Marsenina stearnsii
| Marsenina stearnsii | ||||||||||||
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| Scientific name | ||||||||||||
| Marsenina stearnsii | ||||||||||||
| ( Dall , 1871) |
Marsenina stearnsii ( Syn. : Lamellaria stearnsii ) is a screw from the family of velutinidae extending from sea squirts fed. She lives on the North American Pacific coast .
features
The white, thin-shelled snail shell of Marsenina stearnsii , which in adult snails reaches a length of about 1.5 cm, has a widely projecting mouth. The right and left mantle lobes are fused dorsally and cover a large part or the entire shell. In contrast to some Lamellaria species, Marsenina stearnsii does not have a complete bond , so that there is still a slit on the back. In this way, the snail, which measures up to 4 cm, can reveal its shell in the event of a malfunction. The soft parts of the snail are pink to white with a few darker spots, namely acid glands located in the skin. This color corresponds exactly to the color of the sea squirts with their dark mouth openings, on whose colonies the snails live. The hidden house is held in place by two muscles, one on each side, and not just a single muscle as in most other Caenogastropoda .
distribution
Marsenina stearnsii occurs on the North American Pacific coast from Alaska to Islas Marías ( Mexico ). It lives under rocks and in sheltered places in the lower tidal zone and below, mostly on colony-forming sea squirts .
Way of life
Unlike members of the related genus Volutina , but like most front gill snails , Marsenina stearnsii is of separate sex.
The diet of the nocturnal Marsenina stearnsii consists of colony-forming sea squirts , including the species Trididemnum opacum and Ascidia ceratodes . The meat is eaten out from the inside. After mating , the female of the snail lays egg capsules in the sheaths of the sea squirts, from which Veliger larvae of the Echinospira type hatch. During the following pelagic phase, the larva feeds on microscopic algae. During this time, the later jaws are placed in a ventral sac of the foregut, while nutrition is provided through a primary mouth. During the metamorphosis to the finished snail, the new mouth opening is created at the point of the bulge. The young snail is equipped for its new animal food, sea squirts.
literature
- Donald Putnam Abbott, Eugene Clinton Haderlie: Prosobranchia , in: Robert Hugh Morris, Donald Putnam Abbott, Eugene Clinton Haderlie: Intertidal Invertebrates of California . Pp. 230–307, here pp. 272, 13.64: Lamellaria stearnsii Dall, 1871 . Stanford University Press, 1st ed., Stanford (CA, USA) 1980. ( Google Books )
Individual evidence
- ^ LR Page: Larval and metamorphic development of the foregut and proboscis in the caenogastropod Marsenina (Lamellaria) stearnsii. In: Journal of morphology. Volume 252, Number 2, May 2002, pp. 202-217, doi : 10.1002 / jmor.1099 , PMID 11921045 .