Amorphinopsis atlantica Carvalho, Hajdu, Mothes & van Soest, 2004 (Porifera: Halichondriidae): notes on its distribution in the Colombian Caribbean.

Amorphinopsis atlantica (Halichondriidae) is the only known species of its genus in the Atlantic Ocean. It is a brittle, massive sponge with variable projections and coloration ranging from yellow to dark green, characterized by oxeas and accessory styles. Originally described from Brazil's southwestern coast, it has since been reported in several Caribbean sites, typically inhabiting submerged mangrove stilt-roots in coastal lagoons. Although shallow-water sponges in the Colombian Caribbean have been studied, this conspicuous species had not been previously documented in lagoonal systems of the region. This study reports its presence for the first time in the Mallorquín (Atlántico Department) and La Escollera (Magdalena Department) coastal lagoons. The report includes new information on its morphology, habitat, substrata, distribution, and ecology in the Colombian Caribbean. Two potential threats to the species were identified: in some areas of the Mallorquín coastal lagoon, a high degree of sedimentation was observed, causing individuals to become buried within the sediment, while in La Escollera, recent heavy rainfall and runoff events were followed by the disappearance of sponges from mangrove roots. These findings highlight the need to incorporate A. atlantica into local management plans to ensure its protection.