Maze Coral or Is It Rose Coral

Judging from the title of this article, you may have gathered their can be confusion identifying coral fossils and you would be right. All corals are not single organisms, but rather are a colony of individuals we know as polyps (the jelly like part). The polyps band together and slowly build a calcium carbonate skeleton. Herein lies the physical diversity of corals as each species builds a slightly different style of skeleton.

I feel fairly confident I have several maze coral fossils in my possession inherited from my mother in law, Winkie’s, collection. They are commonly found in the Bahamas, Caribbean and Florida shores where she discovered them lying on the beaches during family vacations in the 60’s and 70’s.

Can you tell the difference between the maze coral and the rose coral below?

Rose Coral Fossil

Maze Coral Fossil

While searching, I realized that maze corals are sometimes lumped together with brain corals or are even called maze brain corals.  The most distinguishing features from other brain corals is that the maze brain coral have thicker convoluted ridges and well defined plates. Also, there is an indentation running along the crest of the walls where the adjoining plates “corallites” meet. Colonies form both flat heads and or hemispherical plates which fits the description of the one in the photo above.

CLASSIFCATION

  • Kingdom: Animalia
  • Phylum: Cnidaria (Animal with stinging cells)
  • Class: Anthozoa (Flower like animals)
  • Subclass: Hexacorallia (corals having parts in multiples of 6)
  • Order: Scleractinia (Stony Skeleton)
  • Family: Meandrininidae (Meandering Colony Corals)
  • Genus: Meandrina (forms massive hemispherical heads or have large flat plates and can grow to a metre (yard) across)
  • Species: M. meandrites
Rose Coral Fossil (Shows Cone Shape Underside)

Rose Coral Fossil
(Shows Cone Shape Underside)

Rose coral, Manicina, areolata,  often have irregular cone shaped undersides and at times consist of a short stalk which can be unattached to the substrate. The most common rose corals forms elliptical or oval colonies (shone below) with a long continuous central valley and several short side valleys.

Colors: Yellowish-brown, tan or dark brown, often with the valleys and walls being contrasting colors. Like most corals, the polyps are only extended at night and are often green.

Manicina areolata Rose Coral Fossil

Manicina areolata
Rose Coral Fossil

Manicina areolata Rose Coral Fossil (Underside)

Manicina areolata
Rose Coral Fossil (slight cone shaped underside)

Interesting Behavior

Manicina areolata is one of only a few corals that can be actively mobile depending if its the colony form.

If a small colony gets turned over it gorges its stomach with water to become bloated, and then jets water from one side at a time. This causes a back and forth rocking motion until the center of gravity shifts, allowing it to rapidly flip upright. The entire process takes a few hours until the final flip occurs in an instant. Larger colonies are more likely to die by smothering in the sediments placing a limit on the size any given colony can grow.

Second Growth Form (Hemispherical)

Manicina, areolata rose coral occurs in two distinct grow patterns making matters even more confusing. The second form consists of semicircular heads with  flattish undersides, winding wide valleys and ridges forming irregular furrows. 

Manicina aerolata Source: http://reefguide.org/carib/rosecoral.html

Rose Coral Manicina aerolata
Source: http://reefguide.org/carib/rosecoral.html

Rose Coral Fossil

Rose Coral Fossil

Habitat: Rose coral Manicina, aerolata is very abundant off the Floridian shores as well as the Bahamas and Caribbean. It prefers shallow, productive, near shore habitats characterized by abundant sediments such as seagrass meadows, or along the fringes of mangrove forests.

CLASSIFICATION

  • Kingdom: Animalia
  • Phylum: Cnidaria (Animals with stinging cells)
  • Class: Anthozoa (Flower Animal)
  • Order: Scleractinia (Stony Skeleton)
  • Family: Faviidae (generally spherical shape and grooved surface which resembles a brain)
  • Genus: Manicina
  • Species: M. areolata

The genus Manicina sp. includes over 10 species, but Manicina areolata is the only species that survives today. The heyday for Manicina was during the Miocene and Pliocene eras between (24 million to 1.6 million years ago). About one million years ago, approximately half the species of reef corals living in the Caribbean became extinct.

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Two Related Genus’s of Star Coral

Elliptical Star Coral

Elliptical Star Coral Fossil (Click to view large for fine details, then arrow back)

 

 

 

 

 

 

 

 

Because the variety of corals is so vast, it can be difficult  to identify species which requires a discreet eye. After close examination and research, I believe I have targeted its identity!

Elliptical star coral is named for its oval elongated shaped corallites or the calcareous cups from which the polyps protrude. Scientifically named Dichocoenia, stokesi, shown above, is a massive colonial coral that forms round humps up to 16 inch (40 centimetres) in diameter. These two characteristics coincide with my fossil quite well.

It is a fairly uncommon species, and has been placed on the Red List for Endangered Species. In 1995 off the Florida Keys, Dichocoenia, stokesi suffered from a disease called white plague which killed 95% of its colonies. It’s a slow growing variety for which the struggle to come back is fast diminishing, unless we humans do something about its plight and that of many other coral varieties.

Kingdoms : Animalia

Phylum:  Cnardia (Marine group with stinging cells)

Class:  Anthozoa (Flower Animal)

Order:  Scleratinia  (Modern species of Stony Coral)

Family:  Meandrinidae (meandering  form)

Genus: Dichocoenia (hump-forming or flattened corals with irregular calyces)

Species: stokesi (elliptical or pineapple star coral)

Blushing Star Coral Fossil

Blushing Star Coral Fossil (View Large)

Blushing Star Coral Fossil Side view showing flat plate form)

Blushing Star Coral Fossil
(Side view showing flat plate form)

 

 

 

 

 

Stephanocoenia, intersept  have tentacles that are commonly extended during daylight, unlike most coral. When touched, it rapidly retracts them causing a slight color change, which gives this coral its common name of “Blushing Star Coral”. It can be found in Florida, the Caribbean and Central American regions and as far south as Brazil. It’s found in a number of reef habitats including channels and lagoons. It grows massive encrusting colonies forming flattened domes. Corallites can be circular to polygonal. The two characteristics of flattened domes and corallite shapes are in line with my coral fossil shown above.

Nutrition: Like all coral, it has a symbiotic relationship with algae zooxanthellae. Through photosynthesis, the algae provides energy to the coral which in turn homes the algae. Food is caught as it passes by the coral tentacles whereby stinging cells called nematocysts stun and hold onto it.

Its earliest fossil record dates back to the Eocene period between 55 and 33 million years ago.

The Blushing Star Coral is also susceptible to white plague type II which exposes the skeleton by rapid tissue destruction and is also on the Red List of Threatened species.

star coral blushing 3

Blushing Star Cora. (View Large)
Source:
http://reefguide.org/carib/pixhtml/blushingstarcoral2.html

Kingdoms : Animalia

Phylum:  Cnardia (Marine group with stinging cells)

Class:  Anthozoa (Flower Animal)

Order: Scleratinia (Modern species of Stony Coral)

Family:  Astrocoeniid  (small family made up of  both reef building and non reef building  genus, both with and without symbiotic zooxanthellae as well as both branching and encrusting species.

Genus: Stephanocoenia (Colonies are flattened usually with regular, smooth surfaces. Corallites are small and the wall between them may be relatively wide.)

Species: intersepta

 

Two Genus’s of Brain Coral

HPIM1028

Colpophyllia, natans
(Boulder Brain Coral Fossil)

OLYMPUS DIGITAL CAMERA

Colpophyllia, natans (Boulder Brain Coral) Source: en.wikipedia.org

Click on the images to enlarge for fine details, then arrow back

The coral genus groups Diploria and Colpophyllia both belong to the family of Faviidae and earn the common term “brain coral” due to their convoluted surfaces and general spherical shapes.  They are slow growing, colony forms which may reach colossal sizes a few meters in length and live for 100’s of years. The oldest know brain coral is 900 years old. Both these species grow in shallow parts of the Caribbean Sea, the Bahamas, Bermuda and Texas, as well as Florida.

HPIM1075

Symmetrical Brain Coral Fossil
(Diploria, strigosa)

Symmetrical Brain Coral (Diploria, strigosa) Source: http://reefguide.org/carib/pixhtml/symmetricalbrain2.html

Symmetrical Brain Coral
(Diploria, strigosa)
Source:
http://reefguide.org/carib/pixhtml/symmetricalbrain2.html

 

A KEEN COMPARISON OBSERVED LIKE A TRUE PALEONTOGIST:

Colpophyllia, natans  or Boulder Brain Coral is a very large brain coral whose domed hemispherical colonies may exceed one meter across. Smaller colonies may be flat topped discs. Its valleys may stretch the entire width, or be subdivided into shorter series. The valleys and walls may be two centimeters broad distinguishing it from the genus group, Diplorias sp., which are narrower. Walls commonly have a fine groove running along their tops. There is a sharp break between the wall and the valley floor. The colors vary with ridges being various shades of brown, and the valleys either whitish, green, or tan.

Diploria, strigosa, or Symmetrical Brain Coral forms  flat plates or massive hemispherical domes up to 1.8 meters, 6ft. diameters. There are sometimes and sometimes not a very narrow groove along the tops of the walls, and the walls have sloping or rounded sides. Valleys may run straight for considerable distances or be highly irregular in direction. They range in color from purplish brown to grey or green, often with the groove floors being a contrasting paler color.

BRAIN CORAL CLASSIFICATION

  • Kingdom  –  Animalia
  • Phylum  –    Cnidaria (means stinging cells)
  • Class  –     Anthozoa (means flower animal)
  • Order  –  Scleratinia (stony skeleton)
  • Family  –  Faviidae (spherical group with grooved surfaces)
  • Genus  –  Diploria /  Colpophyllia
  • Species – strigosa /  natans

Diploria, strigosa is the most widespread of all the Diploria species, being more resistant to threats with the ability to thrive in muddy stretches of seabed where  many other corals are not able to flourish.

Brain Coral Open Polyps At Night

Brain Coral Open Polyps At Night

ABOUT SCLERACTINIA: The order, Scleractinia, in which all living corals belong today, means they develop a stony skeleton. They possess a light, porous skeleton consisting of external sheathing which forms a cup. Scleractinians were fairly rare in North America until the Cretaceous, about 100 million years ago, when they first built reefs in Texas and Mexico. It wasn’t until the Pleistocene Period, about 2.6 mya, that reefs flourished where they do today.

NIGHT TIME ACTIVITY : The coral polyps, the living breathing jelly-like part of the animal, are found in single file in the valleys of the convolutions. They are normally contracted during daylight, but expand at night to catch microbits of food drifting by.