Historical warming consistently decreased size, dispersal and speciation rate of fish

There is ongoing debate as to whether fish body size will decrease with global warming and how these changes may impact dispersal ability and speciation rate. Theory predicts that, under warmer temperatures, fish grow to a smaller size, undergo a reduction in dispersal ability and increase speciation rates. However, evaluations of such predictions are hampered owing to the lack of empirical data spanning both wide temporal and geographical scales. Here, using phylogenetic methods, we show that smaller clupeiform fish (anchovies and herrings) occurred historically in warmer waters, moved the shortest distances at low speed and displayed the lowest speciation rates. Furthermore, fish moved faster and evolved rapidly under higher rates of temperature change but these historical rates are far lower than current warming rates. Our results predict a future where smaller clupeiform fish that have reduced ability to move will be more prevalent; this, in turn, may reduce future speciation

Body Size Evolution in Extant Oryzomyini Rodents: Cope's Rule or Miniaturization?

At the macroevolutionary level, one of the first and most important hypotheses that proposes an evolutionary tendency in the evolution of body sizes is “Cope's rule". This rule has considerable empirical support in the fossil record and predicts that the size of species within a lineage increases over evolutionary time. Nevertheless, there is also a large amount of evidence indicating the opposite pattern of miniaturization over evolutionary time. A recent analysis using a single phylogenetic tree approach and a Bayesian based model of evolution found no evidence for Cope's rule in extant mammal species. Here we utilize a likelihood-based phylogenetic method, to test the evolutionary trend in body size, which considers phylogenetic uncertainty, to discern between Cope's rule and miniaturization, using extant Oryzomyini rodents as a study model. We evaluated body size trends using two principal predictions: (a) phylogenetically related species are more similar in their body size, than expected by chance; (b) body size increased (Cope's rule)/decreased (miniaturization) over time. Consequently the distribution of forces and/or constraints that affect the tendency are homogenous and generate this directional process from a small/large sized ancestor. Results showed that body size in the Oryzomyini tribe evolved according to phylogenetic relationships, with a positive trend, from a small sized ancestor. Our results support that the high diversity and specialization currently observed in the Oryzomyini tribe is a consequence of the evolutionary trend of increased body size, following and supporting Cope's rule

Genetic variability in jack mackerel Trachurus murphyi Nichols: New SSRs loci and application Variabilidad genetica en jurel (Trachurus murphyi Nichols): Nuevos loci SSRs y aplicación

Nine novel microsatellite loci were developed for Trachurus murphyi. These loci were characterized in samples from three sites along the eastern South Pacific Ocean. One of the loci was monomorphic, whereas the rest of the loci had between six and 19 alleles per locus and showed the expected heterozygosity ranging from 0.653 to 0.933. These loci do not show genetic differentiation among the analyzed sites.<br>Nueve nuevos loci microsatélites fueron desarrollados para Trachurus murphyi. Estos loci fueron caracterizados en muestras de tres localidades a lo largo del océano Pacífico suroriental. Uno de los loci fue monomórfico, mientras que para el resto de los loci el número de alelos por locus oscilo entre 6 a 16 y la heterocigosidad esperada entre 0.653 a 0.933. Estos loci no muestran diferenciación entre las diferentes localidades analizadas

Usefulness of heterologous microsatellites obtained from Genypterus blacodes (Schneider 1801) in species Genypterus off the Southeast Pacifc Utilidad de microsatélites heterólogos de Genypterus blacodes (Schneider 1801) en especies de Genypterus del Pacífco suroriental

<abstract language="spa">Analizamos la utilidad de cinco loci de microsatélites aislados en Genypterus blacodes de Australia en especies de Genypterus presentes en Chile (G. chilensis, G. maculatus y G. blacodes). Los resultados muestran que los loci microsatélites amplifcan positivamente en cada especie y podrían ser utilizados en futuros estudios poblacionales

Identificación genética de poliquetos bentónicos en un hotspot in the southeast Pacific

The aim of this study was to evaluate the utility of COI, of the mitochondrial DNA, for the taxonomic determination of soft-bottom benthic polychaetes in the Chiloé Inner Sea as a particularly important zone for polychaete fauna of the southeast Pacific. The results show high genetic differentiation between morphological species of polychaetes (posterior probabilities upper 0.9), and Onuphis pseudoiridescens showed the greatest divergence (3.08 ± 0.08 S.D.). The results support the role of the COI gene as a useful molecular marker for fast and accurate taxonomic determination of benthic polychaetes. This study leads the way for research on the biodiversity and systematics of polychaetes off the Chilean coast using molecular phylogenetic criteria

SSRs in Octopus mimus: development and characterization of nine microsatellite loci

Nine microsatellite loci were developed for Octopus mimus, a cephalopod of commercial importance for artisanal fishermen. Genetic variation at these loci was examined in samples from Clavelito, a Benthic Resources Management Area (AMERB, in Spanish). All nine loci were highly polymorphic, with the number of alleles per locus ranging from 4 to 28 and the expected heterozygosity ranging from 0.651 to 0.946. These markers will be useful to address issues of population genetics, ecology, conservation and fisheries management related to that species