Texotli Blue Sponge, Amphimedon texotli

Texotli Blue Sponge, Amphimedon texotli  Underwater photographs taken in Zihuantanejo Bay, Guerrero, March 2018. Photographs courtesy of Ron Woheau, Zihuantanejo.

Phylogeny: The Texotli Blue Sponge, Amphimedon texotli (Cruz-Barraza and Carballo), 2008  is a member of the Niphatidae Family of Demosponges that are in the Phylum Porifera. The genus Amphimedon is one of nine genera in this family, and there are fifty-six species in this genus. It is relatively new to science and first reported and well described in 2008 by Cruz-Barraza, J.A. and Carballo, J.L., Zoological Studies, 47(6), 741-758 (2008).  The specific name texotli come from the Nahuatl, the Uto-Aztecan language of indigenous Mexicans, and means “blue.” In Mexico it is known as esponja texotli.

Morphology: The Texotli Blue Sponge grows in large, finger-like, tubular projections that may form branches. They have a smooth exterior with a firm consistency that tears easily. They have numerous oscules either in a line around the rim, or scattered on the branches. They are bright blue in color. These sponges reach around 20 cm (8 inches) in height.

Habitat and distribution: Texotli Blue Sponges are found growing on living and dead pocillopora corals and on rocks within coral communities. Where they are found, they can be fairly abundant, covering up to 6.8% of the sea floor. They live primarily at depths between 2 m (6 feet) and 4 m (13 feet). The Texotli Blue Sponge is a resident of the Pacific but has a limited geographic distribution, ranging along the coast of Colima southward to the coastal waters of Guerrero in southwestern Mexico. It is the first species in this genus to be found in the Eastern Pacific Ocean. Its closest relative, the Great Barrier Sponge, Amphimedon queenslandica, is found in Australia and the Green Sponge, Amphimedon viridis, found in the Atlantic.

Diet:  Texotli Blue Sponges are filter feeders, eating bacteria, organic matter, and plankton, and other microorganisms that they filter out of the surrounding sea water.

Predators:  Texotli Blue Sponges are eaten by fish such as angelfish, blennies, butterflyfish, gobies, and wrasses. They may also be eaten by sea turtles and invertebrates.

Reproduction:  Texotli Blue Sponges are simultaneous hermaphrodites ( having both male and female sex organs). Reproduction is sexual and is done via spermcast spawning. Spermcast spawning involves releasing sperm into water, while retaining the eggs. The eggs are then fertilized internally. The embryos develop in brood chambers until they reach a certain size, then disperse as planktonic parenchymella larvae. During this larval stage, they have a strong preference for darkness.

Ecosystem Interactions:   Ecosystem interactions specifically for the Texotli Blue Sponge have not been documented. Other sponges of this genus are know to provide shelter for fish, amphipods, decapods, isopods, and other small invertebrate life.

Human Interactions: While the Texotli Blue Sponge is attractive and might be popular in the aquarium trade, efforts to maintain this sponge in captivity have been unsuccessful to date. Texotli Blue Sponges have no direct impact on human activities. From a conservation perspective they have not been formally evaluated. They have limited distribution however they are fairly common and should be consider to be of Least Concern.