Batillaria multiformis
From Wikipedia, the free encyclopedia
| Batillaria multiformis | |
|---|---|
 | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| Subclass: | Caenogastropoda |
| Family: | Batillariidae |
| Genus: | Batillaria |
| Species: | B. multiformis |
| Binomial name | |
| Batillaria multiformis (Lischke, 1869) | |
Batillaria multiformis is a species of sea snail, a marine gastropod mollusk in the family Batillariidae.[1] They are colloquially known as salt marsh or mudflat snails, due to their benthic nature in intertidal zones and salt marshes.[2] They are endemic to the West Pacific Ocean, but are most commonly observed on the southern coast of Japan.[1] B. multiformis feed on phytoplankton in their larval stage, and various terrestrial and aquatic primary producers once in their benthic adult form.[3] They are intermediate hosts to several Cercaria trematodes.[4] While still highly prevalent in remaining mudflat regions, available suitable habitat has declined with increasing land reclamation in Japan.[2] Since 2020, B. multiformis has been considered a "near-threatened" species by the Japanese Ministry of the Environment.[5]
Batillaria multiformis was first recorded in 1869 by Lishke in Japan, and was initially classified Lampania multiformis.[1] This genus is synonymous with genus Batillaria, determined by W.H. Benson in 1842. It is a gastropod within the subclass Caenogastropoda, which contains other sea snails, freshwater snails and land snails.
Molecular phylogeny analysis suggests that Batillaria multiformis is most closely related to species Batillaria flectosiphona within the genus, with both being derived from the basal species Batillaria zonalis.[6] Recent mitochondrial DNA analysis suggests that shell morphology is not always an accurate measure of identifying genetically different species.[6]
Morphology
The shell of Batillaria multiformis has a dark brown to grey base coloration with varying patterns and an overall knobbed appearance, with between eight and nine flat whorls.[7] The upper whorls have pronounced ribs, and roughly five spiral-shaped striae.[7] Whorls lower to the body have roughly 15 spiral striae.[7] The sutures between the whorls are impressed (indented). The outer lip of the opening of the shell is straight, with a smooth columella and a short siphonal canal.[7] The operculum is brown and horny.[7] The shell morphology is visually similar to B. attramentaria, which has led to developments in PCR-RFLP techniques, requiring the use of two restriction enzymes to determine the species at a genotype level.[8] However, the two can be differentiated by their life history, as they exhibit notably different developmental styles.
In Southern Japan, average shell size of fully grown individuals appears to fall within the range of 25 to 40 mm.[9] However, in a survey of individuals residing in Mutsu Bay in the northernmost part of Japan, shell length reached almost 50 mm.[10] Shell growth stops when sexual maturity is reached, at which time a callus knob is formed at the top of the aperture.[10] When sexually mature, the digestive gland is covered by the gonad.[10]
Shell color and pattern variability
Color and pattern has been observed to be variable in the shell of B. multiformis. There are two main color patterns: a dark, unbanded shell, and shells with white banding on the upper side of each whorl.[11] These two patterns are also expressed in B. attramentaria. The unbanded, darker shell is more prominent in the northern coast of Japan that borders the Pacific Ocean, and is the only type of pattern found on the west coast of Japan.[11] The white-accented shell becomes more prominent in populations on the southern coast bordering the Pacific Ocean.[11] It may be that the darkest shells are favored in the northern parts of Japan because it allows for greater levels of UV absorption, acting as an adaptation to survive in colder weather.[11] Areas with higher average minimum temperatures experience greater shell color diversity. Shell coloration and patterns do not have an observable effect on the predation of or parasitism in B. multiformis.[11]
