Gastropoda

Shell is tough armor: golden scale snail
 

The shell of hydrothermal vent snails serves as tough armor thanks to a three-layered structure incorporating iron sulphide granules.

 
  "During the second ever expedition to hydrothermal vents in the Indian Ocean, biologists spotted a snail with a strange-looking foot. Many snails can close the opening to their shell with a flat, round bit of shell called an operculum. But this snail instead protects itself with scales, a feature seen before only in long extinct species, although the vent snail itself evolved recently. Even more unusually, the scales are reinforced with the iron sulphide minerals fool's gold and greigite, giving them a golden colour. No other multicellular animal is known to use these materials." (Schrope 2005:38)

"…[T]he snail has evolved a tri-layered shell structure consisting of an  outer layer embedded with iron sulfide granules, a  thick organic middle layer, and a calcified inner layer.  This creates a configuration in which the inner compliant layer is  sandwiched  between two rigid layers.
 
  "Ortiz and her colleagues, including MIT Dean of Engineering  Subra Suresh, used nanoscale experiments and computer modeling to  determine  the shell's structure and mechanical properties. They found  that the unique three-layer structure dissipates mechanical energy,  which  helps the snails fend off attacks from crabs that squeeze  the shell with their claws in an attempt to fracture it. The shell of  the  scaly-foot snail possesses a number of additional energy  dissipation mechanisms compared to typical mollusk shells that are  primarily  composed of calcium carbonate." (Trafton 2010)

  Learn more about this functional adaptation.

Foot aids underwater movement: water snail
 

The foot of water snails helps them move upside down beneath the water's surface by creating small ripples in the mucus-water interface.

 
  "A UC San Diego engineer has revealed a new mode of propulsion based on  how water snails create ripples of slime to crawl upside down beneath  the surface.

"Eric Lauga, an assistant professor of mechanical and aerospace  engineering at the Jacobs School of Engineering, recently published a  paper…that explains how and why water snails can drag themselves across a  fluid surface that they can't even grip.

"Based on Lauga's research, the secret is in the slime. The main finding  of Lauga's research is that soft surfaces, such as the free surface of a  pond or a lake, can be distorted by applying forces; these distortions  can be exploited (by an animal, or in the lab) to generate propulsive  forces and move. Some freshwater and marine snails crawl by 'hanging'  from the water surface while secreting a trail of mucus. The snail's  foot wrinkles into little rippling waves, which produces corresponding  waves in the mucus layer that it secretes between the foot and the air. Parts of the mucus film get squeezed while other parts are stretched,  creating a pressure that pushes the foot forward." (Jacobs School of Engineering News 2008)

Watch Video Here
  Learn more about this functional adaptation.

Membrane reduces evaporation: land snail
 

A secreted mucus membrane across the opening of the shells of some land snails protects them from drying out by reducing evaporation.

 
  "And certain land snails, particularly desert dwellers, seal themselves inside their shells to avoid desiccation in dry conditions, secreting a special membrane across their shells' opening that reduces evaporation; they can remain encased for years if need be until rain returns." (Shuker 2001:105)
  Learn more about this functional adaptation.

Barcode of Life Data Systems (BOLD) Stats
Specimen Records:74749
Specimens with Sequences:65859
Specimens with Barcodes:58246
Species:9734
Species With Barcodes:8557
Public Records:57430
Public Species:6993
Public BINs:10548