High Genetic Diversity, Large Inter-oceanic Divergence and Historical Demography of the Striped Mullet

The striped mullet Mugil cephalus L. is a circumtropical species whose extreme conservative morphology stands in contrast with the degree of genetic differentiation at a global scale. One hundred and fourteen mitochondrial control region DNA sequences were analysed from four localities in the Gulf of Mexico (Texas, Louisiana, Mississippi, Florida), one on the U.S.A. east coast (N. Carolina), and one in Hawaii, giving very high levels of molecular diversity (h = 1.0 every haplotype was unique in all samples, pi = 1.1-2.0% in Gulf-Atlantic and pi = 3.1% in Hawaii). With no genetic evidence of dramatic population expansions, mismatch distributions were still very different in each ocean. Stable population levels in Hawaii have fostered the generation and persistence of very high molecular diversity, but Gulf-Atlantic samples suggest a shorter span of population stability. Ninety-five per cent of the molecular variance was allocated between ocean basins and virtually none among Gulf-Atlantic samples. A neighbour-joining reconstruction revealed Atlantic- and Pacific-specific lineages separated by more than 24% uncorrected sequence divergence (d = 0.49 Tamura-Nei Gamma-corrected). The lack of phylogeographic structure among Gulf-Atlantic samples corroborated the AMOVA results and supported the existence of a single population with high levels of gene flow along the Gulf of Mexico and north-west Atlantic coasts. The genetic differentiation between oceans points to the absence of gene how and an accelerated rate of mitochondrial evolution in the genus Mugil. (C) 2000 The Fisheries Society of the British Isles

Chave ilustrada para identificação das zoés de Brachyura do estuário da Lagoa dos Patos (RS) e região costeira adjacente

The goal of this study is to provide an illustrated identification key to distinguish zoeal phase of Brachyuran larvae that occur in the estuarine and nearby coastal region of the Patos Lagoon. The key includes species, collected monthly, using a conical net (165 cm long, 60 cm mouth and 330 μm mesh). Sampling was carried out on surface and deep waters. The identification was based on specimens reared under laboratory conditions as well as from previous published studies. This key was constructed upon external morphological characters, easy to observe under a stereomicroscope and moreover, the presentation of figures allows a non-specialist to make identifications more easily.O objetivo do presente estudo é a elaboração de uma chave de identificação ilustrada das espécies de Brachyura que ocorrem no estuário da Lagoa dos Patos e sua região costeira adjacente. A chave abrange espécies as quais foram coletadas mensalmente, usando uma rede de plâncton (165 cm de comprimento, 60 cm de boca e 330 μm de malha). As amostragens foram realizadas na superfície e fundo. Os especimens foram identifcados mediante comparação com larvas cultivadas em laboratório e com descrições já existentes. A chave utiliza caracteres que não sofrem grandes transformações ao longo do desenvolvimento, e a utilização de figuras para ilustrar a chave permite a não especialistas facilmente identificar as espécies

Embriologia do siri Arenaeus cribrarius (Lamarck) (Crustacea, Brachyura, Portunidae)

Ovigerous females of Arenaeus cribrarius were collected at Ubatuba, São Paulo, and maintaining in aquaria under controlled temperature (25±1ºC), salinity (35±1 ) and photoperiod (12:12). A small sample of eggs was collected for each 24h, for morphological description, chromatic changes and biometric analysis throughout the embryonic development. Eight egg stages were photographed and had their small and large diameters measured under a microscope provided with camera lucida. The egg's shape was low elliptical during all the embryogenesis and showed size increase (24.4%) and volume (91.1 %), when the last stage were compared with the first one. According to mean egg diameter and volume, the eggs should be pooled in three different groups (1-3; 4-6; 7-8) corresponding to initial, intermediate and final stages. The attained results were compared with the literature which emphasizing the species of Portunidae's family.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP