| Bythinella bicarinata | |
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| Species: | B. bicarinata |
| Binomial name | |
| Bythinella bicarinata (des Moulins, 1827) | |
| Synonyms | |
Bithynia moulinsiiDupuy, 1849 Contents | |
Bythinella bicarinata is a species of very small freshwater snail, an aquatic gastropod mollusk in the family Amnicolidae.
The shell of this species measures about 2.2–2.6 mm long and has a pupoidal shape (shaped like a fly's puparium). [2] In the population first described, there are two ribs running along the length of the shell; hence the scientific name bicarinata ("two-keeled").
This species was believed to be endemic to France and severely threatened with extinction. In 1996 it was classified as Critically Endangered (A1ce) by the IUCN, as its habitat – essentially the Fontaine de la Vierge and nearby springs in the Dordogne [2] – was being affected by pollution and the local snail populations had declined more than 80% in the late 20th century. [1]
However, analysis of mtDNA COI and nDNA ITS1 sequence data showed that the "typical" two-keeled Bythinella bicarinata are actually part of a clade widespread in central to northeastern France and nearby regions. Consequently, Bythinella dunkeri, Bythinella lalindei, Bythinella moulinsii and Bythinella poujolensis are now provisionally treated as junior synonyms of Bythinella bicarinata. These all lack the shell keels, though Bythinella lalindei and Bythinella poujolensis are otherwise essentially identical. The other two differ a bit more, though those described as Bythinella moulinsii are quite variable in size and shape. As the study proposing the synonymy applied the phylogenetic species concept which does not recognize subspecies, the question whether the other taxa are valid subspecies or simply local morphs remains unresolved. [2]
Considering the lack of the two-keeled phenotype outside the extreme southeastern end of the range of Bythinella bicarinata and the fact that the region where it occurs is at the very limits of the range, it is probably advisable to recognize several subspecies. In any case, Bythinella bicarinata in the loose sense is not globally threatened. The populations from Belgium and western Germany described as Bythinella dunkeri were in 1996 classified as Vulnerable (B1+2c), as they were known from less than ten freshwater springs which are affected by pollution. [3] Given that they occur at the other end of the species' range and are consistently most distinct morphologically from the "keeled" specimens, they might also warrant recognition as subspecies.
The keeled box turtle is a species of turtle in the family Geoemydidae. The species is endemic to Asia.
Bythinella badensis is a species of very small freshwater snail, an aquatic gastropod mollusk in the family Amnicolidae. This species is endemic to Germany.
Bythinella is a genus of very small freshwater snails, an aquatic gastropod mollusk in the family Bythinellidae.
Bythinella bavarica is a species of species of very small freshwater snail, an aquatic gastropod mollusk in the family Amnicolidae. This species is endemic to Germany.
Bythinella carinulata is a species of very small freshwater snail, an aquatic gastropod mollusk in the family Amnicolidae. This snail is endemic to France.
Bythinella cylindrica is a species of very small freshwater snail, an aquatic gastropod mollusk in the family Amnicolidae. This species is endemic to Austria.
Bythinella padiraci is a species of very small freshwater snail, an aquatic gastropod mollusk in the family Amnicolidae. This snail is endemic to France, from a very little place named "Gouffre de Padirac".
Bythinella pupoides is a species of very small freshwater snail, an aquatic gastropod mollusk in the family Amnicolidae. This snail is found in France and Switzerland.
Bythinella reyniesii is a species of very small freshwater snail, an aquatic gastropod mollusk in the family Amnicolidae.
Bythinella vesontiana is a species of very small freshwater snail, an aquatic gastropod mollusk in the family Amnicolidae. This species is endemic to France.
Bythinella viridis is a species of very small freshwater snail, an aquatic gastropod mollusc in the family Amnicolidae. This species is found in Belgium and France.
Bythinella austriaca is a species of very small freshwater snail with an operculum, an aquatic gastropod mollusk in the family Amnicolidae.
The twist-necked turtle also known as the flat-headed turtle, is distributed widely across northern South America. Twistoofnecked turtles have extremely flat shells that help them hide from predators under rocks and debris. When threatened, this turtle withdraws by twisting its head into its shell. P. platycephala is the only species of the genus Platemys and occurs in northern and central South America. Platemys platycephala means “flat turtle, flat-head” and accurately describes the structure of the head and shell. This species inhabits shallow creek beds and frequently forages on the floor of the Amazon rainforest for insects, amphibians, and mollusks. Camouflage, head and body shape, and advanced sexual anatomy allow this species of turtle to effectively populate much of South America. Mating occurs during rainy months (March–December) and egg deposit occurs during dry months (January–March). Males have been known to behave aggressively towards females during copulation by squirting water from nostrils and biting. A few genomic studies show mosaicism exists among populations of the twist-necked turtle in Surinam. In other words, diploid and triploid levels exist among individuals at this particular location. No threats have been reported for this species and the International Union for Conservation of Nature does not have a current listing. Lack of human consumption due to the species' small size and its wide range explain why scientists are not concerned about this turtle species.
Marstoniopsis is a genus of minute freshwater snails with a gill and an operculum, aquatic gastropod mollusks or micromollusks in the family Amnicolidae.
Bythinella bouloti is a species of very small freshwater snail, an aquatic gastropod mollusk in the family Amnicolidae.
Bythinella galerae is a species of very small freshwater snail, an aquatic gastropod mollusk in the family Amnicolidae.
Bythinella gloeeri is a species of very small freshwater snail, an aquatic gastropod mollusk in the family Amnicolidae.
Bythinella markovi is a species of very small freshwater snail, an aquatic gastropod mollusk in the family Amnicolidae.
