ABSTRACT Two new species of rheophilic water mites _Arrenurus _(_Micruracarus_)_ curvus _and _A. _(_Micruracarus_)_ bulbus _obtained from the River Nile at Sohag, upper Egypt, were described and identified. Among the specific characters, the male petiole of the first species is hyaline, striated, W-shaped and did not extend beyond the pygal lobes, while that of the second species is toothed, bulb-shaped ... Read more

ABSTRACT The water mite _Unionicola tetrafurca_tus Ramadan and Aboul-Dahab, 2002, is a symbiont on the freshwater mussels, _Caelatura aegyptiaca_ (Cailliaud) and _Unio abyssinicus_ Martens. The two hosts harbored 91 and 88% female mites, respectively. The infection percent of the different stages of the mite was related to the host size, and was 100% all-over the year, except in August when ... Read more

ABSTRACT The water mite _Unionicola niloticus _(Aboul-Dahab, 1998) is commonly parasitizing the molluscan host _Anodonta rubens. _It has a powerful pedipalp used for host attachment, making rooms for embryos and feeding process. The action of the pedipalp causes displacement, rupture, erosion and cellular reactions in the host gill tissue. The cellular reactions include infiltration and accumulation of leucocytes in different ... Read more

ABSTRACT The life cycle of the present species, as in other species of water mites, consists of fertilized egg, prelarva, larva, postlarva, protonymph, deutonymph, tritonymph and adult. The cleavage has a karyokinasis process leading to a superficial blastula. Gastrulation starts with the formation of the germinal disc, which acts as growth zone. The growth zone forms a large number of ... Read more

Abstract The abundance and sex ratio of four species of water mites: _Parafissicepheus africanus _(Mazen, 1979), and _Cheiroseiulus crassipes, C. spinosus, C. punctum_ (Ramadan, 1998) which inhabit the roots of the aquatic plant _Eichhornia. crassipes,_ were studied. The first species belongs to suborder Cryptostigmata, while the other three species belong to suborder Mesostigmata. The present data showed that the cryptostigmatid ... Read more

ABSTRACT The present investigation was designed to assess the extent of sexual variations in some taxonomical paramerters in the populations of water mites _Unionicola anodontae, U. niloticus _and _U. palpatus, _collected from the freshwater mussel _Anodonta rubens _living in River Nile. The primary sexual differences are the presence of genital flaps in females and genital skeleton in males. The secondary ... Read more

Abstract Four new species belonging to the genus Cheiroseiulus, were collected from the floating plant roots; _Eichhomia crassipes_, in River Nile, Sohag Governorate. These are _Cheiroseiulus crassipes, C. spinosus, C. punctum_ and _C. longisetosus_. They are described, using the Scanning Electron Microscope and compared with relative identified species. Read more

ABSTRACT The acarine species, _Parafissicepheus africanus_ Mazen, 1979 is associated with the roots of the floating plant, Eichhornia crassipes. It is an asynchronous brooder. The maximum and minimum brooding percentages were recorded in July, 1996 and March, 1996, respectively. The brooding of embryos was common in the middle-size classes of female populations. The optimal level of brood size was 3.7 ... Read more

Abstract A description is given for a new species of water mites belonging to the genus _Unionicola_. Adults and nymphs of the mite are residence the mantle cavity of the molluscan bivalve _Anodonta rubens_, while the other developmental stages are inhabiting the gills of the host. The descriptive characters of the present species are in accordance with those of superfamily, ... Read more

SUMMARY Two new species of mesostigmatid water mites were collected from the Wild sponge, Red Sea, Egypt, _Planodiscus furcatus _n. sp. and _Zercon reticulatus _n. sp .. They are recorded and described for the first time. Read more