Meeting Abstract
The aquarium trade provides an affordable and consistent supply of hundreds of fish species that are underutilized in scientific research. In this exploratory study, we examined the mechanosensory lateral line system in the tetras (Order Characiformes; Family Characidae, ~ 1,000 species). We examined two to four individuals in each of seven species from six genera: Pristella maxillaris, Gymnocorymbus ternetzi, Hasemania nana, Hyphessobrycon pulchripinnis, Hemigrammus bleheri, Paracheirodon axelrodi, and P. innes. We also examined Danio rerio (n=3) and Carassius auratus (n=8) (Order Cypriformes; Family Cyprindae) both of which have well documented lateral line systems. Superficial neuromasts (SNs) and canal neuromasts (CNs) were stained with the fluorescent mitochondrial stain, 4-di-2-ASP, and visualized on a dissecting microscope with a GFP epifluorescence filter. After imaging neuromast distributions, fishes were prepared for SEM analysis. Similar groupings of SNs were found among all species examined, including lines or clusters on the caudal edge of the mandible and in a V-shaped line on the operculum, however the relative size difference between CNs and SNs was not consistent among the genera. For instance P. innesihas CNs and SNs of similar size, while in species of other genera, such as G. ternetzi and H. bleheri, the CNs were substantially larger than the SNs. These results reveal that the number, size, and distribution of SNs among genera of tetras should be evaluated as taxonomic characters, which may contribute to our understanding of their systematic interrelationships.
