The title, Coral Sponge, gives reference to the beautiful coral color of this sample and because I’m 95% certain it’s a sponge and not a coral fossil. The main reason is because of the lack of vertical septa walls inside the cups, or in the case of sponges, pores. If you have reason to believe it’s not a sponge, feel free to comment.
There are some 5,000 to 10,00 known species of sponges and identification usually depends on the patterns and shapes of their spicules (tiny rods used for defense), usually only visible through a microscope in order to distinguish.
In lieu of this, I can only wager a guess as to its exact identity. It’s a rather attractive piece from my mother-in-law’s collection she gathered in the 70’s and 80’s off Florida beaches. So, I’m guessing it’s some kind of calcareous type which forms a hard calcium carbonate skeleton; and I would also say that it’s a tube type of some kind as well.
Below, I found an image of a tube type of sponge from a Florida reef. It looks fairly close in comparison.
Source: http://reefguide.org/carib/pixhtml/brownclusteredtube1.html
INTERESTING SPONGE FACTS
- Sponges are multicellular organisms that have bodies full of pores and channels allowing water to circulate through them.
- Sponges do not have nervous system, nor digestive or circulatory systems; instead their water flow system perform all the necessary functions.
- For defense, sponges shed rod-like spicules forming a dense carpet several meters deep that keep away echinoderms (i.e. starfish) which prey on them. They also may produce toxins that prevent other prey from growing on or near them.
- Their bodies have two outer layers, separated by a non-living gel layer which contains the tiny rod-like spicules.
- Sponges are sessile (attached to a substrate or hard surface).
- Most sponges live in quiet, clear waters because sediment stirred up by waves or currents would block their pores making it difficult for them to feed and breathe.
- Sponges improve water quality as effective biological filterers, extracting microscopic food and bacteria from the current.
- Sponges evolved over 500 million years ago.
- Sponges form different shapes, including tubes, fans, cups, cones, blobs, barrels, and crusts.
Sponge Classification
Kingdom: Animalia (animals)
Phylum: Porifera (having pores)
Four Classes
Demosponges – Largest class; Inner structure reinforced with collagen fibers and spine-like spicules made of silica minerals; Usually barrel shaped; Can live in a wide variety of habitats; Some are bath sponges
Hexactinellida – Glass Sponges; Spiny spicules made of silica minerals forming inner scaffolding structure with gelatin substance weaved in between framework; likes Polar Regions
Calcareous – Outer exoskeleton and inner spicules made of calcium carbonate. Restricted to shallow marine waters where production of calcium carbonate is easiest to obtain.
Scleropongiae (Coralline or Tropical Reef Sponges) soft body that covers a hard, often massive skeleton made of calcium carbonate, either aragonite or calcite. The layered skeletons look similar to reef corals, therefore are also called coralline sponges.
Fossil Lady 