Ranitomeya aquamarina Mônico, Koch, Dayrell, Moravec & Lima, 2025, sp. nov.
Creators: name: Mônico, Alexander Tamanini
name: Koch, Esteban Diego
name: Dayrell, Jussara Santos
name: Moravec, Jiří
name: Lima, Albertina Pimentel
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Amphibia
Anura
Dendrobatidae
Ranitomeya
Ranitomeya aquamarina

description: Ranitomeya aquamarina sp. nov.
Figs 2, 3, 4, 6, 7, 8, 10, Tables 2, 3, 4
Chresonymy.
Ranitomeya sp. Envira – Twomey et al. (2023); Ranitomeya aff. sirensis – Lima et al. (2024).
Vernacular names.
Suggested English name: Metallic poison frog.
Suggested Spanish name: Rana venenosa metálica.
Suggested Portuguese name: Rãzinha-venenosa-metalizada.
Type material.
Holotype. • INPA-H 47568 (field number APL 24805; Fig. 2), adult male collected by Alexander Tamanini Mônico and Albertina Pimentel Lima on 15 March 2024, from RAPELD sampling module of the Eiru River, tributary of the Juruá River, municipality of Eirunepé, Amazonas state, Brazil (6°47'04.9"S, 69°52'00.3"W, WGS 84, 137 m elevation). Paratypes. Twelve adult specimens (7 males and 5 females), same locality as holotype • one male [INPA-H 47561; field number APL 24481] collected on 26 February 2023 by A. P. Lima • 3 males [INPA-H 47563, INPA-H 47564 and MPEG 45220; field numbers APL 24765, 24766 and 24768, respectively] and 3 females [INPA-H 47562, INPA-H 47565 and MPEG 45221; field numbers APL 24764, 247667 and 24769, respectively] collected on 24 March 2023 by A. P. Lima and J. Dayrell • 3 males [INPA-H 47566, MPEG 45223 and INPA-H 47570; field numbers APL 24800, 24808 and 24809, respectively] and 2 females [INPA-H 47569 and MPEG 45222; field numbers APL 24806 and 24807, respectively) collected on 14–15 March 2024 by A. T. Mônico and A. P. Lima.
Generic placement.
We assign the new species to Ranitomeya, based on the phylogenetic placement (Fig. 1) and the following external characteristics: coloration is bright and aposematic, finger I is greatly reduced and shorter than finger II, finger discs two and four are greatly expanded, dorsal skin texture is smooth (to shagreen), and toe webbing is absent (see Brown et al. 2011; Kahn et al. 2016).
Characterization.
This new species of Ranitomeya is characterized by the following combination of characters: (1) dorsal color jet black with three parallel stripes metallic light yellowish green to metallic light turquoise-green, mid-dorsal stripe extending from between eyes to slightly before the vent, dorsolateral stripes extending from the snout to the groin, where they become medium sulfur yellow; (2) venter jet black with metallic olive-yellow to metallic light yellowish green reticulations on belly, and gular region metallic light yellowish green to olive-yellow; ventrolateral stripes light yellowish green; extending from through the loreal region, to the thighs integrating into the ventral reticulate pattern, becoming medium sulfur yellow on the arms; (3) limbs medium metallic chrome orange with dark carmine spotting, presence of a conspicuous sulfur yellow spot on the dorsal surface of the thighs, forming an ‘ ocellus’ like pattern; (4) dorsal skin shagreen to granular, and smooth on head; (5) gular and ventral skin shagreen to granular; (6) limbs smooth to shagreen; (7) SVL in adult males of 15.4–17.7 mm (n = 8) and in females of 17.3–18.5 mm (n = 5); (8) sexual dimorphism, females with greater SVL, BW and KK; presence of vocal slits in males, located near jaw articulation; (9) head width 0.8–1.0 × body width; (10) head width 1.1–1.2 × larger than head length; (11) head width 31–34 % of SVL; (12) snout moderately long (SL 36–42 % of HL), rounded in dorsal view and rounded to protruding in lateral view; (13) canthus rostralis rounded, loreal region flat; (14) nostril directed frontolaterally at the angle of the snout, internarial distance 33–39 % of head width; (15) tympanum visible, tympanic membrane poorly differentiated, tympanum diameter 38–48 % of eye diameter; (16) tongue ovoid, attached anteriorly; (17) dentigerous processes of vomers absent; (18) choanae ovoid and small, located marginally in the maxilla; (19) hand 24–28 % of SVL, arm 25–30 % of SVL; (20) fingers III> IV> II> I, Finger I 58–68 % of Finger II, finger discs rounded on Finger I, and expanded and truncate on fingers III and IV; (21) thenar tubercle elliptical, palmar tubercle large and ovoid; (22) proximal subarticular tubercles ovoid, present in each finger; distal subarticular tubercle present only on Finger III; (23) knee-knee distance 80–84 % of SVL, femur 94–98 % of tibia; (24) toes IV> III> V> II> I, Toe I 48–64 % of Toe II, finger discs not expanded and rounded on Finger I to elliptical on toes III and IV and truncate on Finger V; (25) outer metatarsal tubercle ovoid, poorly visible; inner metatarsal tubercle elliptical; (26) proximal subarticular tubercles ovoid on all toes, distal subarticular tubercles on toes III – V; (27) advertisement call with 21–45 notes and average call duration of 647–1,424 ms, note rate (28–36 notes / s) and dominant frequency of 4,996 –6,288 Hz; and (28) tadpole head translucent in life, and posterior tooth rows P- 1> P- 2> P- 3.
Differential diagnosis.
External morphology. The new species differs from all currently recognized Ranitomeya species (R. amazonica, R. benedicta, R. cyanovittata, R. defleri, R. fantastica, R. flavovittata, R. imitator, R. reticulata, R. sirensis, R. summersi, R. toraro, R. uakarii, R. vanzolinii, R. variabilis, R. ventrimaculata, and R. yavaricola) by its unique coloration (light yellowish green to light metallic turquoise-green dorsal stripe pattern, medium metallic chrome orange limbs with dark carmine spotting, and conspicuous sulfur yellow ocellus-like spot on the dorsal surface of the thighs). Ranitomeya aquamarina sp. nov. is generally most similar to R. cyanovittata and R. yavaricola but it can be easily distinguished from R. cyanovittata by light yellowish green to light metallic turquoise green dorsal stripes and medium metallic chrome orange limbs with dark carmine spotting (dorsal stripes turquoise blue, limbs with bluish reticulation and black spots; Pérez-Peña et al. 2010) and from R. yavaricola by light yellowish green to light metallic turquoise green dorsal stripes with no or only minor breaks and by dark carmine spotting on the limbs (dorsal stripes sage color, formed by points, that can become dashes, limbs solid bronze; Pérez-Peña et al. 2010).
In addition, Ranitomeya aquamarina sp. nov. is distinguished by its smaller male SVL (15.4–17.7 mm) from R. fantastica (~ 20 mm; Boulenger 1884), R. imitator (~ 19 mm; Schulte 1986) and R. summersi (17.5–19.5 mm; Brown et al. 2008); and larger than R. cyanovittata (13.8 mm; Pérez-Peña et al. 2010), R. sirensis (14.7–15.4 mm; Aichinger 1991), R. toraro (14.8–15.6 mm; Brown et al. 2011) and R. uakari (14.8–15.5 mm; Brown et al. 2006); by its larger female SVL (17.3–18.5 mm) from R. sirensis (16.8 mm; Aichinger 1991), R. toraro (16.2–16.7 mm; Brown et al. 2011), R. uakari (15.7–16.2 mm; Brown et al. 2006); R. yavaricola (16.7–16.8 mm; Pérez-Peña et al. 2010); by its greater female head width (5.7–5.9 mm) from R. cyanovittata (5.6 mm; Pérez-Peña et al. 2010), R. sirensis (5.4 mm; Aichinger 1991), R. toraro (5.0– 5.3 mm; Brown et al. 2011), R. uakarii (5.0– 5.2 mm; Brown et al. 2006), R. yavaricola (5.1–5.7 mm; Pérez-Peña et al. 2010); by its greater male head length (4.8–5.4 mm) from R. cyanovittata (3.6 mm; Pérez-Peña et al. 2010) and R. sirensis (3.0– 3.8 mm; Aichinger 1991), but smaller than R. imitator (~ 6 mm) and R. yavaricola (5.5–6.6 mm; Pérez-Peña et al. 2010); by its smaller female head length (5.1–5.2 mm) from R. toraro (5.5 mm; Brown et al. 2011) and R. yavaricola (5.9–6.3 mm; Pérez-Peña et al. 2010) and larger than R. sirensis (4.0 mm; Aichinger 1991).
Bioacoustics. The advertisement call of R. aquamarina sp. nov. is distinguished by its longer call duration (647–1,424 ms) from the call of R. amazonica (160–360 ms; Brown et al. 2011), R. benedicta (100–170 ms; Brown et al. 2008), R. defleri (410–620 ms; Twomey and Brown 2009), R. fantastica (180–320 ms; Brown et al. 2011), R. reticulata (180–290 ms; Brown et al. 2011), R. summersi (380–500 ms; Brown et al. 2008), R. uakarii (260–290 ms; Brown et al. 2006, Brown et al. 2011), R. vanzolinii (570–640 ms; Brown et al. 2011), R. variabilis (140–440 ms; Brown et al. 2011) and R. ventrimaculata (320–380 ms; Brown et al. 2011). Furthermore, it differs by its higher dominant frequency (4,996 –6,288 Hz) from the calls of R. benedicta (3,190 –4,240 Hz; Brown et al. 2008), R. fantastica (2,950 –3,790 Hz; Brown et al. 2011), R. reticulata (4,140 –4,480 Hz; Brown et al. 2011), R. summersi (2760–3220 Hz; Brown et al. 2008), R. uakarii (3,790 –4,130 Hz; Brown et al. 2006, Brown et al. 2011), and R. ventrimaculata (4190–4400 Hz; Brown et al. 2011); by its lower number of notes (21–45) from the calls of R. reticulata (48–94; Brown et al. 2011) and R. ventrimaculata (58–63; Brown et al. 2011); by greater number of notes from the calls of R. fantastica (10–13; Brown et al. 2011), R. summersi (14–16; Brown et al. 2008), R. uakarii (14–16; Brown et al. 2006, Brown et al. 2011), and R. vanzolinii (16–17; Brown et al. 2011); by its smaller note rate (28–36 notes / s) from the calls of R. amazonica (85–138 notes / s; Brown et al. 2011), R. defleri (94–104 notes / s; Twomey and Brown 2009), R. fantastica (41–57 notes / s; Brown et al. 2011), R. reticulata (270–382 notes / s; Brown et al. 2011), R. summersi (39–40 notes / s; Brown et al. 2008), R. uakarii (50–58 notes / s; Brown et al. 2006; Brown et al. 2011), R. variabilis (106–297 notes / s; Brown et al. 2011), and R. ventrimaculata (166–181 notes / s; Brown et al. 2011).
The advertisement call of R. aquamarina sp. nov. is highly similar to the calls of all other species of the R. vanzolinii group, which have long-lasting trills, but it can still be distinguished from the call of R. vanzolinii, which has slightly lower note rate of 26–28 notes / s (Brown et al. 2011). On the other hand, based on the literature, the call of R. aquamarina sp. nov. is indistinguishable from the calls of R. flavovittata, R. imitator, R. sirensis, and R. yavaricola (Perez-Peña et al. 2010; Brown et al. 2011). There is no available information about minimum and maximum frequencies, note duration and inter-notes interval in these species. In addition, the calls of R. toraro and R. cyanovittata remain completely unknown.
Tadpole morphology. There is little information available about the tadpoles of the Ranitomeya species, but we did find information for ten species (R. amazonica, R. benedicta, R. defleri, R. flavovittata, R. imitator, R. reticulata, R. toraro, R. uakarii, R. vanzolinii and R. variabilis). The tadpoles of R. aquamarina sp. nov. differ from the tadpoles of all these species by absence of emarginate marginal papillae.
Because there is great variation between the initial (25–27), intermediate (28–32), and final (37–40) stages, we compared them using the ratios between measurements (the characteristics of compared species are given in parentheses). The labial tooth row formula in R. aquamarina sp. nov. is 2 (2) / 3 (1) in all stages and differs from the formula of R. toraro 2 (2) / 2 (1) (Brown et al. 2011). The ratios (in percentages) tail length / total length are in R. aquamarina sp. nov. (63 to 64 % in all stages) greater than in R. amazonica (45 % st. 29, Brown et al. 2011), R. flavovittata (57 % st. 26; Brown et al. 2011), R. imitator (62 % st. 26; Brown et al. 2011), R. reticulata (41 % st. 30; Brown et al. 2011), R. uakarii (62 %, st. 29; Brown et al. 2011) and R. variabilis (37 % st. 28; Brown et al. 2011), and smaller than in R. toraro (64.2 % st. 25; Brown et al. 2011), R. vanzolinii (67.9 % st. 38; Brown et al. 2011) and R. yavaricola (64.4 % st. 25; Pérez-Peña et al. 2010). The ratios oral disc width / body width are in R. aquamarina sp. nov. (42 % at stage 26, 36 % at stage 29, and 35 % at stage 39) greater than in R. amazonica (29 % st. 26, 22 % st. 29, 33 % st. 38; Brown et al. 2011, Klein et al. 2020), R. flavovittata (28 % st. 26; Brown et al. 2011), R. imitator (38 % st. 26; Brown et al. 2011), R. toraro (36 % st. 25; Brown et al. 2011), R. reticulata (14 % st. 30; Brown et al. 2011), R. uakarii (35 %, st. 29; Brown et al. 2011), and smaller than in R. vanzolinii (38.9 % st. 38; Brown et al. 2011).
The ratios tail muscle width / tail muscle height are in R. aquamarina sp. nov. (91 % at stage 26 and 115 % at stage 29) greater than in R. flavovittata (63 % st. 26; Brown et al. 2011), R. imitator (52 % st. 26; Brown et al. 2011), R. amazonica (76 % st. 29; Brown et al. 2011), R. reticulata (92 % st. 30; Brown et al. 2011), R. uakari (88 %, st. 29; Brown et al. 2011), and R. variabilis (72 % st. 30; Brown et al. 2011), and smaller than in R. toraro (100 % st. 25; Brown et al. 2011).
Posterior tooth row formula of R. aquamarina sp. nov. (P- 1> P- 2> P- 3 in all stages) differs from the formulas of all other described tadpoles: R. amazonica (P- 1 = P- 2> P- 3, P- 3 = 80 % of P- 1; Brown et al. 2011), R. benedicta (P- 1 = P- 2 = P- 3; Klein et al. 2020), R. flavovittata (P- 1 = P- 2> P- 3, P- 3 = 80 % of P- 1; Brown et al. 2011), R. imitator (P- 1 = P- 2> P- 3, P- 3 = 55 % of P- 1; Brown et al. 2011; Klein et al. 2020), R. reticulata (P- 1 = P- 2> P- 3, P- 3 = 80 % of P- 1; Brown et al. 2011; Klein et al. 2020), R. toraro (P- 1> P- 2; Brown et al. 2011), R. uakarii (P- 1 = P- 2> P- 3, P- 3 = 75 % of P- 1 and P- 2; Brown et al. 2011), R. vanzolinii (P- 1 <P- 2 = P- 3, P- 1 = 44.6 % of P- 2; Brown et al. 2011), R. variabilis (P- 1 = P- 2> P- 3, P- 3 = 75 % of P- 1; Brown et al. 2011) and R. yavaricola (P- 1 = P- 2> P- 3; Pérez-Peña et al. 2010).
In life, tadpoles of R. aquamarina sp. nov. have a translucent brownish head in all stages, which differs from all the other tadpoles described: R. amazonica (head and body black to gray; Brown et al. 2011, Klein et al. 2020), R. benedicta (head and body dark gray, with a reddish area anterior and posterior to the eye; Klein et al. 2020), R. imitator (head beige strongly dotted with yellowish green spots; Klein et al. 2020), R. reticulata (head and body gray; Brown et al. 2011), and R. toraro (head and body gray; Brown et al. 2011), R. uakari (head gray; Brown et al. 2011), R. vanzolinii (head and body dark gray to black; Klein et al. 2020), R. variabilis (head and body gray; Brown et al. 2011) and R. yavaricola (light grey; Pérez-Peña et al. 2010). When preserved, the tadpoles of R. aquamarina sp. nov. are cream with brown reticules on the lateral, dorsal, anterior half belly, spiracles, tail muscle and fins and differ from R. amazonica (dorsum dark gray and hindlimbs bluish gray, spotted with dark dots; Klein et al. 2020), R. benedicta (dorsum and hindlimbs dark gray; Klein et al. 2020), R. imitator (beige, densely spotted with gray dots; Klein et al. 2020) and R. vanzolinii (dorsum of body grayish brown, tail musculature light yellowish brown and fins translucent; Brown et al. 2011).
Holotype description.
Adult male (INPA-H 47568, field number APL 24805, Figs 2 – 4). SVL 17.1 mm; head width slightly smaller than body width; head width larger than head length; head width 30 % of SVL (Fig. 2 A, B). Snout rounded in dorsal view and rounded to protruding in lateral view (Fig. 2 C). Nostril directed frontolaterally at the angle of the snout, 1.0 mm from the tip of the snout; internarial distance 2.0 mm, 35.6 % of head width. Canthus rostralis rounded, loreal region flat. Eye-nostril distance 1.5 mm, 74.0 % of horizontal eye diameter. Tympanic annulus and tympanic membrane present. Tympanum slightly ovoid, posterodorsal margin hidden by depressor muscle, tympanum 44.4 % of eye diameter. Tongue ovoid, attached anteriorly, longer than wide, median lingual process absent. Dentigerous processes of vomers absent. Choanae ovoid and small (0.4 mm), located marginally in the maxilla, not visible in ventral view. Paired vocal slits present, located near jaw articulation.
Forelimbs slender, hands relatively large, 25.9 % of SVL. Finger I shorter (66.9 %) than Finger II; Finger III> IV> II> I. Discs on fingers III and IV considerably expanded and truncate, disc of Finger II moderately expanded and elliptical, disc of Finger I rounded. Ulnar tubercles absent. Hands lacking lateral fringes and webbing. Palmar tubercle rounded, unpigmented, ~ 4 × larger than the subarticulars. Thenar tubercle elliptical, small. Large unpigmented, rounded, proximal subarticular tubercles present on base of each finger. Rounded distal subarticular tubercle visible only on Finger III (Fig. 2 D).
Length of legs moderate, femur slightly smaller than tibia, with 93.7 % of the tibia length; knee-knee distance 80 % of SVL. Relative lengths of appressed toes IV> III> V> II> I. First toe short, Toe I disc not expanded and rounded, Toe II with slightly expanded and rounded disc, toes III – V with moderately expanded discs, III and IV elliptical, and V truncated. Tarsal tubercle absent; feet lacking webbing; lateral fringes poorly developed. Outer metatarsal tubercle ovoid, unpigmented, poorly visible. Inner metatarsal tubercle elliptical, unpigmented. Proximal subarticular tubercles present at base of each toe, large and ellipticals on toes I and II, small and rounded on toes III – V, all unpigmented. Distal subarticular tubercles large on toes III and V, and poorly distinguished on Toe IV. Two medial subarticular tubercles diffused on Toe IV (Fig. 2 E). Holotype measurements summarized in Table 2.
Skin texture nearly smooth to shagreen on head, becoming weakly granular on the dorsum and limbs. Ventral surface of limbs smooth to shagreen. Gular region and venter shagreen. Arms smooth to shagreen.
In life, dorsal surface jet black (color 300 by Köhler 2012) with three parallel metallic pale yellowish green stripes (color 100 by Köhler 2012) (Figs 3 B, 4 A), middorsal stripe extends from between the eyes to slightly before the vent. Dorsolateral stripes extend from the snout, where they merge, to the groin. Slightly before the groin, the dorsolateral stripes become metallic light sulfur yellow (color 93 by Köhler 2012), and merge with a medium sulfur yellow (color 94 by Köhler 2012) spot on the dorsal surface of the thigh. Ventrolateral stripes metallic light yellowish green (color 100 by Köhler 2012), extending through the loreal region, without touching the upper labium, to the thighs and integrating into the ventral reticulate pattern; its color leaks slightly on the arms, becoming medium sulfur yellow (color 94 by Köhler 2012) and integrating into the arms reticulate pattern. On the side of the head, the stripe does not reach the nostril, eye, and tympanum. Venter jet black (color 300 by Köhler 2012) with metallic olive-yellow (color 117 by Köhler 2012) to metallic light yellowish green (color 100 by Köhler 2012) reticulations on belly. Gular region fully metallic light yellowish green (color 100 by Köhler 2012; Fig. 3 B). Both forelimbs and hindlimbs medium metallic chrome orange (color 75 by Köhler 2012) with dark carmine spots (color 61 by Köhler 2012) in the ventral surface of the thighs proximal to the body. Iris jet black (color 300 by Köhler 2012).
After four months in alcohol, general color pattern remained, but colors faded (Fig. 2 A, B). Stripes and limb reticulations become pale cyan (color 157 by Köhler) and ventral surfaces cyan-white (color 156 by Köhler). Forelimb and hindlimb spots become raw umber (color 280 by Köhler 2012).
Variation.
SVL ranges from 15.4 to 17.7 mm in males (n = 7) and from 17.3 to 18.5 mm in females (n = 5) (Table 2). The dorsal stripe pattern is very consistent among individuals (Figs 3, 4). The middorsal stripe is complete and extends from between the eyes to slightly before the vent, except for one individual, where the stripe interrupted in the scapular region. Dorso-lateral stripes are complete and extend from eyes to the groin (Fig. 4), except for two individuals, where the stripes are interrupted in the arm region (unilaterally or bilaterally).
The head stripes have five patterns in the type series (Fig. 5). The basis is formed by three dots: one on the tip of the snout and another on the underside of each eye. These dots can be connected with the dorsal stripes. Three of the five patterns found do not have the dots connected with the middorsal stripe (Fig. 5 A – C), while the other two do (Fig. 5 D, E). The most common pattern presents the three unconnected dots (n = 53.8 %; Fig. 5 A), followed by the pattern of three dots connected with dorsolateral stripes forming a W-shape (Fig. 5 B) and three dots connected in the margin of the snout with one of the lateral dots connected with the mid-dorsal stripe (Fig. 5 D) (n = 15.4 % each). The less frequent patterns are formed by three dots connected at the margin of the snout (Fig. 5 C) or connected with the mid-dorsal stripe forming an O-shape (Fig. 5 E) (n = 7.7 % each).
The coloration of the stripes varies from metallic light yellowish green (color 100 by Köhler 2012) to metallic pale turquoise green (color 146 by Köhler 2012; Fig. 3). All individuals show a medium sulfur yellow (color 94 by Köhler 2012) spot in the dorsal surface of the thigh, well-defined in most of them (n = 84, 6 %; Fig. 3). Limb coloration is very constant, but the spots can vary in their size and quantity, going from denser, small, rounded spots to less dense large merging spots.
Advertisement call.
The advertisement call of Ranitomeya aquamarina sp. nov. (n = 7 males) consist of a long-lasting trill of 21–45 notes (n = 44 calls) — most commonly of 32–38 notes (n = 24 calls) — a call duration of 984 ± 197 ms (647–1,424 ms) — and silence between calls of 5.8– 115.3s (most commonly between 7 and 18 s) (n = 24 silence between calls). Notes are distinct, separated by silence intervals, with note duration of 11.7 ± 0.14 ms (9.6–14.8 ms), a silence between notes of 19.4 ± 0.2 ms (15.6–22.7 ms), and a note rate of 32.8 ± 2.2s (28–36). Calls are emitted with a minimum frequency (LF) of 5,139 ± 283 Hz (4,699 –5,860 Hz), a maximum frequency (HF) of 6,054 ± 255 Hz (5,545 –6,600 Hz) and a dominant frequency (DF) of 5,633 ± 289 Hz (4,996 –6,288 Hz) (Fig. 6). However, the first note is emitted at approximately 300 Hz – a lower frequency compared to the subsequent notes (LF of 4,921 ± 187 Hz, HF of 5,683 ± 211 Hz and a DF of 5,340 ± 202 Hz). Temporal and spectral traits, summarized according to individual call arrangement, are presented in Table 3.
Tadpole morphology.
Tadpole description is based on three specimens (vouchers INPA-H 47567) at Gosner (1960) stages 26, 29, and 39 (for measurements see Table 4). Since few tadpoles of Ranitomeya were described and each at a different stage, it is important to present the measurements for the three stages that were found (see Table 4).
Body shape in stage 26 ovoid in dorsal and lateral view (Fig. 7 A). In stages 29 and 39, depressed, broadly rounded to truncate each end of body (Fig. 7 B). Body length corresponds to 36.9 %, 36.4 %, and 36.3 % of the total length, respectively. Tail length 63 %, 64 %, and 63 % of the total length, respectively. Snout rounded in dorsal and lateral view in all stages (Fig. 7). Eyes positioned dorsally, directed dorsolaterally (Fig. 7), eye diameters stage 26 = 0.44 mm, stage 29 = 0.65 mm, and stage 39 = 0.88 mm (Table 4) correspond to 8.7 %, 9.0 %, and 9.6 % of body length, respectively. Nostrils small and elliptical, with slightly elevated marginal rim, located dorsally in the middle between the tip of snout and eyes, in all stages, directed antero-laterally, spiracle sinistral, opening dorsoposteriorly, located well below at the middle line of the body axis, length 10.2 %, 9.1 % and 8.9 % of body length, respectively. In all stages, the spiracle is visible dorsally, ventrally, and laterally (Fig. 7). Digestive tract dark, folded, occupies half of the belly, without visible organs. Dextral vent tube measures 0.5 mm at stage 26, 1.1 mm at stage 29, and partially absorbed at stage 39. Caudal musculature robust, tapering gradually, width at body-tail junction of 1.1 mm at stage 26, 1.9 mm at stage 29 and 2.1 mm at stage 39), tail muscle height of 1.2 mm, 1.6 mm, and 2.3 mm, respectively, not reaching the tail tip. Dorsal fin slightly higher than ventral fin, 54.7 % to 57.4 % of the height of the tail muscles, originating at posterior end of the body. Ventral fin 24.3 % to 26.4 % of tail width (Table 4). Tail tip ovoid.
Oral apparatus located antero-ventrally, not emarginated laterally. Transverse width of oral disc 42 % of body width at stage 26, 36 % at stage 29, and 35 % at stage 39, respectively. Lower and lateral labium free from body wall. Anterior labium with groups of five or six short elliptical papillae, distributed in a single row on each side of the lateral margins and split by a medial gap. Posterior labium with a single row of marginal short elliptical papillae in all stages. Jaw sheaths oval, upper jaw sheath slightly wider than lower jaw sheath, edges of both jaw sheaths serrated along their entire length. Labial tooth row formula 2 (2) / 3 (1) in all stages; tooth row A- 1 complete; tooth row A- 2 interrupted medially, consisting of two pieces of tooth of the same length, the medial gap broadly larger than tooth lines. Posterior tooth rows P- 1 slightly longer than P- 2, and P- 2 longer than P- 3 in all stages. P- 1 with medial gap, 0.1 mm, 0.3 mm, and 0.1 mm, respectively (in each stage).
After four months preserved in 10 % formalin, the tadpoles have a cream background color with brown reticulations on lateral, dorsal, anterior half of the belly, spiracles, tail muscle, and fins. Ventral fin less reticulated than dorsal fin (Fig. 7). The posterior half of the digestive tract is dark brown, iris black (Fig. 7).
In life, translucent head, eyes black, anterior portion of body gray in the middle and translucent on sides, posterior body portion gray. Tail musculature uniform gray, dorsal and ventral fins transparent Abdomen mostly transparent, digestive tract gray, heart visible (Fig. 8).
Etymology.
The specific epithet ‘ aquamarina ’ is a Latin adjective that means “ pale blue-green ”, referring to the coloration of the dorsal-lateral stripes of the new species. Another aspect that led us to use this epithet was the metallic blue and greenish tones of the stripes, which resemble seawater. Additionally, aquamarine is a gemstone, which philosophically conveys the value of this discovery.
Distribution, habitat, natural history, and conservation.
Ranitomeya aquamarina sp. nov. is only known from its type locality, in preserved forests on the Eiru River, a tributary of the Juruá River, near the Comunidade de Santo Antônio, municipality of Eirunepé, state of Amazonas, Brazil (Fig. 9). We sampled four RAPELD modules in the region, and the new species has only been recorded at one site. We did not find the new species living in sympatry with any other species of the genus. However, other Dendrobatoidea occur at the site: Allobates femoralis, Allobates sp. undescribed (A. P. Lima, unpublished data), Ameerega hahneli and A. trivittata.
Ranitomeya aquamarina sp. nov. is diurnal, showing greater activity in the early morning and late afternoon. On rainy days, activity lasts throughout the day. Most individuals were observed in clusters of ‘ banananeira brava ’ (Phenakospermum guyannense, Strelitziacaea; Fig. 10 A), but the species was also found in a phytotelma in the forest understory, ~ 3 m above the ground (Fig. 10 B). Individuals climb vertically through vegetation (Fig. 10 C) and are very agile.
Eggs are deposited in water accumulated in cavities in the vegetation. We found eggs (Fig. 10 D) and tadpoles in the ‘ banananeira brava ’ axils and in small holes in trees (Fig. 10 B). The eggs are small and brown, wrapped in a thick transparent gelatinous layer. Furthermore, we found tadpoles at different stages of development and metamorphizing in the same area, which suggests that reproduction is prolonged, probably occurring during the entire rain season. Juveniles (n = 5; not collected) and adults (n = 8) were seen foraging among the dry leaves of the same plants. In juveniles, dorsolateral stripes are uniformly yellow and are not fully formed (Fig. 10 E).
Males perform calling perched on vegetation (Fig. 10 F). They start calling at dawn (~ 6 am) and remain active until ~ 9 am, with a peak between 7 am and 8 am. After that, their activity remains sporadic until ~ 11 am. They call again in the late afternoon, but with a lower intensity. Most of the time, we observed adults as couples (n = 8; Fig. 10 G, H), which strongly suggests that the species is monogamous. Males appear to be territorial, responding to and approaching the playback. Additionally, when we captured the females, the respective males called incessantly.
The new species was found in only one of the four sampling sites (5 km RAPELD trails) and appears to be strongly associated with ‘ bananeira brava ’ plants. Therefore, this species is not expected to be abundant nor homogeneously distributed throughout its range. Its known extent of occurrence and area of occupancy are restricted, suggesting that its conservation status deserves attention. Nevertheless, we currently do not have enough information to assign Ranitomeya aquamarina sp. nov. to any IUCN category, and here we classify it as Data Deficient (DD).
description: Published as part of Mônico, Alexander Tamanini, Koch, Esteban Diego, Dayrell, Jussara Santos, Moravec, Jiří & Lima, Albertina Pimentel, 2025, An Amazonian hidden gem: a new metallic-colored species of Ranitomeya (Anura, Dendrobatidae) from Juruá River basin forests, Amazonas state, Brazil, pp. 51-83 in ZooKeys 1236 on pages 51-83, DOI: 10.3897/zookeys.1236.146533