Fauna associada a esponjas em ambiente recifal da Ponta Verde, Maceió, Alagoas, com ênfase em anelídeos

Abstract

Sponges are essential for maintaining the marine ecosystem, sustaining communities of various organisms and serving as shelter, breeding grounds, and refuge. Annelida is one of the most abundant groups in sponges, possessing morphological and reproductive adaptation capabilities and can be found in various life stages. Despite efforts to understand the relationship between sponges and annelids, there are still gaps to be filled. In this regard, this study aims to: study the marine macrofauna community associated with Amphimedon viridis and Cinachyrella spp. found in the intertidal zone of the Antigo Iate Clube Alagoinhas Pillars at Ponta Verde Beach, Maceió, Alagoas. The specific objectives include: Describing the composition, abundance, density, and richness of annelids associated with these sponge species; Identifying reproductive organisms that use sponges as a site for reproduction; and describing a possible new species of annelid. The study was conducted at the Antigo Iate Clube Alagoinhas Pillars and adjacent areas located at Ponta Verde Beach in Maceió, Alagoas. Three specimens of each sponge species were randomly collected monthly for a year during spring tides. All fauna present in the sponges was separated and identified at the lowest possible taxonomic level, with individuals in reproductive stages being separated and analyzed to identify reproductive organisms. Species richness, abundance, and density calculations were made based on the total count of individuals and taxa. A total of 69 sponge specimens were examined, revealing a total of 4,080 individuals represented by Annelida, Crustacea, Echinodermata, Nematoda, Chelicerata, and Mollusca. Cinachyrella spp. presented a richness of 36 taxa, with 23 annelid taxa and a total abundance of 853 individuals in this group. In this sponge, Haplosyllis sp.1 and Branchiosyllis sp. n. were the annelid taxa with the highest densities. In A. viridis, 26 taxa were recorded, with 10 annelid taxa and a total abundance of 1,750 individuals in this group. In this sponge, the density of Haplosyllis sp.1 stood out. Reproductive stage organisms were found, represented by the major groups: Annelida, present in Cinachyrella spp. and Amphimedon viridis; Crustacea and Chelicerata present in A. viridis. The species described here has a dorsoventrally flattened body, light brown pigmentation along the posterior region, body length of 4-6 mm, with ~65 setigers, multilobed gills with five lobes; the proventricle and pharynx occupying 4-6 setigers each, the former with 23-35 muscle cells. It is found in Cinachyrella spp. and Amphimedon viridis. The results presented show that Annelida, Crustacea, Mollusca, Echinodermata, Nematoda, and Chelicerata use sponges as shelter, with Annelida being the most abundant group. It was possible to determine the richness, abundance, and density of taxa. Additionally, information about a possible new species for science was provided, and reproductive stage organisms were reported.