Sea Butterfly: Limacina retroversa (Fleming, 1823)
A subarctic shelled pteropod of Atlantic arctic waters
Size
- larvae ~ 0.15 mm
- Adults up to 7 mm
Color & Characteristics
- Foot modified into a pair of large pad-shapped lobes
- Body often darkly pigmented
- Left coiled shell with high spire
- 6 to 9 transparent, striated shell whorls
- Two subspecies occur, with Limacina retroversa retroversa occuring in the North Atlantic, within which 2 forma retroversa and balea are recognized
Habitat
- Subpolar North Alantic, advected into Barents Sea, Icelandic and Greenlandic waters
- Bipolar
- Epipelagic (shallow dwelling)
- Often found in swarms
Feeding
- Mucus nets are produced on foot-wings to trap phytoplankton and small particles
- Net is periodically eaten to acquire the food stuck to it
- Animals must regularly swim upward to offset their sinking
Life cycle
- protandrous hermaphrodite (males first, then females later)
- Spermatophores used for sperm transfer
- Eggs are released in ribbons during spring and summer spring that hatch into ciliated veligers
- Generation times thought to be 1 year in the arctic and perhaps 2 per year in the subarctic
Page Author: Russ Hopcroft
Created: June 28, 2010
