Species New to Science's Journal

[Herpetology • 2019] Scinax fontanarrosai • A Review of the Elusive Bicolored Iris Snouted Treefrogs (Anura: Hylidae: Scinax uruguayus group)

Scinax fontanarrosai

Baldo, Araujo-Vieira, Cardozo, Borteiro, Leal, Pereyra, Kolenc, Lyra, Garcia, Haddad & Faivovich, 2019

DOI: 10.1371/journal.pone.0222131

Abstract

The genus Scinax currently includes more than 120 species, recovered in two major clades, the S. catharinae and the S. ruber clades. The latter comprises 75 species, most of which remain unassigned to any species groups, while 12 are included in the S. rostratus and S. uruguayus groups. In this paper we present a taxonomic review of the two species currently included in the S. uruguayus group, discussing some putative phenotypic synapomorphies of this group. Although S. pinima and S. uruguayus have been considered as distinct species, this has been based on scant evidence, and several authors doubted of their distinctiveness. Our study of available specimens of S. pinima and S. uruguayus corroborates that both are valid and diagnosable species based on phenotypic evidence. Furthermore, our results show that S. pinima previously known only from its type locality, has a much widespread distribution than previously thought (including the Brazilian states of Paraná, Santa Catarina, and Rio Grande do Sul), which, added to the biological information presented here allows to suggest the removal of this species from the “Data Deficient” IUCN Red List category to “Least Concern”. Also, we describe a new species formerly reported as S. aff. pinima and S. uruguayus from NE Argentina and some localities from the Brazilian State of Rio Grande do Sul. All species are diagnosed and characterized using adult and larval morphology, osteology, vocalizations, cytogenetics, and natural history.

Fig 1. Dorsal (left) and ventral (right) views of the body.
(A) Scinax fontanarrosai sp. n. (LGE 4451, holotype), (B) S. pinima (WCAB 46238, holotype; now MZUSP 73668), and (C) S. uruguayus (FMNH 10567, holotype). Scale bars = 50 mm.

Fig 3. Adult external morphological characters. Scinax fontanarrosai sp. n. (left), S. pinima (central), and S. uruguayus (right).
(A) Head in dorsal view. (B) Color pattern of the bicolored iris. (C) Dorsal views of right hand and foot showing the color pattern of the discs in life. (D) Color pattern of the posterior surface of thighs in life.

Males of (A–B) Scinax fontanarrosai sp. n. and (C–D) S. uruguayus calling at breeding sites.

Scinax fontanarrosai sp. n.

urn:lsid:zoobank.org:act:39C933EB-7EDF-4AEC-9B52-F068FAA33047.

Hyla uruguaya—non Schmidt [15]. Giraudo et al. [14], partim.

Scinax uruguayus—Leite et al. [51], partim. Kwet et al. [52], partim. Vaira et al. [54]. Zaracho et al. [55]. Marin da Fonte et al. [56], partim.

Scinax aff. pinima—Alcalde et al. [53].

Julianus uruguayus—Duellman et al. [9], partim. Ferrão et al. [57], partim.

Diagnosis: The new species is assigned to the Scinax uruguayus group of the S. ruber clade based on the presence of bicolored iris in adults and two keratinized and dark colored plates on the sides of the lower jaw sheath in larvae; the two known putative synapomorphies of this group [3,6]. Additionally, it could be diagnosed by the following set of characters: (1) small size in females (SVL 24.1–24.2 mm; n = 2); (2) head sub-elliptical in dorsal view; (3) presence of two or three poorly distinguishable interorbital grooves; (4) anterior portion of the choanae not concealed by the palatal shelf of the maxillary arch when roof of mouth is viewed from below; (5) V-shaped cephalic blotch; (6) bicolored iris with a golden upper half and a dark brown to black lower half; (7) discs of the fingers and toes gray to dark brown in life; (8) hidden surfaces of thighs and tibia orange in life; (9) frontoparietals juxtaposed or slightly separated, almost completely concealing fontanelle; (10) laminar dentigerous process of the vomers without teeth; (11) palatines reduced to thin slivers; (12) intercalary elements between ultimate and penultimate phalanges partially mineralized; (13) larynx with oval arytenoids, which have a slight medial constriction in dorsal view; (14) advertisement call composed of a single, short (49–66 ms), and pulsed note (25–31 pulses/note), emitted at a rate of 3.9–4.9 notes/s; (15) pulse rate of 490–540 pulses/s; (16) notes with pulses that are increasingly modulated for the first quarter of the note, remaining with relatively constant amplitude in the second quarter, and then decrease up to the end; (17) highly pitched advertisement call, with harmonic structure; and (18) dominant frequency between 5513–6159 Hz.

Etymology: The new species is named in honor to the writer and cartoonist Roberto “El Negro” Fontanarrosa (1944−2007), in recognition of his vast contribution to the Argentinean culture. His work always included elements of nature, like the amphibians.

Fig 4. Color pattern of Scinax fontanarrosai sp. n. in life.
(A–C) Dorsolateral, (D–F) dorsal, and (G–I) ventral views.

Fig 11. Calling males, defensive behavior, and egg clutches. Males of (A–B) Scinax fontanarrosai sp. n. and (C–D) S. uruguayus calling at breeding sites. Male of (E) S. fontanarrosai sp. n. and a juvenile of (F) S. uruguayus performing the passive defensive “crouching down” behavior. (G) and (H) egg clutches of S. uruguayus. Note the dark brown to black animal pole and a dark cream vegetal pole in G.

Geographic distribution: Scinax fontanarrosai sp. n. occurs in open areas of at least ten localities in the Provinces of Misiones and Corrientes, northeastern Argentina, and two localities in the State of Rio Grande do Sul in southern Brazil (95–163 m a.s.l.). These areas are part of the Southern Cone Mesopotamian Savanna and the western part of the Uruguayan Savanna Ecoregions, respectively (Fig 10).

Natural history: Adult specimens of Scinax fontanarrosai sp. n. were collected at night, when breeding in temporary ponds after heavy rains. Males called from herbaceous and shrubby vegetation perched between 5 and 120 cm high (Fig 11A and 11B). This species has explosive reproduction (sensu [59]), most commonly during spring and summer seasons (between October and early April), and was occasionally detected in reproductive activity during July. Tadpoles and juveniles were collected at the same temporary ponds where adult males are calling. Tadpoles can be included in the nektonic guild [36]. Two specimens (male and juvenile) of S. fontanarrosai sp. n. were observed performing the passive defensive behavior “crouching down” (Fig 11E).

At the type locality, Scinax fontanarrosai sp. n. is sympatric with Melanophryniscus atroluteus (Miranda-Ribeiro, 1920), Rhinella azarai (Gallardo, 1965) (Bufonidae), Dendropsophus nanus (Boulenger, 1889), S. fuscovarius (Lutz, 1925), S. similis (Cochran, 1952), S. squalirostris (Lutz, 1925) (Hylidae), Leptodactylus fuscus (Schneider, 1799), L. gracilis (Duméril and Bibron, 1840), L. mystacinus (Burmeister, 1861), Physalaemus albonotatus (Steindachner, 1864), P. cuvieri Fitzinger, 1826, Pseudopaludicola falcipes (Hensel, 1867) (Leptodactylidae), Elachistocleis bicolor (Guérin-Méneville, 1838) (Microhylidae), and Odontophrynus sp. aff. americanus (Odontophrynidae).

Diego Baldo, Katyuscia Araujo-Vieira, Dario Cardozo, Claudio Borteiro, Fernando Leal, Martín O. Pereyra, Francisco Kolenc, Mariana L. Lyra, Paulo C. A. Garcia, Célio F. B. Haddad and Julián Faivovich. 2019. A Review of the Elusive Bicolored Iris Snouted Treefrogs (Anura: Hylidae: Scinax uruguayus group). PLoS ONE. 14(9): e0222131. DOI: 10.1371/journal.pone.0222131

Una nueva especie de rana fue nombrada en homenaje a Fontanarrosa chacodiapordia.com/2019/09/26/una-nueva-especie-de-rana-fue-nombrada-en-homenaje-a-fontanarrosa/ via @CHACOdxd

Una nueva especie de rana fue nombrada en homenaje a Fontanarrosa conicet.gov.ar/una-nueva-especie-de-rana-fue-nombrada-en-homenaje-a-fontanarrosa/