Belgrandiella (Belgrandiella hessei)

Belgrandiella hessei shell
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Belgrandiella fact file

Belgrandiella description

GenusBelgrandiella (1)

Belgrandiella hessei is a tiny, poorly-known freshwater snail found only in a single underground stream in Bulgaria (1). Snails within the Hydrobiidae family rarely have any colouration in the shell, which is ordinarily white (3). Belgrandiella hessei is likely to be most easily distinguished from related species by features of its reproductive system (1).

Shell height: 2.0 - 2.3 mm (2)
Shell width: 1.0 - 1.2 mm (2)

Belgrandiella biology

Belgrandiella hessei is a troglobite, meaning it is not able to survive outside its underground cave habitat (1). Little is known about the biology of Belgrandiella hessei; however, members of the Hydrobiidae family generally feed on organic debris and algal films on the surface of aquatic vegetation and rocks (4) (5).


Belgrandiella range

Belgrandiella hessei is endemic to a stream in Temnata Dupka Cave, in the Stara Planina Mountains of Bulgaria (1).


Belgrandiella habitat

Found in a single freshwater stream, Belgrandiella hessei lives permanently underground within a karst formation (1).


Belgrandiella status

Belgrandiella hessei is classified as Vulnerable (VU) on the IUCN Red List (1).

IUCN Red List species status – Vulnerable


Belgrandiella threats

Belgrandiella hessei is not known to be facing any major threats at present. However, in the foreseeable future visitors to the Temnata Dupka cave may potentially cause pollution, resulting in habitat destruction. As Belgrandiella hessei is restricted to a single stream, it is particularly vulnerable to any changes in the amount or quality of the water in the cave, which could quickly lead to this species becoming Critically Endangered (CR).


Belgrandiella conservation

There are currently no specific conservation measures known to be in place for Belgrandiella hessei. Habitat monitoring should be implemented in order to prevent the future degradation of its habitat (1).


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Simple plants that lack roots, stems and leaves but contain the green pigment chlorophyll. Most occur in marine and freshwater habitats.
A species or taxonomic group that is only found in one particular country or geographic area.
Karst formation
An area of irregular limestone in which erosion has produced fissures, sinkholes, underground streams, and caverns.


  1. IUCN Red List (November, 2011)
  2. Georgiev, D.G. (2011) New species of Belgrandiella (Wagner 1927) (Mollusca: Gastropoda) from caves in northern Bulgaria. Acta Zoologica Bulgarica, 63: 7-10.
  3. Hershler, R. and Ponder, W.F. (1998) A Review of Morphological Characters of Hyrobioid Snails. Smithsonian Institute, Washington.
  4. Clark, S. (2004) Hydrobiidae. In: Perez, K.E., Claark, S.A. and Lydeard, C. (Eds.) Showing Your Shells: A Primer to Freshwater Gastropod Identification. Freshwater Mollusk Conservation Society, Tuscloosa, Alabama.
  5. Barker, G.M. (2001) The Biology of Terrestrial Molluscs. CABI Publishing, Oxford, UK.

Image credit

Belgrandiella hessei shell  
Belgrandiella hessei shell

© Dilian Georgiev

Dilian Georgiev


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