Blanfordia
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| Blanfordia | |
|---|---|
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| Blanfordia bensoni | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| Subclass: | Caenogastropoda |
| Order: | Littorinimorpha |
| Family: | Pomatiopsidae |
| Genus: | Blanfordia A. Adams, 1863[1] |
| Diversity[2] | |
| 3 species | |
| Synonyms[3] | |
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Vicina Pilsbry, 1924[4] | |
Blanfordia is a genus of terrestrial gastropod mollusks in the family Pomatiopsidae.[2] They are land snails which have an operculum.
The generic name Blanfordia is in honor of English naturalist William Thomas Blanford.[1]
The genus Blanfordia is endemic to Japan.[2] Blanfordia species live on Honshu and on Hokkaido.[2][5]
Blanfodia and Fukuia are the only two genera of Pomatiopsidae that are endemic to Japan.[2] They occur especially in the northern and western part of Japan on the coast of the Sea of Japan.[2] There is a unique climate in the Sea of Japan with high precipitation as snowfall during the winter in the area of distribution of Blanfordia.[2] Such species, unique to the region near the Sea of Japan, are known as "Japan Sea elements".[2]
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Description
Some species of Blanfordia have a shell with varix.[5]
Blanfordia has short stubby triangular tentacles.[1][5][6] Short tentacles is derived character, while long tentacles is a primitive character (a plesiomorphic trait) within the Littorinimorpha.[6] Eyes are at the base of tentacles.[1] According to Nelson Annandale the snout is narrow and long.[7]
There are lobes on each side of the frontal part of the foot and there is also a lobe with operculum on the foot.[1] There is a groove on the foot dividing the foot into frontal and back part.[7] While moving, it will put the tip of its snout on the ground and then it will drag itself while it is moving each part of the foot separately like a leech.[7]
Gill filaments (ctenidium) are reduced in all species of Blanfordia.[5] There is a verge with a massive gland in some species of Blanfordia.[5] The nervous system of Blanfordia is concentrated.[5]
Reproductive system: the bursa copulatrix is partly surrounded by albumen gland (posterior pallial oviduct).[5] Albumen gland and spermathecal duct have a common opening.[5] Sperm duct and also spermathecal duct emerges from mid-ventral part of the bursa copulatrix.[5]
Paul Bartsch (1936)[3] provided nomenclatural review of the genus Blanfordia with detailed description of its species.[3]
Comparison of apertural views of shells (the scale is 1 mm):
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Species
Species within the genus Blanfordia include:
- Blanfordia bensoni (Adams, 1861)[2] - type species.[5] The type species was subsequently designated by Geoffrey Nevill (1878).[5][8]
- Blanfordia japonica (Adams, 1861)[2]
- Blanfordia simplex Pilsbry, 1902[2]
"Fukuia" ooyagii is the most closely related species to Blanfordia according to the molecular phylogeny analysis, but its generic assignment should be determined coupled with the investigation of its soft-part morphology.[2]
The speciation of genus Blanfordia likely started around 6.4 million years ago in the Late Miocene,[2] while the divergence between Blanfordia and "Fukuia" ooyagii is estimated to be around 17.4 million years ago in Early Miocene.[2]
Synonyms:
- Blanfordia integra Pilsbry, 1924 is a synonym of Fukuia integra (Pilsbry, 1924).[2] According to the molecular analyses of 18S ribosomal RNA, 28S ribosomal RNA, 16S ribosomal RNA, and cytochrome-c oxidase I (COI) genes by Kameda & Kato (2011)[2] noted that Blanfordia integra is undoubtedly a member of the genus Fukuia.[2] As early as 1979, Davis hypothetized that Blanfordia and Fukuia are either the same genus or that they may have a common ancestor.[5]
Cladogram
A cladogram showing phylogenic relations of genera within Pomatiopsidae:[2]
| Pomatiopsidae |
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