Littorina saxatilis


Littorina saxatilis, common name the rough periwinkle, is a species of small sea snail, a marine gastropod mollusc in the family Littorinidae, the winkles or periwinkles. First identified in the 1700s, it has been misidentified as a new species 112 times.

Distribution

This species is native to the shores of the North Atlantic Ocean, including Hudson Bay, Baffin Island, Greenland, and the Barents Sea, south along the American East Coast to Chesapeake Bay, and along the European coast to the Straits of Gibraltar. Only one population of this intertidal species occurred in the Mediterranean basin i.e., Venice lagoon. The Venice population represents the earliest confirmed introduction of an exotic species in the Mediterranean Sea. Abiotic environmental features such as salinity and water temperature have influenced the past and current distributions of this snail and limited its invasion of the Mediterranean Sea.
This species has also been introduced to San Francisco Bay, on the West Coast of the United States, where it was first observed in 1992.

Shell description

The shell in life often appears green with algae, but the shell itself can be white, red, or brown, sometimes with checkered lines. The shell has 4–5 whorls. Maximum recorded shell length is 19 mm.

Ecology

Habitat

This species frequently lives in salt marshes. it can also be found in crevices of intertidal bedrock, in empty barnacle shells, and under rocks. Like many other periwinkles, this species can survive long exposures out of the water.
The species has been recorded alive from depth range 0 – 46 m or up to 183 m.
In the exposed Galician coast in the Northern Spain, two well differentiated ecotypes are adapted to different shore levels and habitats. The RB ecotype lives on barnacles in the upper shore. This ecotype displays a larger and more robust shell to resist the attack from predators such as crabs, and a smaller shell aperture in order to reduce the desiccation due to high sunshine exposure. The SU ecotype is found at the lower shore living on mussels. This ecotype shows a smaller and thinner shell with a wider shell aperture to allocate a relatively larger muscular foot providing a higher ability to avoid the dislodgment caused by the heavy wave action. Both ecotypes coexist in an intermediate habitat at the middle shore.

Genetics

Littorina saxatilis has been shown to be an excellent model system for speciation genetics. In the seminal 2001 paper, Wilding et al demonstrated, using amplified fragment length polymorphism, that the low shore M form of the species were divergent from the high shore H form at number of loci despite gene flow between the forms.

Feeding habits

This snail is a herbivore which grazes on the surface of rocks and mud flats.

Life cycle

The marine snail Littorina saxatilis has separate sexes, internal fertilization, and a brood pouch with non-planktonic shelled embryos.

Synonyms

Litorina groenlandica Menke, 1830Litorina incarnata Philippi, 1846Litorina marmorata L. Pfeiffer, 1839Litorina sulcata Menke, 1830Littorina castanea Deshayes in Deshayes & Milne Edwards, 1843Littorina danieli Locard, 1886Littorina groenlandica Littorina neglecta Bean, 1844Littorina nervillei Dautzenberg, 1893Littorina nervillei var. major Pallary in Seurat, 1924Littorina nigrolineata Gray, 1839Littorina palliata var. turritella Schlesch, 1916Littorina rudis Littorina rudis f. elatior Middendorff, 1849Littorina rudis var. albida Dautzenberg, 1887Littorina rudis var. alticola Dacie, 1917Littorina rudis var. aurantia Dautzenberg, 1887Littorina rudis var. brevis Dautzenberg, 1887
  • Littorina rudis var. conoidea Schlesch, 1916Littorina rudis var. fasciata Dautzenberg, 1887Littorina rudis var. finmarchia Herzenstein, 1885Littorina rudis var. globosa Jeffreys, 1865Littorina rudis var. globosa Martel, 1901Littorina rudis var. laevis Jeffreys, 1865Littorina rudis var. major Dautzenberg & P. Fisher, 1912Littorina rudis var. rubescens Monterosato, 1878Littorina rudis var. scotia S.M. Smith, 1979Littorina rudis var. similis Jeffreys, 1865Littorina rudis var. sulcata Martel, 1901Littorina rudis var. tenebrosapallida L.E. Adams, 1896Littorina rudis var. tessellata Dautzenberg, 1893Littorina saxatile La Roque, 1953Littorina saxatile saxatile La Roque, 1953Littorina saxatilis Johnston, 1842Littorina saxatilis f. abbreviata Dautzenberg & P. Fisher, 1912Littorina saxatilis f. conoidea Dautzenberg & P. Fisher, 1912Littorina saxatilis f. elongata Dautzenberg & P. Fisher, 1912Littorina saxatilis f. minor Dautzenberg & P. Fisher, 1912Littorina saxatilis groenlandica Littorina saxatilis groenlandica var. sculpta Schlesch, 1931Littorina saxatilis jugosa Montagu, 1803Littorina saxatilis jugosa var. bynei Dautzenberg & P. Fisher, 1912Littorina saxatilis jugosa var. tenuis James, 1968Littorina saxatilis nigrolineata Gray, 1839Littorina saxatilis rudis Littorina saxatilis rudis var. rudissimoides James, 1968Littorina saxatilis scotia Graham, 1988Littorina saxatilis tenebrosa Littorina saxatilis tenebrosa var. biinterrupta Fischer-Piette & Gaillard, 1963Littorina saxatilis tenebrosa var. bizonaria James, 1963Littorina saxatilis tenebrosa var. elata Dautzenberg & P. Fisher, 1912Littorina saxatilis tenebrosa var. maculata Fischer-Piette & Gaillard, 1963Littorina saxatilis var. clarilineata Fischer-Piette & Gaillard, 1971Littorina saxatilis var. flammulata Dautzenberg & P. Fisher, 1912Littorina saxatilis var. fulva Dautzenberg & P. Fisher, 1912Littorina saxatilis var. fusca Dautzenberg & P. Fisher, 1912Littorina saxatilis var. gascae Fischer-Piette & Gaillard, 1971Littorina saxatilis var. groenlandica Littorina saxatilis var. hieroglyphica Fischer-Piette, Gaillard & Jouin, 1961Littorina saxatilis var. interrupta Fischer-Piette, Gaillard & Jouin, 1961Littorina saxatilis var. lagunae Barnes, 1993Littorina saxatilis var. lineata Dautzenberg & P. Fisher, 1912Littorina saxatilis var. lugubris Dautzenberg & P. Fisher, 1912Littorina saxatilis var. nigra Fischer-Piette & Gaillard, 1971Littorina saxatilis var. nojensis Fischer-Piette & Gaillard, 1964Littorina saxatilis var. rubra Fischer-Piette & Gaillard, 1971Littorina saxatilis var. rubrolineata Fischer-Piette, Gaillard & Delmas, 1967Littorina saxatilis var. salvati Fischer-Piette, Gaillard & Delmas, 1967Littorina saxatilis var. sanguinea Coen, 1933Littorina saxatilis var. sellensis Fischer-Piette & Gaillard, 1964Littorina saxatilis var. tractibus Fischer-Piette, Gaillard & Jouin, 1961Littorina saxatilis var. trifasciata Dautzenberg & P. Fisher, 1912Littorina saxatilis zonata Daniel, 1883Littorina saxoides Nardo, 1847Littorina simplex Reeve, 1857Littorina tenebrosa Littorina tenebrosa f. elatior Middendorff, 1849Littorina tenebrosa var. costulata Middendorff, 1849Littorina tenebrosa var. densecostulata Middendorff, 1849Littorina tenebrosa var. grisolacteus Middendorff, 1849Littorina tenebrosa var. intermedia Forbes & Hanley, 1850Littorina tenebrosa var. rubidus Middendorff, 1849Littorina tenebrosa var. tessellatus Middendorff, 1849Littorina tenebrosa var. zonatus Middendorff, 1849Littorina zonaria Bean, 1844Nerita rustica Nardo, 1847Turbo obligatus Say, 1822Turbo rudis Maton, 1797Turbo rudissimus Johnston, 1842