Neotropical region

Molecular taxonomy and evolutionary hypothesis concerning Astyanax fasciatus (Characiformes, Characidae) from Vila Velha State Park and Tibagi and Iguaçu Rivers

D. A. Matoso, da Silva, M., Artoni, R. F., and Torres, R. A., Molecular taxonomy and evolutionary hypothesis concerning Astyanax fasciatus (Characiformes, Characidae) from Vila Velha State Park and Tibagi and Iguaçu Rivers, vol. 12, pp. 631-638, 2013.

A species complex hypothesis involving Astyanax fasciatus from southern Brazil was tested using 12S mtDNA sequences. Phylogenetic inferences were performed with maximum likelihood, maximum parsimony and Bayesian as phylogenetic methods and Hemigrammus bleheri as the outgroup. Besides 11 sequences from A. fasciatus, the data set was comprised of other partial 12S sequences including material from Astyanax altiparanae (two sequences) and Astyanax sp (four sequences), both from the Iguaçu River. The hypothesis of an A.

Characterization and description of a multiple sex chromosome system in Potamotrygon motoro (Chondrichthyes, Myliobatiformes) from the Paraná River, Argentina

D. R. Aichino, Pastori, M. C., Roncati, H. A., Ledesma, M. A., Swarça, A. C., and Fenocchio, A. S., Characterization and description of a multiple sex chromosome system in Potamotrygon motoro (Chondrichthyes, Myliobatiformes) from the Paraná River, Argentina, vol. 12, pp. 2368-2375, 2013.

The Potamotrygonidae family represents the only freshwater group of specialized elasmobranchs and is composed of 4 genera: Plesiotrygon, Paratrygon, Potamotrygon, and Heliotrygon. Individuals of Potamotrygon motoro were collected from the Paraná River at Ituzaingó (Province of Corrientes) in Argentina. Mitotic preparations were obtained using direct techniques and lymphocyte cultures. Chromosomes were studied with conventional Giemsa, C-band and nucleolus organizer region stainings.

First chromosome data on Steindachneridion scripta (Pisces, Siluriformes, Pimelodidae) from Brazilian rivers: Giemsa, CBG, G-, and RE banding

A. Claudia Swarça, Fenocchio, A. Sergio, Cestari, M. Margarete, and Dias, A. Lúcia, First chromosome data on Steindachneridion scripta (Pisces, Siluriformes, Pimelodidae) from Brazilian rivers: Giemsa, CBG, G-, and RE banding, vol. 4, pp. 734-741, 2005.

A cytogenetic study was performed on the large pimelodid species Steindachneridion scripta (Siluriformes, Sorubiminae) from the Paraná River basin (Brazil). Chromosome preparations were obtained avoiding sacrifice of the specimens, by means of lymphocyte culture, and several staining and chromosome banding techniques were applied. The karyotype consisted of 56 chromosomes, 24 metacentrics, 20 submetacentrics, 4 subtelocentrics, and 8 acrocentrics (fundamental number = 104).

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