads, but all have vocal slits, a distinct subgular vocal sack and, therefore, are regarded as adults. Females are represented by one adult (NMP-P6V 76020) and two subadult (MUSM 31957, NMP-P6V 75068) specimens. Snout-vent length of the adult female exceeds the size published for the type specimens (24.2 vs. 19.7–20.7 mm in Duellman and Hedges 2007).

(Fig. 9). The dorsal colouration resembles the colouration of the adult females. In one individual (MUSM 31956), the light brown colouration of the dorsum is sharply contrasting with the light tan flanks. The throat is brown with cream flecks, the belly is cream with brown mottling and the vocal sack is greenish-yellow.

Figure 9. 

Colouration in life variation of males of Pristimantis albertus A, B (MUSM 31956, SVL 13.7 mm) C, D (IWU 257, SVL 13.4 mm) E, F (MUSM 31959, SVL 12.9 mm). Photos by E. Lehr.

Our record of Pristimantis albertus from the PPPF lies ca. 65 km straight SE of the species type locality and represents the first record of this species for the Region Junín (Fig. 3).

One male: MUSM 31952, from the Pui Pui Protected Forest (Rio Huatziroki valley, 11°07'37.2"S, 75°10'37.0"W; Fig. 3), 1970 m a.s.l., Distrito Pichanaqui, Provincia Chanchamayo, Región Junín, Peru, collected on 14 June 2013 by Edgar Lehr, Jiří Moravec, Juan Carlos Cusi and Rudolf von May.

Our record of Pristimantis sagittulus from the PPPF lies ca. 65 km straight SE of the species type locality (Lehr et al. 2004) and represents the first record of this species for the Region Junín (Fig. 3).