Gerardo Green’s Sponge, Aplysina gerardogreeni
Gerardo Green’s Sponge, Aplysina gerardogreeni. Underwater photographs taken in Bahía de Banderas, Puerta Vallarta, Jalisco, July 2026. Photographs and identifications courtesy of Greg Timms, youtube.com/@CoralmasterdivesPuertoVallarta/videos.
Phylogeny: The Gerardo Green’s Sponge, Aplysina gerardogreeni (Gomez & Bakus, 1992), is a member of the Aplysinidae Family of Sponges. The Aplysina Genus is one of three genera in the Aplysinidae Family, and the are forty-three species in the Aplysina Genus. The family name Aplysinidae and the genus name Aplysina come from the Greek words meaning “without a shield”. This refers to these sponges lacking the silicate or calcium carbonate spicules that protect sponges in other families. The species is named in honor of Mexican biologist Gerardo Green, whose research has contributed to the establishment of biosphere reserves. They are known in Mexico as Esponja de Gerardo Green.
Morphology: Gerardo Green’s Sponges may be cushion-like or a lobular mass with several tubular lobules, each of which is topped with a oscular aperture. The lobules are from 1 to 2.5 cm (1,0 inch) high and 1.0 cm (0.4 inch) wide. The basal sponge mass can reach 10 cm (3.9 inches) in diameter. Their surface is fairly smooth, with circular or oval-shaped oscules that are 1 mm to 5 mm in the length ones. Their skeletal structure consists of fibers, which form a regular tridimensional polygonal network. In contrast to other keratose sponges, Aplysina skeletons are mostly made not of spongin, but of alpha-chitin. Living specimens vary in color from bright to dull yellow and some parts are slightly pink, red or brown. They turn dark brown or purple when removed from water. Gerardo Green’s Sponges differ from the Latticed Sponge, Aplysina clathrata, which has interconnected tubes throughout the surface, forming a lattice-like structure.
Habitat and Distribution: Gerardo Green’s Sponges are generally found attached to hard substrates such as rocks, coral rubble, wreckage, and concrete. They live from the intertidal zone, and to depths up to 30 m (100 feet). Gerardo Green’s Sponges are a tropical to sub-tropical Eastern Pacific species that are found in Mexican waters of the Pacific Ocean from from Isla Espiritu Santo, Baja California Sur, southward along the entire mainland coast to Guatamala. Some sources extend their northern range to the southern Sonora. They are the most prevalent sponge species in most of this range. They are absent from the west coast of the Baja Peninsula.
Diet: Gerardo Green’s Sponges are filter feeders that pump water through their body wall and filter out micro-plankton and suspended organic matter. The water enters the body through the pores and is expelled through the osculi. In doing so, they filter the water around them and recycle organic matter to higher trophic levels.
Predation: While Gerardo Green’s Sponges rely on bad-tasting or toxic chemical metabolites to deter most generalist predators, they are vulnerable to specialized spongivorous predators. Their primary predator is the Yellow Umbrella Slug, Tyodina fungina.
Reproduction: The reproduction of Gerardo Green’s Sponges is not well documented. Most likely, as in other demosponges, it is logical to assume that reproduction occurs through both sexual and asexual processes, with asexual fragmentation being their primary method of reproduction.
Ecosystem Interactions: Gerardo Green’s Sponges contribute to the ecosystem by filtering the water in a localized area and moving organic matter to higher trophic levels. They also have mutualistic relationships with multiple species, whereby the other animals receive a place to live, and the sponge feeds on their waste matter. These symbionts include brittle stars, crabs, small fish and shrimp.
Human Interactions: Gerardo Green’s Sponges have no direct impact on human activities. From a conservation perspective they have not been formally evaluated.
Synonyms: None