Sea butterfly

Seeschmetterlinge ( Thecosomata )

The Thecosomata (Greek " body shell " ), formerly Pteropoda ( " Flügelfüßer " ), also referred to as " Seeschmetterlinge " or " conch ", are a suborder of the opisthobranch. The planktonic marine snails are all very small; the size of their housing is usually less than 1 cm.

Features

The Thecosomata branch a number of adaptations to the planktonic lifestyle. So has her walking the form of two wing-shaped flaps ( parapodia ) with which they can be backward drift in open water or actively move by rowing movements. Your in the form of calcite shells are very different, if present, bilaterally symmetrical, as the whole animal usually colorless and usually less than 1 cm long. Shell and gills are regressed in some families.

The snails live on plankton, which is caught in some species with up to 5 cm wide, the worm in size far surpassing power. For fault the network is discarded. The animals migrate in the daily routine vertically, they follow their plankton food: At night, they are near the surface during the day to meet at greater depths.

System

The taxonomy of the worm is subject to revision and change. Therefore, there are different classifications. On J.Thiele (1929-1935) is usually considered going back as classical. She was recognized until the 1990s. A more modern and the last established on purely morphological approaches to systematics is that of Ponder & Lindberg (1997). The current system is phylogenetically oriented and goes back to Bouchet & Rocroi ( 2005).

The Thecosomata once part of the existing up into the 20th century group of pteropods ( Pteropoda ). The Pteropoda formed the end of the 19th century an order of Gastropoda, early 20th century des even has its own class of molluscs. In more modern taxonomies form a subordination or occupy a comparable rank.

Bouchet & Rocroi classification by (2005)

• Class Gastropoda Cuvier, G., 1797 Clade Heterobranchia J. E. Gray, 1840 informal group Opisthobranchia H. Milne Edwards, 1848 Clade Thecosomata H.D.M. de Blainville 1824 Superfamily Cavolinioidea J. E. Gray, 1850 (1815) Family Cavoliniidae J. E. Gray, 1850 (1815)
• Family Limacinidae Costa, 1873
• Family † Sphaerocinidae Pelseneer, 1886
• Family Pneumodermatidae P. A. Latreille, 1825

• Family Cymbuliidae J. E. Gray, 1840
• Family Desmopteridae Chun, 1889
• Family Peraclidae Tesch, 1913

The Pneumodermatidae the family moved from the Gymnosomata in the superfamily Cavolinioidea.

Classification by Ponder & Lindberg (1997)

• Class Gastropoda Cuvier, G., 1797 Subclass Orthogastropoda W. F. Ponder & D. R. Lindberg, 1995 Subclass Apogastropoda L. Salvini - Plawen & G. Haszprunar, 1987 Superorder Heterobranchia J. E. Gray, 1840 Group Euthyneura J. W. Spengel, 1881 H. Milne Edwards 1848 order Opisthobranchia Subordination Thecosomata H.D.M. de Blainville, 1824 Partial order Euthecosomata Superfamily Cavolinioidea J. E. Gray, 1850 (1815)
• Superfamily Limacinoidea J. E. Gray, 1840

• Superfamily Cymbulioidea J. E. Gray, 1840
• Superfamily Peraclidoidea