- Auricula myosotis Draparnaud 1801: 53.
- Many more synonyms worldwide.
Identification. Shell elongate-ovate. Spire tall, with sides straight or scarcely convex. Apex acutely pointed. Suture rather shallow. Whorls c. 7, not very convex in profile. Periphery rounded, medial. Protoconch smooth, but most often eroded. Teleoconch with first three whorls deeply pitted in spiral rows, then smoothish or with irregular, often quite strong growth wrinkles; particularly when shell eroded, low colabral riblets often evident; occasional varix present at site of growth rest. Juveniles and occasionally well-preserved adults with 1 spiral row of well-spaced periostracal hairs (which correspond to the pits). Aperture subovate-elongate, acutely angled above, c. 70% of shell height, with 1 strong, medial parietal plica, 1 strong columellar plica, and 1 low, callus-like protuberance (usually absent) above; plicae white. No palatal lirae in BC specimens, although 1 or more are reported elsewhere (Frias Martins 1996). Lip expanded when mature but generally thin. Parietal callus glazed, transparent, inconspicuous. No umbilicus. Shell weakly glossy, yellowish or more frequently reddish brown; lip pale. Height to 8.4 mm (higher than wide).
Animal greyish-white, darker, blackish anteriorly and dorsally and on tentacles; sole of foot yellowish grey. Blackish eye spots at the base of tentacles. Foot yellowish.
Comparison. This species is unlike any other snail in BC, where it is the only semimarine ellobiid. This semi-marine salt-marsh snail is included here to complete the family Ellobiidae.
Habitat. Myosotella myosotis inhabits the semimarine supralittoral zone along the coast, in salt marshes of sheltered bays and occasionally along the strand line where salt marshes are absent. Snails are usually gregarious in damp places under driftwood and other debris, living plants such as pickleweed (Salicornia L.), and washed up, dislodged eelgrass (Zostera L.). They also live in loose soil and occasionally among stones.
Biology. Snails can survive fully submerged for weeks, and they are tolerant of a broad range of salinity, although normal development of eggs is possible only at lower salinity. Eggs are deposited in masses on the substrate and develop in about 18 days (Seelemann 1968).
The diet includes bacteria, cyanobacteria, diatoms, and outer cells of salt-marsh vegetation (Seelemann 1968; Berman and Carlton 1991).
In experiments to test if the establishment of the invasive M. myosotis in the Northeast Pacific came at the expense of native salt-marsh snails Angustassiminea californica (Tryon, 1865) and Littorina subrotundata (P.P. Carpenter, 1864), Berman and Carlton (1991) found that it did not.
Geographic range. Myosotella myositis is introduced to BC. It was first reported from the province by Grass (1967) as Alexia myosotis. In BC, it is known from around the Strait of Georgia in suitable habitat, north to at least Union Bay, on the east coast of Vancouver Island. This species is native to the Mediterranean and eastern Atlantic coasts.
All North American occurrences of M. myosotis, BC south to California and Nova Scotia to Cuba, are introductions, and it has also been introduced to Bermuda, the Azores and Madeira, South Africa, South Africa, and Australia (Frias Martins 1996). The wide distribution to many places worldwide is probably due to being transported in ships’ ballast or cargo (Climo 1982).
Etymology. Myosotella: derived from the species epithet with the addition of the Latin diminutive suffix -ella; the gender is feminine. Myosotis: from the Greek myos, mouse + otis, ear, a reference to the shape of the shell.
Remarks. In the literature, M. myosotis has variously been placed in Alexia Leach, 1847, “Phytia“, or Ovatella Bivona e Bernardi, 1832 (among others), but Myosotella is used instead of Ovatella for this species following Frias Martins (1996, 1999), based on morphology of the shell and anatomy. The many introductions to many places worldwide have resulted in an extensive synonymy (Frias Martins 1996). However, anatomical and molecular data of this species from various places worldwide have shown unsuspected genetic diversity in what has been known as M. myosotis (Frias Martins and Marques Mendes 2013).
References
- Berman J, Carlton JT (1991) Marine invasion processes: interactions between native and introduced marsh snails. Journal of Experimental Marine Biology and Ecology 150: 267–281.
- Climo FM (1982) The systematic status of Auricula (Alexia) meridionalis Brazier, 1877 and Rangitotoa insularis Powell, 1933 (Mollusca: Ellobiidae) in Australasia. National Museum of New Zealand Records 2: 43–48.
- Draparnaud J (1801) Tableau des Mollusques terrestres et fluviatiles de la France. Renaud & Bossange, Masson & Besson, Montpellier & Paris, 116 pp.
- Frias Martins AM de (1996) Anatomy and systematics of the Western Atlantic Ellobiidae (Gastropoda: Pulmonata). Malacologia 37: 163–332.
- Frias Martins AM de (1999) On the generic separation of Ovatella Bivona, 1832 and Myosotella Monterosato, 1906 (Pulmonata: Ellobiidae). Iberus 17: 59–75.
- Frias Martins AM de, Marques Mendes AR (2013) Do cosmopolitans speciate? Anatomical diversity of Myosotella in Azores. World Congress of Malacology 2013, Azores. https://doi.org/10.13140/2.1.3483.4564
- Grass AL (1967) Alexia myosotis (Ellobiidae) in British Columbia. The Canadian Field-Naturalist 81: 278–279. https://doi.org/10.5962/p.342814
- Seelemann U (1968) Zur Überwindung der biologischen Grenze Meer—Land durch Mollusken. Untersuchungen an Alderia modesta (Opisth.) und Ovatella myosotis (Pulmonat.). Oecologia 1: 130–154.