Elachistocleis muiraquitan, Nunes-De-Almeida, Carlos Henrique L. & Toledo, Luís Felipe, 2012

Nunes-De-Almeida, Carlos Henrique L. & Toledo, Luís Felipe, 2012, A new species of Elachistocleis Parker (Anura, Microhylidae) from the State of Acre, Northern Brazil, Zootaxa 3424, pp. 43-50 : 44-47

Elachistocleis muiraquitan sp. nov.

Holotype. BRAZIL: ACRE: Xapuri (10º39’07.00”S, 68º30’15.00”W; 172 m above sea level), ZUEC 5666, adult male, collected by A. J. Cardoso, M. Martins and J. Marinho, 12/22/1983 ( Fig. 1 ).

Paratopotypes. BRAZIL: ACRE: Xapuri: Males: ZUEC 5661 - 12/22/1983, ZUEC 5662 - 12/22/1983, ZUEC 5663 - 12/22/1983, ZUEC 5664 - 12/22/1983, ZUEC 5742 - 12/23/1983, ZUEC 5751 - 12/24/1983, ZUEC 5758 - 12/25/1983. Females: ZUEC 5657 - 12/22/1983, ZUEC 5658 - 12/22/1983, ZUEC 5659 - 12/22/1983, ZUEC 5660 - 12/22/1983, ZUEC 5665 - 12/22/1983, ZUEC 5667 - 12/22/1983, ZUEC 5743 - 12/23/1983.

Diagnosis. A small sized species (SVL 26.3–32.7 mm in adult males and 30.6–39.7 mm in adult females) characterized by the head length shorter than head width, HL about 84.7 % of HW; postcommisural gland poorly developed; dorsum smooth; in preservative uniformly dark brown with a thin middle longitudinal light stripe from the post-cephalic transverse skinfold to the vent, but absent on the head; venter immaculate; limit between the dorsal and ventral regions well defined; a broad irregular line on the posterior surface of the thighs; a large light spot on the proximal internal surface of tibiae; a narrow light stripe surrounding the knees and reaching the middle of the tarsus.

Comparisons with other species. For comparison between species we followed the taxonomic characters (external morphology and bioacoustics) currently used for the genus Elachistocleis (see Caramaschi 2010; Toledo 2010; Toledo et al. 2010). Elachistocleis muiraquitan distinguishes from E. bumbameuboi , E. carvalhoi , E. cesarii , E. erythrogaster Kwet and Di-Bernardo , E. magnus , E. piauiensis Caramaschi and Jim , E. skotogaster Lavilla, Vaira and Ferrari , E. surinamensis (Daudin) and E. surumu by presenting an immaculate venter (vs. spotted in the other species). This character did not show intraspecific variation in the examined specimens. From the only three species with immaculate venter, E. matogrosso , E. bicolor (Guérin-Méneville) and E. helianneae , the new species is readily distinguished by presenting a longer head (HL about 84.7 % of HW in E. muiraquitan ; 90 % in E.

bicolor , 92 % in E. matogrosso and 94.6 % in E. helianneae ), by the presence of the light and merged mid-dorsal stripe from the post-cephalic dermal fold to vent (mid-dorsal stripe absent in E. bicolor , mid-dorsal stripe from the tip of snout to vent in E. helianneae ) and by the absence of minute light spots on dorsum and dorsal surfaces of members (present in E. helianneae ). From E. matogrosso it also distinguishes by the larger SVL size (males of E. matogrosso are smaller than 25 mm and males of E. muiraquitan are larger than 30 mm) and by the lower frequency advertisement calls, in E. matogrosso the frequency of the advertisement call varies from 2.88 to 4.79 kHz, and the dominant frequency is 4.15 kHz (based on Nunes et al. 2011: calls recorded at type locality); and in E. muiraquitan it varies from 2.61 to 4.28 kHz and the dominant frequency is 3.84 kHz. The PCA was able to distinguish E. muiraquitan from the two morphologically closest species, almost without overlap in the first component (Factor 1), which explained most of the variation ( Fig. 2 ). Factor 1 is mostly influenced by THL, TBL, and FL (contributing with about 13 % of the variation), SVL, IOD, and END (contributing with about 12 % of the variation). Other variables contributed with less than 10 % of the variation. When plotting Factor 1 against Factor 2 we observed two groups of E. matogrosso , which includes individuals of the same populations, indicating larger intraspecific variation for this species ( Fig. 2 ). Variation in Factor 2 is mostly influenced by UEW (27 %) and HL (24 %).

Description of holotype. Body ovoid; head small, triangular, slightly broader than long; HL 83.36 % of HW and 18.9 % of SVL; HW 22.67 % of SVL. Snout sub-elliptical in dorsal view, protruding in lateral view. Nostrils small, not protuberant, directed anterolaterally, closer to tip of snout than to eye; internarial distance smaller than the eye-nostril and interorbital distances, and larger than the eye diameter and the upper eyelid width. Canthus rostralis rounded; loreal region flat, sloping abruptly to the upper lip. Postcommisural gland poorly developed. Eyes small, dorsolateral, only slightly protruding. Interorbital space slightly convex, more than twice the upper eyelid width. No cranial crests. A defined transversal skinfold across back of the head, bending downwards slightly behind the eyes. Tympanum concealed; supratympanic fold absent. Lower jaw truncate, with trilobed anterior margin. Tongue large, oval, without a notch on posterior border. Subcircular choanae, widely separated. Premaxillary, maxillary, and vomerine odontophores not observable under stereomicroscope. Vocal sac subgular, slightly expanded externally. A weak skinfold crossing the chest between axilla. Arms moderately robust, no tubercles or crests on forearm; palmar tubercle large, divided longitudinally, twice as large than thenar tubercle; fingers slender, free, with subarticular tubercles developed, rounded; supranumerary tubercles absent; tip of fingers not flattened or expanded; terminal grooves absent. Relative lengths of fingers, 1<2<4<3. Prepollex not evident; nuptial pads or asperities absent. Legs short, robust. Thigh length shorter than tibia length and shorter than foot length; thigh length 91.19 % of tibia length. Sum of thigh and tibia lengths 77.86 % of SVL; thigh length 37.14 % of SVL; tibia length 40.72 % of SVL. Heel of adpressed legs reaching axilla; no tibial or tarsal ridges; oval inner metatarsal tubercle, outer metatarsal tubercle absent; plantar tubercles absent. Toes slender, free, weakly fringed; subarticular tubercles developed, rounded; supranumerary tubercles absent; tips of toes not flattened or expanded; terminal grooves absent. Relative lengths of toes, 1<2<5<3<4. Skin on dorsum slightly rugose, belly smooth; cloacal opening not modified, no para-cloacal tubercles.

In preservative ( Fig. 1 ), dorsum and dorsal surfaces of limbs uniformly brown; a middorsal longitudinal light cream stripe, from the vent to the middle of the dorsum to vent; well defined color limit between the dorsal and ventral regions; venter immaculate clear cream; throat cream with few spots; few, small spots on axilla and groin; an irregular broad light cream stripe on the posterior surface of thighs; a large irregular, light cream spot on the proximal internal surface of tibiae; a light cream stripe surrounding the knees and reaching the middle of the tarsus.

Etymology. The specific epithet, a noun in apposition, derived from the Tupi word muiraquitã (or mbïraki'tã), a noun given to Amazonian Indigenous artifacts carved in stone (primarily jade) or wood representing animals (especially frogs) or people. The muiraquitã as a frog-shaped green stone (exceptionally similar to an Elachistocleis species) was used in the Brazilian Amazon as an amulet by the women from Tapajós to prevent disease and avoid infertility. It is also related to a legend in which the amulet was offered as a gift by female Icamiaba (a matriarchal Indian society) to all those male Guacaris warriors who annually visited their camp at the river Nhamundá during a ceremony dedicated to the moon. At midnight the Icamiaba warriors dived into the river and brought up a greenish clay in their hands, which they molded into various forms (mainly frogs), and presented these to their loved ones. To date, this amulet is considered a sacred object, believed to bring happiness, luck, fertility, and also to cure many diseases.

Variation. SVL in males ranges from 26.8 to 32.7 mm, females from 30.6 to 39.7 mm, and the intensity of the color on throat has dark color, where in females it is immaculate. The females are larger than males ( Table 1 ).

E. muiraquitan

Geographical distribution. Northern Brazil, in the southeastern of the state of Acre ( Fig. 3 ). Besides the type locality we found one specimen collected in the municipality of Rio Branco, Acre (ZUEC 5652) on 22 December 1983 ( Fig. 3 ). It is possible that this species is distributed over other areas of the Amazon.

Natural history Notes. One adult female (SVL 39.7 mm; 5.70 g without the ovules; ZUEC 5660) had its belly opened revealing 961 mature ovules (1.15 g) in its ovaries. The estimated reproductive effort (as percentage of gonad mass in relation to body mass) was 20.2 %. Mature ovules presented a dark animal pole and a beige vegetal pole and had a mean diameter of 3.9 ± 0.17 mm (3.3 – 4.1 mm, n = 10).

Call description. Nine advertisement calls of one male were recorded in downtown, Xapuri, Acre, on 22 December 1983 at 22:15 (FNJV 11823). Air temperature was 27ºC and water temperature 28ºC. The call consists of a loud, high pitched, sustained whistle, which can be divided in two parts ( Fig. 4 ). In the first part, the frequency is ascendant modulated varying from 2.76 ± 0.06 to 3.78 ± 0.07 kHz. In the second part the frequency is sustained (not modulated), and ranging from 3.36 ± 0.07 to 4.20 ± 0.02 kHz. The mean pulse rate is 195.69 per second and there are 802.34 pulses per call in average. Further spectral characteristics are presented in Table 2 .

Dominant Frequency (kHz) Not applied 3.78 ± 0.03 (3.75–3.93) Pulse duration (ms) Not applied 5.11 ± 0.13 (5.00–6.00)

Figures

FIGURE 1. Holotype (ZUEC 5666) of Elachistocleis muiraquitan sp. nov. in dorsal (A), ventral (B) and lateral (C) views.

FIGURE 2. First and second (A), first and third (B) principal components of the PCA distinguishing three groups represented by Elachistocleis muiraquitan sp. nov. (black circles), E. helianneae (red squares), and E. matogrosso (blue triangles). Analysis made based only on adult males.

FIGURE 3. Type locality of Elachistocleis muiraquitan sp. nov. Xapuri, Acre, Brazil.

FIGURE 4. Spectrogram (above) and waveform (below) of the advertisement call of Elachistocleis muiraquitan sp. nov., recorded at type locality (air temperature = 27 ºC; water temperature = 28 ºC; FNJV 11823), Xapuri, Acre, Brazil. Note the ascendant modulated initial portion of the call and its abrupt end.

Tables

TABLE 1. Values, in mm, presented as mean ± standard deviation (range) of the type specimens of Elachistocleis muiraquitan sp. nov., males of E. helianneae, and males of E. matogrosso.

SVL HL HW	Holotype male 31.8 6.0 7.2	Paratype males (n=7) 31.1 ± 0.9 (26.3–32.7) 5.9 ± 0.2 (5.2–6.5) 6.9 ± 0.2 (6.4–7.3)	Paratype females (n=7) 33.5 ± 1.4 (30.6–39.7) 5.9 ± 0.2 (5.5–6.5) 7.0 ± 0.2 (6.4–7.5)	E. helianneae (n=8) 26.5 ± 1.3 (24.7–28.4) 5.7 ± 0.4 (5.3–6.3) 6.4 ± 0.5 (5.5–7.2)	E. matogrosso (n=20) 24.7 ± 2.6 (19.9–29.4) 6.2 ± 0.8 (4.7–7.9) 5.9 ± 0.7 (4.6–8.0)
ED UEW IOD END IND HnL	2.0 1.0 3.6 2.6 1.7 7.3	2.0 ± 0.1 (1.7–2.3) 1.1 ± 0.1 (0.9–1.4) 3.6 ± 0.1 (3.3–4.1) 2.7 ± 0.1 (2.5–2.9) 1.8 ± 0.1 (1.5–2.1) 6.8 ± 0.2 (6.0–7.3)	2.0 ± 0.1 (1.7–2.3) 1.1 ± 0.1 (0.9–1.3) 3.7 ± 0.1 (3.5–4.0) 3.0 ± 0.1 (2.7–3.4) 2.1 ± 0.1 (1.7–2.6) 7.4 ± 0.2 (6.8–8.2)	2.0 ± 0.2 (1.8–2.4) 1.1 ± 0.2 (0.9–1.4) 2.8 ± 0.2 (2.6–3.0) 2.4 ± 0.3 (2.1–2.8) 1.9 ± 0.2 (1.7–2.2) 5.3 ± 0.5 (4.7–6.2)	1.8 ± 0.3 (1.1–2.3) 1.4 ± 0.5 (0.8–2.7) 2.6 ± 0.2 (2.3–3.0) 2.0 ± 0.3 (1.5–2.5) 1.6 ± 0.2 (1.1–1.9) 5.4 ± 0.4 (4.5–6.8)
THL TBL FL	11.8 13.0 14.1	11.7 ± 0.5 (10.1–13.1) 12.4 ± 0.3 (11.3–13.4) 14.0 ± 0.4 (13.1–15.3)	12.9 ± 0.3 (12.5–14.1) 13.2 ± 0.3 (12.5–14.6) 15.3 ± 0.5 (14.5–16.7)	9.8 ± 0.5 (8.9–10.5) 10.6 ± 0.3 (9.8–11.0) 12.1 ± 0.7 (11.0–13.1)	9.1 ± 0.9 (7.0–11.7) 9.3 ± 1.0 (7.2–11.3) 11.3 ± 1.1 (9.0–13.0)

TABLE 2. Advertisement call parameters of Elachistocleis muiraquitan sp. nov. N = 9 calls of one male; water temperature = 28 ºC; air temperature = 27 ºC. Values presented as mean ± standard deviation (range).

	Initial and modulated portion of the call	Final and sustained portion of the call
Initial minimum frequency (kHz) Initial maximum frequency (kHz) Final minimum frequency (kHz)	2.76 ± 0.06 (2.61–2.92) 3.19 ± 0.04 (3.04–3.32) 3.18 ± 0.06 (3.06–3.34)	Not applied Not applied Not applied
Final maximum frequency (kHz) Duration (s) Minimum Frequency (kHz) Maximum Frequency (kHz)	3.78 ± 0.07 (3.64–3.99) 0.16 ± 0.01 (0.12–0.22) Not applied Not applied	Not applied 3.94 ± 0.18 (2.86–4.42) 3.36 ± 0.07 (3.10–3.50) 4.20 ± 0.02 (4.13–4.28)