Blanfordia
Encyclopedia
Blanfordia is a genus
of terrestrial gastropod mollusks in the family
Pomatiopsidae
. They are land snail
s which have an operculum
.
The generic name
Blanfordia is in honor of English naturalist William Thomas Blanford
.
and on Hokkaido
.
Blanfodia and Fukuia
are the only two genera of Pomatiopsidae that are endemic to Japan. They occur especially in the northern and western part of Japan on the coast of the Sea of Japan
. 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. Such species, unique to the region near the Sea of Japan, are known as "Japan Sea elements".
with varix
.
Blanfordia has short stubby triangular tentacle
s. Short tentacles is derived character, while long tentacles is a primitive character (a plesiomorphic trait) within the Littorinimorpha
. Eyes are at the base of tentacles. According to Nelson Annandale
the snout
is narrow and long.
There are lobes on each side of the frontal part of the foot and there is also a lobe with operculum
on the foot. There is a groove on the foot dividing the foot into frontal and back part. 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
.
Gill filaments (ctenidium
) are reduced in all species of Blanfordia. There is a verge with a massive gland in some species of Blanfordia. The nervous system
of Blanfordia is concentrated.
Reproductive system
: the bursa copulatrix is partly surrounded by albumen gland (posterior pallial oviduct). Albumen gland and spermathecal duct have a common opening. Sperm duct and also spermathecal duct emerges from mid-ventral part of the bursa copulatrix.
Paul Bartsch
(1936) provided nomenclatural review of the genus Blanfordia with detailed description of its species.
Comparison of apertural views of shells (the scale is 1 mm):
"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.
The speciation
of genus Blanfordia likely started around 6.4 millions years ago in the Late Miocene
, while the divergence between Blanfordia and "Fukuia" ooyagii is estimated to be around 17.4 millions years ago in Early Miocene.
Synonyms:
showing phylogenic relations of genera within Pomatiopsidae:
) are the only genera of terrestrial gastropods within the family Pomatiopsidae, which otherwise consists of mainly freshwater (but also seasonally amphibious) snails. Species of Blanfordia can be found from the sea coast to the mountains. They live in coastal dunes and littoral forests (Blanfordia simplex
), from coastal to inland forests (Blanfordia japonica
) and on the forest floor of inland forests (Blanfordia bensoni
). Other land snails living in habitats of Blanfordia snails include for example diplommatinids, camaenids and bradybaenids.
The phylogenetic analyses by Kameda & Kato (2011) indicates that Japanese Pomatiopsinae have adapted
from freshwater environment to terrestrial life (terrestrialization) at least twice (three Blanfordia species in one clade and Fukuia integra
- formelly Blanfordia intergra species in another clade). This change has happened in regions with heavy snowfalls that face the Sea of Japan.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of terrestrial gastropod mollusks in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Pomatiopsidae
Pomatiopsidae
Pomatiopsidae is a family of small mainly freshwater snails with gills and an operculum, aquatic gastropod mollusks in the superfamily Rissooidea ....
. They are land snail
Land snail
A land snail is any of the many species of snail that live on land, as opposed to those that live in salt water and fresh water. Land snails are terrestrial gastropod mollusks that have shells, It is not always an easy matter to say which species are terrestrial, because some are more or less...
s which have an operculum
Operculum (gastropod)
The operculum, meaning little lid, is a corneous or calcareous anatomical structure which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails...
.
The generic name
Generic name
Generic name may be:*Generic name, name of a biological genus*Generic name, International Nonproprietary Name for a drug*A placeholder name, referring to nobody in particular, such as Joe Bloggs or John Q. Public...
Blanfordia is in honor of English naturalist William Thomas Blanford
William Thomas Blanford
William Thomas Blanford was an English geologist and naturalist. He is best remembered as the editor of a major series on The Fauna of British India, Including Ceylon and Burma.-Biography:Blanford was born in London...
.
Distribution
The genus Blanfordia is endemic to Japan. Blanfordia species live on HonshuHonshu
is the largest island of Japan. The nation's main island, it is south of Hokkaido across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyushu across the Kanmon Strait...
and on Hokkaido
Hokkaido
, formerly known as Ezo, Yezo, Yeso, or Yesso, is Japan's second largest island; it is also the largest and northernmost of Japan's 47 prefectural-level subdivisions. The Tsugaru Strait separates Hokkaido from Honshu, although the two islands are connected by the underwater railway Seikan Tunnel...
.
Blanfodia and Fukuia
Fukuia
Fukuia is a genus of amphibious freshwater snails and land snails with an operculum, gastropod mollusks in the family Pomatiopsidae.-Distribution :...
are the only two genera of Pomatiopsidae that are endemic to Japan. They occur especially in the northern and western part of Japan on the coast of the Sea of Japan
Sea of Japan
The Sea of Japan is a marginal sea of the western Pacific Ocean, between the Asian mainland, the Japanese archipelago and Sakhalin. It is bordered by Japan, North Korea, Russia and South Korea. Like the Mediterranean Sea, it has almost no tides due to its nearly complete enclosure from the Pacific...
. There is a unique climate in the Sea of Japan with high precipitation
Precipitation (meteorology)
In meteorology, precipitation In meteorology, precipitation In meteorology, precipitation (also known as one of the classes of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation...
as snowfall during the winter in the area of distribution of Blanfordia. Such species, unique to the region near the Sea of Japan, are known as "Japan Sea elements".
[File:Blanfordia map.svg|thumb|left|upright=1.4|Nowadays distribution of species of Blanfordia:
]] |
Description
Some species of Blanfordia have a shellGastropod shell
The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...
with varix
Varix (mollusc)
A varix is an anatomical feature of the shell of certain sea snails, marine gastropod molluscs.It is a thickened axial ridge in the shell of some families of gastropods. A varix is located at intervals around the whorl, and is formed by considerable thickening of the outer lip at a resting stage...
.
Blanfordia has short stubby triangular tentacle
Tentacle
A tentacle or bothrium is one of usually two or more elongated flexible organs present in animals, especially invertebrates. The term may also refer to the hairs of the leaves of some insectivorous plants. Usually, tentacles are used for feeding, feeling and grasping. Anatomically, they work like...
s. Short tentacles is derived character, while long tentacles is a primitive character (a plesiomorphic trait) within the Littorinimorpha
Littorinimorpha
Littorinimorpha is a large clade of gastropods within Hypsogastropoda consisting primarily of marine species, but also aquatic and terrestrial species as well....
. Eyes are at the base of tentacles. According to Nelson Annandale
Nelson Annandale
Thomas Nelson Annandale CIE was a Scottish zoologist, entomologist and anthropologist.The eldest son of Thomas Annandale, the regius professor of clinical surgery at the University of Edinburgh, Nelson was educated at Rugby School, Balliol College, Oxford, and the University of Edinburgh.Annandale...
the snout
Snout
The snout, or muzzle, is the protruding portion of an animal's face, consisting of its nose, mouth, and jaw.-Terminology:The term "muzzle", used as a noun, can be ambiguous...
is narrow and long.
There are lobes on each side of the frontal part of the foot and there is also a lobe with operculum
Operculum (gastropod)
The operculum, meaning little lid, is a corneous or calcareous anatomical structure which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails...
on the foot. There is a groove on the foot dividing the foot into frontal and back part. 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
Leech
Leeches are segmented worms that belong to the phylum Annelida and comprise the subclass Hirudinea. Like other oligochaetes such as earthworms, leeches share a clitellum and are hermaphrodites. Nevertheless, they differ from other oligochaetes in significant ways...
.
Gill filaments (ctenidium
Ctenidium
Ctenidium may be:* Ctenidium , , a comb-like gill, part of the respiratory system of gastropods and bivalves* Ctenidium, , a row of peg-like spines in some insects...
) are reduced in all species of Blanfordia. There is a verge with a massive gland in some species of Blanfordia. The nervous system
Nervous system of gastropods
The nervous system of gastropods consists of a series of paired ganglia connected by major nerve cords, and a number of smaller branching peripheral nerves.The brain of a gastropod consists of three pairs of ganglia, all located close to the oesophagus...
of Blanfordia is concentrated.
Reproductive system
Reproductive system of gastropods
The reproductive system of gastropods varies greatly from one group to another within this very large and diverse taxonomic class of animals...
: the bursa copulatrix is partly surrounded by albumen gland (posterior pallial oviduct). Albumen gland and spermathecal duct have a common opening. Sperm duct and also spermathecal duct emerges from mid-ventral part of the bursa copulatrix.
Paul Bartsch
Paul Bartsch
Paul Bartsch was an American malacologist and carcinologist.Paul Bartsch emigrated to the U.S.A in 1880. He graduated from the University of Iowa with a B.S. in 1896, and M.S. in 1899, and PhD in 1905...
(1936) provided nomenclatural review of the genus Blanfordia with detailed description of its species.
Comparison of apertural views of shells (the scale is 1 mm):
Species
Species within the genus Blanfordia include:- Blanfordia bensoniBlanfordia bensoniBlanfordia bensoni is a species of land snail which has an operculum, a terrestrial gastropod mollusk in the family Pomatiopsidae.Blanfordia bensoni is the type species of the genus Blanfordia.- Distribution :This species is endemic to Japan...
(Adams, 1861) - type species. The type species was subsequently designated by Geoffroy Nevill (1878). - Blanfordia japonicaBlanfordia japonicaBlanfordia japonica is a species of land snail which has an operculum, a terrestrial gastropod mollusk in the family Pomatiopsidae.- Distribution :This species is endemic to Japan. The type locality is Sado.It is a Near Threatened species....
(Adams, 1861) - Blanfordia simplexBlanfordia simplexBlanfordia simplex is a species of land snail that has an operculum, a terrestrial gastropod mollusk in the family Pomatiopsidae.Henry Augustus Pilsbry described it as Blanfordia japonica var. simplex in 1902. He has elevated this taxon to specific level in 1903.- Distribution :This species is...
Pilsbry, 1902
"Fukuia" ooyagii
Fukuia ooyagii
Fukuia ooyagii is a species of freshwater snail which has an operculum, an aquatic gastropod mollusk in the family Pomatiopsidae.- Taxonomy :...
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.
The speciation
Speciation
Speciation is the evolutionary process by which new biological species arise. The biologist Orator F. Cook seems to have been the first to coin the term 'speciation' for the splitting of lineages or 'cladogenesis,' as opposed to 'anagenesis' or 'phyletic evolution' occurring within lineages...
of genus Blanfordia likely started around 6.4 millions years ago in the Late Miocene
Late Miocene
The Late Miocene is a sub-epoch of the Miocene Epoch made up of two stages. The Tortonian and Messinian stages comprise the Late Miocene sub-epoch....
, while the divergence between Blanfordia and "Fukuia" ooyagii is estimated to be around 17.4 millions years ago in Early Miocene.
Synonyms:
- Blanfordia integra Pilsbry, 1924 is a synonym of Fukuia integraFukuia integraFukuia integra, also known as Blanfordia integra, is a species of land snail which has an operculum, a terrestrial gastropod mollusk in the family Pomatiopsidae.- Taxonomy :...
(Pilsbry, 1924). According to the molecular analyses of 18S ribosomal RNA18S ribosomal RNA18S ribosomal RNA is a part of the ribosomal RNA. The S in 18S represents Svedberg units. 18S rRNA is a component of the small eukaryotic ribosomal subunit...
, 28S ribosomal RNA28S ribosomal RNA28S ribosomal RNA is the eukaryotic nuclear homologue of the prokaryotic 23S ribosomal RNA; this is the structural RNA for the large component of eukaryotic cytoplasmic ribosomes, and thus one of the basic components of all eukaryotic cells....
, 16S ribosomal RNA16S ribosomal RNA16S ribosomal RNA is a component of the 30S subunit of prokaryotic ribosomes. It is approximately 1.5kb in length...
, and cytochrome-c oxidase IMain subunit of cytochrome c oxidaseCytochrome C and Quinol oxidase polypeptide I is main subunit of cytochrome c oxidase complex.Cytochrome c oxidase is a key enzyme in aerobic metabolism. Proton pumping heme-copper oxidases represent the terminal, energy-transfer enzymes of respiratory chains in prokaryotes and eukaryotes...
(COI) genes by Kameda & Kato (2011) noted that Blanfordia integra is undoubtedly a member of the genus Fukuia. As early as 1979, Davis hypothetized that Blanfordia and Fukuia are either the same genus or that they may have a common ancestor.
Cladogram
A cladogramCladogram
A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...
showing phylogenic relations of genera within Pomatiopsidae:
Ecology
Blanfordia and Fukuia (that contain terrestrial Fukuia integraFukuia integra
Fukuia integra, also known as Blanfordia integra, is a species of land snail which has an operculum, a terrestrial gastropod mollusk in the family Pomatiopsidae.- Taxonomy :...
) are the only genera of terrestrial gastropods within the family Pomatiopsidae, which otherwise consists of mainly freshwater (but also seasonally amphibious) snails. Species of Blanfordia can be found from the sea coast to the mountains. They live in coastal dunes and littoral forests (Blanfordia simplex
Blanfordia simplex
Blanfordia simplex is a species of land snail that has an operculum, a terrestrial gastropod mollusk in the family Pomatiopsidae.Henry Augustus Pilsbry described it as Blanfordia japonica var. simplex in 1902. He has elevated this taxon to specific level in 1903.- Distribution :This species is...
), from coastal to inland forests (Blanfordia japonica
Blanfordia japonica
Blanfordia japonica is a species of land snail which has an operculum, a terrestrial gastropod mollusk in the family Pomatiopsidae.- Distribution :This species is endemic to Japan. The type locality is Sado.It is a Near Threatened species....
) and on the forest floor of inland forests (Blanfordia bensoni
Blanfordia bensoni
Blanfordia bensoni is a species of land snail which has an operculum, a terrestrial gastropod mollusk in the family Pomatiopsidae.Blanfordia bensoni is the type species of the genus Blanfordia.- Distribution :This species is endemic to Japan...
). Other land snails living in habitats of Blanfordia snails include for example diplommatinids, camaenids and bradybaenids.
The phylogenetic analyses by Kameda & Kato (2011) indicates that Japanese Pomatiopsinae have adapted
Adaptation
An adaptation in biology is a trait with a current functional role in the life history of an organism that is maintained and evolved by means of natural selection. An adaptation refers to both the current state of being adapted and to the dynamic evolutionary process that leads to the adaptation....
from freshwater environment to terrestrial life (terrestrialization) at least twice (three Blanfordia species in one clade and Fukuia integra
Fukuia integra
Fukuia integra, also known as Blanfordia integra, is a species of land snail which has an operculum, a terrestrial gastropod mollusk in the family Pomatiopsidae.- Taxonomy :...
- formelly Blanfordia intergra species in another clade). This change has happened in regions with heavy snowfalls that face the Sea of Japan.