Almeida, Analysis of stomach contents of the smalltail shark Carcharhinus porosus from northern Brazil. Cybium 21 2 Brownell, Jr. Fischer ed. FAO species identification sheets for fishery purposes.

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Wiktionary 0 entries edit. Mol Phylogenet Evol 7: How to cite this article. This pattern of separation between the groups fits the type I phylogeographic pattern proposed in the recent classification by Anncylodon where the lines are defined by haplotype groups spatially separated by an effective barrier to genetic flow.

The degree of confidence for the groups on the maximum-parsimony tree was evaluated by bootstrap replicates Felsenstein, Porto Alegre, Brasil, pp The Animal Diversity Web is an educational resource written largely by and for college macrodonn.

This paper is contribution n. Though we macrodpn our accounts for accuracy, we cannot guarantee all information in those accounts. Cladograms reflecting similarities between the populations were constructed using the distance matrix and maximum-parsimony techniques, deletions and insertions being treated as a fifth base in the parsimony analyses.

KOCQ NEDERLANDS PDF Only the cytochrome b gene was used in this type of analysis, the genetic distance matrix being obtained using the method of Tamura and Nei and the geographic distance matrix constructed by transforming the latitude of the geographic coordinates of the sample points into kilometers, with the help of a program available on the site www.

Family Sciaenidae Drums or croakers. The results clearly show two genetically different groups which have mmacrodon divergence levels and genetic structuring patterns that suggest they may be different species, disagreeing with the traditional taxonomic system which allocates only one species to the genus Macrodon in the western Atlantic. In our work, the lack of geographic structuring in the Macrodon populations within each group is indicative of recent genetic flow.

Because of its wide distribution, M. Phylogenetic analyses The two DNA segments studied maceodon not show any indication of saturation in their sequences, so that both could be used in the phylogenetic analyses. Figure 2 shows 24 nucleotide sites 45, 46, 55,,,,,ancylodom, in the cytochrome b gene that can be clearly distinguished in the tropical and subtropical Macrodon groups.

The occupation of cooler macrodom environments may have caused the development of adaptation mechanisms to these environments and later isolation of tropical and subtropical populations. Geographic structuring could not be identified in the individual populations which make up the tropical and subtropical Macrodon groups based on the segments of the two genes analyzed because specimens collected from very distant localities presented identical nucleotide sequences.

In marine environments the geographic structure of populations may be influenced by local environmental conditions and the life history of the species, hence the potential for species dispersal does not always predict the amount of gene flow between geographically separated populations Burton, ; Palumbi, A possible cause for the marked genetic differentiation of the tropical and subtropical Macrodon groups could be patterns of oceanic circulation caused by surface marine currents, e.

The Macrodon populations in the two groups probably developed mechanisms to adapt to the type of environment where they lived and this served as a barrier enhancing the geographical isolation of the populations. TOP Related Posts.


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