Aramayo, V. | bioRxiv Science

bioRxiv2022

Biodiversity and distribution of sea anemones (Cnidaria, Anthozoa, Actiniaria) in Peru

Diverse and abundant sea anemones are common in shallow marine areas. Detailed biodiversity analysis in Peru are comparatively scarce. To contribute to the biodiversity inventory and distribution information of this taxa, we analyzed exhaustively the available bibliography in Peruvian waters. A total of 23 anemone species were identified, distributed in 68 localities, and grouped into 1 Order (Actiniaria), 6 Families (Actiniidae, Actinostolidae, Aiptasiidae, Isanthidae, Phelliidae and Sagartiidae) and 20 Genera. The most reported species are Anthothoe chilensis (37 references), Phymactis clematis (28), Phymanthea pluvia (27), Oulactis concinnata (18), and Antholoba achates (15). Lima is the region with the highest number of publications, followed by La Libertad, Piura, Lambayeque, and Ancash. Anthothoe chilensis occurs in almost all the Peruvian coastal regions. On the contrary, O. concinnata has been primarily observed in Lima, while A. achates occurred only in the southern regions (Ica, Arequipa, and Moquegua). Rocky substrates (~55% records) seem to be the most suitable habitat for sea anemones in Peru, corresponding to exposed (e.g. vertical walls) and sheltered zones (e.g. rocky crevices, caves, under rock areas). Although most of the species in Peru exhibit a relatively wide spatial distribution, our results suggest that there are several regions with little or no research efforts. Despite a growing study effort over the past 30 years (>50% of biodiversity reported), the current biodiversity status for this group is still unclear. A significant effort is needed to better analyze occurrence patterns and unveil new species regarding a changing environmental scenario with human influence.

ecology↗

bioRxiv2020

Free-living marine nematodes diversity at Ponta Delgada-Sao Miguel (Azores archipelago, North-East Atlantic Ocean): first results from shallow soft-bottom habitats

Contrasting (sand, algae, rocky-dominated, mixed) benthic habitats were sampled to characterize marine nematode diversity inhabiting surface sediments in Sao Miguel (Azores, North-East Atlantic Ocean) in July 2019. Nematodes were extracted from the surface layer of sediments and morphologically identified using light microscopy. Nematode taxonomy was based on living/fresh specimens) to ensure a suitable recognition of morphological traits. Our results provide a preliminary checklist of free-living marine nematode genera from 21 intertidal and sublittoral sandy beach sites along the coast of Sao Miguel island, Azores archipelago, Portugal. The nematode fauna was represented by 4 orders, 21 families, and 43 genera. Cyatholaimus, Desmodora and Daptonema had two morphospecies each. Enoplida was represented by 8 families and 13 genera, while Chromadorida by 7 families and 18 genera, the latter corresponding to the most diverse nematode group. Monhysterida had 5 families and 10 genera and Araeolaimida was represented by a single 1 family and 2 genera. The most common genera (i.e., accounting for 75% of all organisms) included Adoncholaimus (most abundant genus, 32 specimens), Axonolaimus (18), Cyatholaimus (17), Enoploides (13), Rhabdocoma, and Acanthopharynx (11). Viscosia and Enoplolaimus were represented by 7 specimens, whilst Halalaimus, Desmoscolex, Monophostia, Daptonema, and Theristus obtained only 6 each. The dominant nematode taxa of Sao Miguel island have been commonly previously reported in other coastal habitats including sandy beaches. They can be considered typical meiofaunal components of intertidal sandy beaches. Many of the nematode morphotypes found in Sao Miguel island could represent new species to science. As far as we know, this is the first report on free-living nematodes for Sao Miguel Island and for marine shallow water in the Azores. Our findings will serve as an import baseline for future research aiming to improve our understating of nematode communities in volcanic islands such as Sao Miguel in the Azores archipelago.

ecology↗