Carcharhinus galapagensis and Carcharhinus obscurus are challenging species to distinguish based on their physical characteristics, particularly after processing, which can hinder species-level monitoring in fisheries and conservation programs. In this study, we utilized diagnostic single nucleotide polymorphisms (SNPs) to identify 17 shark specimens collected from the Saint Peter and Saint Paul Archipelago in Brazil, a remote...

Epigenomic changes are a hallmark of aging, and DNA methylation (DNAm) has emerged as the most reliable molecular marker of an individual's age. Genome‐wide patterns of age‐associated hypo‐ and hypermethylation have been applied to generate predictive models (i.e., “epigenetic clocks”) capable of estimating chronological age in an increasingly diverse set of species including many mammals, a few birds, a reptile, and several b...

Introduction Discoveries of coelacanth populations off the East African coast and in the Indo-Pacific warrant an analysis of their potential distributions, but the necessary tools to model and project their distributions in 3 dimensions are lacking. Methods Using occurrence records for the West Indian ocean coelacanth, Latimeria chalumnae , we produced 3D and 2D maximum entropy ecological niche models and projected them into t...

The magnificent catshark Proscyllium magnificum was described in 2004 based off five specimens collected in the Andaman Sea off Myanmar. It was originally allocated to the genus Proscyllium, but recent molecular analyses suggested it was more closely related to the harlequin catshark Ctenacis fehlmanni from the western Indian Ocean. This study incorporated meristics and external and internal morphology, together with molecular...

The increased availability of reference genome assemblies of sharks and rays has contributed greatly to our understanding of their biology, including their sex-determination mechanisms. However, several publicly available genome assemblies of sharks and rays appear to be missing information about the sex of the source individuals. This can confound the investigation into genetic sex-determining elements and hinder the discover...

Management of thorny skate ( Amblyraja radiata ) in the Northwest Atlantic has posed a conservation dilemma for several decades due to the species' lack of response to strong conservation efforts in the US Gulf of Maine and the Canadian Scotian Shelf, confusion over the relationship between two reproductive size morphs of differing life histories that are sympatric in the Northwest Atlantic, and conflicting data on regional po...

Aim Biogeographic boundaries and genetic structuring have important effects on the inferences and interpretation of effective population size ( N e ) temporal variations, a key genetics parameter. We reconstructed the historical demography and divergence history of a vulnerable coastal high‐trophic shark using population genomics and assessed our ability to detect recent bottleneck events. Location Western and Central Indo‐Pac...

The genus Dichichthys was resurrected for five species previously allocated to the genus Parmaturus in the family Pentanchidae. Supraorbital crests on the chondrocranium distinguish Dichichthys from Parmaturus and other members of the family Pentanchidae. A new family, Dichichthyidae, has been proposed to contain Dichichthys. The sequence of the NADH2 mitochondrial gene confirms the placement of Dichichthys outside of the Pent...

Elasmobranchs are characterised by the presence of placoid scales on their skin. These scales, structurally homologous to gnathostome teeth, are thought to have various ecological functions related to drag reduction, predator defense or abrasion reduction. Some scales, particularly those present in the ventral area, are also thought to be functionally involved in the transmission of bioluminescent light in deep-sea environment...

An integrative approach by the congruence of genetics, morphology and ecological niche modelling (ENM) was used to delimit a new species of Hypanus (Rafinesque, 1818), a recently resurrected genus of marine stingrays comprising eight species, five of which occur in the western Atlantic. The species with the widest distribution, Hypanus americanus (Hildebrand and Schroeder, 1928), from the northeastern coast of the United State...

The Eocene whiptail stingrays of the family Dasyatidae from the Bolca Lagerstätte, NE Italy, are revised herein in detail. The analysis of the anatomical and morphometric features allows us to identify the species “ Dasyatis ” zigni (Molin, 1861) as a junior synonym of “ D. ” muricatus (Volta, 1796), and to assign it to the new genus Tethytrygon gen. n. This new taxon exhibits a unique combination of features (e.g., rhombic di...

The boom of massive parallel sequencing ( MPS ) technology and its applications in conservation of natural and managed populations brings new opportunities and challenges to meet the scientific questions that can be addressed. Genomic conservation offers a wide range of approaches and analytical techniques, with their respective strengths and weaknesses that rely on several implicit assumptions. However, finding the most suita...