Michelle Rezende Duarte

Holocene crustaceans from the Tarioba shell mound, Rio das Ostras, Rio de Janeiro, Brazil

Crustacean remains from the Tarioba shell mound (Sambaqui da Tarioba) archaeological site were investigated in order to produce a reference inventory of this taxonomic group. Information on past crustacean diversity is important for establishing baselines on biodiversity, as well as recovering paleoenvironmental information and comprehension of evolutionary change patterns for the Brazilian coast. The archaeological site was excavated by delayering the soil by artificial 10 cm sections which revealed five archaeological stratigraphic layers. A sample of mollusk shells for each of these layers was used for dating based on the C 14 method. The results show an occupation period of 550 yr for the Tarioba shell mound, with dates ranging between 4,070 cal BP (beginning of occupation) and 3,520 cal BP (occupation ending) and record nine species of crustaceans from the shell mound. However, a reduction of biodiversity over time was found that was not statically significant. Therefore, it seems that patterns of composition, richness and distribution of crustaceans have been stable in the last 4,070 years BP.

Shell Mounds of the Southeast Coast of Brazil: Recovering Information on Past Malacological Biodiversity

Brazilian classical studies on archaeology have attempted to explain human settlement and cultural trajectories in different geographical regions. However, zoological remains found in archaeological sites can also provide important information on biological diversity. Shell mounds (or sambaquis, the Brazilian term for them derived from the Tupi language) are acknowledged as artificial constructions made under cultural aims. These deliberated accumulations enclose a sample of the fauna existing between at least 6500 years BP and the start of the Common Era. In this chapter studies dedicated to use archaeozoological remains as surrogates for Late Holocene malacological biodiversity of the Central-South Brazilian coast are reviewed. Important issues such as the establishment of baselines and the problem of bioinvasion are addressed. In pursuance, raw data from the reviewed publications are used to test the main assumption lying under all inferences done by them, namely that shell mounds can be used as samplers of the past mollusk fauna. In conclusion it is sustained that shell mounds can be useful proxies for Late Holocene biodiversity.

High Levels of Genetic and Morphological Variability in Invasive Limnoperna fortunei (Dunker, 1857) Populations in South America

ABSTRACT Five populations of the invasive species Limnoperna fortunei were studied using polymorphic molecular (nine allozyme loci) and morphological (11 traits) markers in order to understand the patterns of genetic and morphological variability, structure and dispersion dynamics of this species in South America. High levels of genetic variability were found in South American invasive populations, and significant deviations from the Hardy-Weinberg proportions clearly indicated that the invasion process is still under way, probably by means other than natural migration.

Genetic variation and population homogeneity of the sea star Coscinasterias tenuispina (Forcipulatida: Asteroidea) on the coast of Rio de Janeiro, Brazil

Genetic variation and population structure of the sea star Coscinasterias tenuispina were investigated using allozyme electrophoresis (seven polymorphic loci out of nine sampled) at seven sites on the coast of Rio de Janeiro State. Observed values of heterozygosities were high (H OBS = 0.31 - 0.53), although similar to those found for others marine invertebrates. Departures from Hardy-Weinberg expectations were found only for one locus in three populations. No evidence of linkage disequilibrium was found among any loci for any population. The genetic identities vary from 0.882 to 0.988. The average q was low and insignificant statistically ( q = 0.017). Furthermore, Bayesian analysis of population partitioning showed that the highest LnP(D) value was achieved for K = 1. These results do not corroborate any affect by upwelling limiting gene flow among the analysed populations or the hypothesis that the strong sex ratio imbalance previously recorded to Itaipu population has been maintained by asexual reproduction

Taxonomic status of two morphotypes of Coryphaena hippurus (Perciformes: Coryphaenidae)

Dois morfotipos de Coryphaena hippurus (dourado e palombeta) encontrados ao longo da costa brasileira sao considerados especies diferentes por pescadores e mercadores das regioes de desembarque do estado do Rio de Janeiro. Alem disso, esses morfotipos sao comercializados por valores diferentes e sofrem diferentes pressoes de pesca. Desta forma, a definicao do status taxonomico desses morfotipos e importante, tanto em termos economicos quanto biologicos. A fim de investigar esse problema foi utilizado o metodo de eletroforese de aloenzimas com a amostragem de dezessete loci para 117 individuos dos dois morfotipos de C. hippurus obtidos em desembarques pesqueiros na regiao de Cabo Frio/RJ (Brasil). Os dados indicaram uma homogeneidade entre os conjuntos genicos dos morfotipos. A despeito disso, diferencas entre os conjuntos genicos de dourado e palombeta foram encontradas, devido, especialmente, ao locus alcool desidrogenase. A hipotese de selecao natural e discutida como possivel explicacao para esses resultados.