Dorsal view of the head of Leptodactylus gualambensis (L. fuscus clade 2; A, B, C) and L. fuscus sensu stricto (L. fuscus clade 1; D, E, F). A LGE 23548, Urundel, Salta, Argentina, male, SVL 44.19 mm (topotype); B IIBP-H 720, Pozo Colorado, Presidente Hayes, Paraguay, male, SVL 42.4 mm; C IIBP-H 5984, Tarumandy, Central, Paraguay, male SVL 42.33 mm; D NZCS-A 2339, Anton de Kom University, Paramaribo, Suriname, male, SVL 38.81 mm; E MZUSP 65632, Ilha de Maraca, Roraima, Brazil, male, SVL 39.70 mm; F MZUSP 58252, Kourou, French Guiana, male, SVL 41.98 mm. Scale bar = 5 mm.