Stingrays genus Hypanus currently encompasses nine valid species from the Atlantic and Pacific oceans, though the phylogenetic relationships amongst some
of them were based on a single mitochondrial gene and did not involve all putative Hypanus species. To address the monophyly of the genus and its relationship to
other Dasyatinae genera, we sequenced the whole mitochondrial genomes of all species that supposedly belong to this genus and representatives of Dasyatinae,
Neotrygoninae, and, as an outgroup, Fontitrygon (Urogymninae). Based on phylogenetic analyses, Hypanus is the sister-genus to all other Dasyatinae, and
this subfamily is closely-related to Neotrygoninae within the family Dasyatidae. The species F. geijskesi is closely related to H. guttatus rather than to its congeners
and should be allocated to Hypanus as H. geijskesi for the genus monophyly. After lineage delimitation analyses, we identified three species complexes composed of H. americanus, H. guttatus, and H. say, with two distinct evolutionary lineages within each, leaving the genus with 13 evolutionary units, of which six are currently under threat and only H. sabinus is of least concern. The urgency in identifying these new lineages lies in the fact they might already be under threat
before being formally described.

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 States to southeastern Brazil, was demonstrated to be paraphyletic based on protein-coding mitochondrial genome analyses. This data set also indicates that the genetic distance between the new species Hypanus berthalutzae sp. nov. and its
three closely related species (H. americanus, H. longus and H. rudis) varies from 0.82% to 3.14%. In addition, Bayesian Analysis of Population Similarity using the mitochondrial gene mt-nd2 supports the separation of H. berthalutzae sp. nov. (southwestern Atlantic) from its sister species H. rudis (eastern Atlantic). Similarly, morphological and morphometric analyses corroborated four morphotypes within the H. americanus species group and indicated the ventral caudal fold height and length and interspiracular
and interorbital lengths as useful measurements to distinguish among them. Claspers of adult males also exhibit morphological differences among species. The ENM agreed with molecular and morphological analyses and delimits the distribution of H. berthalutzae sp. nov. to shallow areas close to shore along the Brazilian coast, from the mouth of the Amazon River to S~ao Paulo State, including the northeastern oceanic
islands, suggesting that the great outflow of fresh water and sediments and the Mid-Atlantic Ridge might act as barriers. The integration of these data to describe a
new species provides information relevant to their conservation status, because all species of the H. americanus species group are under the “data-deficient” status.

IntroductionSharks of the squalomorph shark family Dalatiidae are distributed worldwide and usually occur in open water ranging from the surface to more than 3,500 meters in depth. Dalatiid sharks have a highly conspicuous morphology, being characterized by a short snout without barbels, strong jaws [1], and lower teeth with strong, greatly developed cusps, as well as a striking dignathic heterodonty [2]. These sharks also have two small dorsal fins, with the first smaller or equal to the second...