The round stingray, Urobatis halleri, is a viviparous elasmobranch that inhabits inshore, benthic habitats ranging from the western U.S.A. to Panama. The population genetic structure of this species was inferred with seven polymorphic microsatellite loci in samples collected at three sites in coastal southern California, one near Santa Catalina Island, California and one in the eastern Gulf of ...

The kinetic characteristic (Km) of cholinesterase from the crab Chasmagnathus granulata, the shrimp Farfantepenaeus paulensis and the fish Odontesthes bonaeriensis were compared and correlated with the anticholinesterasic effect of eserine (physostigmine). For the crustaceans, the estimated Km values were about 5-8 times higher than that estimated for the fish (0.04 mM). In the crab and the shr...

A redescription of conchological and anatomical characters of the planorbidae mollusc Plesiophysa ornata (Haas, 1938) is presented, based on topotypic material and specimens from 14 additional localities in the Brazilian states of Rio Grande do Norte, Paraíba, Sergipe, Bahia, Espírito Santo and Minas Gerais. Due to the close similarity of their shells, a sure discrimination of the five species ...