Scinax x‑signatus (Spix, 1824) Hyla x‑signata Spix, 1824. Hyla affinis Spix, 1824 – Considered a synonym of Hyla x‑signata by Hoogmoed & Gruber (1983). Sturaro & Peloso (2014) questioned this association based on the description and figure provided by Spix (1824). Our study of photographs of the holotype (ZSM 2945) indicates that the situation is uncertain. Only a study of the taxonomy of amazonian populations associated with Scinax x‑signatus would allow to clarify the status of this nomen. Hyla coerulea Spix, 1824 – Considered a synonym of Hyla x‑signata by Hoogmoed & Gruber (1983). Sturaro & Peloso (2014) questioned this association based on the description and figure provided by Spix (1824). Our study of photographs of the lectotype designated by Hoogmoed & Gruber (1983) (ZSM 2710-0-1) indicates that the situation is uncertain. Only a study of the taxonomy of amazonian populations associated with Scinax x‑signatus would allow to clarify the status of this nomen. Hyla rubra Daudin, 1802 (part) – Duméril & Bibron, 1841. First treatment as a synonym of Hyla rubra Laurenti, 1768 (not Daudin, 1802; see León, 1969; Rivero, 1969; Duellman & Wiens, 1993). Scytopis xsignatus [sic] – Cope, 1870. First combination with Scytopis Cope, 1862. Hyla rubra var. x‑signata – Peters 1872. First treatment as a variety of Hyla rubra Laurenti. Hyla rubra x‑signata – Müller, 1927. First treatment as a subspecies of Hyla rubra Laurenti, 1768. Hyla x‑signata x‑signata – Lutz, 1973. First use as nominal subspecies. Ololygon x‑signata – Fouquette & Delahoussaye, 1977. First combination with Ololygon Fitzinger, 1843. Scinax x‑signata – Duellman & Wiens, 1992. First combination with Scinax Wagler, 1830. Scinaxx‑signatus – Köhler & Böhme,1996.Gender change. Neotype CFBH 44688, adult male, campus of the Universidade Estadual de Santa Cruz – UESC, Salobrinho, Ilhéus, State of Bahia, Brazil [39°10′24″W, 14°47′52″S; about 30 m above sea level (a.s.l.)], collected 10 April 2018 by G. Novaes-e-Fagundes. urn:lsid:zoobank. org:act: F357D8CC-446B-4F2C-9B53-190AFEEFD533 Referred specimens Fifteen adults (12 males and three females) from eight localities in the State of Bahia, Brazil. CFBH 21071 (male), Povoado Senote, Caetité (42°28′48″W, 14°04′55″S); MHNJCH 1014 (male), Floresta Nacional Contendas do Sincorá, Contendas do Sincorá (41°07′04″W, 13°55′20″S); MZUESC 20683 (male), Condomínio Parque Universitário, Salobrinho, Ilhéus (39°10′43″W, 14°47′44″S); CFBH 44687 (male), Fazenda Lagoa Nova, Irajuba (39°59′57″W, 13°12′19″S); CFBH 18797 (male), Fazendas Santo Onofre and Cana Brava, Maracás (approx. 40°25′23.58″W, 13°23′29.30″S); MHNJCH 1701 (male), near Fazendas Santo Onofre and Cana Brava, Maracás (40°26′26.23″W, 13°21′59.10″S); MHNJCH 1698-1700 (males), Assentamento do Cumbe, Maracás (40°27′38″W, 13°26′40″S); MZUESC 14890, 14893 (males), and 14891 (female), Companhia de Pesquisa de Recursos Minerais – CPRM, Morro do Chapéu (41°09′28″W, 11°32′56″S or 41°06′26″W, 11°29′34″S); MZUESC 15894 and 17503 (females), Praça Municipal, Potiraguá (39°57′30″W, 15°37′07″S); and UFMG 4787 (male), Route Sebastião Laranjeiras-Candiba, Sebastião Laranjeiras (approx. 42°56′21.34″W, 14°33′13.74″S). Diagnosis (based on neotype and referred specimens) Scinax x‑signatus is a species of Scinax, as it shares three synapomorphies of this genus: webbing between toes I and II that does not extend beyond the subarticular tubercle of toe I; origin of the m. pectoralis abdominalis through well-defined tendons; and m. pectoralis abdominalis overlapping m. obliquus externus (da Silva, 1998; Faivovich, 2002; Faivovich et al., 2005). A single synapomorphy is known for the S.ruber Clade: tadpoles with the vent tube above the margin of the lower fin (Faivovich, 2002; Faivovich et al., 2005). While tadpoles unequivocally associated to S. x‑signatus remain unknown, this species was associated to the S. ruber Clade by having the unique combination of external vocal sac and presence of pectoral fold [internal vocal sac and pectoral fold absent in most species of the S. catharinae Clade; in few species where the vocal sac is external, the pectoral fold is absent (e.g., S. garibaldiae, S. rizibilis); otherwise, in the two cases where the pectoral fold is present, the vocal sac is internal (S.agilis and S.melanodactylus); J.Faivovich & K. Araujo-Vieira, pers. obs.; see also Bokermann, 1964; Cruz & Peixoto, 1982; Faivovich, 2002; Lourenço et al., 2014, 2019]. Scinax x‑signatus can be differentiated from all other species of the S. ruber Clade by the combination of the following characters: (1) male SVL 34.5-38.4 mm, n = 13; (2) snout rounded in dorsal view and profile; (3) pointed tubercles on lower jaw absent; (4) vocal sac subgular, weakly bilobate; (5) spicule-shaped papillary epidermal projections on the nuptial pads and pectoral region present in males; (6) pectoral glands present in males; (7) dorsal color pattern with large irregular dark blotches, commonly with dark X-shaped mark composed of one or two pairs of inverted parenthesis-like blotches; (8) hidden surfaces of thighs dark with irregular pale blotches, yellow in living specimens; (9) iris yellowish golden or bronze with a median black streak; (10) physiological chlorosis absent; and (11) advertisement call composed of a single, multipulsed note, 0.11- 0.25 s duration, 6-14 pulses/note, 52-64 pulses/s. Comparisons with other species of Scinax ruber Clade The SVL in males of Scinax x‑signatus (34.5-38.4 mm, n = 13) distinguishes it from the larger species S. castroviejoi and S.eurydice (SVL males 44.0-52.0 mm; De la Riva, 1993; Bokermann, 1968), and from the smaller species S. altae, S. auratus, S. cabralensis, S. caldarum, S. cruentomma, S. danae, S. exiguus, S. fuscomarginatus, S. juncae, S. karenanneae, S. lindsayi, S. madeirae, S. maracaya, S. ruberoculatus, S. rupestris, S. staufferi, S. strussmannae, S. tymbamirim, S. villasboasi, and S. wandae (SVL males 15.7-29.0 mm; Lutz, 1968, 1973; Duellman, 1970, 1986; Pyburn & Fouquette, 1971; Cardoso & Sazima, 1980; Duellman & Wiens, 1993; Pyburn, 1992, 1993; Drummond et al., 2007; Nunes & Pombal, 2010, 2011; Nunes et al., 2012; Brusquetti et al., 2014; Araujo-Vieira et al., 2015; Ferrão et al., 2018a, b). The snout rounded in dorsal view and profile differentiates Scinax x‑signatus from S. alter, S. auratus, S. cretatus, S. crospedospilus, S. imbegue, S. juncae, and S. tymbamirim (sub-elliptical with a pointed tip in dorsal view and slightly acute in profile), S.fuscovarius (roundly acute in dorsal view and protruding in profile), S. caldarum, S. curicica, S. duartei, S. maracaya, S. rossaferesae, and S. tigrinus (sub-elliptical or subovoid in dorsal view and slightly acute in profile), S. squalirostris (pointed in dorsal view and acute in profile), and species of the S. rostratus group (elongate pointed in dorsal view and acute with or without a fleshy proboscis in profile). Furthermore, the absence of pointed tubercles on the lower jaw differentiates S. x‑signatus from almost all species of the S. rostratus Group; exceptions are S.kennedyi and S.rostratus (e.g., Duellman, 1972 a, 1973; Pyburn, 1973; Lescure & Marty, 2000; Lima et al., 2005; this study). The presence of a weakly bilobate subgular vocal sac in Scinax x‑signatus distinguishes it from S.camposseabrai (bilobate subgular vocal sac; see also Caramaschi & Cardoso, 2006: fig. 1) and from the remaining species of the S. ruber Clade with single subgular vocal sac;exceptions are S.acuminatus, S.dolloi, S.funereus, S.fuscovarius, S.hayii, S.karenanneae, S.montivagus, S.onca, S.oreites, S.pachycrus, S.perereca, S. ruberoculatus, and S.tsachila, that have a weakly bilobate subgular vocal sac (e.g., Cei, 1980; Duellman & Wiens, 1993; Pyburn, 1993;Ferrão et al., 2017, 2018a; this study). The presence of spicule-shaped papillary epidermal projections on the nuptial pad and pectoral region in males differentiates Scinax x‑signatus from all other species of the S. ruber Clade, except for S. fuscovarius (see also Luna et al., 2018: fig. 10A, C). The presence of pectoral glands in males differentiates S. x‑signatus from most species of the S. ruber Clade, except for S. funereus, S.fuscovarius, S.nasicus, S.onca, and S.similis, and species of the S. uruguayus Group (e.g., Müller & Hellmich, 1936; Lutz, 1973; Cei, 1980; this study). The dorsal pattern with large irregular dark blotches, commonly with dark X-shaped marks composed of one or two pairs of inverted parenthesis-like blotches, distinguishes Scinax x‑signatus from S. altae, S. alter, S. auratus, S. boesemani, S. caldarum, S. cretatus, S. crospedospilus, S. curicica, S. cuspidatus, S. duartei, S. exiguus, S. fuscomarginatus, S. imbegue, S. juncae, S. madeirae, S. oreites, S. pachycrus, S. quinquefasciatus, S. ruber, S. squalirostris, S. staufferi, S. tsachila, S. tymbamirim, and S. villasboasi (variable number of dorsal and/or lateral stripes; e.g., Duellman, 1970; Lutz, 1973; Duellman & Wiens, 1993; Pugliese et al., 2004; Nunes et al., 2012; Brusquetti et al., 2014; Ron et al., 2018; this study), and S. blairi, S. cabralensis, S. chiquitanus, S. danae, S. iquitorum, S. lindsayi, S. maracaya, and S. strussmannae (scattered or homogeneously distributed spots and/or irregular blotches; e.g., Fouquette & Pyburn, 1972; Cardoso & Sazima, 1980; De la Riva, 1990; Drummond et al., 2007; Ferrão et al., 2018b; this study). The hidden surfaces of thighs dark colored with light irregular pale blotches, yellow in living specimens differentiate Scinax x‑signatus from S. altae, S. auratus, S. baumgardneri, S. boesemani, S. cretatus, S. crospedospilus, S. cruentomma, S. cuspidatus, S. danae, S. elaeochroa, S. exiguus, S. fuscomarginatus, S. ictericus, S. iquitorum, S. madeirae, S. manriquei, S. pachycrus, S. ruberoculatus, S. staufferi, S. strussmannae, S. squalirostris, S. tsachila, S. villasboasi, S. wandae, and species of the S. uruguayus Group (hidden surfaces of thighs uniform, light or dark colored; e.g., Rivero, 1961; Duellman, 1970, 1986; Lutz, 1973; De la Riva, 1990; Duellman & Wiens, 1993; Barrio-Amorós et al., 2004; Nunes & Pombal, 2011; Brusquetti et al., 2014; Ferrão et al., 2018a, b; Ron et al., 2018; Baldo et al., 2019; this study), S. funereus, S. onca, and S. iquitorum (hidden surfaces of thighs with horizontal or irregular dark blotches; Duellman, 1971; Ferrão et al., 2017; Moravec et al., 2009; this study), and from species of the S. rostratus Group (hidden surfaces of thighs uniform light or marked with bold dark and light mottling or broad vertical bars; Duellman, 1972 a, 1973; Henle, 1991; Lescure & Marty, 2000; Lima et al., 2005; this study). The yellowish golden or bronze iris, with a median black streak, distinguishes Scinax x‑signatus from S. cruentomma (silvery bronze iris, with a median red streak; Duellman et al., 1972b), S. ruberoculatus (bicolored, reddish upper half and grey lower half; Ferrão et al., 2018a), and species of the S. uruguayus Group (bicolored, golden upper half and dark brown to black lower half; Baldo et al., 2019). The absence of physiological chlorosis in S. x‑signatus distinguishes it from S. boesemani, S. caprarius, S. cruentomma, S. cuspidatus, S. elaeochroa, S. funereus, S. ictericus, S. iquitorum, S. karenanneae, S. manriquei, S. onca, S. strussmannae, and S. tsachila (present in these species; León, 1969; Lutz, 1973; Pyburn, 1993; La Marca, 2004;Moravec et al., 2009;Cole et al., 2013; Melo-Sampaio & Souza, 2015; Ferrão et al., 2017, 2018b; Acosta-Galvis, 2018; Ron et al., 2018;Taboada et al., 2020). The advertisement call composed of a single multipulsed short note (0.11- 0.25 s), with 6-14 pulses/note, and pulse rate of 52-64 pulses/s differentiates Scinax x‑signatus from S. castroviejoi and S. eurydice (two or three multipulsed notes; De la Riva, 1993; De la Riva et al., 1994; Pombal et al., 1995a; Magrini et al., 2011; Mângia et al., 2017), S. alter, S. curicica, and S. perereca (note duration 0.28- 4.5 s and 21-152 pulses/note; Pombal et al., 1995a, b; Pugliese et al., 2004), S. cruentomma, S. fuscomarginatus, and S. strussmannae (17-90 pulses/note and 113-272 pulses/s; De la Riva et al., 1994; Duellman, 1972b; Brusquetti et al., 2014; Carvalho et al., 2015;Ferrão et al., 2018b), S. exiguus (23-90 pulses/note; Carvalho et al., 2017), S. madeirae (note duration 0.72- 1.16 s and 104-145 pulses/s; Brusquetti et al., 2014), S. staufferi (100-130 pulses/s; León, 1969), S. wandae (note duration 0.44- 0.69 s and 70-108 pulses/note; Pyburn & Fouquette, 1971; Duellman, 1986; Pombal et al., 2011), and from some large species of the S. rostratus Group: S. boulengeri and S. proboscideus (80-230 pulses/s; León, 1969; Duellman, 1972a), S. jolyi (note duration 2.5 s and 180 pulses/note; Lescure & Marty,2000), S.kennedyi (note duration 0.66- 2.9 s; Pyburn, 1973),and S.sugillatus (note duration 0.28- 0.60 s and 110-140 pulses/s; Duellman, 1973). Description of the neotype Head as wide as long, HL 35.1% and HW 33.2% of SVL (Fig. 2). Snout rounded in dorsal view and profile, with a low protuberance on the tip (Fig. 3A, B). Nostrils dorsolateral, elliptical, protruded; IND 39.7% of IOD. Canthus rostralis marked, convex. Loreal region slightly concave. Eyes large, protuberant, ED 94.7% of IOD and 92.3% of END. Pupil horizontal, subelliptical. Tympanum rounded, separated from eye by a distance almost half TD; TD 75.0% of ED. Tympanic annulus rounded, with the posterior upper portion hidden by the supratympanic fold. Supratympanic fold evident, from the posterior upper portion of the tympanum to the insertion of the forearm. Vocal sac subgular, weakly bilobate, externally evident by the loose skin, not occupying space between head and body, and ventrally not reaching the pectoral fold (Fig. 2B). Pectoral fold present, with pre- and postaxillar elements. Vocal slits present, nearly parallel to the mandible, originating laterally to the tongue and running towards the corner of the mouth. Tongue ovoid, free laterally and posteriorly, slightly notched posteriorly. Vomerine teeth in two slightly separated convex series, bearing five (right) and four (left) teeth. Choanae oval. Axillary membrane absent. Upper arm more slender than forearm. A series of small, flat, ulnar tubercles on the forearm. Fingers short and slender, fringed (Fig. 3C). Relative finger length II

Published as part of Araujo-Vieira, Katyuscia, Caramaschi, Ulisses, Novaes-e-Fagundes, Gabriel, Orrico, Victor G. D. & Faivovich, Julián, 2020, A neotype for Hyla x-signata Spix, 1824 (Amphibia, Anura, Hylidae), pp. 1-30 in Papéis Avulsos de Zoologia 60 on pages 7-18, DOI: 10.11606/1807-0205/2020.60.56, http://zenodo.org/record/4614061