A new species of Hoplomyzon (Siluriformes: Aspredinidae) from Maracaibo Basin, Venezuela: osteological description using high-resolution computed microtomography of a miniature species

ABSTRACT A new miniature species of banjo catfish of the genus Hoplomyzon is described from the Lake Maracaibo Basin in Venezuela. The new species is distinguished from all its congeners by the straight anterior margin of the mesethmoid (vs. a medial notch); a smooth and straight ventral surface of the premaxilla (vs. presence of bony knobs on the ventral surface of premaxilla); absence of teeth on dentary (vs. teeth present on dentary); configuration of ventral vertebral processes anterior to anal fin, which are composed of single processes anterior to anal-fin pterygiophore (vs. paired process); presence of several filamentous barbel-like structures on the ventral surface of head of adults (vs. small papillous structures in the ventral surface of head of adults); and 8 anal-fin rays (vs. 6 or 7). An extensive osteological description is made of the holotype using high-resolution x-ray computed microtomography (HRXCT)

One thousand DNA barcodes of piranhas and pacus reveal geographic structure and unrecognised diversity in the Amazon

Piranhas and pacus (Characiformes: Serrasalmidae) are a charismatic but understudied family of Neotropical fishes. Here, we analyse a DNA barcode dataset comprising 1,122 specimens, 69 species, 16 genera, 208 localities, and 34 major river drainages in order to make an inventory of diversity and to highlight taxa and biogeographic areas worthy of further sampling effort and conservation protection. Using four methods of species discovery - incorporating both tree and distance based techniques - we report between 76 and 99 species-like clusters, i.e. between 20% and 33% of a priori identified taxonomic species were represented by more than one mtDNA lineage. There was a high degree of congruence between clusters, with 60% supported by three or four methods. Pacus of the genus Myloplus exhibited the most intraspecific variation, with six of the 13 species sampled found to have multiple lineages. Conversely, piranhas of the Serrasalmus rhombeus group proved difficult to delimit with these methods due to genetic similarity and polyphyly. Overall, our results recognise substantially underestimated diversity in the serrasalmids, and emphasise the Guiana and Brazilian Shield rivers as biogeographically important areas with multiple cases of across-shield and within-shield diversifications. We additionally highlight the distinctiveness and complex phylogeographic history of rheophilic taxa in particular, and suggest multiple colonisations of these habitats by different serrasalmid lineages. © 2018 The Author(s)

A case for conserving common species

I grew up in a country where fish were, first and foremost, food. At the age of nine or so, I started following my dad and uncle to nearby rivers to fish on weekends, and soon I learned to make my own tackle and go back to the rivers to fish with my friends. We never caught a lot of fish, but every fish we caught came home with us to be eaten. It never occurred to us to consider what ecological role these fish might play or how they fit into the ecosystem. In Ghana, West Africa, like in almost all the developing countries in sub-Saharan Africa, viewing fish primarily as food flows naturally from the need to survive. Once survival is secured, humans can start thinking about other things, like prestige or social status, for example [1]. As I entered my postdoc in ecology and conservation—me, a Ghanaian who identified more with fisheries and natural resource management—I felt the distinction keenly. I had not studied for any of my degrees under brand-name ecologists or conservation scientists, which I had come to realize was helpful in launching an academic career in our field. I understood then that professional pedigree really matters. What I know now is that this is not merely for the prestige and access such mentorship provides but for the intellectual shelter and sustenance I must provide as a principal investigator (PI). This is the story of building my niche as an ecosystem engineer. But it is also the story of recognizing the ecological role of species we take for granted—and why we should fund research on common species that may sustain the rare ones, some of which we have yet to discover