Phylogeographic patterns of Cyphocharax from trans-Andean rivers and northward expansion to lower Central America (Teleostei, Curimatidae).

Phylogenetic analyses of mitochondrial and nuclear data of 31 specimens of Cyphocharax from trans-Andean rivers support the presence of one lineage of Cyphocharax aspilos in Lago Maracaibo and three cryptic lineages of Cyphocharax magdalenae: (1) Cauca-Magdalena and Ranchería, (2) León and Atrato, and (3) Chucunaque-Tuira, Santa María, and Chiriquí basins of Central America. Results suggest that the Serranía del Perijá facilitated Late Miocene cladogenetic events, whereas post-Isthmian C. magdalenae expansion was enabled by gene flow across the lower Magdalena valley and Central American lowlands.

A new species of Pimelodella Eigenmann amp; Eigenmann, 1888 (Siluriformes: Heptapteridae) from the Sierra Nevada de Santa Marta, Colombia.

A new species of Pimelodella is described from northern coastal drainages of the Sierra Nevada de Santa Marta (SNSM), Colombia. The new species is diagnosed from all trans-Andean congeners by the following unique combination of characters: head length 22.2-23.

Karyotypic Divergence of Two Co-Occurring Species of Andean Climbing Catfishes (Siluriformes: Loricarioidei: Astroblepidae).

The monotypic Astroblepidae fish family includes 81 species distributed along Central and Northern Andes in South America and Panamá in Central America; most aspects regarding its biology, taxonomy, and chromosomal features remain largely unknown. This study reports the karyotype of two sympatric Astroblepus species from the Colombian Andes, aiming to provide novel information on karyotype organization and reveal possible chromosomal rearrangements occurred on these species, through mapping of different repetitive DNA classes, including microsatellites and ribosomal DNA multigene families. The results showed differences in the chromosome number and karyotypic formula: Astroblepus grixalvii had 2n = 52 (28m+8sm +12st +4a) with the metacentric pair number 1 as the largest chromosome pair, whereas Astroblepus homodon had 2n = 54 (30m+8sm +8st +8a) and less evident chromosome size differences.

A new species of Creagrutus (Characidae: Stevardiinae) from the upper Río Magdalena, Colombia.

A new species of Creagrutus is described from several localities in the upper Río Magdalena drainage, Colombia. Creagrutus dulima n. sp.

An Unusual Accumulation of Ribosomal Multigene Families and Microsatellite DNAs in the XX/XY Sex Chromosome System in the Trans-Andean Catfish Pimelodella cf. chagresi (Siluriformes:Heptapteridae).

This work constitutes the first cytogenetic characterization of a trans-Andean species of Heptapteridae. The catfish Pimelodella cf. chagresi from the Upper Rio Magdalena was studied, applying standard cytogenetic techniques (Giemsa, C-banding, and argyrophilic nucleolar organizer region [Ag-NOR]) and fluorescence in situ hybridization techniques using repetitive DNA probes: microsatellites (CA and GA) and ribosomal RNA (rRNA) multigene families (18S and 5S recombinant DNA [rDNA] probes).