Anomaloglossus

Remarks: Genus Anomaloglossus, recognized by the presence of a median lingual process (MLP), was described by Grant et al. (1997). Currently 28 species are known from the Guiana Shield and northern Amazon (Frost 2018). The seven trans-Andean species with MLP now belong to Ectopoglossus Grant, Rada, Anganoy-Criollo, Batista, Dias, Jeckel, Machado and Rueda-Almonacid, 2017.

Type species: Colostethus beebei Noble, 1923, by original designation.

Larval morphology. The following description is based on three tadpoles at stage 26, 28 and 30 (Fig. 6). Tadpoles correspond to a Type 4 tadpole of Orton (1953); exotrophic; body skin smooth; TL 12.21 – 19.43 mm; BL 4.41 – 7.14 mm, 35 – 37 % of TL, 164 – 181 % of BW, 221 – 256 % of BH; BW 131 – 143 % of BH (Table 3); body ovoid, snout round in dorsal and lateral view; eyes positioned and directed laterally; ED 0.48 – 0.63 mm, 45 – 98 % of IOD; IOD equal to IND; nares frontally positioned and directed laterodorsally; narial opening reniform in lateral view; END 0.34 – 0.73 mm. Spiracular tube sinistral, conical, projecting posterodorsally, its tip located at 60 – 63 % of BL posteriorly to snout. Lateral-line system inconspicuous. Caudal musculature highest at its base, tapering posteriorly, terminating at tail tip; tail tip rounded; upper fin originating at junction of body and tail, gradually increasing in height to about 3 / 4 of tail; UTF 28 – 53 % of TMH; LTF 38 – 55 % of TMH; MTH 14 – 17 % of TL (Fig. 6, Table 3). Mouth ventral, oral disc strongly emarginated, width 1.90 mm. Labial teeth long, in single rows, LTRF 2 (2) / 3. A- 2 consisting of two short rows, separated by a large and deep gap; P- 1 not interrupted. Marginal papillae long, of equal size on each labium, tapered, blunt-tipped, in a single row, evenly distributed; median gap on upper labium approximately 2 / 3 the length of A- 1; jaw sheaths large, serrated, lower jaw sheath broadly V-shaped. In life, the entire body is dark grey with abundant golden flecks, particularly on dorsum. Golden flecks become scarce ventrally. Posteriorly, dark grey coloration fades and tail becomes translucent. Tadpoles of Anomaloglossus mitaraka can be distinguished from those of any other described Anomaloglossus of the stepheni group (A. stepheni and A. baeobatrachus - this study) by the presence of a functional mouth with marginal papillae and labial teeth.

Morphological comparisons with other Anomaloglossus. The only other species group co-occurring with the Anomaloglossus stepheni group is the A. degranvillei group, represented by A. blanci, A. degranvillei, A. dewynteri and A. surinamensis, which are readily distinguishable by their moderate webbing (basal in A. mitaraka) and well-developed fringes on all toes (smaller and more developed on Toe II, III, IV) and the absence of a dorsolateral stripe (present). Outside these two groups all the other described Anomaloglossus species exclusively occur in Pantepui (i. e., the Guiana Shield highlands, see Kok et al. 2018) and have moderate to extensive toe webbing except A. meansi Kok, Nicolaï, Lathrop & MacCulloch, 2018, A. kaiei (Kok, Sambhu, Roopsind, Lenglet & Bourne, 2006), A. rufulus (Gorzula, 1990) and A. roraima (La Marca, 1997). However, unlike A. mitaraka, A. meansi lacks a conspicuous dorsolateral stripe, Finger III in males of A. kaei is not distinctly swollen, A. rufulus has as an extensively spotted ventral face, and A. roraima lacks well-developed fringes. Within the Anomaloglossus stepheni group, A. mitaraka can be distinguished from its probable sister species (Fouquet et al. 2019) A. leopardus (Figs. 2 – 3) by (1) narrower dark brown bars on legs vs large and more conspicuous dark transverse bars on legs in A. leopardus; (3) ventral coloration with orange restricted to the posterior part in males in A. mitaraka vs. generally entirely yellow in A. leopardus; (4) dorsolateral line thin in A. mitaraka vs. thick and well defined in A. leopardus; (5) advertisement call with a slower note rate (mean = 11.43, range 10.8 – 12.3 note / s in A. mitaraka [n = 6] vs. mean = 13.4, range 12.9 – 13.6 notes / s in A. leopardus [n = 4]) (Table 2). Anomaloglossus mitaraka can be distinguished from A. stepheni (Figs. 2 – 3, Table 1) by (1) a larger body size (mean = 18.6; range 18.2 – 19.3 mm in males [n = 7] and mean = 20.1; range 19.2 – 21.0 mm in females [n = 3] in A. mitaraka vs. mean = 17.15, range 16.5 – 18.0 mm in males [n = 10] and mean = 17.3, range 17.0 – 18.0 mm in females [n = 5] [from Martins 1989] in A. stepheni); (2) skin of dorsum with scattered tubercules in A. mitaraka vs. evenly tuberculate in A. stepheni; (3) orange ventral coloration posteriorly and laterally in males of A. mitaraka vs. entirely translucent white in A. stepheni; (4) dorsolateral line thin but well defined and continuous in A. mitaraka vs. thick and ill-defined dorsally in A. stepheni; (5) advertisement call much longer (mean = 1.04 s, range 0.74 – 1.23 s in A. mitaraka [n = 6] vs. mean = 0.25 s, range 0.18 – 0.29 s in A. stepheni [n = 4]), emitted at a slower pace (call rate mean = 0.43, range 0.32 – 0.52 calls / s in A. mitaraka [n = 6] vs. mean = 1.40, range 1.10 – 1.89 calls / s in A. stepheni [n = 4]) (Table 2). Anomaloglossus mitaraka can be distinguished from A. baeobatrachus by (1) a larger body size (mean = 18.6; range 18.2 – 19.3 mm in males [n = 7] and mean = 20.1; range 19.2 – 21.0 mm in females [n = 3] in A. mitaraka vs. mean = 16.2; range 14.8 – 17.1 mm in males [n = 16] and mean = 18.4; range 17.3 – 19.4 mm in females [n = 4] in A. baeobatrachus); (2) ventral coloration posteriorly and laterally in males in A. mitaraka vs. yellow and less extensive in A. baeobatrachus; (3) dorsolateral line thin but well defined and solid in A. mitaraka vs. narrower and interrupted in A. baeobatrachus; (4) call with lower note rate (mean = 11.43 notes / s, range 10.83 – 12.28 in A. mitaraka [n = 6] vs. mean = 16.10, range 15.62 – 16.85 s in A. baeobatrachus [n = 9]) lower dominant frequency (mean = 4.44, range 4.13 – 4.76 kHz in A. mitaraka [n = 6] vs. mean = 5.39, range 4.96 – 5.59 kHz in A. baeobatrachus [n = 9]) (Table 2). Description of the holotype. An adult male, 18.6 mm SVL; body robust; head wider than long, HL 94 % of HW; HL 33 % of SVL; dorsal skin tuberculate, one enlarged tubercle on each eyelid, snout long (SL 52 % of HL), rounded to nearly truncate in dorsal view, protruding in lateral view, extending past lower jaw. Nares located anterolaterally; canthus rostralis rounded, loreal region concave; IN 39 % of HW; EN 29 % of HL, 75 % of ED. Tympanum distinct anteroventrally; supratympanic fold inconspicuous; choanae small, circular, located anterolaterally (Figs. 2 – 3). Forelimb slender, skin tuberculate; metacarpal ridge present; HAND 24 % of SVL; Finger I longer than Finger II when fingers adpressed; fingers large and flattened; webbings absent on fingers; lateral fringes present on preaxial edges of Finger II; Finger III distinctly swollen dorsally and preaxially; tip of Finger IV not reaching distal subarticular tubercle on Finger III when fingers adpressed; finger discs expanded, wider than long, about 1.5 times width of digit; width of disc on Finger III 0.6 mm; discs with distinct dorsal scutes. Relative lengths of adpressed fingers III> IV> I> II; palmar tubercle large, heart-shaped, 0.8 mm in diameter (larger than Finger’s III disc), thenar tubercle elliptic, small (equal to Finger III’s disc in maximum diameter), elliptic, half the size of palmar tubercle, well separated from palmar tubercle. Only basal subarticular tubercles on Fingers are conspicuous; subarticular tubercles on fingers I and II the largest, followed by Finger IV’s subarticular tubercles and basal subarticular tubercle on Finger III. Hind limb robust, skin tuberculate; TL 47 % of SVL; heels in contact when hind limbs are flexed at right angles to the sagittal plane of body; FL 42 % of SVL; relative length of adpressed toes IV> III> V> II> I; Toe I very short, its tip reaching the base of subarticular tubercle on Toe II when toes adpressed; toe discs larger than width of toes. Width of disc on Toe IV 0.7 mm. Foot basally webbed; lateral fringes present on all toes. Toe webbing formula I 1 + – 1 - II 1 + – 1 - III 1 + – 1 + IV 0 – 1 + V. One to three subarticular tubercles on toes as follows: one on Toes I and II, two on Toes III and V, three on Toe IV. Inner metatarsal tubercle protuberant elliptical, 0.5 mm in length, outer metatarsal tubercle round, protuberant, 0.3 mm in diameter. Tarsal keel well defined, tubercle-like and strongly curved at proximal end. Metatarsal fold strong. Color of holotype in life. Dorsal color uniformly dark brown. Dorsolateral stripe thin, continuous, bluish white (yellow near groin) (Fig. 2). Dark brown lateral band extending from tip of snout to the groin and containing the indistinct dorsal part of tympanum, tapering posteriorly. Upper lip with small white blotches. Lower flanks pale white anteriorly and orange posteriorly with small white blotches. Throat white covered with melanophores, more densely anterolaterally; belly anteriorly white, white laterally, orange posteriorly, ventral surfaces of thighs and arms orange. Iris with coper metallic pigmentation and pupil ring interrupted dorsally and ventrally by transversal pigmentation (Fig. 2). Upper and lower arm pale red dorsally, light brown with small dark brown spots elsewhere. Dorsal surfaces of thigh, shank and tarsus brown with dark brown transverse bars and ill-defined blotches. Paracloacal marks orangish, elongated anteroposteriorly. Toes and digits with small light blue dots dorsally and laterally. Palms and soles dark brown. Color of holotype in preservative. After three years in 70 % ethanol, some colors of the specimen faded and the dorsal coloration now varies from brown to grey with interorbital, mid-dorsal and sacral dark brown blotches and the orangish ventral coloration disappeared (Fig. 3). Bluish freckles and orange and reddish marks turned cream.

Distribution and natural history. Anomaloglossus mitaraka is a diurnal species inhabiting the leaf litter in primary forest at low to mid elevations (from 150 to 500 m a. s. l.). The species is usually found close to streams next to which it deposits its exotrophic tadpoles into puddles, but some specimens can be found more than 50 m from water bodies. Males call all day long when the weather is rainy. Breeding occurs during the rainy season, between January and May. The males respond to intraspecific playbacks with shorter and more rapidly emitted note trills. Males are territorial, their small territories being spaced at least a few meters apart. Males usually call slightly above the leaf litter, exposed on a branch or a dead leaf. Eggs are deposited in the fold of a dead leaf (a single observation). This clutch was raised (Fig. 6) and some tadpoles were genotyped. Populations have been documented in southwestern French Guiana and adjacent Suriname (Mitaraka massif, Pic Coudreau, Haute Marwini, upper Tapanahony; Fig. 1). It also likely occurs in adjacent Brazil and may occupy similar habitats in other regions of Suriname.

Etymology. The specific epithet is a noun in apposition and refers to the type locality (Mitaraka, French Guiana). Definition. (1) Medium-sized Anomaloglossus (average male SVL 18.6 mm [18.2 – 19.3, n = 7], female SVL 20.1 mm [19.2 – 21.0, n = 3]) (Table 1); (2) body robust; (3) skin on dorsum with irregularly scattered tubercles becoming denser on the posterior half and legs, with a larger tubercle on each eyelid, ventral skin smooth; (4) inconspicuous supratympanic fold; (5) tympanum distinct anteroventrally; (6) snout short and protruding in lateral view; (7) nares oriented ventrolaterally, situated near tip of snout; (8) Finger II equal to Finger I when fingers adpressed; (9) tip of Finger IV not reaching distal subarticular tubercle on Finger III when fingers adpressed; (10) distal subarticular tubercle distinct on Finger III, absent on the other fingers; (11) Finger III swollen dorsally and preaxially, extending largely towards dorsal surface of hand in males; (12) fringes present on all fingers particularly developed preaxially on Finger II in males and females; (13) toes basally webbed, with well-developed fringes on all toes, more developed preaxially on Toe II, and pre- and postaxially on toes III and IV (sensu Grant et al. 2006; keel-like lateral folds sensu Myers & Donnelly 2008); (14) tarsal keel well-defined, curved; (15) black arm gland at the junction with wrist in males (sensu Grant & Castro 1998, see also Grant et al. 2006); (16) cloacal tubercles present; (17) paracloacal mark present (orangish in life, cream in preservative); (18) pale dorsolateral stripe present, solid (white to orangish anteriorly, yellow posteriorly in life, white in preservative), flanks and dorsum uniformly dark brown in males, reddish brown with dark brown blotches in females in life; (19) ventrolateral stripe absent; (20) sexual dichromatism in throat color pattern present in life, sometimes anteriorly yellow in males with sparse black melanophores, evenly and entirely yellow in females; (21) sexual dichromatism in ventral color pattern present, abdomen mostly cream, posteriorly and laterally yellow in males, uniformly bright yellow in females in life; (22) iris with metallic pigmentation and pupil ring interrupted ventrally and dorsally by transversal black pigmentation; (23) median lingual process as long as wide, tapered, bluntly pointed, smooth (non-papillate), reclined in pit; (24) a 0.74 – 1.23 s length call consisting of a train of 8 – 16 notes of 0.028 – 0.036 s in length and spaced by intervals of 0.051 – 0.068 s and of dominant frequency at 4.13 – 4.76 kHz (n = 6); (25) tadpole of type 4 (Orton 1953), exotrophic, with a functional mouth with marginal papillae and labial teeth (Fig. 4; Table 2).

Holotype. MNHN 2018.64 (field n ° AF 2814), an adult male, collected by A. Fouquet and M. Dewynter, 24 February 2015, Mitaraka, French Guiana, 2.23577 ° N 54.44928 ° W, ~ 150 m elevation (Figs. 2 – 3). Paratopotypes. Nine specimens: MNHN 2018.65 – 70 (field n ° AF 2732, 2750 - 1, 2754, 2808, 2878) six adult males and MNHN 2018.71 – 73 (field n ° AF 2724, 2731, 2824) three females collected with the holotype by A. Fouquet and M. Dewynter.

Variation among type specimens. Measurements (range, mean, and standard deviation) of the type series are provided in Table 1. Coloration of limbs varies from brown to reddish brown, females being paler and with more conspicuous dark dorsal blotches. Colour of dorsolateral line varies from white to orangish. Overall dorsal and lateral coloration and tuberculation may vary with light intensity, time of the day and probably reproductive activity as males carrying tadpoles apparently display overall lighter colors, smoother skin and sharper contrasts, whereas calling males are very dark and highly tuberculate. Ventral coloration of female is entirely orangish while the orangish parts are limited in various extent to the posterior region and throat in males. Vocal sac, slits and small dark melanophores on throat only observed in males as well as swelling on the Finger III. Advertisement call. Six specimens (one uncollected) calling from the leaf litter were recorded from a distance of about 1 m and at temperatures ranging from 23 to 26 ° C. Descriptive statistics of call parameters are presented in Table 2. Anomaloglossus mitaraka emits trains (call length mean = 1.04 s; range 0.74 – 1.23 s) of short notes (note length mean = 0.030 s; range 0.028 – 0.036 s; inter-note interval mean = 0.060 s; range 0.051 – 0.068 s). The spectral structure of the note has a developed harmonic structure and the dominant frequency is 4.44 kHz on average (range 4.13 – 4.76 kHz) with a slight upward modulation (ca. 0.2 kHz) (Fig. 4, Table 2).

We first present a focussed comparison between the new species and the ten Anomaloglossus species known to occur in the Eastern Pantepui District (i. e. east of the Rio Caroní). The Rio Caroní likely acts as a biogeographic barrier for Anomaloglossus species since no species has been reported to occur on both sides of the river in the Guiana highlands of Venezuela and Guyana (it must be noted that very few Pantepui anurans are known to occur on both sides of the river). But, in order to provide a more comprehensive comparison, we also compared the new species with the six known Anomaloglossus species that occur in the Western Pantepui District (i. e. west of the Rio Caroní) in the Guiana highlands of Venezuela.

Among the Western Pantepui Anomaloglossus species, A. ayarzaguenai (La Marca, 1998) and A. moffetti Barrio-Amorós and Brewer-Carías, 2008 are the geographically closest species to A. megacephalus (ca. 400 km airline to the west). Anomaloglossus ayarzaguenai and A. moffetti are very similar to each other, geographically close (from Cerro Jaua and Cerro Sarisariñama, respectively) and possible synonyms (Kok & Barrio-Amorós unpubl. data). Anomaloglossus megacephalus is distinguished from A. ayarzaguenai and A. moffetti in having a comparatively longer snout, and a larger, somewhat more massive head [compare Figs. 1 and 2 B with fig. 4 a – c illustrating A. moffetti in Barrio-Amorós & Brewer-Carías (2008)], in having a distinct tympanum in life (barely distinct in A. ayarzaguenai and A. moffetti), separated from eye by 42 – 60 % of its greatest length (25 % or less in A. ayarzaguenai and A. moffetti), and in lacking a dark area spotted with white ventrolaterally at the level of arm insertion (always present in A. ayarzaguenai and A. moffetti).