Species Description: The mangrove periwinkle, Littorina angulifera, is a common intertidal snail in mangrove forests of the southeast United States. The shell color of L. angulifera varies from bluish white, orange to dull yellow, reddish brown to grayish brown (Andrews 1994). The shell is comprised of 6 whorls, with the body whorl about half of the total height of the snail. Darker dashes on the ribs of the shell are often fused to form stripes on the body whorl. The early whorls around the base bear regularly-spaced vertical white spots below the channeled sutures.
IRL Distribution: The mangrove periwinkle can be found along the shores and spoil islands of the IRL on red mangrove branches and prop roots.
Age, Size and Lifespan: The maximum age of L. angulifera is unknown, and the lifespan can vary with food availability and environmental factors. The maximum reported length for the mangrove periwinkle is about 3 cm (eg. Kaplan 1988).
Reproduction: Reproductive strategies are quite diverse within the Littorina genus. Some species release egg masses from with larvae hatch, others attach egg masses to hard substrata, and some brood their young until giving birth to larvae or juvenile snails (Ruppert & Barnes 1994). The mangrove periwinkle is considered ovoviviparous, internally brooding fertilized eggs and releasing planktonic larvae (Merkt & Ellison 1998, Tanaka & Maia 2006).
Embryology: Like many other mollusks, the mangrove periwinkle reproduces via a planktonic larva called a veliger (Kolipinski 1964). These larvae remain in the water column for 8-10 weeks until they reach the final stage, or pediveliger, at which time they search for a suitable location to settle and metamorphose into juvenile snails (Gallagher & Reid 1979).
Temperature: Little information is available concerning the thermal tolerance for L. angulifera, but the tropical to subtropical range of the species suggests it prefers warmer waters and air temperatures.
Salinity: The mangrove periwinkle is most commonly found in brackish estuaries (Andrews 1994), with larger individuals in less saline waters (Chaves 2002).
Trophic Mode: The mangrove periwinkle is herbivorous, grazing on algae and fungi (Kohlmeyer & Bebout 1986). The feeding structure, called a radula, varies in populations from different habitat types (Andrade & Solferini 2006). The radula is a belt of small teeth used to scrape food from hard surfaces (Ruppert & Barnes 1994).
Predators: Few predators are documented for L. angulifera, but the snail is likely preyed upon by a variety of birds, fishes, large crabs and mammals.
Associated Species: No known obligate associations exist for L. angulifera. However, mangrove periwinkles are associated with several organisms common to mangroves and other intertidal areas. For extensive lists of other species found in the habitats in which L. angulifera occurs, please refer to the 'Habitats of the IRL' reference of the inventory.
Abbott, RT. 1974. American seashells: the marine Mollusca of the Atlantic and Pacific coasts of North America. Van Nostrand Reinhold Co. New York, NY. USA.
Abbott, RT & PA Morris. 1995. A field guide to shells: Atlantic and Gulf coasts and the West Indies, 4th edition. Houghton Mifflin Co. Boston, MA. USA.
Andrade, SCS & VN Solferini. 2006. The influence of size on the radula of Littoraria angulifera (Gastropoda: Littlorinidae). Malacologia. 49: 1-5.
Andrews, J. 1994. A field guide to shells of the Florida coast. Gulf Publishing Co. Houston, Texas. USA. 182 pp.
Chaves, AMR. 2002. Entre o seco e o molhado, do costão ao manguezal: distribuição de gastrópodes fa família Littorinidae em gradients vertical e horizontal no litoral do estado de São Paulo. Master's Thesis. Universidade Estadual de Campinas. Brazil.
Gallagher, SB & GK Reid. 1979. Population dynamics and zonation in the periwinkle snail, Littorina angulifera, of the Tampa Bay, Florida region. Nautilus. 94: 162-178.
Kaplan, EH. 1988. A field guide to southeastern and Caribbean seashores: Cape Hatteras to the Gulf coast, Florida, and the Caribbean. Houghton Mifflin Co. Boston, MA. USA. 425 pp.
Kohlmeyer, J & B Bebout. 1986. On the occurrence of marine fungi in the diet of Littorina angulifera and observations on the behavior of the periwinkle. Mar. Ecol. 7: 333-343.
Merkt, RE & AM Ellison. 1998. Geographic and habitat-specific variation of Littoraria (Littorinopsis) angulifera (Lamarck, 1822). Malacologia. 40: 279-295.
Ruppert, EE & RD Barnes. Invertebrate zoology, 6th edition. Saunders College Publishing. Orlando, FL. USA. 1056 pp.
Tanaka, MO & RC Maia. 2006. Shell morphological variation of Littoraria angulifera among and within mangroves in NE Brazil. Hydrobiologia. 559: 193-202.