Underneath our feet, water lurks along murky tunnels. No light
penetrates the never ending darkness. The substratum is muddy and
dank. Weird, limiculous creatures reside within this rather univiting
habitat- including the subterranean sponges of Italy.
Unlike cave men, cave sponges are quite adapted to their environment.
Subterranean cave sponges lack photosynthetic and light interactions.
Energy levels are reduced considerably.
Demospongiae is the only class including subterranean and
freshwater sponges. Generally, freshwater sponges are very closely
related to their marine relatives. Also, they are not completely
dwellers of freshwater. In correlation to the waters, it is often
brackish, containing at least some fraction of salt. Within the
caves, the sponges live partially in light and in the proximity
of the cave entrance. These are not entirely freshwater. Classifications
living entirely in freshwater are stygobitic- a very rare group.
Recently, in Italy and surrounding areas of the Mediterranean,
stygobitic sponges have been discovered! In Italy, there are at
least twenty-five species of the rare stygobitic group. The caves
inhabited by these sponges are completely freshwater. Such species
live entirely in darkness, but they probably don't notice the difference
as much as a human would, being accustomed to darkness.