Cryptic Caribbean species of Scorpaena (Actinopterygii: Scorpaeniformes) suggested by cytogenetic and molecular data

Molecular Analysis and Chromosome Mapping of Repetitive DNAs in the Green Terror Andinoacara rivulatus (Cichlidae: Cichlasomatini)

Neotropical cichlids include hundreds of species whose taxonomy has benefited of molecular phylogeny and whose karyotype evolution has been related to the amount and distribution of different classes of repetitive sequences. This study provides the first integrative molecular (cytochrome c oxidase subunit 1 and 16S sequences) and cytogenetic analyses of wild samples of the green terror Andinoacara rivulatus, a cichlid naturally distributed in Ecuador and spread throughout the world as an aquarium pet. Molecular data revealed that sequences of green terror constitute a single monophyletic clade within the genus and allowed species attribution of uncertain samples previously cytogenetically analyzed. Chromosome number (2n = 48) conforms to the general trend observed within neotropical cichlids. However, mapping of different classes of repeated sequences (18S rDNA, 5S rDNA, U1 snDNA and telomeric) revealed the presence of features uncommon among representatives of these fishes, like multiple major rDNA sites, and suggested a recent occurrence of rearrangements (fusion/inversion) in two chromosome pairs.

Chromosomal polymorphism and molecular variability in the pearly razorfish Xyrichtys novacula (Labriformes, Labridae): taxonomic and biogeographic implications

The pearly razorfish Xyrichtys novacula (Linnaeus, 1758) is a sedentary benthic species distributed in both sides of the Atlantic Ocean and in the Mediterranean Sea. Previous cytogenetic analysis reported different diploid numbers in samples from Italy, Venezuela and Brazil. This research aims to test the hypothesis that samples from American Atlantic coast and Mediterranean Sea belong to the same single evolutionary lineage, characterized by intra-specific chromosome polymorphism. To this purpose a cytogenetic and molecular (mitochondrial COI sequences) survey was undertaken. Results revealed the existence of three different pearly razorfish molecular lineages: one present in Mediterranean Sea and two in the central and south American area, which are characterized by different karyotypes. One of these lineages shows substantial intra-population chromosomal polymorphism (2n = 45-48) determined by Robertsonian fusions that produce large metacentric chromosomes. On the whole data suggest that specimens morphologically identified as X. novacula correspond to three cryptic species.

Lesser devil rays Mobula cf. hypostoma from Venezuela are almost twice their previously reported maximum size and may be a new sub-species

Three rays opportunistically obtained near Margarita Island, Venezuela, were identified as lesser devil rays Mobula cf. hypostoma, but their disc widths were between 207 and 230 cm, which is almost double the reported maximum disc width of 120 cm for this species. These morphometric data suggest that lesser devil rays are either larger than previously recognized or that these specimens belong to an unknown sub-species of Mobula in the Caribbean Sea. Better data are needed to describe the distribution, phenotypic variation and population structure of this poorly known species.