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The composition, numerical abundance and seasonal distribution of mesozooplankton, in addition to copepod biomass, were studied in the Sa˜o Sebastia˜o Channel (SSC) during different seasonal periods and hydrographic regimes. Two stations were sampled every 3 months from . Temporal differences in oceanographic conditions in the SSC were observed; there was clear seasonal variation in the thermohaline structure. Phytoplankton composition, standing-stock and biomass also showed consistent seasonal variation, peaking during summer due to advection of cold and nutrient-rich South Atlantic Central Water (SACW). Sixty-nine mesozooplankton taxa were identified and counted. Mesozooplankton density also increased during summer, ranging from 93 to 12,774 ind m )3 . In contrast, a unimodal peak of copepod biomass was recorded during winter and under the influence of the oligotrophic Coastal Water (CW), suggesting that copepod biomass at SSC is driven by resource control. There was no significant evidence of seasonal pattern in overall community composition or evidence of changes due to water mass advection. The mesozooplankton community was continuously dominated by coastal and warm-water species, particularly the copepods Acartia lilljeborgi, Paracalanus aculeatus, P. quasimodo, Parvocalanus crassirostris, Corycaeus giesbrechti and Oithona oswaldocruzi, the cladocerans Penilia avirostris and Evadne tergestina, in addition to the appendicularians Oikopleura longicauda and O. dioica, all of which are perennial species in the SSC. This taxonomic composition may represent an efficient biotic structure for rapid recycling of primary production during periods of SACW influence.

some taken recently of! Santo" Rio de l.aneiro aNl Cabo Frio (BrrnJ.l1 were rertudied. The cnitriliútion ofthe several speclesofthe genus Paracalinus (c:raealroltris, nanull, quuIinoclo, parvus I. m., liuUcus, acu1eatua), of the genu, CaulOcalanuI (furcatus, mastlgophorul, pergens, Ingena, paululua, parapergens and arcuicomia) -were surveyed in Braztlúm waten. Two new rpeckl ParacalanUI campaneri and DeUus seweW were described. · Two Ctenocalanu& wel'e found in BNztlian wateTl not co"espondillg to the dtlcriptlon ofCten0calanus citar. The distribution of these especies was compared off South America. IntroduçloOs Clausocalanus e osParacalanus são em geral os mais numerosos primeiros consumidores pertencentes ao plâncton, em todos os oceanos, exceçlo das águas antárticas e de algumas águas mais frias co,steiras, onde são substituídos pelos Ctenocalanus. F . Dahl, 1894 (Andronov, 1970, 1977.Baseados na abundância destes pequenos Calanoida, tornou-se imperativa a revisão dos estudos feitos em 1963, também porque, sendo o primeiro trabalho sobre uma distribuição geral dos copépodos ao largo do Brasil, poderia conter identificações errôneas de espécies e outras il1UleneicÕes. Heron & Bowman, 1971, não foi registrado com certeza em nenhuma das amostras estudadas, parecendo ser característico de águas antárticas; os outros Ctenocalanus registrados em amostras tiradas ao largo de Santos e do Rio Grande do Sul, diferem uns dos outros e suas características são descritas mais adiante.Paracalanus , campaneri sp. nov_ -Sinonímia: Paraca1Jmus aeuleatus Bjornberg, 1963 (parÚ Diagnose: Cj .l = 1,05 a 1,03 mm de compfr mento, o comprimento do urosoma é mais ou menos 1/3 a 1/3 e meio do comprimento do cefalotorax, as antênulas ultrapassam os ramos caudais em dois artículos, receptáculo seminal bifurcado em vista ~ateral, segundo artículo do exópodo da segunda e terceira patas natatórias espinulado, espínulos marginais externos do último artículo dos exópodos fortes e numer9SQ~ nas ~. terc.ciras e quartas patas, quinto par de patas com dois ou três artículos e dõiS espínulos terminais e uma cérdula.

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A new nicothoid (Choniomyzon libiniae Santos and Bj rnberg, new species) was found on the eggs of the decapod crustacean Libinia spinosa collected at Anchovas Beach (S o Sebasti o Island, SP, Brazil). The material obtained was fixed in formalin, cleared in lactic acid and glycerin, and the different forms of the parasite were drawn with the aid of a microscope and a camera lucida. The parasite eggs were attached to the host's eggs. Nauplii, three forms of copepodids, and adult females and males were found. The 12-segmented first antennae, the segmented urosome, the long and branched caudal setae, the oval form of the female, the lecithotrophic nauplius, a copepodid similar to the one described for Choniomyzon permitted the inclusion in this genus. It differs from the species described (C. panuliri Pillai) by the ornaments of the antenna and of the female legs, also by the presence of three types of copepodids.

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ABSTRACTthe qualitative composition, numerical abundance and seasonal distribution of microzooplankton in the São Sebastião channel were studied in different seasonal periods. Data are presented for 43 protozoa, 4 rotifer and 30 copepod nauplii specimens. tintinnids represented the most abundant group within the microzooplankton community, with 31 species recorded, among which Amphorellopsis acuta, Codonellopsis morchella, Eutintinnus tenuis, Favella ehrenbergii, Leprotintinnus nodqvisti, Tintinnopsis buetschlil, T. lobiancoi and T. radix stood out, followed in abundance by copepod nauplii. our findings indicated that water masses play a fundamental role in the seasonal composition of microzooplankton assemblages in the São Sebastião channel.

SUMÁRIO