Pristimantis achuar, Elmer, Kathryn R. & Cannatella, David C., 2008

Elmer, Kathryn R. & Cannatella, David C., 2008, Three new species of leaflitter frogs from the upper Amazon forests: cryptic diversity within Pristimantis “ ockendeni ” (Anura: Strabomantidae) in Ecuador, Zootaxa 1784, pp. 11-38 : 13-15

Pristimantis achuar sp. nov.

Figures 1–4 , 6.

Holotype. QCAZ 25463 (field number SC11438) an adult female collected at Kapawi Jungle Lodge, Pastaza province, Ecuador (S 02° 32.32, W 76° 51.50, altitude 239 m) on 24 June 2003 by KRE and I.G. Tapia.

Paratypes. (25 specimens: 10 males, 10 females, 5 juveniles) QCAZ 25454, 25456-63, 25490-92, 25523- 30, 25532, 25534, 25538, 25545, 25547, and tissues were collected at Kapawi Jungle Lodge (type locality) from 24–27 June 2003 by KRE and I.G. Tapia.

Referred specimen. QCAZ 25273 collected from Auca 14 Rd near Dayuma, Orellana province, Ecuador (S 00°41.85, W 76°43.79, altitude 255 m) on 20 March 2003 by KRE, P. Menéndez-Guerrero, and S. Padilla.

Etymology

This species is named for the Achuar indigenous nation of the upper Amazon basin, who are ardent protectors of their biodiversity and generously granted permission to KRE to sample frogs from their land at Kapawi Lodge. The epithet is a noun in apposition.

Diagnosis

(1) skin of dorsum smooth to finely shagreened with W-shaped occipital-scapular ridges; skin of venter areolate; discoidal folds absent; dorsolateral folds absent; (2) tympanum distinct, tympanic annulus barely or slightly discernable, approximately one-third eye width; (3) snout subacuminate (weakly pointed) in dorsal view, rounded in lateral profile, canthus rostralis from anterior corner of eye to nostril straight in profile, concave in dorsal view, sharply angled in cross-section; (4) upper eyelid bearing one or two low tubercles in some individuals; (5) odontophores weakly raised, oval, oblique; (6) males with moderately sized vocal slits, nuptial pads absent; (7) first finger shorter than second; all fingers bearing pads with circumferential grooves; discs slightly truncate, almost rounded, discs on fingers IV and III largest; (8) fingers fringed with blunt edges; (9) ulnar tubercles absent; (10) heel bearing two small subconical tubercles; inner tarsus tubercles absent; outer edge of tarsus bearing low tubercles in some specimens; (11) inner metatarsal tubercle elliptical, 4–5 times conical outer metatarsal tubercle; plantar supernumerary tubercles on finger I and II; (12) toes weakly fringed, webbing absent; toe V much longer than III; discs approximately equal size and shape as finger discs; (13) dorsum medium to dark brown, W-shaped scapular ridge, outer lines of W black, black dots at base in all; postsacral bar dark brown or black; posterior surface of thighs uniform brown; venter cream; (14) adults small size, males 14.3–16.6 mm, females 19.6–23.5 mm SVL (paratype series).

Description

Head slightly wider than body, approximately as long as wide; head width of females 36–39% SVL (x = 37%, N = 8), of males 34–39% SVL (x = 37% N = 9); snout subacuminate (weakly pointed) in dorsal view, in lateral profile rounded; upper jaw slightly overhanging lower jaw at anterior tip; snout of moderate length, eye-nostril distance of females 88–107% of eye width (x = 99%, N = 8), of males 68–103% (x = 87%, N = 9); canthus rostralis from anterior corner of eye to nostril straight in profile, canthus rostralis concave in dorsal view, sharply angled in cross-section; loreal region slightly concave, lips not flared; nostrils slightly protuberant, directed laterally with slight dorsal inclination; interorbital space flat; cranial crests absent, interorbital distance in females 52–62% of head width (x = 58%, N = 8), in males 52–60% (x = 56%, N = 9); temporal region vertical, sloping slightly laterally towards jaw; supratympanic ridge absent, postrictal tubercle present, in some specimens line of tubercles posterior to tympanum; tympanum visible, tympanic membrane distinct in most individuals, tympanic annulus barely or slightly discernible, in females tympanum width 34–44% of eye width (= 40%, N = 9), in males tympanum width 30–50% eye width (x = 37%, N = 9), size and shape not sexually dimorphic; distance from tympanum to eye less than diameter of tympanum; choanae mediumsized, round, well within borders of jaws; vomerine odontophores weakly raised, oval, and oblique (less raised in females), slightly smaller than and posterior to choanae, separated medially by approximately two times width of odontophore, females more teeth than males (female median 4 left/5 right, male median 1 left/ 1 right), teeth of males somewhat covered by mucosal tissue; tongue longer than wide, slight posterior notch, attached at front of mouth, posteriorly and laterally not adherent to floor of mouth; in males lateral vocal slits moderate sized, in some male specimens slightly distended subgular vocal sac visible. Nuptial pads absent.

Skin of dorsum smooth to finely shagreened; skin of venter areolate, skin of flanks shagreened; no discoidal fold (that can be discerned from preservation artefact); pair of W-shaped prominent ridges from posterior eyelid to scapular region, two scapular tubercles at posterior end of W; one or two low tubercles on mid-eyelids in some; two low tubercles on dorsum equidistant between posterior end of sacral vertebrae and vent, dark coloured bar in some (postsacral bar); tubercles on elbow absent or low, forearm smooth; palmar tubercle bifid, creased into thirds in some, wider than elongate thenar tubercle; palm bearing elongate tubercles smaller than subarticular tubercles; subarticular tubercles elliptical, supernumerary tubercles on finger I and II, distal subarticular tubercles flattened and rounded; proximal subarticular tubercles subconical; fingers bluntly fringed; all fingers bearing slightly truncate discs on pads, all pads wider than long, pads in decreasing order of size IV=III-II-I (barely wider than digit); decreasing finger length III-IV-II-I.

Heel bearing one or two small subconical tubercles; inner edge of tarsus lack tubercles, outer edge of tarsus low tubercles in some specimens; tarsal fold weak; inner metatarsal tubercle elliptical, 4–5 times longer than smaller and conical outer metatarsal tubercle; subarticular tubercles subconical; toes weakly fringed, lacking webbing; toe IV much longer than V; toe discs wider than long, approximately equal size and shape to finger discs, in order of descending size, IV=V-III-II-I; hindlimbs of moderate length, shank of female 53– 60% SVL (x = 57%, N = 8), of males 58–63% SVL (x = 61%, N = 9).

Colour in preservation

Central dorsum medium to dark brown, paler on flanks, diagonal brown stripes on flanks, thin white line extending from tip of snout to vent in one specimen; sacral chevron present in some, dark anal triangle present; scapular W-shaped ridge black in most, base of W with two black dots on each side separate or longitudinally joined; background colour of head and scapular region the same colour as dorsum in most specimens, with more grey or darker brown in some specimens, grey interorbital bar in one specimen; prominent dark labial bar at anterior margin of eye; less prominent labial bar at posterior margin of eye in some; eyelids dark grey; dark band at mid-forearm, upper arm lacking markings, elbow with dark spot; brown bands on thigh, shank, and tarsus; inner and posterior surfaces of thighs uniform brown; postsacral dorsal bar dark brown or black; discs of fingers and toes approximately same colour as remainder of digits; venter cream, small melanophores concentrated around jaw and flanks in some specimens; underside of thighs brown, paler line along mid-ventral region of thigh and shank due to absence of melanophores.

One specimen (QCAZ 25273) from Auca 14 Rd, Orellana province (approximately 200 km N of Kapawi Lodge) differs from the paratype series by having a darkened supratympanic ridge. Phylogenetic analysis of mtDNA cytochrome b and 16S has confirmed that this specimen is P. achuar ( Elmer et al. 2007b, see discussion below).

Colour in life

Dorsum pale, medium or dark brown, grey brown in some individuals, lighter coloured tinged either grey (e.g. QCAZ 25454) or reddish laterally (e.g. QCAZ 25547); some individuals with scattered cream flecks on dorsum (e.g. QCAZ 25456), some individuals with dark brown or light brown reticulate pattern or stripes on dorsum, some individuals with thin white snout-vent line (e.g. QCAZ 25526); outer lines of W almost invariably black, sometimes accompanied by a reddish line alongside the black (e.g. QCAZ 25454, 25456, 25524, 25528); yellow-orange patch at base of W in a few (e.g. QCAZ 25457, 25458, 25463, 25532); often lighter or darker patch from snout to top of head between eyes (e.g. QCAZ 25458, 25461, 25463, 25490, 25492, 25529) or from top of head between eyes to W (e.g. QCAZ 25491) some individuals with tan interorbital bar at top of head (e.g. 25526); venter cream, light speckling on throat and venter in some individuals, throat yellow in some males (e.g. QCAZ 25457, 25458, 25460, 25490, 25523, 25524, 25528, 25529, 25530, 25547). Colour of iris not noted.

Description of holotype

Measurements (in mm): 21.4 SVL, 12.4 tibia length, 16.1 foot length, 8.3 head width, 7.9 head length, 4.6 IOD, 2.9 END, 2.8 eye width, 1.2 tympanum. Colouration in preservation: light brown dorsum, outer arms of W thin black, two points at base of W are separate, tan coloured from the top of the head (between orbitals) to nose, lacking stripes and chevrons, dark bands on forearms, dark bar eye from anterior corner of eye to lip; very little speckling on throat. Colouration in life: “light brown dorsum; black W; orange mark at base of W; lighter from inter-orbital to nose; vague or absent stripes on body, some on legs”.

Molecular diversity

Cytochrome b DNA sequences examined for five paratype specimens (QCAZ 25457-25459, 25526, 25527) and the holotype are identical (one haplotype). rDNA 16S sequences for four paratypes (QCAZ 25457, 25462, 25492, 25527) are also identical (one haplotype). GenBank accession numbers (cytochrome b/ 16S): QCAZ 25457 EU 130668 / EU 130618 , QCAZ 25458 EU 130669 /, QCAZ 25459 EU 130670 /, QCAZ 25462 / EU 130619 , QCAZ 25492 / EU 130620 , QCAZ 25526 EU 130671 /, QCAZ 25527 EU 130672 / EU 130621 .

Natural History

Individuals were found in primary forest and presumably can also be found in secondary forest. By night they were often perched on the leaves of low vegetation from 0.2 to 1.3 m elevation. By day they were found in the leaflitter.

Figures

FIGURE 1. Photograph of P. achuar holotype (QCAZ 25463) in life.

FIGURE 2. Dorsal view of three paratypes of P. altamnis (top row; QCAZ 25313, 25302, 25304), P. kichwarum (middle row; QCAZ 25287, 27762, 25782), and P. achuar (bottom row; QCAZ 25538, 25490, 25491). Note the presence of a canthal stripe in P. kichwarum and its absence in P. altamnis and P. achuar.

FIGURE 3. Ventral view of three paratypes of P. altamnis (top row; QCAZ 25445, 25442, 25447), P. kichwarum (middle row; QCAZ 25287, 25558, 25759), and P. achuar (bottom row; QCAZ 25461, 25530, 25534). Note the difference in ventral colouration between the three species, with P. altamnis having the most dense flecking of melanophores and P. achuar having the palest venter.

FIGURE 4. Lateral view of specimens of P. kichwarum (QCAZ 18033), P. achuar (QCAZ 25463), and P. altamnis (QCAZ 25311). Note the presence of a canthal stripe and darkened supratympanic ridge in P. kichwarum and their absence in P. achuar and P. altamnis.