Comparing Two Starlet Corals

starlet fossil

Starlet Coral Fossil (Click to enlarge for fine details , then arrow back)

Starlet corals remains, not to be confused with star corals, are commonly found off the Caribbean, Florida and Bahama shores. I have two species from the genus Siderastrea. As I’ve mentioned in previous posts, these corals were discovered off Florida’s beaches in the 70’s and 80’s by my mother in law Winkie during family vacations.

Winky and Joe (83')

1983 Winkie Mirto with Son, Joseph (my late mother-in-law and husband)

 

Massive Starlet Coral (Siderastrea, sidereal ) httpcoral.aims.gov.aufactsheet.jspspeciesCode=0614

Massive Starlet Coral (Siderastrea, sidereal )
Source:
http://coral.aims.gov.au/factsheet.jsp?speciesCode=0614

Siderastrea, sidereal, commonly referred to as  Massive Starlet Coral is a very slow growing species that lives to a great age forming large colonies, sometimes, over a meter across. It’s closely related to the Lesser Starlet Coral, Siderastrea, radians. You must look very closely in order to observe their differences!

One way you can tell them apart is by their growth patterns. I’ve provided a comparison chart below. But another interesting way worth mentioning, first, is by observing the environment where they grow, which most people are only able to do through pictures. Nevertheless, unlike the Massive Starlet Coral, the Lesser Starlet Coral often looks as though the colony is  growing under the materials around it.

starlet coral radians httpcoral.aims.gov.aufactsheet.jspspeciesCode=0613

Lesser Starlet Coral (Siderastrea, radians Source: httpcoral.aims.gov.aufactsheet.jspspeciesCode=0613

starlet fossil -

Lesser Starlet Coral (Siderastrea, radians) Fossil

(Click to enlarge for fine details, then arrow back)

starlet fossil - underside

Lesser Starlet Coral (Siderastrea, radians) Fossil Underside

CLASSIFICATION

  • Kingdom: Animalia
  • Phylum: Cnidaria (Animals with Stinging Cells)
  • Class: Anthozoa (Flower Animal)
  • Subclass: Hexacorallia (Polygon Structures)
  • Order: Scleractinia (Modern Stony Corals)
  •  Family: Sideractinia
  • Genus: Siderastrea
  • Species: sidereal and radians

 

 

 

 

COMPARISON CHART 

Massive Starlet Coral (Siderastrea, sidereal)               Lesser Starlet Coral (Siderastrea, radians)

  • Usually Dome Shaped                                                Mostly Encrusting Flat or Uneven Sphere
  • Large Colonies Up To A Meter                              Usually Small Colonies About 1 ft. Across
  • Roundish Corallites (Holes)                                    Somewhat Angular Asymmetrical Corallites
  • Shallow Corallites                                                        Deeper Pitted Corallites
  • Obscure Septa (Ridges)                                             Pronounced Septa (Ridges)
  • Thin Fine Walls Between Septa                             Wider Walls Between Septa
  • Septa Uniformly Separated                                     Septa Separated Unevenly
  • 50 to 60 Septa In Each Corallite                           30 to 40 Septa In Each Corallite
  • Smooth Surface                                                            Pitted Surface
  • Uniform Color                                                              Contrasting Dark Centers
  • Pink, Cream, Brown, Grey                                      Whitish, Grey, Green, Light Brown
  • Depth from 40 to 10 meters                                   Only Shallow Depths 10 meters
  • Not tolerant of tide pools and silt                         Tolerant of tide pools and silt