Abstract Santaremicaris gen. nov. is proposed to accommodate Santaremicaris amazonensis sp. nov., a new species collected by Noodt from the hyporheic zone of the Amazonas River at Santarém, Brazil, and Parastenocaris santaremensis Noodt, 1963, which is redescribed and designated as the type species of the new genus. The new genus is recorded also from several localities of the Amazonian hydrographic basin. Santaremicaris gen. nov. is well supported by clear autapomorphies, e.g., 1) the absence of distal spinules on the endopod of the second swimming leg of the male, which is ornamented with strong outer spinules along the first 2/3 of the segment and armed with a long distal seta the insertion area of which covers almost the whole width of the segment; 2) the presence of a triangular, short and strongly sclerotized endopod on the fourth swimming leg of the male; and 3) the presence of a long and slim male fifth leg ending in a long distal spiniform process, with irregular margins, armed with only three setigerous elements on the outer margin, and reaching the middle of the subsequent urosomal segment or beyond it. The new genus is closely related to Murunducaris Reid, 1994, with males sharing conspicuous ornamentation on the inner margin of the first swimming leg basis, represented either by an enlarged spinule accompanied by minute accessory spinules or by a row of strong spinules. In addition, the males of both Murunducaris and Santaremicaris gen. nov. share an enlarged intercoxal sclerite with a median process on the fifth leg.

No presente artigo são apresentados novos registros de Boeckella bergi em vários corpos de água na Argentina e no Brasil. Dentro desses registros estão incluídos os limites setentrionais e meridionais de ocorrência de B. bergi na América do Sul. A ampla gama de distribuição é consistente com estudos anteriores, mas se mostra muito mais extensa do que conhecida anteriormente. Observações sobre a taxonomia e os habitats também são feitas. Esta espécie é tolerante a condições de clima temperado na região da América do Sul, com uma grande amplitude de temperatura entre o verão e inverno, e padrões irregulares de precipitação.

We present new records of Boeckella bergi at several water bodies in Argentina and Brazil. Within these records the northernmost and southernmost limits of occurrence of B. bergi in South America are included. The ample range of distribution is consistent with former studies, but it is more extensive than previously known. Observations on habitat preferences are also made. This species is tolerant to temperate climate conditions in this region of South America, with wide amplitude of temperature between summer and winter seasons, and irregular patterns of precipitation.

Resumo Halicyclops aberrans sp. n. é descrito de material proveniente de duas localidades do Rio Capim (Estado do Pará), ocupadas por água doce. Ela difere de todas as espécies conhecidas de Halicyclops por ter o espinho apical interno do último artículo do endopodito do terceiro e quarto par de patas natatórias reduzido e inclinado para cima, e pelo número de espinhos no último artículo do exopodito dos quatro pares de patas natatórias (2.3.3.2).

ABSTRACT Halicyclops aberrans sp. n. from two localities of the River Capim, Pará State, Brazil, is described and figured. It differs from all previously described species of the genus in possessing the inner apical spine of the third endopodal segment of swimming legs 3 and 4 reduced and turned upwards, and by the spinal formula of the third exopodal segment of the swimming legs (2.3.3.2).