Carlos E. Paz-Ríos

Intertidal and shallow water amphipods (Amphipoda: Gammaridea and Corophiidea) from Isla Pérez, Alacranes Reef, southern Gulf of Mexico

Tropical coral reefs are known to exhibit high levels of biodiversity. Amphipod crustaceans are successfully adapted to a wide range of marine habitats in coral reefs, but some regions, such as the Campeche Bank in southern Gulf of Mexico, are poorly studied or even unsurveyed for amphipods. To begin to address this paucity of information, the present study records amphipod species from Isla Perez, an island of the Alacranes Reef National Park, southern Gulf of Mexico. Twenty sites were sampled in the intertidal zone and shallow water adjacent to the island. Thirty-one species of amphipod were identified, 15 of which represented a geographical range extension to the northern Yucatan Peninsula, with four new records for the Mexican south-east sector of the Gulf of Mexico; nine for the Gulf Coast of Mexico; and two for the entire Gulf of Mexico. Significantly, a difference in faunal composition between windward and leeward areas of the intertidal zone was found.

Dulichiella celestun, a new species of amphipod (Crustacea: Amphipoda: Melitidae) from the Gulf of Mexico, with a key and zoogeographic remarks for the genus in the western Atlantic

The discovery of a new melitid amphipod in the Celestun Biosphere Reserve (northern Yucatan peninsula, SE Gulf of Mexico) is reported. Dulichiella celestun sp. nov. differs from its congeners by an unique set of characteristics: truncated lateral cephalic lobe, mandibular palp article 1 having inner margin produced distally, carpus longer than the propodus of gnathopod 1, gnathopod 2 propodus distolateral crown with four spines, pereopods 3-7 dactylar unguis anterior margin with two accessory spines, and urosomite 3 bearing four dorsal spines. A key to species and zoogeographical affinities among members of the genus in the western Atlantic are also provided.

Caprellids (Crustacea: Amphipoda) from the Gulf of Mexico, with observations on Deutella mayeri, redescription of Metaprotella hummelincki, a taxonomic key and zoogeographical comments

Seventeen species of caprellid amphipods have been recorded so far in the Gulf of Mexico. New distributional and habitat data are included for 12 species. Pseudaeginella biscaynensis has been recorded again in the Gulf of Mexico for the first time since it was originally described 45 years ago. New morphological information based on the development of Deutella mayeri and a redescription of Metaprotella hummelincki are also provided, along with a key for species identification and zoogeographical comments at the regional and global scales.

Intra-Annual Variability of a Benthic Amphipod Assemblage (Crustacea: Amphipoda) in a Tropical Shallow Coastal Environment

The community structure of tropical soft-bottom macrofauna is generally considered temporally stable. Here, we document the intra-annual variability of an amphipod assemblage from a tropical benthic habitat. The study was carried out in a shallow coastal environment of the southern Gulf of Mexico, based on historical data obtained from monthly samplings from June 2007 to May 2008, which encompassed three seasons: rainy, cold fronts and dry. Water and sediment variables were recorded to characterize the habitat, and amphipods were collected to assess changes in composition, density, and feeding modes. Using habitat characteristics, the predefined climatic seasons were examined with a discriminant analysis to order the sampling months into the three seasons. A nested analysis of variance showed that, at monthly and seasonal scales, the assemblage is more variable than expected. The species richness and density varied significantly over time, mostly at the monthly scale. Furthermore, a correspondence analysis showed that the species composition was distributed seasonally; this ordination was validated by a permutational multivariate analysis of variance. Finally, a redundancy analysis between species and habitat characteristics revealed seasonal relationships between the environmental conditions and the amphipod fauna. We propose a conceptual model to summarize the joint variation of environmental and biological factors. The present study suggests that an ecological turnover occurs at the site, along with habitat partitioning among the species through time, which depends on the species and its trophic preferences.

Species richness and spatial distribution of benthic amphipods (Crustacea: Peracarida) in the Alacranes Reef National Park, Gulf of Mexico

The diversity and distribution of benthic amphipods has been explored in the Alacranes Reef, which is the largest coral reef ecosystem in the Gulf of Mexico. New insights into species richness, spatial distribution and extension of geographical ranges are presented by using data from published records and field surveys. A total of 117 species have been recorded, 9 of which are potentially new to science, 39 of which have new geographical records, and 7 are non-indigenous and previously reported in the literature as potentially invasive. Based on the use of a species-richness indicator (Chao 2), the expected species number is 40% higher, up to 200 spp., when compared to the observed species richness. The spatial distribution of amphipods varied significantly as a function of habitat type, showing the highest richness values on coral patches and the major abundances on man-made structures, such as navigation buoys and fishing traps. Multivariate analyses suggested the distinction between three taxonomically diverse species assemblages that showed similar ecological affinities, i.e. those on: (1) soft-bottom environments, grouping bare substrata and seagrass beds habitats; (2) hard-bottom environments, grouping coral patch and reef wall habitats; and (3) artificial substrata. The results highlight the importance of this reef ecosystem for a high amphipod diversity, but it is susceptible to future modifications in the presence of non-indigenous species, potentially invasive, on artificial substrata.

A dataset on the species composition of amphipods (Crustacea) in a Mexican marine national park: Alacranes Reef, Yucatan

Abstract Background Alacranes Reef was declared as a National Marine Park in 1994. Since then, many efforts have been made to inventory its biodiversity. However, groups such as amphipods have been underestimated or not considered when benthic invertebrates were inventoried. Here we present a dataset that contributes to the knowledge of benthic amphipods (Crustacea, Peracarida) from the inner lagoon habitats from the Alacranes Reef National Park, the largest coral reef ecosystem in the Gulf of Mexico. The dataset contains information on records collected from 2009 to 2011. Data are available through Global Biodiversity Information Facility (GBIF). New information A total of 110 amphipod species distributed in 93 nominal species and 17 generic species, belonging to 71 genera, 33 families and three suborders are presented here. This information represents the first online dataset of amphipods from the Alacranes Reef National Park. The biological material is currently deposited in the crustacean collection from the regional unit of the National Autonomous University of Mexico located at Sisal, Yucatan, Mexico (UAS-Sisal). The biological material includes 588 data records with a total abundance of 6,551 organisms. The species inventory represents, until now, the richest fauna of benthic amphipods registered from any discrete coral reef ecosystem in Mexico.