Bradybaenidae

Bradybaenidae
A live individual of Fruticicola fruticum
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
(unranked): clade Heterobranchia

clade Euthyneura
clade Panpulmonata
clade Eupulmonata
clade Stylommatophora
informal group Sigmurethra

Superfamily: Helicoidea
Family: Bradybaenidae
Pilsbry, 1934 (1898)
Genera

See text

Bradybaenidae is a taxonomic family of medium-sized to small land snails, terrestrial pulmonate gastropod mollusks in the superfamily Helicoidea.

These snails are found mainly in Asia, with only one species occurring in Northwestern Europe: Fruticicola fruticum.

The name of the family and the genus Bradybaena is derived from the Greek words bradus (= slow) and baino (= walk), meaning "slow walker".

Molecular phylogenetic studies from 2007 showed that bradybaenids are closely related with the Camaenidae, which are currently recognized as a distinct family. In these studies both Bradybaenidae and Camaenidae are mutually polyphyletic, together forming a monophyletic group, however. This finding suggests that the distinction of both families as based essentially on the absence (Camaenidae) or presence (Bardybaenidae) of a diverticulum, is arbitrary. This anatomical structure was apparently lost (or was gained) in several groups in convergence and is therefore not suitable for the delimitation of natural groups.[1]

As a result, the Bradybaenidae being the younger taxon are likely to represent a junior synonym of the Camaenidae.

Anatomy

Some genera of snails in this family create and use love darts as part of their mating behavior. The dart sac contains one to two glands. They are also defined by missing a diverticulum.

In this family, the number of haploid chromosomes lies between 26 and 30 (according to the values in this table).[2]

Taxonomy

The following two subfamilies have been recognized in the taxonomy of Bouchet & Rocroi (2005):

Genera

Two live individuals of Aegista tokyoensis, one retracted and one active

Genera within the family Bradybaenidae include:

subfamily Bradybaeninae - they are defined by the presence of two divided glands with one to two accessory sacs.
tribe Aegistini

tribe Bradybaenini

tribe Euhadrini

subfamily Helicostylinae - they are defined by the presence of one gland that is being inserted without accessory sac (Tricheulota group) or with accessory sac (Helicostyla group).

The genus Monadenia Pilsbry, 1895 used to be placed in this family,[4] but it has been moved to the family Xanthonychidae.

References

  1. ↑ Wade C. M., Hudelot C., Davison A., Naggs F., Mordan P. B. (2007). "Molecular phylogeny of the helicoid land snails (Pulmonata: Stylommatophora: Helicoidea), with special emphasis on the Camaenidae". Journal of Molluscan Studies 73(4): 411-415. doi:10.1093/mollus/eym030.
  2. ↑ Barker G. M.: Gastropods on Land: Phylogeny, Diversity and Adaptive Morphology. in Barker G. M. (ed.): The biology of terrestrial molluscs. CABI Publishing, Oxon, UK, 2001, ISBN 0-85199-318-4. 1-146, cited pages: 139 and 142.
  3. ↑ Davison A. & Chiba S. (2006). "Labile ecotypes accompany rapid cladogenesis in an adaptive radiation of Mandarina (Bradybaenidae) land snails". Biological Journal of the Linnean Society 88(2): 269-282. doi:10.1111/j.1095-8312.2006.00624.x.
  4. ↑ Integrated Taxonomic Information System (ITIS) Bradybaenidae Taxonomic Serial No.: 77713 cited 18 July 2007

External links

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