Macrofaunal assemblages associated with two common seagrass‐dwelling demosponges (Amorphinopsis atlantica and Haliclona implexiformis) in a tropical estuarine system of the southern Gulf of Mexico

Among the ecological roles that sponges play in marine ecosystems, one of the highlights is their ability to host a wide diversity and abundance of epibenthic organisms. However, of the different marine environments, this role has been less investigated in seagrass-dwelling sponges. In this study, the main objective was to determine whether the structure of the associated faunal assemblages in two common sympatric species of seagrass-dwelling sponges ( Amorphinopsis atlantica and Haliclona implexiformis ) vary depending on the volume and morphology of the host sponge as well as the environment to which both sponges are exposed. Even though the collection sites had the same habitat type (seagrass meadows composed by Thalassia testudinum and Halodule wrightii ) and depth, there were substantial differences in faunal composition (ANOSIM test, R = 0.86) between both sponge species. The value of the data on species richness, diversity, and abundance of associated organisms was significantly higher in the individuals of A. atlantica than in those of H. implexiformis . These differences in the community structure of associated fauna could be influenced by the differential growth form of the hosts (e.g. growth form and oscula diameter) as well as their distinct environmental preferences (sites with different degrees of exposure to wind-generated waves and levels of human disturbance). This study contributes to the knowledge on the functional role that sponges play in seagrass meadows, one of the world’s most endangered ecosystems. Furthermore, it underlines the importance of examining both, the sponge morphology and the local environmental conditions, to explain spatial variations in the macrofaunal assemblages associated with sponges.