Do the morphological and functional traits of free-living marine nematodes mirror taxonomical diversity?

The taxonomical structure and diversity of nematode assemblages are the main attributes analyzed in ecology, but nematode adaptations to their habitats are still understudied. Accordingly, a survey on some known and other newly proposed morpho-functional traits was carried out in order to: determine if the morpho-functional diversity of nematodes mirrors their taxonomical diversity; and assess potential nematode adaptations to sediment type and hydrodynamic stress. Morpho-functional traits were investigated both singularly and together and showed significant differences related to these environmental factors. The greatest taxonomical and morpho-functional diversity was found in medium-coarse sand (M-CS) and at an intermedium energy level (IEL). The M-CS and IEL were probably richer in micro-habitats and subject to a low selective pressure, hosting nematodes with a wide range of adaptations. The mirroring of morpho-functional diversity with taxonomical diversity is crucial for the future growth of the use of nematodes in biomonitoring. This is because the study of their morpho-functional traits could reduce the level of work involved and the costs of any analyses.