Common names: Coffee Bean Snail, more...
Rhizophora mangle. Photo L. Holly Sweat, Smithsonian Marine Station at Fort Pierce." alt="Melampus coffeus image" />
Species Description: The coffee bean snail, Melampus coffeus, is a small intertidal snail. The shell is ovate, tapering toward the base. Most snails are brown with three horizontal light bands (Kaplan 1988), but the background color in some individuals may range from shades of gray or tan to yellowish brown. The aperture is narrow and long, with a sharp outer lip and an inner margin bearing two teeth (Kaplan 1988). The pale brown inner lip is turned slightly backwards, and the spire is conical. Unlike many other snails, M. coffeus lacks an operculum (Ruppert & Barnes 1994).
Potentially Misidentified Species: The coffee bean snail may be mistaken for the eastern melampus, M. bidentatus, which is very similar in appearance. The shell of the eastern melampus is also brown with light bands, and reaches a length of about 1.8 cm (Andrews 1994). In addition, incised spiral lines are present on the upper shoulder of the shell. The eastern melampus is more prevalent in salt marshes (Mook 1973); whereas M. coffeus is found mostly among mangrove roots and branches (Proffitt & Devlin 2005).
Regional Occurrence: The coffee bean snail inhabits intertidal zones along both coasts of Florida and throughout the Caribbean. Most populations are found around roots and branches of mangroves (Proffitt & Devlin 2005).
Age, Size, Lifespan: Little information is available concerning the maximum age and size of M. coffeus. Most adult snails are approximately 1-2 cm (Kaplan 1988). Studies on populations in Tampa Bay documented size ranges between 0.5 and 1.9 cm in length (Proffitt & Devlin 2005). Maia & Tanaka (2007) found the largest snails in one Brazilian estuary on stands of the red mangrove, R. mangle.
Abundance: Abundance estimates for M. coffeus in the IRL are scarce. However, previous studies have documented densities between 1 and 143 individuals per square meter in various mangrove ecosystems throughout Florida (Proffitt & Devlin 2005, Raulerson 2004).
Reproduction, Embryology & Larval Development: The coffee bean snail is a simultaneous hermaphrodite, and individuals copulate to produce gelatinous egg masses which are laid under leaves and on decaying wood (Russell-Hunter et al. 1972). Both M. coffeus and M. bidentatus can lay several batches, totaling over 33,000 eggs per year (Apley 1968). Melampus is one of the few pulmonate snails that reproduce via planktonic larvae called veligers (Ruppert & Barnes 1994). Once the eggs hatch, the veligers spend approximately 4-6 weeks in the plankton before returning to the mangroves on a high tide and metamorphosing into juvenile snails (Apley 1968, Holle & Dineen 1957).
Temperature: Little information exists regarding the temperature tolerances for M. coffeus. However, the tropical and subtropical range of the species suggests that it thrives best in warmer waters.
Salinity: Little information exists regarding the temperature tolerances for M. coffeus. However, the tropical and subtropical range of the species suggests that it thrives best in warmer waters.
Respiration & Migration: The coffee bean snail is one of over 16,000 described species of pulmonate gastropods found in temperate to tropical latitudes worldwide (Ruppert & Barnes 1994). These snails are characterized by the presence of a lung, which had been converted from the mantle cavity. A small opening, called a pneumostome, is present on the right side where the mantle cavity remains unfused. Gills are absent, and the mantle cavity has become highly vascularized. Most gas exchange occurs through diffusion in the pneumostome. The coffee bean snail migrates vertically as the tide rises (eg. Proffitt & Devlin 2005) to avoid predation and approaching water, though it descends into the water to release larvae (Ruppert & Barnes 1994).
Ecological Importance: The coffee bean snail is an important consumer of leaf litter and detritus in mangrove ecosystems, and is the only known direct consumer in southwest Florida (Proffitt et al. 1993, McIvor & Smith 1995, McKee & Faulkner 2000). These snails also consume dead or dying leaves from the tree, with removal rates exceeding 200 g m-2 annually (McKee & Faulkner 1995), depending on the mangrove species. In addition, an average population can produce about 3 x 106 larvae annually (Proffitt & Devlin 2005), providing an energy pathway within mangrove communities from detritus and leaf litter to higher order consumers.
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