Leptodactylus watu Da Silva & Magalhães & Thomassen & Leite & Garda & Brandão & Haddad & Giaretta & De Carvalho 2020, sp. nov.

Leptodactylus watu sp. nov. (Figs. 2, 4a, 4c, 5h, 6h, 10) [http://zoobank.org/ urn:lsid:zoobank.org:act: 5D79A081-C50C-463A-8101-04351E87AD23] Leptodactylus aff. spixi: Guimarães et al. (2019) Holotype. UFMG 21332, an adult male from Parque Estadual do Rio Doce (19.753922°S, 42.633047°W, approximately 280 m a.s.l.), in Marliéria, Minas Gerais State, southeastern Brazil, collected by H. Thomassen on 21 November 2017. Paratypes. Seven adult males (UFMG 21327–21331 and 21337–21338) and five adult females (UFMG 21333– 21336 and 21339) collected from the type locality by H. Thomassen from November 2017 to February 2018. Additional material. One genetic voucher (UFMG 16995) from Santa Bárbara do Leste, Minas Gerais State (Fig. 1). Etymology. The word watu, a noun in apposition, is derived from the dialect of the Borún indigenous people and is a reference to the Doce River (Costa-Reis & Genovez 2013). In 2015, the Doce River experienced the worst environmental disaster that ever took place in Brazil, the collapse of a mining tailings dam owned by Samarco (and co-owned by the Brazilian Vale and Australian BHP Billiton). The catastrophic dam failure released around 60 million cubic meters of iron ore tailings (toxic slurry) directly into the Doce River watershed, killing 20 people and affecting biodiversity across hundreds of kilometers around the river drainage, riparian lands, and the Atlantic coast, in addition to a severe contamination of the soil and water table within the affected region. The epithet is a tribute to the resistance of the Borún people and to the Watu (Doce River) in southeastern Brazil. Diagnosis. Leptodactylus watu is characterized by the following combination of character states: (1) small to moderate size, male SVL = 38.5–42.2 mm, female SVL = 40.5–47.9 mm; (2) sole of foot with few, non-obvious tubercles; (3) advertisement call composed of single, pulsed notes; (4) note duration varying from 27–70 ms; (5) note dominant frequency varying from 495–1098 Hz; (6) frequency upsweep varying from 0–560 Hz. Comparisons with members of the L. mystaceus complex. Leptodactylus watu is distinguished from other species belonging to the L. mystaceus complex, except L. barrioi, L. kilombo and L. notoaktites, by having the sole of the foot covered with few, non-obvious tubercles, whereas L. didymus, L. elenae, L. mystaceus, and L. spixi have prominent tubercles (Heyer 1978, 1983; Heyer et al. 1996). The new species can be further distinguished from some species by a smaller size (Table 2): L. didymus (male SVL = 45.9–52.2 mm, mean = 49.3; female SVL = 45.8–53.5 mm, mean = 49.8; Heyer et al. 1996), L. mystaceus (male SVL = 42.4–52.2 mm, mean = 47.4; female SVL = 44.8– 56.1 mm, mean = 50.0; Heyer et al. 1996), and L. notoaktites (male SVL = 42.5–54.2 mm, mean = 47.5; female SVL = 43.4–55.8 mm, mean = 48.0; de Sá et al. 2014). Members of the L. mystaceus complex are mainly distinguished from each other by their distinct advertisement calls (Fig. 6). Acoustic comparisons in the L. fuscus group. The advertisement call of Leptodactylus watu is composed of single, pulsed notes (Table 3; Fig. 6h), differing from species with trill calls (L. cunicularius, L. cupreus, L. oreomantis, and L. plaumanni; Fig. 7; Carvalho et al. 2013) and species with nonpulsed calls (L. albilabris, L. bufonius, L. camaquara, L. didymus, L. elenae, L. furnarius, L. fuscus, L. gracilis, L. jolyi, L. kilombo sp. nov., L. laticeps, L. latinasus, L. longirostris, L. marambaiae, L. mystacinus, L. notoaktites, L. poecilochilus, L. sertanejo, L. spixi, L. syphax, L. tapiti, and L. troglodytes). From other species with pulsed calls, L. watu is distinguished by having its call formed by partly fused pulses, whereas the calls of L. barrioi, L. mystaceus and L. cf. mystaceus are formed by complete pulses (Fig. 6). From species also having calls with partly fused pulses (L. caatingae, L. fragilis, and L. labrosus), L. watu is distinguished by a shorter note (27–70 ms) from L. fragilis (> 100 ms; Heyer et al. 2006). The calls of L. watu, L. caatingae, and L. labrosus are the most similar to each other in the L. fuscus group, but these species can be distinguished, although value ranges partially overlap, by differences in the dominant frequency (L. watu: 495–1098 Hz, mean = 763; L. caatingae: 1148–1430 Hz, mean = 1315, in our sample; 943–1620 Hz, mean = 1423 Hz, in the original description; Heyer & Juncá 2003) or duration (L. watu: 27–70 ms, mean = 40; L. labrosus: 64–133 ms, mean = 100; Carvalho & Ron 2011) of their calls. Still, these species differ markedly in morphology and size (see previous paragraph; Heyer 1978; Heyer & Juncá 2003). Description of holotype. Body robust. Snout sub-elliptical in dorsal and ventral views (Fig. 10 a–b), acuminate in lateral view (Fig. 10e). Canthus rostralis rounded; loreal region flat; tympanic annulus well-defined, circular (TD = 62.4% ED); supratympanic fold from the posterior corner of the eye, passing over the dorsal edge of the tympanic annulus, and ending at the base of the arm; vocal sac subgular; vocal slits present; vomerine teeth in two nearly straight rows, almost connected, medial and posterior to choanae and almost parallel to sagittal plane. Tongue rounded, free at its posterior third. Relative finger lengths II = IV <I <III; fingers without lateral fringing or webbing; finger tips rounded, unexpanded; inner metacarpal tubercle oval, divided, outer metacarpal tubercle rounded; outer metacarpal tubercle twice the maximum width of the inner; subarticular tubercles rounded; supernumerary tubercles absent (Fig. 9c). Dorsal surfaces of body and forelimbs smooth, shagreened on flank and dorsal surface of shank. Dorsolateral fold from the posterior corner of the eye, extending posteriorly to the groin. Flank with a fragmented line of granules posteriorly. Dorsal surface of hindlimbs with tiny tubercles (more conspicuous in life). Ventral surface of body and limbs smooth, underside of thigh areolate. Relative toe lengths I <II <V <III