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We present unique data of abundance, spatial diversity, and bathymetric patterns of the Peracarida communities of the economic and ecological important scarce studied area of the southern Gulf of Mexico. Peracarida macrofauna was collected from 63 sites in a large geographical area (92.67°– 96.70° W, 18.74°–23.04° N) with a wide bathymetric gradient (185–3740 m depth) of the deep-sea southwestern Gulf of Mexico. The samples were obtained onboard the R/V Justo Sierra (Universidad Nacional Autónoma de México, UNAM) using a Reineck-type box corer during four oceanographic cruises (SOGOM 1–4; 2015–2018). We examined the bathymetric and spatial patterns of standardized abundance (ind. m-2) and taxonomic diversity (Hill numbers, q = 0, 1, and 2). Abundance patterns were related to environmental parameters (organic matter, aromatic and aliphatic hydrocarbons, bottom water temperature, dissolved oxygen and grain composition). We collected 684 specimens belonging to 53 Peracarida families of 4 orders (Amphipoda, 19; Isopoda, 17; Tanaidacea, 13; and Cumacea, 4). The most abundant orders were Amphipoda and Tanaidacea, representing 36.4% and 35.8% of the total abundance, respectively, followed by Isopoda (25.1%). Cumacea was the least abundant order (2.7%). The top ten abundant families in order were Apseudidae, Phoxocephalidae, Caprellidae, Desmosomatidae, Nototanaidae, Nannoniscidae, Tanaellidae, Ischnomesidae, Podoceridae, and Agathotanaidae, accounting for 66% of the total relative abundance. The abundance decreased with increasing depth. Highest values were recorded in the northwestern region of the study area and in the Campeche Bay salt domes zone, whereas the lowest abundance values were registered at the abyssal locations and in some sites located in the Coatzacoalcos and Campeche Canyons. The composition and structure of the peracarid community showed shifts related to depth. The major structural abiotic factors of the Peracarida community were: latitude, depth, temperature, and sediment aliphatic hydrocarbons. The diversity based on the three estimated Hill numbers consistently decreased with increasing depth. We recorded intermediate and low diversity values in almost the entire study area, except for the Campeche Bay salt domes zone and northwestern region, where intermediate and high diversity values were registered. • The Peracarida abundance decrease with increasing depth. • The alpha Peracarida diversity decrease with increasing depth. • Amphipoda, Tanaidacea, and Isopoda where the must abundant orders. • The peracarid community composition and structure shifted along the depth range. • Latitude, depth, temperature, and aliphatic hydrocarbons were the community drivers. [ABSTRACT FROM AUTHOR]

Four oceanographic cruises were carried out between April 2011 and May 2013 on the continental slope of the southern Gulf of Mexico (GoM) in a depth range of 290 to 1200 m on board the R/V JUSTO SIERRA. A total of 91 trawls covered a total swept area of 170.49 hectares. We recorded 177 fish species belonging to 80 families. Fifteen species extended their distribution into the south of the gulf and 37 increased their depth ranges. Five species could have commercial importance: Aphanopus carbo Lowe, 1839; Hydrolagus mirabilis (Collett, 1904); Helicolenus dactylopterus (Delaroche, 1809); Lophius gastrophysus Miranda Ribeiro, 1915, and Merluccius albidus (Mitchill, 1818). The most abundant species were Polymixia lowei Günther, 1859; Parasudis truculenta (Goode & Bean, 1896); M. albidus, Chlorophthalmus agassizi Bonaparte, 1840; Dibranchus atlanticus Peters, 1876; Nezumia aequalis (Günther, 1878); Yarrella blackfordi Goode & Bean, 1896; and Laemonema barbatulum Goode & Bean, 1883. High values of fish species richness, diversity, and evenness were registered throughout the study area. A high percentage of the fish species (97%) collected during this project are distributed in the entire GoM. Most of the species showed a wide depth distribution; however, a vertical zonation of species can be observed. [ABSTRACT FROM AUTHOR]

We examined the diversity, abundance, distribution, and average size of squat lobsters collected during eight cruises conducted on the continental shelf and slope of the Gulf of Mexico (Mexican/USA border to the Caribbean Sea). Six species belonging to two genera of Chirostyloidea, and 25 species of four genera of Galatheoidea are reported. A total of 1513 specimens were obtained of which 95 were Chirostylidae, two Galatheidae, 285 Munidopsidae, and 1131 Munididae. Of the species collected, 13.8% were only known from Caribbean Sea. Three species of Chirostylidae--G. salvadori, U. capillatus, and U. spiniger--as well two of Munidopsidae, M. bradleyi and M. riveroi, are recorded for the first time in the Gulf of Mexico. The upper bathymetric range of one species and the lower one for eight species are extended. Biological and ecological traits of squat lobsters in the southern Gulf of Mexico are also provided. [ABSTRACT FROM AUTHOR]

A new hermit crab species of the family Paguridae, Tomopaguropsis ahkinpechensis sp. n., is described from deep waters (780-827 m) of the Gulf of Mexico. This is the second species of Tomopaguropsis known from the western Atlantic, and the fifth worldwide. The new species is morphologically most similar to a species from Indonesia, T. crinita McLaughlin, 1997, the two having ocular peduncles that diminish in width distally, reduced corneas, dense cheliped setation, and males lacking paired pleopods 1. The calcified plates on the branchiostegite and anterodorsally on the posterior carapace, and the calcified first pleonal somite that is not fused to the last thoracic somite, are unusual paguroid characters. A discussion of the affinities and characters that define this new species is included, along with a key to all five species of Tomopaguropsis. [ABSTRACT FROM AUTHOR]

Introduction: The Ophiuroidea class is the most diverse of the Phylum Echinodermata, with 2 064 described species, which can be found from intertidal zones to abyssal depths, but the fauna of Yucatan peninsula needs more study. Objective: To describe the diversity of ophiuroids in the Yucatan continental slope. Methods: Information was compiled from four oceanographic surveys carried out in August 2005, June 2007 (BIOREPES 1 and 2: BRP1 and BRP2), April 2011 and August 2014 (COBERPES 2 and 6: CBP2 and CBP6). The specimens were obtained by trawling with a shrimp net in soft substrates and with a skimmer-type trawl dredge at a depth range of 200 to 1 071 m off the states of Yucatán and Quintana Roo, Mexico. Results: We found members of two superorders, five orders, six suborders, five superfamilies, 18 families, 28 genera and 43 species. Conclusions: The northeast zone Yucatan Peninsula has at least 43 species, of which 19 are new records for the area. [ABSTRACT FROM AUTHOR]

A new species of squat lobster, Munidopsis shulerae sp. nov., from the Gulf of Mexico and western Caribbean, is fully described and illustrated. This new species is named in honor of the late Barbara Shuler Mayo (1945-1988), who first recognized this new taxon in her 1974 unpublished doctoral dissertation, but never formalized it. This new species is placed in the Anoplonotus group based on the presence of simple, narrow rostrum, spineless eyes, fused sternites 3 and 4, well-marked carapace regions, unarmed pleonal tergites, and smooth dactyls of pereopods 2-4. Among western Atlantic congeners, M. shulerae sp. nov. is most similar to M. polita (Smith, 1883), from which it can be distinguished by the straight shape of the rostrum with a tuberculate dorsal carina extending to the epigastric region, coarse ornamentation of the carapace, and a conspicuous submarginal protuberance on each side of the carapace between the antennal and ocular peduncles.

Distribution and abundance of species of Crangonidae and Glyphocrangonidae in the Mexican deep-waters of the Gulf of Mexico were analyzed through six research cruises onboard of the R/V Justo Sierra of the Universidad Nacional Autónoma de México using an otter trawl in a depth range of 300-1200 m. We collected two and five species of the Crangonidae and Glyphocrangonidae families, respectively. We provide information about its depth and geographic distribution, abundance, frequency of occurrence and size structure. Glyphocrangon, composed of five species (G. aculeata, G. alispina, G. haematonotus, G. longleyi and G. spinicauda), was the most common and abundant component during the benthic trawls with a total of 1125 individuals. The family Crangonidae recorded only one genus and two species (Parapontocaris caribbaea and P vicina) with 21 individuals. A taxonomic key for these crangonid and glyphocrangonid shrimps of the Gulf of Mexico is also provided.