Helicigona trizona
Trivalent rock worm ( Helicigona trizona )
The Trivalent rock worm ( Helicigona trizona ) is a terrestrial snail from the family of helicid ( Helicidae ).
Features
The body is flattened to almost flat. It measures 13 to 18 × 25 to 32 mm. The turns take only slowly; to the adult stage about 4.5 to 5 turns to be created. In cross section, the turns are flattened at the top and the bottom and sides rounded. The last whorl descends clearly from the turns off and becomes rounded on the upper side. The basic color is gray to yellowish - white with three brown spiral bands. The width of the strips decreases from the upper to the lower band to some. The middle band is much stronger, darker color than the upper and lower band. Near the navel and at the mouth rim, the periostracum turns slightly greenish. The outside has only distinct growth lines and very fine and indistinct spiral strips. The muzzle is rounded and is oblique to the axis of coiling (about 45 °). The whitish mouth edge is only slightly thickened and is made up on the inner side. The umbilicus is relatively narrow. The body of the animal is light brown ..
Geographical occurrence, habitat and behavior
The species occurs on the central Balkans (Serbia, Bulgaria and southwestern Romania). The summed up by many authors as a subspecies of H. trizona H. rumelica ( Rossmaessler, 1838) is now recognized as a distinct species. This occurrence is reduced to the above areas. She lives in moderately moist habitats up to 1700 m above sea level (Bulgaria). About the way of life is as good as nothing is known.
System
Previously, some, today provided they accept as independent species taxa as subspecies to Helicigona trizona, such as Helicigona rumelica ( Rossmaessler, 1838) and Helicigona haberhaueri ( Sturany, 1897).