Brachycephalus actaeus Monteiro & Condez & Garcia & Comitti & Amaral & Haddad 2018, sp. nov

Brachycephalus actaeus sp. nov. Figures 1, 2, 6, 7, and 8 Holotype. CFBH 39850, adult male, collected at Serra da Palha, Laranjeiras, Ilha de São Francisco do Sul, municipality of São Francisco do Sul, state of Santa Catarina, Brazil (26°17'50"S; 48 ° 40'28"W, Datum WGS 84, ca 60 meters above sea level), on 19 May 2015, by C.F.B. Haddad, J.P.C. Monteiro, and E.C. Nardin (Figures 1 and 2). Paratopotypes. CFBH 39851, adult female, collected with the holotype; CFBH 39872, 39873, and UFMG 18973, adult males, collected on 25 November 2015, by J.P.C. Monteiro, T.H. Condez, and E.C. Nardin; CFBH 39876, adult male, and CFBH 39877, adult female, collected on 0 2 December 2015, by J.P.C. Monteiro and E.C. Nardin. Paratypes. CFBH 39846, adult male, cleared and double-stained, collected at Fazenda Morro Grande, Morro Grande, Ilha de São Francisco do Sul, municipality of São Francisco do Sul, state of Santa Catarina, Brazil (26 ° 17'47"S; 48°37'10"W, Datum WGS 84, ca 60 meters above sea level), on 14 November 2014, by E.J. Comitti. UFMG 18970, adult female, collected on 15 November 2014, by J.P.C. Monteiro, T.H. Condez, and E.J. Comitti; CFBH 39849, sub-adult female, collected on 21 November 2014, by J.P.C. Monteiro and E.C. Nardin; CFBH 39848, adult male, cleared and double-stained, collected on 21 January 2015, by C.F.B. Haddad, J.P.C. Monteiro, T.H. Condez, and E.J. Comitti; UFMG 18971, adult male, collected on 0 1 August 2015, by J.P.C. Monteiro and E.C. Nardin; CFBH 39855–39858 and 39861, adult males, CFBH 39860, adult female, CFBH 39859, juvenile, collected on 23 November 2015, by J.P.C. Monteiro, T.H. Condez, and E.C. Nardin; all collected at Centro de Estudos e Pesquisas Ambientais da Univille (CEPA), Vila da Glória, Distrito do Saí, municipality of São Francisco do Sul, state of Santa Catarina, Brazil (26 ° 13'39"S; 48 ° 41'31"W, Datum WGS 84, ca 120 meters above sea level). CFBH 39853 and 39854, adult males, collected on 27 August 2015, by J.P.C. Monteiro and E.C. Nardin; CFBH 39862, adult female, collected on 23 November 2015, by J.P.C. Monteiro, T.H. Condez, and E.C. Nardin; at Estrada do Saí, Distrito do Saí, municipality of São Francisco do Sul, state of Santa Catarina, Brazil (26°12'06"S; 48 ° 41'37"W, Datum WGS 84, ca 80 meters above sea level). CFBH 39863, 39864, 39867, 39868, and UFMG 18972 adult females, CFBH 39865 and 39870, adult males, collected on 24 November 2015, by J.P.C. Monteiro, T.H. Condez, and E.C. Nardin; CFBH 39875, adult female, collected on 30 November 2015, by J.P.C. Monteiro and E.C. Nardin; at Braço do Norte, municipality of Itapoá, state of Santa Catarina, Brazil (26°07'29"S; 48 ° 43'48"W, Datum WGS 84, ca 220 meters above sea level). CFBH 42005–42008, adult females, collected on 17 September 2016, by J.P.C. Monteiro and E.C. Nardin; Fazenda Palmito Juriti, municipality of São Francisco do Sul, state of Santa Catarina, Brazil (26°08'09"S; 48 ° 43'54"W, Datum WGS 84, 125–170 meters above sea level). Diagnosis. Brachycephalus actaeus sp. nov. is a new species of the B. pernix group, distinguished from all its congeners by the following combination of characters: (1) “bufoniform” body; (2) general dorsal body color dark green with a dark brown vertebral stripe, and orange background more evident in ventral view; (3) absence of hyperossification of the skull and skeleton; (4) pectoral girdle arciferal and robust, with small ovoid fenestra, distant from the epicoracoid; (5) radius and ulna fused; (6) finger IV greatly reduced, almost not visible externally; (7) manus with two prepollical elements; (8) tips of terminal phalangeal elements of fingers I and IV pointed, II and III arrow-shaped; (9) tibiale and fibulare completely fused; (10) toes I and V present but externally indistinguishable, toe II greatly reduced, toe III short and distinct, and toe IV larger and robust; (11) pes with distal tarsal element I present; (12) pes with phalangeal formula 1–2–3–4–0; (13) tips of terminal phalangeal elements of toes I and II pointed, and of toes III and IV arrow-shaped; (14) arytenoid cartilages not mineralized; (15) body size (SVL of adults: 9.2–10.8 mm for males and 11.1–12.4 mm for females); (16) proportional measurements HL/SVL 18–24% and ED/HL 52–73%; (17) rounded snout in dorsal and lateral views; (18) protuberant nostrils; (19) skin texture rough; and (20) advertisement call short (0.02–0.03 seconds), composed of one high-frequency note (dominant frequency 6.6–7.3 kHz). Comparisons with other species. Brachycephalus actaeus sp. nov. exhibits a “bufoniform” body and an orange background color, both characteristics that clearly differentiate it from the “leptodactyliform” species: B. didactylus, B. hermogenesi, B. pulex, and B. sulfuratus (Izecksohn 1971; Giaretta & Sawaya 1998; Napoli et al. 2011; Condez et al. 2016). These species are generally smaller, exhibit “leptodactyliform” bodies, and always exhibit a brown background color (Napoli et al. 2011; Condez et al. 2016). The absence of hyperossification of the skull and skeleton distinguishes Brachycephalus actaeus sp. nov. from B. darkside, B. ephippium, B. garbeanus, and B. margaritatus, which exhibit the extreme condition of hyperossification within Brachycephalus, including a dorsal bony shield (Clemente-Carvalho et al. 2009; Guimarães et al. 2017). The absence of hyperossification also distinguishes the new species from B. alipioi, B. atelopoide, B. bufonoides, B. crispus, B. guarani, B. nodoterga, B. pitanga, B. toby, and B. vertebralis, which exhibit the intermediate condition of hyperossification within Brachycephalus (Clemente-Carvalho et al. 2009; Haddad et al. 2010; Pombal 2010; Clemente-Carvalho et al. 2011; Condez et al. 2014; Condez et al. 2016). Brachycephalus actaeus sp. nov. differs from B. brunneus, B. coloratus, B. ferruginus, B. izecksohni, and B. pombali, which possess pectoral girdles with larger fenestra, disposed closer to the epicoracoid (small fenestra distant from the epicoracoid in the new species). Likewise, B. brunneus, B. ferruginus, B. izecksohni, and B. pombali differ in having the radius and ulna not fused, pes with distal tarsal element I absent, and toe V reduced (Ribeiro et al. 2005; Alves et al. 2006); the new species has the radius and ulna fused, pes with distal tarsal element I present, and toe V externally not visible. Also, B. albolineatus , B. coloratus, B. curupira, B. ferruginus, and B. pombali have just one prepollical element, and B. izecksohni has no prepollical element (Ribeiro et al. 2005; Alves et al. 2006; Bornschein et al. 2016b; Ribeiro et al. 2017); the new species has two prepollical elements. The phalangeal formula for the pes of B. brunneus , B. izecksohni, and B. pombali is 0–2–3–4–0 (Ribeiro et al. 2005; Alves et al. 2006), and for B. curupira it is 0–1–3–4–0 (Ribeiro et al. 2017); the phalangeal formula of the pes of the new species is 1–2–3–4–0. In B. albolineatus, B. coloratus, and B. curupira the fibulare and tibiale are not completely fused; tips of terminal phalangeal elements of toes II–IV are arrow-shaped (fibulare and tibiale completely fused; tips of terminal phalangeal elements of toes I and II pointed, III and IV arrow-shaped in the new species). Finally, the arytenoid cartilages are mineralized in B. albolineatus and B. coloratus (arytenoid cartilages not mineralized in the new species). Although the osteology of B. pernix was not studied in detail (Pombal et al. 1998), on the basis of the available information its osteology is quite similar to that of the new species. See Figure 3 for osteological details of the new species. Body size (males SVL = 9.2–10.8 mm; females SVL = 11.1–12.4 mm) distinguishes the new species from Brachycephalus ferruginus (males SVL = 11.6–12.5 mm; females SVL = 13.0– 14.5 mm; Alves et al. 2006), B. pernix (males SVL = 12.0– 13.3 mm; females SVL = 14.1–15.8 mm; Pombal et al. 1998), and B. pombali (males SVL = 12.6–13.9 mm; females SVL= 14.6–15.3 mm; Alves et al. 2006). Also, in B. coloratus (males SVL = 10.3– 10.6 mm; females SVL = 12.2–13.3 mm; Ribeiro et al. 2017), B. izecksohni (males SVL = 10.3–12.1 mm; females SVL = 12.5–13.1 mm; Ribeiro et al. 2005), and B. tridactylus (males SVL = 10.6–11.6; females SVL = 13.5–13.8 mm; Garey et al. 2012) males and/or females are slightly larger than in the new species. Brachycephalus actaeus sp. nov. is distinguishable from B. albolineatus, B. auroguttatus, B. boticario, B. fuscolineatus, B. leopardus, B. mariaeterezae, B. olivaceus, B. quiririensis, and B. verrucosus by a proportionally shorter head relative to body length (HL/SVL) and by a proportionally larger eye diameter related to head length (ED/HL). In B. actaeus sp. nov., HL/ SVL is 18–24% (x̄= 20, SD = 1) and ED/HL is 52–73% (x̄= 63, SD = 4), for the 32 adult specimens of the type series, without sexual distinction. In B. albolineatus, HL/SVL is 28–34% (x̄= 31, SD = 4) and ED/HL is 36–42% (x̄= 38, SD = 4); in B. auroguttatus, HL/ SVL is 29–38% (x̄= 33, SD = 2) and ED/HL is 30–44% (x̄= 33, SD = 3); in B. boticario, HL/ SVL is 31–36% (x̄= 34, SD = 2) and ED/HL is 30–34% (x̄= 32, SD = 1); in B. fuscolineatus, HL/ SVL is 29–34% (x̄= 31, SD = 1) and ED/HL is 36–41% (x̄= 39, SD = 1); in B. leopardus, HL/ SVL is 31–35% (x̄= 33, SD = 1) and ED/HL is 34–43% (x̄= 38, SD = 3); in B. mariaeterezae, HL/ SVL is 29–36% (x̄= 33, SD = 2) and ED/HL is 36–42% (x̄= 39, SD = 2); in B. olivaceus, HL/ SVL is 32–36% (x̄= 34, SD = 1) and ED/HL is 26–36% (x̄= 32, SD = 3); in B. quiririensis, HL/ SVL is 31–36% (x̄= 34, SD = 1) and ED/HL is 28–34% (x̄= 32, SD = 2); and in B. verrucosus, HL/ SVL is 30–36% (x̄= 33, SD = 2) and ED/HL is 30–40% (x̄= 34, SD = 3) (Pie & Ribeiro 2015; Ribeiro et al. 2015; Bornschein et al. 2016b). Additionally, Brachycephalus actaeus sp. nov. exhibits a rounded snout in dorsal and lateral views, which distinguishes it from B. brunneus, which has a slightly mucronate snout in dorsal view (Ribeiro et al. 2005); from B. leopardus, which has a slightly truncate snout in dorsal and lateral views (Ribeiro et al. 2015); and from B. quiririensis, which has a mucronate snout in dorsal view (Pie & Ribeiro 2015). Nostrils are not protuberant in B. auroguttatus, B. pernix, and B. fuscolineatus (Pombal et al. 1998; Ribeiro et al. 2015), which differ from the protuberant nostrils of the new species. In Brachycephalus tridactylus, finger IV is not externally visible (Garey et al. 2012), while in the new species it is reduced but externally distinct. In B. actaeus sp. nov., fingertips I, II, and IV are rounded, differing from B. pernix in which these fingertips are pointed (Pombal et al. 1998) and from B. brunneus, B. izecksohni, and B. leopardus, which have the tip of finger II pointed (Ribeiro et al. 2005; Ribeiro et al. 2015). The texture of the skin on the dorsum of Brachycephalus actaeus sp. nov. is rough; this characteristic distinguishes the new species from B. albolineatus, B. brunneus, B. coloratus, B. curupira, B. ferruginus, B. izecksohni, B. leopardus, B. pernix, B. pombali, and B. tridactylus, which have a smooth dorsum (Pombal et al. 1998; Ribeiro et al. 2005; Alves et al. 2006; Garey et al. 2012; Ribeiro et al. 2015; Bornschein et al. 2016b; Ribeiro et al. 2017). The dark green general color of Brachycephalus actaeus sp. nov. in life is very distinct from B. boticario, B. coloratus, B. ferruginus, B. fuscolineatus, B. izecksohni, B. leopardus, B. mariaeterezae, B. quiririensis, B. pernix, B. pombali, B. tridactylus, and B. verrucosus, which exhibit a bright yellow or orange general dorsal body color (Pombal et al. 1998; Ribeiro et al. 2005; Alves et al. 2006; Garey et al. 2012; Pie & Ribeiro 2015; Ribeiro et al. 2015; Ribeiro et al. 2017). The body color of the new species is similar to B. albolineatus, which has a greenish general coloration (Bornschein et al. 2016b), and B. olivaceus, which is predominantly dark green to brown (Ribeiro et al. 2015). The advertisement call of Brachycephalus actaeus sp. nov. differs in structure and frequency from all known advertisement calls within Brachycephalus. It is clearly distinct from B. crispus, B. darkside , B. ephippium, and B. pitanga by having higher frequencies together with a different call structure (Pombal et al. 1994; Araújo et al. 2012; Condez et al. 2014; Guimarães et al. 2017). In these species, the advertisement call is characterized by the regular repetition of one low-frequency note with several pulses, while in B. actaeus sp. nov. the high-frequency notes are composed of just two pulses. In B. crispus, the notes generally last 0.28 seconds and are composed of 10 pulses; the frequency range is 3.5–5.7 kHz, while the dominant frequency is 4.6 kHz (Condez et al. 2014). In B. darkside, the average note duration is 0.11 seconds and notes are composed of six pulses; the frequency range is 2.5–5.8 kHz [considered dominant frequency in Guimarães et al. (2017)], while the dominant frequency is 3.4 kHz [considered peak frequency in Guimarães et al. (2017)]. In B. ephippium, notes typically last 0.12 seconds and are also composed of 12 pulses; the minimum and maximum frequencies are 3.4–5.3 kHz (Pombal et al. 1994). In B. pitanga, notes last 0.17 seconds and are composed of 11 pulses; the dominant frequency is 4.9 kHz (Araújo et al. 2012). The high frequency of the advertisement call of the new species is comparable to that described for B. hermogenesi and B. sulfuratus, the latter having the highest dominant frequency known for the genus (Condez et al. 2016). Nevertheless, the advertisement calls of these species differ from the new species in general structure, which is long and composed of a set of high-frequency notes. In B. hermogenesi, the call is composed of 1–5 notes; call lasts 0.2 seconds, with 1–5 pulses (Verdade et al. 2008). The dominant frequency in B. hermogenesi is 6.8 kHz (Verdade et al. 2008). In B. sulfuratus, the call is composed of 4–7 notes, each one lasting 0.19 seconds, with 9 pulses (Condez et al. 2016). The frequency range is 4.9–9.3 kHz and the dominant frequency is 6.7 kHz (Condez et al. 2016). When compared to the advertisement calls of its most closely related species, B. pernix and B. tridactylus, the new species call has shorter notes and higher frequencies. In B. pernix, notes last 0.03–0.06 seconds and are composed of three pulses; the frequency range is 4.5 kHz–6.7 kHz (Wistuba 1998). In B. tridactylus, the frequency range is 3.2–6.4 kHz and dominant frequency is 4.8 kHz (Garey et al. 2012). Description of holotype. Body robust, bufoniform; head wider than long; head length 19% of SVL; snout short, rounded in lateral and dorsal views (Figures 1A and 1B); nostrils protuberant; canthus rostralis indistinct; loreal region slightly concave; eyes slightly protruding laterally and dorsally; eye diameter 72% of head length; tympanum absent; lips nearly sigmoid; vocal sac not expanded externally; vocal slits present; tongue longer than wide, with the posterior half not adherent to floor of mouth; vomerine teeth absent; choanae small and ovoid, anterior to eyes. Arm and forearm moderately slender; hands with fingers I and IV reduced; finger II short but distinct; finger III large and robust; fingertips I, II, and IV rounded, fingertip III pointed; finger lengths IV Measurements of holotype (in mm). SVL 9.4; HL 1.8; HW 3.0; ND 0.4; IND 1.1; ED 1.3; IOD 2.1; END 0.6; AL 2.0; FAL 2.1; HAL 1.4; THL 3.8; TBL 3.3; FL 4.6. Color in life. (Figure 6) Iris black. General body color orange, dorsal surface of body covered by dark green blotches; in dorsal view, a poorly defined dark brown stripe extends from the interorbital region to the posterior end of the vertebral column; arms, legs, fingers III and IV and toe IV dark green, other fing