Scinax camposseabrai (Bokermann)

Barreto, Gilvana Santos, Grande, Maria Lúcia Del, Napoli, Marcelo Felgueiras, Garda, Adrian Antonio & Juncá, Flora Acuña, 2019, The tadpole of Scinax camposseabrai (Bokermann) (Amphibia, Anura, Hylidae), Zootaxa 4674 (3), pp. 393-396 : 393-395

The tadpole of Scinax camposseabrai (Bokermann) (Amphibia, Anura , Hylidae )

GILVANA SANTOS BARRETO 1,5, MARIA LÚCIA DEL GRANDE 2, MARCELO FELGUEIRAS NAPOLI 3, ADRIAN ANTONIO GARDA 4 & FLORA ACUÑA JUNCÁ 1

1 Programa de Pós-graduação em Ecologia e Evolução, Museu de Zoologia, Departamento de Ciências Biológicas, Universidade Estadual de Feira de Santana – UEFS, Av. Transnordestina, 44036-900 Feira de Santana , Bahia, Brasil

2 Universidade Estadual do Sudoeste da Bahia, Departamento de Ciências Naturais. Estrada do Bem Querer Km 4, 45083-900 Vitória da Conquista , Bahia, Brasil

3 Museu de Zoologia, Departamento de Zoologia, Universidade Federal da Bahia, Rua Barão de Jeremoabo, Campus Universitário de Ondina , 40170–115 Salvador, Bahia, Brasil

4 Laboratório de Anfíbios e Répteis-LAR, Departamento de Botânica e Zoologia, Universidade Federal do Rio Grande do Norte, Av. Salgado Filho S /N, Lagoa Nova, 59072–970 Natal , Rio Grande do Norte, Brasil

5 Corresponding author. E-mail: [e-mail]

The treefrog Scinax camposseabrai (Bokermann) is endemic to the Brazilian semiarid region and known from the municipalities of Maracás, Igaporã and Curaçá, in the state of Bahia, and from the municipality of Matias Cardoso, northern Minas Gerais state, Brazil ( Frost 2019). It was removed from the synonymy of Scinax x-signatus (Spix) , recognized as a valid species, and placed in the S. ruber clade (sensu Faivovich et al. 2005) by Caramaschi & Cardoso (2006). Taxonomic changes proposed by Duellman et al. (2016) for the genus Scinax were discussed by Lourenço et al. (2016) and Faivovich et al. (2018), and we follow here their suggestion to consider Ololygon and Julianus (erected for the S. uruguayus group) as synonyms of Scinax . This large genus Scinax currently would include 123 species ( Frost 2019), many of which have had their larval morphology formerly described. Here, we describe the external morphology of the previously unknown tadpoles of S. camposseabrai .

We obtained 30 tadpoles of S. camposseabrai at different development stages from its type locality ( Maracás municipality , Bahia state, northeastern Brazil) on November 21, 2012, in a temporary pond (13°18′01.2′′S, 40°26′0.17′′W, 700 m asl). To confirm the species identity, we compared external morphologies and oral discs with three tadpoles of S. camposseabrai that were raised from eggs deposited in a plastic bag by a couple of S. camposseabrai collected by us on October 2009 in the municipality of Vitória da Conquista , state of Bahia, Brazil, ca. 230-airline km southwards Maracás . Syntopic congeneric species include S. x-signatus (Spix) , S. pachycrus (Miranda-Ribeiro) , S. auratus (Wied-Neuwied) , and S. eurydice (Bokermann) , and as we discuss below, all have very different tadpoles, especially regarding oral features.

Specimens used in the present study are housed at the Museu de Zoologia da Universidade Estadual de Feira de Santana, Feira de Santana, Bahia State, Brazil (MZFS lot 1196 and MZFS lot 1333), and at the amphibian scientific collection of Universidade Estadual do Sudoeste da Bahia, Vitória da Conquista, Bahia State, Brazil (UESB 0814 and 0815; tadpole lot 15). Measurements, terminology and labial tooth row formula follow Altig (1970), Altig & McDiarmid (1999) and Mercês & Juncá (2010). The external morphology is based on five tadpoles at stage 33 from Maracás and three tadpoles reared at stages 34–36 from Vitória da Conquista (tadpole stages sensu Gosner 1960). Measurements were taken using an ocular micrometer in a stereomicroscope and are in millimeters: total length (TL), body length (BL), oral disc width (ODW), internarial distance (ID); interorbital distance (IO); maximum tail height (MTH), tail musculature height (TMH); tail length (TaL); body width (BW), dorsal fin height (DFH), ventral fin height (VFH), spiracle–snout distance (SSD), body height (BH), snout–nostril distance (SND), snout-eye distance (SED), eye diameter (ED), eye nostril distance (END), and nostril diameter (DN).

Description is based on five tadpoles from Maracás at Gosner stage 33. Measurement range, mean and standard deviation are given in Table 1 . Body elliptical in dorsal view and triangular in lateral view ( Fig. 1A,B ), slightly higher than wide (BH/BW = 1.10–1.18, 1.13 ± 0.03); body height less than body length (BH/BL = 0.65–0.71, 0.68 ± 0.02); BL approximately one third of tail length (BL/TaL = 0.33–0.35, 0.34 ± 0.01). Snout rounded in dorsal view and truncated in lateral view. Nostrils dorsolateral, rounded, closer to the eye than to the snout (SND/END = 1.63–2.27, 1.91 ± 0.24), without projection on the marginal rim, its major axis 4% to 5% of BW (DN/BW = 0.04–0.05, 0.04 ± 0.01). Eyes lateral, visible in ventral view and dorsal view ( Fig. 1C ); interorbital distance more than half of body width (IO/BW = 0.54–0.64, 0.61 ± 0.04). Spiracle sinistral, opening cylindrical, short, located at the middle third of the body (SSD/BL = 0.65–0.66, 0.66 ± 0.01), directed parallel to the midline of the body and having a wider base at the end, inner wall attached to the body wall and longer than the external wall. Coiled gut. Dextral vent tube positioned above the margin of the ventral fin. Tail longer and higher than the body (TaL/TL = 0.64–0.66, 0.66 ± 0.01; BH/MTH = 0.73–0.84, 0.78 ± 0.04). Dorsal fin beginning at the middle third of the body and slightly lower than the ventral fin (DFH/VFH = 0.71–0.85, 0.77 ± 0.06); dorsal and ventral fins contours arched. Tail ending in short flagellum. Lateral line system not evident without staining. Oral disc anteroventral with lateroventral emargination, less than a half of body width (ODW/BW = 0.39–0.45, 0.41 ± 0.02) ( Fig. 1D ). Marginal papillae in a single row; triangular shaped, larger and more spaced at the lower lip. Dorsal gap on upper lip. Few submarginal papillae lateral, aggregated and extending from the angular region to the infra-angular region. Labial tooth row formula (LTRF) 2(2)/3(1), A1 = A2, P1 = P2> P3, P3 almost 2/3 of P2, P1 slightly shorter than P 2 in one specimen. Labial teeth well developed and curved. Jaw sheaths colored and serrated. Anterior jaw sheath widely keratinized, M-shaped (with medial projection and long lateral process). Lower jaw sheath keratinized, large, width over two times the upper jaw width, V-shaped. Ventrolateral keratinized sheets present ( Fig. 1E ) and keratinized spurs posterior to the edges of the lower jaw sheath ( Fig. 1F ). Tadpoles from Vitória da Conquista (n = 3, stages 34–36) are similar to those described above ( Table 1 ).

Color in preservative. Body and tail musculature cream. Fins transparent. In lateral view, grayish brown spots grouped irregularly forming rounded blotches scattered along the fins and caudal musculature; brown lateral stripe extending from the snout to the eye. In dorsal view, from the anterior portion of the tail musculature to the beginning of the flagellum, there are thick brown stripes transversally positioned. Longitudinally between the eyes, a gray diamond spot that can extend to the beginning of the tail.

Tadpoles included in the Scinax ruber clade have a dextral proctodeal tube positioned above the margin of the lower fin, lateral eyes visible ventrally, and anteroventral oral discs, which are synapomorphic features of this clade ( Faivovich 2002; Faivovich et al. 2005). Tadpoles of S. camposseabrai have all of these features. Furthermore, in most aspects these tadpoles closely resemble larvae of the Scinax uruguayus group. Tadpoles of S. uruguayus (Schmidt) , S. pinimus (Bokermann & Sazima) , and a third undescribed species S. aff. pinimus share a set of distinctive, putative synapomorphic features of the clade ( Kolenc et al. 2003; Faivovich et al. 2005; Alcalde et al. 2011). Like these three species, tadpoles of S. camposseabrai have massive lower jaw sheaths more than two times wider than the upper sheaths, mental marginal papillae large and widely spaced, and keratinized ventrolateral sheets associated to the lower jaw sheath. Additionally, the large infralabial papillae described by Alcalde et al. (2011) occur in the buccal cavity of these tadpoles ( Fig. 1F ). Tadpoles of S. camposseabrai differ from these species in the following characteristics: snout truncate in lateral view in S. camposseabrai , rounded in S. uruguayus and S. pinimus ; spiracle parallel to the midline of the body in S. camposseabrai , posterodorsal spiracle in S. uruguayus and S. pinimus ; tail flagellum present in S. camposseabrai , absent in S. pinimus and S. uruguayus (however Kolenc et al. 2003 described that the tail tip of S. uruguayus tadpoles is rounded at stage 31-33, but mentioned that it becomes acute in older tadpoles and have “flagelliform movements” in vivo); marginal papillae and submarginal papillae conical in S. camposseabrai , submarginal papillae rounded and flat in S. uruguayus ; anterior jaw sheath M-shaped and with long lateral process in S. camposseabrai , U-shaped and inconspicuous lateral process and in S. uruguayus ; P3 almost 2/3 of P 2 in S. camposseabrai and S. pinimus ( Bokermann & Sazima 1973) , P3 almost half of P 2 in S. uruguayus ( Kolenc et al. 2003) ; nostrils rounded in S. camposseabrai , oval in S. uruguayus ; nostrils dorsolateral in S. camposseabrai , dorsal in S. pinimus ; and oral disc with lateroventral emarginations in S. camposseabrai .

The similarity between the oral disc features of S. camposseabrai and Scinax uruguayus group tadpoles should be reinterpreted in a phylogenetic context, in order to elucidate at what level these morphological features are apomorphic.

Figures

FIGURE 1. Tadpole of Scinax camposseabrai. (A) lateral view, (B) dorsal view, (C) ventral view (scale = 10 mm), (D) open oral disc (scale = 1 mm) (stage 33), (E) keratinized sheets associated to the lower jaw sheath and (F) spurs associated to the lower jaw sheath. Drawings: Ednei de Almeida Mercês.