Monthly and seasonal fluctuations in densities of freshwater snails were recorded in six different sites at Qena Governorate during the period of March 2009 February 2010. The study revealed the occurrence of 13 species of freshwater snails belonging to 9 families of class Gastropoda. The snail species and their total catch were: Cleopatra bulimoides (1704 specimens), Lanistes carinatus (1468 specimens), Melanoides tuberculata (1036 specimens), Gabbiella senaariensis (731 specimens) Theodoxus niloticus (670 specimens), Bellamya unicolor (588 specimens), Physa acuta (213 specimens), Lymnaea natalensis (145 specimens), Succinea cleopatra (85 specimens), Bulinus truncatus (73 specimens), Biomphalaria alexandrina (41 specimens), Gyraulus ehrenbergi (12 specimens) and Helisoma duryi (2 specimens) in a descending order. The densities of the recorded snails varied seasonally and the general seasonal peak was recorded during Autumn while the lowest density observed during Winter. Ecological factors which may influence the distribution of the recorded snails were also determined (water temperature, pH, dissolved oxygen conductivity, total hardness, total dissolved salts, water depth and percentage of macrophytes).
T he present work deals with the ecology of eight species of freshwater ostracods (Cypridopsis vidiui, Potamocypris variegattf. Hemicypris dematomarginata, llyocypris gibha, Uyocypris hiplicata, Fabaeformisccmdona holzkampfu Pseudocandona semicognita and Limnocythere inopinata) collected from Qena Govemorate. Monthly samples were collected for a period of one year (from July, 2000 till June, 2001) from four sites. Some ecological factors were measured during the period of investigation and correlated with the density of the ostracod species studied. Statistical analysis was performed by using SPSS software package (version 9) and the model equations controlling the density and the physical factors measured for the studied species were deduced.
Among Oniscidea suborder, Porcellionidae is the richest and widely-distributed Family. However, the phylogeny investigations of its taxa were not completely covered. Therefore, a phylogeographic population and genetic diversity study was carried out here on two cosmopolitan terrestrial isopod species (Porcellionides pruinosus and Porcellio laevis) by utilizing mitochondrial cytochrome c oxidase subunit 1 (CO1) gene. The sequencing of CO1 among the understudied populations showed nucleotide length ranged from 646 base pairs (bp) to 660 bp. The average contents of nucleotide bases A+T in Porcellionides pruinosus and Porcellio laevis were 63.8% and 63.3%, respectively. Also, the average content of pyrimidines (C+T) bases in Porcellionides pruinosus and Porcellio laevis was higher than the purines content. Nucleotide bases A+T contents were higher than nucleotide bases C+G contents in all populations. The pairwise genetic distances among the understudied Porcellionides pruinosus populations ranged from 0.000 to 0.002. The most related populations were in Qeft and Deshna, where the genetic distance was 0.000. The pairwise genetic distances among the understudied populations of Porcellio laevis ranged from 0.017 to 0.033. The most related populations were in Qeft and Hurghada, where the genetic distance was 0.017. Furthermore, Porcellio laevis populations need more investigations, as it seems to be polyphyletic comparing to Porcellionides pruinosus populations.
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