Atlantidae

Atlanta sp.

The Atlantidae are a family of Pterotracheoidea (formerly also Heteropoda ) within the auger. They have a pelagic lifestyle and are predators of snails from the group of Thecosomata.

Features

The family includes small shapes ( about 1 cm) with a dextral, transparent, low profile case with a keel. It is somewhat reminiscent of a housing of Planorbis. Case and keel can be mineralized (Atlanta ), or even the housing ( Protatlanta ) or case and keel are not mineralized ( Oxygurus ). You can still withdraw completely into the housing and close the housing opening with an operculum, in contrast to the representatives of the other families of the Pterotracheidae. The soft body is gelatinous and translucent. The animals swim with the help of the converted into a fin on the back foot. The head has a snout and a pair of long tentacles that sit in front of the eyes. The eyes are highly developed and sit slightly above the head surface. They possess a lens. On the Webbed sits a muscular sucker with which the prey is held. The long radula has 7 elements per transverse row; a central tooth and a Lateralzahn and two marginal teeth on either side of the central tooth. The animals are dioecious. The males transfer sperm packets to the copulatory organ into the mantle cavity. The development proceeds through a planktotrophe ( plankton -eating ) veliger larva.

Lifestyle and diet

The representative of the family live exclusively pelagic in the open sea. They feed preferentially from other snails of plankton ( Thecosomata or Pteropoda ). The prey is captured with the help of the tentacles and held in place with the help of the suction cup at the base, while the animal by means of the radula biting pieces from the prey.

Occurrence

The species of the superfamily worldwide live in the upper 200 meters of the warmer seas. Many species undertake daily walks in the water column, from the shallow water during the day in deeper water layers during the night. The animals are heavier than water, that is, during the day they swim constantly in order not to sink slowly in the water column. In the evening the animals excrete then threads of slime that keep the animals floating in the water column.

System

Currently, two genera are provided to the family:

  • Atlanta Leseur, 1817
  • Oxygyrus Benson, 1835
  • Protatlanta Tesch, 1908
Caenogastropoda Sorbeoconcha Operculum (gastropod)
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