Free-living Nematodes of Brazilian Oceanic Islands: Revealing the Richness in the most isolated marine habitats of Brazil

Abstract

HIGHLIGHTS• A complete taxonomical list of free-living marine nematodes found in Brazilian Oceanic Islands with 9 orders, 39 families, and 143 genera.• Higher nematode richness recorded in all Brazilian Oceanic Islands studied, compared to coastal environments.• Lower nematode densities found in Trindade Island than in Rocas Atoll and Saint Peter and Saint Paul Rocks.• Common dominance of epistrate feeders, predators/omnivores, or different body shapes (not vermiform) in all islands studied due to hydrodynamic processes. ABSTRACT:The taxonomic richness of marine Nematoda in Brazilian oceanic islands and similarities among them are analyzed. Results are from surveys conducted in Saint Peter and Saint Paul Archipelago, Rocas Atoll, and Trindade Island. A complete faunal list is presented, containing 9 orders, 39 families, and 143 genera. Chromadoridae and Desmodoridae were the richest families with 21 and 13 genera, respectively. Among the genera recorded, Pseudonchus and Paradraconema had not yet been recorded in Brazilian coastal environments. So far results have pointed out high richness and low similarity in composition among the studied islands. However, further studies are required, especially more systematic samplings, to help understand and to confirm the patterns found. Furthermore, to allow for complete biogeographical studies, locations not yet sampled, e.g. Fernando de Noronha and Abrolhos, should also be studied.

Meiofauna and free-living nematodes in volcanic sands of a remote South Atlantic, oceanic island (Trindade, Brazil)

“…There are few studies on meiofaunal community and free-living marine nematode associations in the Brazilian oceanic islands (Alves & Castro, 2006). Among them, Rocas Atoll is the most thoroughly studied island (Venekey & Santos, 2017), where the meiofauna community and nematode associations were characterized at different depths and habitats (see Netto et al , 1999a, b, c, 2003). In a recent review on nematodes of Brazilian oceanic islands, Venekey & Santos (2017) observed that up to 2016, nine orders, 39 families and 143 genera had been recorded.…”

“…Among them, Rocas Atoll is the most thoroughly studied island (Venekey & Santos, 2017), where the meiofauna community and nematode associations were characterized at different depths and habitats (see Netto et al , 1999a, b, c, 2003). In a recent review on nematodes of Brazilian oceanic islands, Venekey & Santos (2017) observed that up to 2016, nine orders, 39 families and 143 genera had been recorded. Diversity values can be considered high when compared with overall diversity found in the coasts of Brazil (11 orders, 59 families, 294 genera and 231 species by Venekey et al , 2010).…”

“…Studies in oceanic islands are scarce, probably due to their remote locations. Thus, collecting efforts are usually concentrated in a few sampling opportunities (Venekey & Santos, 2017). Consequently, studies focusing on the temporal variation of meiofaunal communities in these habitats are rare.…”