Blog Flat Topshell, Purple Topshell, Steromphala umbilicalis, portugal seabylou

Flat Topshell || Steromphala umbilicalis

  • Size: 10 to 22 millimeters
  • Color: Purple, blue, green, red, pink, orange, brown
  • Family: Trochidae
  • Fun fact: As the snail grows older, the vibrant purple bands on its shell tend to fade

Flat Topshells (Steromphala umbilicalis) are a common species of gastropod mollusk found in the coastal waters of Portugal, from the southern region of the Algarve up to the northern coastline. These shells are known for their distinctive flat top, which is where they get their name from. Another name for this species is Purple Topshell. The biological name Steromphala umbillicalls has been given by da Costa in 1778.

Close up Flat Topshell, Purple Topshell, Steromphala umbilicalis, sea by lou

Aesthetic Marvel

The Flat Topshell is a unique and fascinating snail species with a distinctive and attractive colorful shell with remarkable features. The shell of the Flat Topshell is strong and characterized by five almost flat volutions that culminate in a rounded apex.

The size of the shell varies between 10 to 22 millimeters and has a striped, wavy pattern It's these intricate details that make the Flat Topshell a true marvel of nature. The coloring is most typically green with reddish or purple lines, but can also vary from yellow to bluish in color. The colors and lines of the shell tend to fade as the snail gets older.


Habitat and Distribution

The Flat Topshell species is found from upper shore into the sublittoral waters and rocky shores, clinging to rocks and algae-covered surfaces to circa 20 meters deep. These snails feed primarily on various types of algae. Their specialized radula (a feeding organ) allows them to scrape and graze on algae found on rocks and other surfaces. Flat Topshells play a crucial role in their ecosystem, by eating algae they help maintain the balance of algae populations and promote the health of intertidal habitats. Therefore, this species can provide valuable insights into the overall health and ecological condition of intertidal areas. 


Besides in the waters of Portugal, the Flat Topshell can also be found from the coast of the British Isles until the Mediterranean Sea, where it has captured the attention of naturalists and collectors for centuries.


Details Flat Topshell, Purple Topshell, Steromphala umbilicalis, seabylou


The Flat Topshell is a true treasure of the sea, captivating shell lovers with its stunning colors, unique shape, and extraordinary features.

Looking for a piece of jewelry or unique artwork with Flat Topshells? Visit our shop here.


Flat Topshell, Purple Topshell, Steromphala umbilicalis, seabylou

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