The taxonomic status of butterfly rays within the genus Gymnura remains a subject of ongoing debate among researchers. Some authors recognize up to five valid species for the Americas, while others considered several to be synonyms, which has posed a persistent challenge. We aimed to shed light on this complexity by employing molecular operational taxonomic units (MOTUs) based on the mitochondrial gene cytochrome oxidase I (COI). Genetic sequences were obtained from fresh muscle tissue collected in the marine ecoregions corresponding to the type locality from all the nominal butterfly ray species distributed along the Eastern Tropical Pacific (ETP). Our results unveiled compelling findings; all the species delimitation models used consistently identified seven MOTUs for the American continent and an extra G. altavela MOTU restricted to Africa. In addition, our results and models exceeded the worldwide accepted interspecific threshold of 2.0%. Remarkably, our results support the taxonomic reinstatement of Gymnura afuerae (Hildebrand, 1946) as a valid species, with a range expanding into the ETP in the Southern Hemisphere. Similarly, our data support the recent suggestion of resurrecting Gymnura valenciennii (Duméril, 1865) as a valid species in the western Atlantic. These findings urge a reassessment of the conservation status and a comprehensive taxonomic revision of American butterfly rays.

Echiophis brunneus, comúnmente conocida como anguila pecosa, es una especie bentónica costera de la familia Ophichthidae. Su distribución se reporta para el Pacífico Oriental desde el Golfo de California (EEUU) hasta el Golfo de Guayaquil (Ecuador). Se reporta por primera vez la presencia de E. brunneus a partir de tres ejemplares capturados en el norte del Perú. Así mismo se registra una nueva talla máxima para la especie y se adiciona la secuencia COI a la base de datos BoldSystems. Las características externas y morfométricas de los ejemplares analizados coinciden con el género Echiophis y la especie E. brunneus. Una de las principales características para su determinación fue la observación del diente canino grande localizado en la zona distal del vómer. A nivel molecular, se alinearon las secuencias COI de las especies del género Echiophis de 652 pares de bases, con 80 sitios variables y 24 sitios informativos de parsimonia. Las distancias genéticas (Kimura, 1980) entre E. brunneus con E. punctifer y E. intertinctus fue de 0.087 ±0.013 y 0.095 ±0.014 respectivamente. Los especímenes fueron hallados en condiciones oceanográficas, ligeramente cálidas con presencia de Aguas Ecuatoriales Superficiales y normales, propias del arribo de ondas Kelvin cálida a la costa Norte Centro de Perú, provocando el desplazamiento de la especie hasta la Región La Libertad, así mismo sugerimos que es posible el establecimiento de una población de esta especie en la costa norte del Perú

This work documents the first record of Anthias noeli Anderson & Baldwin, 2000 in Peru. Between 2016 and 2019, fifteen specimens were captured from the littoral of the Tumbes Department, located in the northernmost of Peru. Fresh photographs were taken of the specimens and meristic and morphometric analyses were conducted for species identification. Additionally, muscle tissue was extracted from five individuals to determine COI gene sequences. Phylogenetic analyses confirmed the specimens' identity as A. noeli, and the sequences were deposited in the public database BOLD Systems, representing the first deposited sequences for this species. This record expands the southern distribution of A. noeli.

A new species of the Aulopidae is described from the waters of southern Ecuador and northern Peru. Aulopus chirichignoae sp. nov. was previously confused with Aulopus bajacali Parin & Kotlyar, 1984, but it differs from this species by a significantly marked elongation of the dorsal fin rays in males (absent in females), a smaller head, modal differences in dorsal and anal ray counts (15 vs 14 and 11 vs 12, respectively), a higher number of vertebrae (50–51 vs 47–49), and color differences, especially on the dorsal fin. DNA barcoding analysis supported the status of new species, evidencing a 4.2% and 2.8% divergence with Aulopus filamentosus (Bloch, 1792) and A. bajacali, respectively. A sequence of an Aulopus sp., collected in the Tropical Eastern Pacific, matches the new species with only a 0.4% divergence, indicating that Aulopus chirichignoae sp. nov. is distributed at least as far north as the Paramount Seamount at 3°20.35’N, ca. 400 km north of the Galápagos Islands.

Specimens of Caranx sexfasciatus (Bigeye trevally) were collected from northern and central Peru between 2021 and 2023, marking the first confirmed record of this species in Peruvian waters. This study represents a significant extension of its known range, previously reported only as far south as Ecuador. Morphological and molecular analyses were conducted to confirm species identification, revealing diagnostic coloration and physical traits. Observations near oil platforms suggest artificial reefs play a critical role in its habitat preference. The species’ presence in the Humboldt Current may be linked to the El Niño-Southern Oscillation (ENSO), which elevates sea temperatures and influences marine biodiversity distribution. This report not only extends the known range of C. sexfasciatus but also highlights the ecological importance of artificial reefs and climate events in shaping its distribution.