Axiinellidae Family of Dermosponges
One Dermosponge from the Axiinellidae Family can be found in this website:
Nayarit Axinella Sponge, Axinella nayaritensis. A representative of the Axinellidae Family of Dermosponges.
Phylogeny: Axinellid Sponges of the Axinellidae Family of Demosponges belong to the phylum Porifera. They are in the class Demospongiae, the subclass Heteroscleromorpha, and the order Axinella. The Axinellidae Family is one of four families in that order. The Axinellidae Family contains nine genera and around ninety-nine species. The family name Axinellidae comes from both the Greek and Latin words meaning “little ax”. This refers to the flattened axial skeletons of these animals. Axinellids are simple organisms, however classifying them is quite complex, requiring microscopic examination and/or genetic analysis. Field identification based on external morphology is always subject to uncertainty.
Morphology: Axinellid Sponges are multi-cellular animals that lack internal organs and a nervous system. They generally grow erect and may be arborescent (tree-like), fan-like, lamellate, tubular, or cup-shaped. Some grow in an encrusting or massive clump form. The branches and lamellae are often flattened, and webbed or fused together. The surface is tough, flexible, and rubbery, with a velvety or microhispid texture. Ectosomal (external) skeletons are either unspecialized or absent. They do have Choanosomal (round or ovate cells with a flagellum and a collar around the flagellum) skeleton of ascending spiculo-fibers. Their oscula (pores) are usually small, single, and located on the tips or sides of branches, or running along the distal edges of lamellae. Water is drawn through these oscula and then circulated through cells within the body, before being expelled through larger openings. This water flow provides oxygen and nutrients, and removes wastes as it passes through the body cells. The water is moved by the beating of choanosomal flagella, which line the surface of chambers that are connected by canals. Axinellid Sponges are often reddish, orange, tan, or yellow in color. They range from 20 cm (7.9 inches) to 40 cm (15.7 inches) in height.
Habitat and Distribution: Axinellid Sponges are found on hard surfaces such as coral, rock, shells, and man made structures and also on soft substrates. The photosynthetic species in the Axinellidae Family generally live in shallow, sunlit water to a depth of 40 m (131 feet), but deep water species can live at depths up to 1,800 m (5,900 feet). Axinellids are found worldwide in temperate to tropical seas. Eleven species from the Axinellidae Family are found in Mexican waters.
Reproduction: Axinellid Sponges may be gonochoric (male or female for life) or simultaneous hermaphrodites (having both male and female sex organs). Sexual reproduction is either oviparous or viviparous. Oviparous spawning is done through broadcast spawning, with external fertilization. Viviparous 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. Axinellid Sponges also reproduce asexually through fragmentation, and some species through budding.
Ecosystem Roles: Axinellids feed by filtering plankton from the surrounding water. The sharp spicules of these sponges deter many predators, and some species are toxic. Even with these defenses, sponges fall prey to echinoderms, fishes, sea slugs and Hawksbill Sea Turtles. Axinellids host many types of animals in commensal relationships, where the other species receive protection from the structure of the sponge, and the sponge is not harmed. These animals include amophipods, brittle stars, small fish, isopods, nematodes and polychaetes. Axinellids are of interest to medical researchers because they contain bioactive compounds that have exhibited anticancer, antimicrobial, anti-tubercular and neuroprotective properties.