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Zophos cf baudoni.png
Zophos cf. baudoni from Dominica
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
(unranked): clade Heterobranchia

clade Euthyneura
clade Panpulmonata
clade Eupulmonata
clade Stylommatophora
informal group Sigmurethra

Superfamily: Rhytidoidea
Family: Haplotrematidae
H. B. Baker, 1931[1]

See text

Haplotrematidae is a taxonomic family of predatory air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Rhytidoidea.


These are North American land snails. They occur from Alaska, through coastal Canada, and as far south as northern Mexico, but they are predominantly snails of the eastern and western United States.[2]

Three views of a shell of Haplotrema vancouverense from W. G. Binney[3]

Shell description[edit]

Their shells vary in size from small (7 mm in diameter, or about 0.3 inches) to medium (32 mm, about 1.3 inches), usually with a low, flattened spire, a very wide umbilicus, and usually with the upper lip margin (at the aperture) curving downwards or straightened.


They have a number of anatomical peculiarities.

The structure of the radula of these snails (their "teeth") is unusual. Essentially, haplotrematids have fewer cusps than most snails, but they are considerably elongated, suitable for the predatory life they follow. Members of this family have been given the common name "lancetooth" snails, presumably based on this last anatomical characteristic. Their sole food source consists, as far as is known, of other terrestrial mollusks.[4][2]

In this family, the number of haploid chromosomes lies between 26 and 30 (according to the values in this table).[5]


Genera within the family Haplotrematidae include:


  1. ^ Baker, Horace B. (1931). Proc. Acad. Nat. Sci. Philadelphia 82: 405.
  2. ^ a b Pilsbry, Henry A. 1946. Land Mollusca of North America (North of Mexico). Acad. Nat. Sci. Philadelphia, Monograph 3, vol. 2(1): 201-230.
  3. ^ Binney, William G. 1878. The Terrestrial Air-Breathing Mollusks of the United States and Adjacent Territories of North America. Vol. 5 (plates). Bull. Mus. Comparative Zool., Harvard. Plate 20.
  4. ^ http://www.xerces.org/Wings/spring2003.htm Atkinson, Jim. Wings: Spring 2003. Living in a World of Tastes and Smells.
  5. ^ 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.
  6. ^ Gude (1911). Proc. malac. Soc. London 9: 269.

External links[edit]