Theridiosoma caaguara sp. nov. from Rio Grande do Sul state, Brazil, is described and illustrated. Baalzebub baubo Coddington, 1986 is recorded for the first time for Brazil and the known geographic distribution of Epilineutes globosus (O. P.-Cambridge, 1896), Naatlo splendida (Taczanowski, 1873) and Ogulnius obtectus O. P.-Cambridge, 1882 is extended.
Araneae; Theridiosoma; Neotropical; taxonomy; distribution