Trona stercoraria
Trona stercoraria
Trona stercoraria is occurring in the Atlantic sea snail and the only extant species of the genus Trona from the family of cowries. The two internationally accepted common names are "Rat Cowry " ( rat Kauri ) and " Droppings Cowry " stercoraria based on the Carl von Linné 1758 assigned name, which can be translated with feces or manure. When naming by Linnaeus was not decisive that the worm feces or is fed with feces in combination in any other way, but the look on dung reminded him. T. stercoraria probably has no subspecies.
Description
The housings of these locally frequent species usually reach a size of 46-80 mm; the smallest documented Fund was 27, the largest at 98.6 mm. The coat of T. stercoraria is thin, brownish in color and bears fine, closely together standing papillae. The foot is voluminous. The color, pattern and shape of the housing varies greatly. In general, the shell is thick-walled, oval or rhombic and braungefleckt. The surface is smooth and shiny, much more often than in other species of the family but are exceptions such as irregular pattern, melanism, overgrowths in the form of small nodules (caused by adhering barnacles ) and the pattern of shell coating layers ( " overcast" ) before. Only the underside is unmistakable in almost all instances. Characteristic, clearly delimited from one another bright teeth with dark brown spaces can be found on both sides of the aperture (the opening of the auger housing at the bottom). The drawing ends on the transition from the back to the base and go over there in a uniform light brown. The fossula is quite large and clearly concave.
Occurrence and habitat
The distribution area extends along the western African coast in the Atlantic waters of Mauritania in the north to Luanda ( Angola) to the south, populated coastline is about 5000 km. Also on the coast of the islands - such as Cape Verde and São Tomé and Principe - comes before the type.
Little is known about the habits. It is known, not least because the bodies are often found damaged, that they live in the intertidal zone on rocky ground.
System
In 1758 Linnaeus described the kind and arranged them the genus Cypraea use any then known to cowries. In 1884, Félix Pierre Jousseaume proposed the genus Cypraea stercoraria Trona and moved to Trona stercoraria. Today, both binomials are used, place in recent scientific work, the assignment of Jousseaume distribution.
Trona stercoraria probably has no subspecies and despite the widely divergent individuals only two versions are worth mentioning. Which is on the one hand the very small shape, which is called a minimum and to the other form, which is referred to and described in 1810 by rattus Lamarck. Although this form is considered by some authors as a subspecies, the status is uncertain. T. stercoraria stercoraria f rattus is 30-86 mm in size, is strongly arched and very wide.
The following names are used interchangeably: