Coral Sponge

Florida Sponge Fossil

Florida Sponge Fossil

 

My title “Coral Sponge”, in this case, refers 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. You can click on the image above to enlarge and observe its finer details. (If you believe it’s not a sponge, feel free to comment)

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Coral cups showing septa walls lacking in sponges

 

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) often only visible enough through the 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. See what you think . . .

 

 

Tube Coral Sponge (Reverse Side)

Tube Coral Sponge
(Reverse Side)

 

 

 

 

  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)

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.

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Mysterious Sponges

HPIM0748

Sponge Fossil Side View

HPIM0749_edited-2

Sponge Fossil

                      

This is one of the more unusual fossil finds on the shores of a Lake Michigan beach in Southwestern Michigan USA! My best guess is that it’s a sponge and not a coral because of the way its dotted with pores lacking septa, vertical walls. From the side view, you can see how the tubes permeate down into the structure.

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INTERESTING FACTS:   The most fascinating fact about sponges is their long extended history on Earth beginning 580 million years ago. The type of sponges we’re most familiar with are the ones we use for our households. Those are actually referred to as, demosponges, having entirely soft fibrous skeletons with no hard elements; and there are only a few species. After thousands of years, humans had almost harvested them to extinction by the 1950’s.  Many are now being researched for a possible source of medicines.

Sponges

Popular Tourist Spot Selling Natural Sponges
Source: en.wikipedia.org

HOW SPONGES LIVE: Sponges have delicate skeletons and rely on a constant water flow through their bodies to capture food and obtain oxygen. They don’t have a digestive or circulatory system like we do. They can actually change the shape of their bodies for maximum water flow.  Most species have the ability to contract and squeeze the water out of their pores in order to flush out sediments clogging them. They can even  escape from predators by squeezing out the water and shrinking themselves. For further defense, many shed their spiky spicules to create a dense hazardous carpet around them which keeps away predators such as star fish.

CLASSIFICATION

Kingdom:  Animalia       Phylum:  Porifera (means to possess 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

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.