Balea heydeni is a species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of air-breathing land snail

Snail

Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...

, a terrestrial

Terrestrial animal

Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...

 pulmonate gastropod mollusk in the family Clausiliidae

Clausiliidae

Clausiliidae, common name door snails, are a taxonomic family of small, very elongate, mostly left-handed, air-breathing land snails, sinistral terrestrial pulmonate gastropod mollusks....

.

The shell of this species is sinistral, or left-handed in its coiling. The species has long been overlooked because of confusion with Balea perversa

Balea perversa

Balea perversa is a species of air-breathing land snail, a terrestrial pulmonate gastropod mollusk in the family Clausiliidae, the door snails...

. It is likely that the name heydeni Maltzan 1881 is not tenable and that lucifuga Bourguignat 1857 must be used.

Distribution

This species is known to occur in:

• Portugal
• Spain
• France
• Belgium
• The Netherlands
• Denmark
• Great Britain
• Ireland