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.
Potentially Misidentified Species
Many of the species of littorinids
common to the western Atlantic are found in the IRL, including:
the marsh periwinkle, Littorina
irrorata; slender periwinkle, L. angustior; lineolate
periwinkle, L. lineolata; white-spot periwinkle, L.
meleagris; and the zebra periwinkle, L. ziczac. All
of these species share a similar shell shape and an intertidal distribution.
The marsh periwinkle attains
a shell length of about 3.2 cm, and is elongate conic in shape,
longer than it is wide (Andrews 1994). Coloration of the shell is
dull grayish white with tiny dashes of reddish brown on the ridges
of the spiral. Eight to ten gradually increasing flat whorls comprise
the shell, with the body whorl measuring about half of the total
height. The aperture is oval with a sharp outer tip and regular
grooves on the inside edge.
The slender periwinkle is
relatively small, reaching a length of about 0.8 cm (Abbott 1974).
The upper whorls of the shell are marked with 6-9 spiral lines,
the sides of the foot are mottled black and gray, and the operculum
is mostly round in shape.
The lineolate periwinkle
reaches a length of about 1.2 to 2.5 cm, has a gray background color
on the shell with oblique zigzag lines of dark brown, and an apex
of reddish brown (Andrews 1994). The shell is composed of 6-8 gradually
increasing whorls, with the body whorl spanning more than half of
the total length, and the suture between whorls is well marked.
The pear-shaped aperture has a sharp, thin outer lip meeting the
body whorl at an acute angle. Males are smaller and more strongly
sutured then females.
The white-spot periwinkle
is also small like the slender periwinkle, measuring about 0.8 cm
in length (Abbott 1974). The shell has a pointed spire with a thin
periostracum or organic covering. The aperture is reddish brown
and the exterior of the shell is brown with large, irregular white
spots, often arranged in spiral roles.
The zebra periwinkle has
a shell length of about 1.3 cm, and is whitish with dark brown or
black wavy stripes (Andrews 1994). The aperture is small and oval,
and the operculum is chitinous. This species is often confused with
L. lineolata, but has a lighter colored shell with a narrower apical
angle than the lineolate periwinkle.
HABITAT AND DISTRIBUTION
Regional Occurrence & Habitat Preference
The range of the mangrove periwinkle extends
from Florida to Brazil, throughout the Caribbean and Bermuda (Abbot
& Morris 1995, Tanaka & Maia 2006). The species is also
found in the eastern Atlantic from Senegal to Angola (Merkt &
Ellison 1998). As its common name implies, L. angulifera
is a common inhabitant of mangrove forests, mainly above the water
line on trunks and prop roots of the red mangrove, Rhizophora
mangle (Kaplan 1988, Merkt & Ellison 1998).
The mangrove periwinkle can be found along
the shores and spoil islands of the IRL on red mangrove branches
and prop roots.
LIFE HISTORY AND POPULATION BIOLOGY
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).
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).
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).
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.
The mangrove periwinkle is most commonly found
in brackish estuaries (Andrews 1994), with larger individuals in
less saline waters (Chaves 2002).
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 &
Few predators are documented for L. angulifera,
but the snail is likely preyed upon by a variety of birds, fishes,
large crabs and mammals.
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's link at the left of this page.
No information is available at this time
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.
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
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.
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.