Abstract. A study of the family Trachyleberididae Sylvester-Bradley from the Equatorial Continental Shelf of Brazil (almost 1400 km in length) revealed the presence of five new species, which are described herein. These are: Cletocythereis atlantica, Cativella paratranslucens, Cativella reticulocostata, Henryhowella tuberculoclaviforma and Australimoosella polypleuron. Two sub-species of the genus Costa, C. variabilicostata brasiliensis subsp. nov. and C. variabilicostata aff. recticostata Bold, are placed within the variabilicostata group. The genus Neocaudites is represented by two species, N. subimpressus Edwards and N. triplistriatus Edwards, originally described from the Upper Miocene and Pliocene of the Duplin Marl, North Carolina, USA. The genus Puriana is represented by P. convoluta Teeter and P. variabilis Chukewiski & Purper, described originally from Belize (British Honduras) and the Brazilian coast, respectively. The geographical distribution of the studied fauna, reveals the presence of two assemblages on the Equatorial Continental Shelf of Brazil, a Northwest and a Southwest assemblage, separated by the area of discharge of the Amazon and Pará rivers and each with its distinctive oceanographical and sedimentological characteristics.