To what extent are ephippia of Mexican Anomopoda (Crustacea, Cladocera) identifiable?

Diapausing embryos encased within cladoceran ephippia result from sexual reproduction and increase genetic diversity. They are also important means by which species bypass harsh environmental conditions and disperse in space and time. Once released, ephippia usually sink to the benthos and remain there until hatching.

Resilience of rotifers and cladocerans communities in four reservoirs with eutrophication pollution and lead concentrations in Aguascalientes, Mexico.

Pollution in aquatic ecosystems has been increasing drastically worldwide changing their water quality. Therefore, species must be adapted to these new scenarios. In Aguascalientes City, four representative urban reservoirs contain lead in the water column and extremely high concentrations of sediments.

A new species of Boeck, 1865 (Copepoda, Harpacticoida, Ameiridae) from the Caribbean coast of Colombia.

Biological samples obtained from a coastal system of northern Colombia yielded male and female specimens of an undescribed harpacticoid copepod of the diverse ameirid genus Boeck, 1865. The new species is a member of the genus group III. We describe the new species based on adult male and female individuals.

Feeding behavior of early life stages of the zebrafish Danio rerio is altered by exposure to glyphosate.

Glyphosate levels and the transfer of glyphosate across trophic levels have rarely been studied in zooplankton. The food preferences of zebrafish during the first-feeding stage (which is critical for the survival of organisms), were analyzed because of the requirement for live food. Larval survival begins to be affected when glyphosate intake exceeds 0.

A new species of Edwards, 1891 (Crustacea, Copepoda, Harpacticoida, Laophontidae) from the Caribbean coast of Colombia.

A new species of the harpacticoid copepod genus is described from specimens collected in Rodadero Beach, on Gaira Bay, on the Caribbean coast of Colombia. The species, , is described, illustrated, and com-pared with its congeners. differs from its known congeners in details of the armature of legs 1-4.

A new species of scavenger Cladocera Pseudochydorus Fryer, 1968 (Cladocera: Anomopoda: Chydoridae) from the Central Mexican Plateau.

A new species of the genus Pseudochydorus Fryer, 1968 is described from Central Mexico. P. margaritalfonsorum sp.

Biological and Biochemical Characterization of Coronado Island Rattlesnake () Venom and Antivenom Neutralization.

The Baja California Peninsula has over 250 islands and islets with many endemic species. Among them, rattlesnakes are the most numerous but also one of the least studied groups. The study of island rattlesnake venom could guide us to a better understanding of evolutionary processes and the description of novel toxins.

A record of Disparalona hamata (Birge, 1879) (Cladocera: Chydoridae) in phytotelmata of Tillandsia aguascalentensis Gardner, 1984 (Poales: Bromeliaceae).

Bromeliads (Bromeliaceae) are an extremely diverse family of the angiosperms widely distributed in the tropical and subtropical regions of the Americas and West Africa. They often serve as phytotelmata, accumulating rainwater between leaves. Such water reservoirs can be inhabited by diverse organisms.

Morphological alterations in the freshwater rotifer Brachionus calyciflorus Pallas 1766 (Rotifera: Monogononta) caused by vinclozolin chronic exposure.

Vinclozolin (VZ) is a dicarboximide fungicide widely used on fruits, vegetables and wines, effective against fungi plagues. In this study we characterized the effects of VZ using a 4-day reproductive chronic assay with the freshwater rotifer Brachionus calyciflorus. The assay included observations of several features of asexual and sexual reproduction.

Morphology and ultrastructure of the freshwater rotifer Brachionus bidentatus (Monogononta: Brachionidae) using scanning and transmission electron microscopy.

The study of sexual reproductive behavior supported by ultrastructural evidence is important in rotifers to describe differences among potential cryptic species. In this research, the morphology of the rotifer Brachionus bidentatus is described at the ultrastructural level, using electronic microscopy, together with a brief description and discussion of its sexual reproductive behavior. The characteristics of the (a) male, (b) the female, (c) the sexual egg or cyst, (d) the partenogenic egg, (e) the no-fecundated sexual egg (male egg), and (f) the trophi, were described.

A new species of Metacyclops Kiefer, 1927 (Copepoda, Cyclopidae, Cyclopinae) from the Chihuahuan desert, northern Mexico.

A new species of the freshwater cyclopoid copepod genus Metacyclops Kiefer, 1927 is described from a single pond in northern Mexico, within the binational area known as the Chihuahuan Desert. This species belongs to a group of Metacyclops species with a 3443 spine formula of swimming legs. It is morphologically similar to Metacyclops lusitanus Lindberg, 1961 but differs from this and other congeners by having a unique combination of characters, including a caudal rami length/width proportion of 3.

Bioconcentration and localization of lead in the freshwater rotifer Brachionus calyciflorus Pallas 1677 (Rotifera: Monogononta).

We studied how lead is bioconcentrated and distributed in the rotifer Brachionus calyciflorus using metal histochemistry to locate lead granules, Leadmium Green® analysis to establish the route of uptake, atomic absorption to determined the bioconcentration factor (BCF), and detected the presence of microelements in the cuticle by X-ray microanalysis with scanning electron microscopy. Our results indicate: (a) the digestive system is the main route of lead uptake in the rotifer B. calyciflorus, (b) after 24-h lead is deposited in granules in the mastax and vitellarium, (c) our energy-dispersive X-ray microanalysis indicates decalcification taking place in the cuticle of the rotifer after a 24-h lead exposure, and (d) we determined a BCF = 115 for lead after a 24 h exposure.

Ultrastructural analysis and identification of membrane proteins in the free-living amoeba Difflugia corona.

Syntaxin-1 and 25-kDa Synaptosome-associated Protein (SNAP-25) are present in the plasma membrane of several different secretory cell types and are involved in the exocytosis process. In this work, the free-living amoeba Difflugia corona was studied in relation to ultrastructure, structural membrane proteins, and proteins such as Syntaxin-1 and SNAP-25. Our results obtained by scanning electron microscopy in the amoeba without its theca, showed many membrane projections and several pore-like structures.