الفهرس 
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Abstract
The main aim of the present study was identification of Egyptian polychaetes using DNA barcoding and morphological characteristics for accurate taxonomy and understanding the relationship between different Egyptian polychaetes using phylogenetic analysis.
Polychaete samples were collected from various localities representing the marine environment in Egypt, including Red sea, Mediterranean sea, Suez Canal, Manzala lake and Borolos lake.
The results of the current study are considered the first data of DNA barcoding of Egyptian Polychaetes using Cytochrome Oxidase 1 gene; a leading gene in molecular taxonomy; which play a major role in identification of specimens and discovering new species as well as solving taxonomic problems in distinguishing the closely allied species and discovering the cryptic species complex.
One of the most important points resulting from the current study is discovering a new species (Marphysa aegypti sp. n) that belongs to the family Eunicidae. This new species was described genetically and morphologically for the first time.
The existence of some shared morphological characteristics in some polychaetes in addition to the widespread spread of these organisms made the differentiation between some species based on the traditional way is extremely difficult, which led to the wrong classification of some species. Here is the role of phylogenetic analysis as a modern tool for accurate taxonomy of species and the extent of the correlation between different species. For example, Hediste diversicolor had previously been misidentified in a previous study as Nereis falsa. Also, in the same study Alttia succinea was misidentified as Pseudonereis anomala.
While the results showed the ability of the DNA barcoding to determine the genetic variation between species, it also proved its ability to determine the genetic similarity of some other organisms accurately. For example, it is proved that Hediste species in Egyptian waters are genetically identical while they are divided by morphological data to two groups depending on some minor differences in some morphological characteristics that are considered intra-species morphological differences.
The current study has proved the misidentification of Oenone fulgida which belongs to the family Oenonidae after careful morphological examination supported by genetic examination, which was previously classified as Halla parthenopeia. This is due to the strong similarity between these organisms and complex morphological composition.
The uses of molecular biology were not limited to the level of the classification of samples collected from Egyptian water, but also used to determine the degree of genetic similarity and variation between species in Egypt and elsewhere in the world by, for example, the genetic examination of the Pseudonereis anomala found in Egypt has been found to be similar to the morphology of and genetically different with those in the world.
An integral part of the study for highlighting the economic importance of many polychaetes is establishment of first known account on feeding behavior and growth of the most commercially feasible polychaete species in the Suez Canal.
One of the commercially common species, O. fulgida, was reared under laboratory conditions after studying the nutritional behavior and natural environmental conditions surrounding these organisms. Three different types of food were used in order to study the impact of food type on the growth rate. Also, the effect of different densities of worms on growth was studied. The success of this laboratory experiment is considered as a seed for future research of the cultivation of these organisms on a wider scale for commercial purposes.
Furthermore, the current study will have a great impact on the conservation of species biodiversity and fisheries management of the Egyptian waters and on the other hand, it highlights the need for further research on marine species complexes and migrated species.
This study recommends further research on Polychaetes in Egypt, on broader scales using molecular and morphological examination, which will increase the possibility discovering of new species that will add to the polychaetes biodiversity.