Anomaloglossus vacheri, Fouquet & Jairam & Ouboter & Kok, 2020

Fouquet, Antoine, Jairam, Rawien, Ouboter, Paul & Kok, Philippe J. R., 2020, Two new species of Anomaloglossus (Anura: Aromobatidae) of the stepheni group from Suriname, Zootaxa 4820 (1), pp. 147-164 : 156-160

Anomaloglossus vacheri sp. nov.

Anomaloglossus baeobatrachus Ouboter & Jairam 2012

Anomaloglossus sp. Bakhuis Vacher et al. 2017

Holotype. MNHN _RA_2019.0009 (field n°AF3413), an adult male, collected by A. Fouquet, S. Cally and R. Jairam on 30 April 2015 at Bakhuis Mountains , Suriname (4.72462 N 56.7638 W, ~ 200 m elevation; Figs. 2‒3 ; Ap-pendix 1).

Paratopotypes. Eight specimens: MNHN _RA_2019.0009‒11, 13‒15 (field n°AF3412, 3424, 3426, 3430, 3434) and NZCS-A1208‒9 (field n°AF3433, 3441) seven adult males and MNHN _RA_2019.0012 (field n° AF3425) one female collected with the holotype by A. Fouquet, S. Cally and R. Jairam .

Etymology. This species is dedicated to Jean-Pierre Vacher, in honour of his strong contribution to the understanding of the diversity and the evolution of the genus Anomaloglossus .

Definition. (1) Small-sized Anomaloglossus (average male SVL 17.4 mm [17.0–17.8, n = 8], female SVL 19.7 mm [n = 1]) ( Table 1); (2) body robust; (3) skin on dorsum finely granular with larger scattered tubercles becoming denser on the posterior half and legs, with a larger tubercle on each eyelid; (4) ventral skin smooth except under thighs, where it is finely granular; (5) inconspicuous supratympanic fold; (6) tympanum distinct anteroventrally; (7) snout long and protruding in lateral view; (8) nares oriented ventrolaterally, situated near tip of snout; (9) Finger II equal to Finger I when fingers adpressed; (10) tip of Finger IV not reaching distal subarticular tubercle on Finger III when fingers adpressed; (11) distal subarticular tubercle distinct on Finger III and IV, inconspicuous on the other fingers; (12) Finger III swollen dorsally and preaxially in males, extending largely towards dorsal surface of hand; (13) fringes present on all fingers, particularly developed post- and preaxially on Finger II and preaxially on Finger III, almost inconspicuous on Finger IV, in males and females; (14) toes basally webbed, with well-developed fringes on all toes, more developed preaxially on Toes II and III; (15) tarsal keel well-defined, strongly curved; (16) glandular supracarpal pad present in both sexes (larger and more glandular in males); (17) cloacal tubercles present; (18) paracloacal mark present (orangish in life, cream to grey in preservative); (19) dorsolateral stripe absent; (20) oblique lateral stripe present, diffuse (composed of yellow and white speckles), particularly diffuse anteriorly, extending along upper eyelid into a diffuse canthal stripe, lateral band uniformly dark brown/black in males and females in life, lower flank yellowish orange to grey with white speckles; (21) ventrolateral stripe absent; (22) dorsal surface of arms barely blotched in males, orange; (23) sexual dichromatism in throat colour pattern present, in life light grey in males with sparse minute black melanophores (chin often yellow), evenly and entirely yellow in females; (24) sexual dichromatism in ventral colour pattern present, in life abdomen entirely yellowish orange in males, uniformly yellowish orange in females; (25) iris with metallic pigmentation and pupil ring inconspicuously interrupted ventrally by transversal black pigmentation; (26) median lingual process as long as wide, tapered, bluntly pointed, smooth (non-papillate), reclined in pit; (27) call 0.47–0.91 s in length, consisting of a train of 8–18 notes of 0.019–0.021 s in length and spaced by intervals of 0.042 s with a dominant frequency at 5.11–5.35 kHz (n = 5; Table 2); (28) type 4 tadpole ( Orton 1953), exotrophic, with a functional mouth with marginal papillae and labial teeth ( Fig. 5 , Table 3).

Morphological comparisons with other Anomaloglossus . Like Anomaloglossus saramaka sp. nov., A. vacheri sp. nov. can be distinguished from species of the A. degranvillei group by its basal webbing (moderate in species of the A. degranvillei group), smaller fringes that are more developed on Toes II-IV (well-developed fringes on all toes) and the presence of a solid oblique lateral stripe (absence) and from all the other described Anomaloglossus species of the Pantepui region by the presence of an oblique lateral stripe.

Within the Anomaloglossus stepheni group (comparisons follow below), A. vacheri sp. nov. is morphologically most similar to A. baeobatrachus , A. leopardus , A. mitaraka and A. saramaka sp. nov. and can easily be confused with these species.

Anomaloglossus vacheri sp. nov. can mainly be distinguished from A. baeobatrachus by (1) oblique lateral stripe extending along upper eyelid into a canthal stripe in A. vacheri sp. nov. (oblique lateral stripe not extending along upper eyelid into a canthal stripe in A. baeobatrachus ); (2) dorsal surface of arms barely blotched and orange in males of A. vacheri sp. nov. (with dark brown blotches and light brown in A. baeobatrachus ); (3) ventral coloration yellowish orange in males in A. vacheri sp. nov. (white or only posteriorly yellow in A. baeobatrachus ); (4) call with higher note rate (mean = 18.2, range 17.3–19.2 note/s in A. vacheri sp. nov. [n = 8] vs mean = 16.2, range 15.6–16.8 note/s in A. baeobatrachus [n = 9]) ( Table 2).

Anomaloglossus vacheri sp. nov. can mainly be distinguished from A. leopardus by (1) narrow, poorly defined dark brown bars on legs (broad and conspicuous dark brown in A. leopardus ); (2) dorsal surface of arms barely blotched and orange in males of A. vacheri sp. nov. (light brown with dark brown blotches in A. leopardus ); (3) oblique lateral stripe extending along upper eyelid into a canthal stripe in A. vacheri sp. nov. (not extending along upper eyelid into a canthal stripe in A. leopardus ); (4) advertisement call shorter (mean = 0.63, range 0.47– 0.91 s in A. vacheri sp. nov. [n = 5] vs mean = 1.52, range 1.08– 2.00 s in A. leopardus [n = 4]) and higher in frequency (mean = 5.25, range 5.11–5.35 kHz in A. vacheri sp. nov. [n = 5] vs mean = 4.45, range 4.40–4.57 kHz in A. leopardus [n = 4]) ( Table 2).

Anomaloglossus vacheri sp. nov. can mainly be distinguished from A. mitaraka by (1) smaller male body size (mean = 17.4; range 17.0– 17.8 mm in males [n = 8] in A. vacheri sp. nov. vs mean = 18.6; range 18.2–19.3 mm in males [n = 7] in A. mitaraka ); (2) dorsal surface of arms barely blotched and orange in males of A. vacheri sp. nov. (with dark blotches and light brown in A. mitaraka ); (3) oblique lateral stripe extending along upper eyelid into a canthal stripe A. vacheri sp. nov. (not extending along upper eyelid into a canthal stripe in A. mitaraka ); (4) advertisement with a higher note rate (mean = 18.2, range 17.3–19.1 note/s in A. vacheri sp. nov. [n = 8] vs mean = 11.4 note/s, range 10.8–12.3 in A. mitaraka [n = 6]) and higher in frequency (mean = 5.25, range 5.11–5.35 kHz in A. vacheri sp. nov. [n = 5] vs mean = 4.43, range 4.12–4.76 kHz in A. mitaraka [n = 6]) ( Table 2).

Anomaloglossus vacheri sp. nov. can mainly be distinguished from A. saramaka sp. nov. by (1) smaller male body size (mean = 17.4; range 17.0– 17.8 mm in males [n = 8] in A. vacheri sp. nov. vs mean = 19.3; range 18.6–19.9 mm in males [n = 10] in A. saramaka sp. nov.); (2) dorsal surface of arms barely blotched and orange in males of A. vacheri (with dark blotches and light brown in A. saramaka sp. nov.); (3) oblique lateral stripe extending along upper eyelid into a canthal stripe in A. vacheri sp. nov. (not extending along upper eyelid into a canthal stripe in A. saramaka sp. nov.); (4) advertisement with a higher note rate (mean = 18.2, range 17.3–19.2 note/s in A. vacheri sp. nov. [n = 8] vs mean = 14.5 note/s, range 14.0– 15.3 in A. saramaka sp. nov. [n = 6]) and higher in frequency (mean = 5.25, range 5.11–5.35 kHz in A. vacheri sp. nov. [n = 5] vs mean = 4.84, range 4.55–5.02 kHz in A. saramaka sp. nov. [n = 6]) ( Table 2).

Anomaloglossus vacheri sp. nov. can be mainly distinguished from A. apiau by (1) solid oblique lateral stripe in A. vacheri sp. nov. (present as a series of conspicuous white dots extending from groin midway along flank in A. apiau ); (2) by its shorter call (mean = 0.63, range 0.47– 0.91 s in A. vacheri sp. nov. [n = 5] vs mean = 19.6, range 7.0– 39.4 s in A. apiau [n = 10]).

Anomaloglossus vacheri sp. nov. can mainly be distinguished from A. stepheni ( Figs. 2‒3 ) by (1) skin on dorsum finely granular in A. vacheri sp. nov. vs evenly tuberculate in A. stepheni ; (2) ventral colouration mostly yellowish orange in males in A. vacheri sp. nov. vs uniformly white in A. stepheni ; (3) oblique lateral stripe extending along upper eyelid into a canthal stripe in A. vacheri sp. nov. vs oblique lateral stripe not extending along upper eyelid into a canthal stripe in A. stepheni ; (4) advertisement call longer (mean = 0.63, range 0.47– 0.91 s in A. vacheri sp. nov. [n = 5] vs mean= 0.25 s, range 0.18– 0.29 s in A. stepheni [n = 4]), and higher in frequency (mean = 5.25, range 5.11–5.35 kHz in A. vacheri sp. nov. [n = 5] vs mean = 4.48, range 4.25–4.85 kHz in A. stepheni [n = 4]) ( Table 2).

Description of the holotype. An adult male, 17.5 mm SVL; body robust; head wider than long, HL 98 % of HW; HL 33 % of SVL; dorsal skin finely tuberculate with larger tubercles posteriorly, one enlarged tubercle on each eyelid, snout long (SL 51 % 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 41 % of HW; EN 30 % of HL, 77 % of ED. Tympanum distinct anteroventrally; supratympanic fold inconspicuous; choanae small, circular, located anterolaterally.

Forelimb slender, skin tuberculate; HAND 23 % of SVL; Finger I as long as Finger II when fingers adpressed; fingers large and flattened; webbing absent on fingers; lateral fringes present, particularly developed post and preaxially on Finger II and preaxially on Finger III; Finger III distinctly swollen dorsally and preaxially, swelling largely extending towards dorsal surface of hand; 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> II> I; palmar tubercle large, heart-shaped, 0.75 mm in diameter (larger than disc on Finger III), thenar tubercle elliptic, small (equal to disc on Finger III in maximum diameter), half the size of palmar tubercle, well separated from palmar tubercle; basal subarticular tubercles on fingers and distal subarticular tubercle of Finger III and IV conspicuous; subarticular tubercles on Fingers I and II the largest, followed by subarticular tubercles and basal subarticular tubercle on Finger III.

Hind limb robust, skin tuberculate; TL 48 % 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 0.8 mm. Foot basally webbed; lateral fringes present on all toes, more developed preaxially on Toes II and III. 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.

Colour of holotype in life. Dorsal colour light brown with dark brown blotches occurring on the interorbital region and at mid-body forming an hourglass pattern. Blotches of the same colour also occur laterally along the oblique lateral stripe. Oblique lateral stripe thin, diffuse (particularly anteriorly), formed by white and yellow speckles, extending along the upper eyelid into a diffuse canthal stripe ( Fig. 2 ). Dark brown lateral band below oblique lateral stripe, tapering posteriorly, extending from tip of snout to groin and containing the indistinct dorsal part of tympanum, tapering posteriorly. Upper lip grey with a few small white speckles. Lower flank (below dark brown lateral band) grey with white speckles. Throat light grey, chin yellowish orange, throat and chin covered with minute melanophores, more densely laterally; belly bright yellowish orange, ventral surfaces of thighs and arms yellowish orange. Iris with coper metallic pigmentation and pupil ring uninterrupted by transversal pigmentation ( Fig. 2 ).

Upper and lower arm light orange dorsally with a few white speckles. Black glandular spot at junction between lower arm and hand, followed by a grey coloured part of the swollen gland extending on Finger III. Dorsal surfaces of thigh, shank and tarsus light brown with ill-defined dark brown transverse bars and ill-defined dark brown blotches. Paracloacal marks light brown, elongate. Toes and digits with small light blueish speckles dorsally and laterally. Palms and soles dark brown.

Colour of holotype in preservative. After four years in 70 % ethanol, colours of the specimen faded and the dorsal colouration now varies from pale brown to grey with darker blotches, the yellowish orange ventral colouration faded to white ( Fig. 3 ). Bluish speckles and orange marks turned white as well.

Variation among type specimens. Measurements (range, mean, and standard deviation) of the type series are provided in Table 1. Colour of oblique lateral stripe varies in its proportion of white and yellow. Overall dorsal and lateral coloration and tuberculation may vary with light intensity, time of the day and probably reproductive activity as calling males are dark coloured and highly tuberculate. Dorsal dark brown hourglass pattern may be absent ( MNHN _RA_2019.0013, field n° AF3426; NZCS-A1208 , field n°AF3433). Paracloacal marks sometimes inconspicuous. Throat colouration of female is entirely yellowish orange while the yellowish orange parts are often limited to the chin in males (extent of coloured part of chin varies). Vocal sac, slits and minute black melanophores on throat only observed in males as well as swelling of Finger III .

Advertisement call. Five collected specimens calling from the leaf litter were recorded from a distance of about 2 m and at temperatures between 25‒26°C and 98% relative humidity. Descriptive statistics of call parameters are presented in Table 2. Anomaloglossus vacheri sp. nov. emits trains (call length mean = 0.63, range 0.47– 0.91 s) of 8–18 short notes (note length mean = 0.020 s; range 0.019 –0.021 s; inter-note interval mean = 0.039 s; range 0.036 –0.042 s). The spectral structure of the note has a developed harmonic structure and the dominant frequency is 5.25 kHz on average (range 5.11–5.35 kHz) with a slight upward modulation (ca. 0.4 kHz) ( Fig. 4 , Table 2).

Larval morphology. The following description is based on two tadpoles at stage 28 and 30 ( Fig. 5 ). Tadpoles correspond to a type 4 tadpole of Orton (1953); exotrophic; body skin smooth; TL 15.00– 19.06 mm; BL 5.27–6.46 mm, 34–35 % of TL, 151–160 % of BW, 261–267 % of BH; BW 135–144 % of BH ( Table 3); body ovoid, snout round in dorsal and lateral view; eyes positioned and directed laterally; ED 0.49–0.61 mm, 55–58 % of IOD; IOD smaller than IND; nares frontally positioned and directed laterodorsally; narial opening circular in lateral view; END 0.55–0.71 mm. Spiracular tube sinistral, conical, projecting posterodorsally, its tip located at 57–59 % 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 47–48 % of TMH; LTF 46–49 % of TMH; MTH 13–16 % of TL ( Fig. 5 , Table 3) .

Mouth ventral, oral disc strongly emarginated, width 1.27–1.89 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 body is dark grey with abundant golden flecks, particularly on dorsum, except the loreal and postocular regions that are pink. Golden flecks become scarce ventrally. Posteriorly, dark grey coloration fades and tail becomes translucent.

The tadpole of Anomaloglossus vacheri sp. nov. can be distinguished from those of Anomaloglossus of the stepheni group that are endotrophic ( A. stepheni and A. baeobatrachus ) by the presence of a functional mouth with marginal papillae and labial teeth. It can be distinguished from the tadpole of A. mitaraka and A. saramaka sp. nov. by its less dense pigmentation particularly ventrally and by a spiracle located more anteriorly.

Distribution and natural history. Anomaloglossus vacheri sp. nov. is a diurnal species inhabiting the leaf litter in primary forest at low elevation (200 m elevaion). The species has only been found in terra firme forest on lateritic crust distant from streams.

Males call after rainfall. Breeding apparently occurs during the rainy season, probably extending between December and July, depending on rainfall. The males respond to intraspecific playbacks with shorter and more rapidly emitted note trills. Males are spaced by at least five meters apart. They usually call slightly above the leaf litter, exposed on a branch or a dead leaf. Eggs are probably deposited under or in the fold of a dead leaf. After they hatch the male probably carries the tadpoles to small water bodies formed in the lateritic crust where tadpoles where found ( Fig. 5 ).

A single population is known to date, in Bakhuis Mountains, Suriname. The species likely occurs throughout the massif, but it unlikely extends much further since other species occur nearby ( A. leopardus , A. mitaraka , A. saramaka sp. nov.), and that other species of this group with exotrophic tadpole display a strong allopatric pattern of distribution.

Figures

FIGURE 2. Two males (top) and one female (bottom) of the two species described herein, Anomaloglossus saramaka sp. nov. and A. vacheri sp. nov., along with one male of the three additional species of the A. stepheni group occurring in Suriname.

FIGURE 3. Views of dorsum, venter, left hand, left foot of the holotype of A. saramaka sp. nov. (left) and of the holotype of A. vacheri sp. nov. (right).

FIGURE 4. Spectrograms and oscillograms of the advertisement calls of the two species described herein, Anomaloglossus saramaka sp. nov. and A. vacheri sp. nov., along with the calls of four additional described species of the A. stepheni group; in a 2 s time window (top) and a close-up in a 0.1 s time window (bottom).

FIGURE 5. The tadpole of Anomaloglossus saramaka sp. nov. and A. vacheri sp. nov., and pictures of habitat and males in situ. Top: ventral and lateral view of AF3865_B at Gosner stage 29, a close-up of the mouth, a male (MNHN_RA_2019.0029, field n°AF3897) carrying 9 tadpoles (note the shredding skin), and habitat where males deposit tadpoles during the wet season (here dry). Bottom: ventral and lateral view of AF3422_A at Gosner stage 30, a close-up of the mouth, a picture of the specimen in situ within a small cavity in the lateritic crust indicated by an arrow, and the calling male nearby on lateritic crust.