Checklist of the Inland Fishes of Louisiana

Since the publication of Freshwater Fishes of Louisiana (Douglas, 1974) and a revised checklist (Douglas and Jordan, 2002), much has changed regarding knowledge of inland fishes in the state. An updated reference on Louisiana’s inland and coastal fishes is long overdue. Inland waters of Louisiana are home to at least 224 species (165 primarily freshwater, 28 primarily marine, and 31 euryhaline or diadromous) in 45 families. This checklist is based on a compilation of fish collections records in Louisiana from 19 data providers in the Fishnet2 network (www.fishnet2.net). The checklist has grown because of descriptions of three new species, new distribution records of both native and non-native species, and the addition numerous of marine species that are known to enter freshwaters in Louisiana

Evolutionary Divergence of Duplicate Copies of the Growth Hormone Gene in Suckers (Actinopterygii: Catostomidae)

Catostomid fishes (suckers) have duplicate copies of the growth hormone gene and other nuclear genes, due to a genome duplication event early in the group’s history. Yet, paralogs of GH in suckers are more than 90% conserved in nucleotide (nt) and amino acid (aa) sequence. Within paralogs across species, variation in nt and aa sequence averages 3.33% and 4.46% for GHI, and 3.22% and 2.43% for GHII, respectively. Selection tests suggest that the two GH paralogs are under strong purifying selection. Consensus trees from phylogenetic analysis of GH coding region data for 23 species of suckers, other cypriniform fishes and outgroups resolved cypriniform relationships and relationships among GHI sequences of suckers more or less consistently with analyses based on other molecular data. However, the analysis failed to resolve all sucker GHI and GHII sequences as monophyletic sister groups. This unexpected topology did not differ significantly from topologies constrained to make all GH sequences monophyletic. We attribute this result either to limitations in our GHII data set or convergent adaptive changes in GHII of tribe Catostomini

Histological evidence for secretory bioluminescence from pectoral pockets of the American Pocket Shark (Mollisquama mississippiensis)

The function of pocket shark pectoral pockets has puzzled scientists over decades. Here, we show that the pockets of the American Pocket Shark (Mollisquama mississippiensis) contain a brightly fluorescent stratified cubic epithelium enclosed in a pigmented sheath and in close contact with the basal cartilage of the pectoral fins; cells of this epithelium display a centripetal gradient in size and a centrifuge gradient in fluorescence. These results strongly support the idea that pocket shark’s pockets are exocrine holocrine glands capable of discharging a bioluminescent fluid, potentially upon a given movement of the pectoral fin. Such capability has been reported in many other marine organisms and is typically used as a close-range defensive trick. In situ observations would be required to confirm this hypothesis

Vacchi's palatal organ: A widespread trait in Holocephali

A palatal organ, possibly used for food sorting and processing, has previously been identified among the vomerine toothplates of the chimaeroid Chimaera monstrosa. In this study, the palatal organ was described in six additional species, confirming it is a widespread trait among holocephalans. It is proposed that this palatal structure, which appears to differ in shape according to each chimaeroid's degree of durophagy and is not homologous to the palatal structure described in teleosts, be hereby referred to as Vacchi's orga

A new Western North Atlantic Ocean kitefin shark (Squaliformes: Dalatiidae) from the Gulf of Mexico

Grace, Mark A., Doosey, Michael H., Denton, John S. S., Naylor, Gavin J. P., Bart, Henry L., Maisey, John G. (2019): A new Western North Atlantic Ocean kitefin shark (Squaliformes: Dalatiidae) from the Gulf of Mexico. Zootaxa 4619 (1): 109-120, DOI: 10.11646/zootaxa.4619.1.

Mapping Life – Quality Assessment of Novice vs. Expert Georeferencers

The majority of the world’s billions of biodiversity specimens are tucked away in museum cabinets with only minimal, if any, digital records of the information they contain. Global efforts to digitize specimens are underway, yet the scale of the task is daunting. Fortunately, many activities associated with digitization do not require extensive training and could benefit from the involvement of citizen science participants. However, the quality of the data generated in this way is not well understood. With two experiments presented here, we examine the efficacy of citizen science participants in georeferencing specimen collection localities. In the absence of an online citizen science georeferencing platform and community, students served as a proxy for the larger citizen science population. At Tulane University and Florida State University, undergraduate students and experts used the GEOLocate platform to georeference fish and plant specimen localities, respectively. Our results provide a first-approximation of what can be expected from citizen science participants with minimal georeferencing training as a benchmark for future innovations. After outliers were removed, the range between student and expert georeferenced points was <1.0 to ca. 40.0 km for both the fish and the plant experiments, with an overall mean of 8.3 km and 4.4 km, respectively. Engaging students in the process improved results beyond GEOLocate’s algorithm alone. Calculation of a median point from replicate points improved results further, as did recognition of good georeferencers (e.g., creation of median points contributed by the best 50% of contributors). We provide recommendations for improving accuracy further. We call for the creation of an online citizen science georeferencing platform