One of the best known crustacean hormones is the crustacean hyperglycemic hormone (CHH). However, the mechanisms involved in hormone release in these animals are poorly understood, and thus constitute the central objective of the present study. Different groups of crustaceans belonging to diverse taxa (Chasmagnathus granulata, a grapsid crab and Orconectes limosus, an astacid) were injected wit...

The species of the genus Cystomutilla André, 1896 are reviewed. A new genus Hemutilla Lelej, Tu et Chen, gen. nov. (type species Hemutilla granulata Tu, Lelej et Chen, sp. nov.) and four new species: H. tuberculata Tu, Lelej et Chen, sp. nov. (China: Henan, Shaanxi), H. ferrugineipes Tu, Lelej et Chen, sp. nov. (China: Hunan), H. granulata Tu, Lelej et Chen, sp. nov. (China: Zhejiang), and H. c...

When the megalopa stage of estuarine crab species becomes competent for settlement and metamorphosis, it responds to specific chemical and physical cues from the adult environment. Delayed metamorphosis in the absence of such cues is beneficial insofar as it increases the probability of finding a suitable habitat, and it may also enhance the genetic exchange between separate populations. Howeve...

The occurrence and response of N a + K + A T P a s e specific activity to environmental salinity changes were studied in gill extracts of all of the gills of the euryhaline crab Chasmagnathus granulata from Mar Chiquita coastal lagoon (Buenos Aires Province, Argentina) All of the gills exhibited a salinity depen­ dent N a + K + A T P a s e activity, although the pat tern of response to environm...

Due to changes in land use, the natural habitats of an increasing number of plant species have become more and more fragmented. In landscapes that consist of patches of suitable habitat, the frequency and extent of long-distance seed dispersal can be expected to be an important factor determining local genetic diversity and regional population structure of the remaining populations. In plant sp...

Numerous studies have shown that melatonin exerts some influence on the antioxidant defense system (ADS) in vertebrates, but for crustaceans no such effect has been demonstrated till now. However, earlier reports did show a similar profile of daily variations in the ADS of the gills and the melatonin content of the eyestalk in the crab Neohelice granulata and, thus, the aim of this study was to...

The spiral intestines of a total of 30 specimens of 14 species of batoids from around the world were examined for rhinebothriideans. These consisted of Taeniura grabata, Dasyatis margaritella, and Dasyatis sp. from Senegal, Dasyatis americana from Florida, Dasyatis dipterura and Dasyatis longa from México, Himantura jenkinsii, Himantura leoparda, Himantura uarnak 2, Urogymnus asperrimus 1, and ...

Hazim O. Khalifa, Ahmed M. Soliman, Ashraf M. Ahmed, Toshi Shimamoto, Tadashi Shimamoto Laboratory of Food Microbiology and Hygiene, Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, Japan; Department of Pharmacology, Faculty of Veterinary Medicine, Kafrelsheikh University, Kafr El-Sheikh, Egypt; Department of Microbiology and Immunology, Faculty of Pharmacy and Dru...

Two new species of tetraphyllidean cestodes inhabiting Himantura pacifica from the northwest coast of Costa Rica are apparently most closely related to species inhabiting Himantura schmardae from the Atlantic coast of Colombia. Acanthobothroides pacificus n. sp. differs from Acanthobothroides thorsoni, the only other species in the genus, primarily by having smaller lateral (98-123 microns rath...