ABSTRACT
The Amazon and neighboring South American river basins harbor the world's most diverse assemblages of freshwater fishes. One of the most prominent South American fish families is the Serrasalmidae (pacus and piranhas), found in nearly every continental basin. Serrasalmids are keystone ecological taxa, being some of the top riverine predators as well as the primary seed dispersers in the flooded forest. Despite their widespread occurrence and notable ecologies, serrasalmid evolutionary history and systematics are controversial. For example, the sister taxon to serrasalmids is contentious, the relationships of major clades within the family are inconsistent across different methodologies, and half of the extant serrasalmid genera are suggested to be non-monophyletic. We analyzed exon capture to reexamine the evolutionary relationships among 63 (of 99) species across all 16 serrasalmid genera and their nearest outgroups, including multiple individuals per species to account for cryptic lineages. To reconstruct the timeline of serrasalmid diversification, we time-calibrated this phylogeny using two different fossil-calibration schemes to account for uncertainty in taxonomy with respect to fossil teeth. Finally, we analyzed diet evolution across the family and comment on associated changes in dentition, highlighting the ecomorphological diversity within serrasalmids. We document widespread non-monophyly of genera within Myleinae, as well as between Serrasalmus and Pristobrycon, and propose that reliance on traits like teeth to distinguish among genera is confounded by ecological homoplasy, especially among herbivorous and omnivorous taxa. We clarify the relationships among all serrasalmid genera, propose new subfamily affiliations, and support hemiodontids as the sister taxon to Serrasalmidae. [Characiformes; exon capture; ichthyochory; molecular time-calibration; piscivory.].
Subject(s)
Characiformes , Diet , Phylogeny , Animals , Characiformes/genetics , Diet/veterinary , FossilsABSTRACT
The morphological characteristics of the autologous platelet concentrate (APC) of 31 dogs were evaluated after cooling and freezing in 6% DMSO. Blood from the jugular vein of each patient was collected and centrifuged at 191g for six minutes to obtain APC. In the fresh sample, the platelet count, MPV, PDW and cell morphology were evaluated. Four samples of each animal were sent for storage, one refrigerated at 4°C for seven days, another for 30 days and two more stored in a freezer at -80°C in the same time interval, using 6% DMSO as cryoprotectant. The conserved samples were submitted to the same laboratory analysis as the fresh sample. There was a difference between fresh and preserved samples for platelet count, cell concentration, MPV and PDW (P<0.05), except in the 30-day refrigerated group, which showed severe morphological changes. In the frozen group for seven days, no difference was observed in the percentage of activation (P>0.05). The results obtained lead to the conclusion that cryopreservation with 6% DMSO at -80°C for seven days is a favorable option for the maintenance of platelet concentrations and the morphological characteristics of APC in dogs.(AU)
