The flyspeck cerith, Cerithium muscarum, is a small gastropod
mollusc of the family Cerithiidae. The elongate shell has 9-10 distinct
whorls and a sharp apex. From 9-11 pronounced nodulose axial ribs crossed
by dotted and dashed spiral lines cover each whorl. The background shell
color is light tan to slate to light brown and the small 'fly specks' that
form the spiral rows are chestnut brown. The aperture is oval and oblique
and the canal is short and turned to the left (Abbot and Morris 1995,
Baily-Matthews Shell Museum undated).
Potentially Misidentified Species
Although there are several similarly sized and shaped ceriths that
co-occur with Cerithium muscarum, the whorl count, the robust
radial ribs, and the distinct color pattern should allow positive
identification of specimens to species.
HABITAT AND DISTRIBUTION
Rosenberg (2005) reports flyspeck ceriths occur from a latitude of 35° to
16.5° north latitude and from 97° to 76° west longitude. This distribution
spans from North Carolina south throughout both Florida coasts, throughout
the Gulf of Mexico and in much of the Caribbean.
Abbot and Morris (1995) report a somewhat more restricted distribution,
including Bermuda, and the Atlantic coast of the Americas from south
Florida to Brazil.
Cerithium muscarum occurs throughout the IRL system.
LIFE HISTORY AND POPULATION BIOLOGY
Age, Size, Lifespan
Rosenberg (2005) notes the maximum reported size for the species is 26 mm. Houbrick (1974) indicates the life span is approximately 1 year.
Young and Young (1977) list Cerithium muscarum as among the top 10
macrobenthic community dominants in the Indian River Lagoon seagrass
habitats they surveyed. This is the most common of the Florida ceriths.
Reproduction in Cerithium is sexual. The sexes are separate and
fertilization is internal although males lack a penis (Cannon 1975). After
copulation, females deposit a stringy egg mass which they
attach to benthic substrata (Houbrick 1970).
Cerithium muscarum lack planktonic larvae, a trait they share with
some other euryhaline shallow water species but one that is not common to
the entire genus (Houbrick 1970, Cannon 1975).
Juveniles grow to adults in a few months (Houbrick 1974).
This gastropod occurs from North Carolina south to the Caribbean,
indicating a moderate degree of thermal tolerance. Salinity and temperature
tolerance experiments by Murray and Wingard (2006) yielded high survival
rates at temperatures as high as 34°C.
Collection records maintained by the NOAA National Benthic Inventory (NBI
undated) indicate the flyspeck cerith is euryhaline, with most collections
occurring at salinities ranging from 18.3 ppt to more than 41 ppt.
Salinity and temperature tolerance experiments by Murray and Wingard (2006)
reveal that survivorship and reproduction are both enhanced under
hypersaline (57-62 ppt) conditions.
Captive-reared Cerithium muscarum consume sand and surface
deposits, spiphytic algae, and seagrass detritus, believed to
be reflective of the typical natural diet of the species (Houbrick 1974).
Several species of crabs prey upon Cerithium muscarum, including
those of genera Callinectes, Menippe, and Libinia.
Carnivorous gastropods known to consume C. muscarum include
Melongena corona, Busycon contrarium, Fasiolaria tulipa,
and Pleuroploca gigantea, and several natacid and muricid snails are
putative predators as well. Stingrays and horseshoe crabs (Limulus
polyphemus) are suspected predators (Houbrick 1974).
Hutton and Sogandaraes-Bernal (1959) identified larval tremetodes
(Mesotephanus appendiculatoides) in Cerithium muscarum. In
later stages of its life cycle, this parasite encysts in the muscles of
mullet (Mugil spp.) and matures in the intestines of a variety of
megafauna including pelicans, cormorants, and raccoons. Cercaria sp.
has also been reported as a parasite of C. muscarum (Hutton 1964).
Rey and Stoner (1984) report a small fraction (around 2%) of the IRL sea
hare (Aplysia brasiliana) egg masses they examined had associated
Cerithium muscarum on them. Houbrick (1974) reports that small
slipper shells (Crepidula) are often found attached to the
shells of C. muscarum.
The flyspeck cerith is a shallow intertidal to subtidal species, typically
occurring at 1 m or less (Rosenberg 2005), although NOAA NBI collection records indicate specimens
have been collected from as deep as 2.6 m. It can be found in seagrass
meadows and on unvegetated soft sediments.
Howard (1987) conducted day-night comparisons of the epifauna of IRL
seagrass beds. The author found that adult Cerithium muscarum were
more abundant in the upper canopy at night while juveniles showed no
preference for day or night.
The empty shells of dead Cerithium muscarum are an important habitat
resource for small hermit crabs such as those of family Paguridae. Tunberg
et al. (1994) report that shells from C. muscarum, Modulus
modulus, and Nassarius vibex accounted for 94% of the shells
utilized by Indian River Lagoon Pagurus maclaughlinae.
Abbot RT and PA Morris. 1995. Shells of the Atlantic and Gulf Coasts and
the West Indies. Peterson Field Guides. Houghton Mifflin Company, NY. 350
Bailey-Matthews Shell Museum. Undated. Cerithium muscarym species
profile. Available online.
Cannon LRG. 1975. On the reproductive biology of Cerithium
moniliferum Kiener (Gastropoda, Cerithiidae) at Heron Island, Great
Barrier Reef. Pacific Science 29:353-359.
Houbrick JR. 1970. Reproduction and development in Florida
Cerithium. Page 74 in: Annual report of the American Malacological
Union, Inc. for 1970.
Houbrick R. 1974. Growth studies on the genus Cerithium
(Gastropoda: Prosobranchia) with notes on ecology and microhabitats.
Howard RK. 1987. Diel variation in the abundance of epifauna associated
with seagrasses of the Indian River, Florida, USA. Marine Biology
Hutton RF. 1964. A second list of parasites from marine and coastal animals
of Florida. Transactions of the American Microscopical Society 83:439 -447.
Hutton RF and F Sogandares-Bernal. 1959. Further notes on Trematoda
encysted in Florida mullets. Quarterly Journal of the Florida Academy of
Murray JB and GL Wingard. 2006. Salinity and temperature tolerance
experiments on selected Florida Bay mollusks. US Geological Survey Open
File Report 2006-1026. Us Department of Interior/US Geological Survey. 59
NOAA National Benthic Inventory (NBI). Undated. Cerithium muscarum
collection information. Available online.
Rey JR and AW Stoner. 1984. Macroinvertebrate associations on the egg
masses of the sea hare, Aplysia brasiliana Rang (Gastropoda:
Rosenberg G. 2005. Malacolog 4.1.0: A database of western Atlantic marine
Mollusca. WWW database (version 4.1.0). Available online.
Tunberg BG, Nelson WG, and G Smith. 1994. Population ecology of Pagurus
maclaughlinae Garcia-Gomez (Decapoda: Anomura: Paguridae) in the Indian
River Lagoon, Florida. Journal of Crustacean Biology 14:686-699.
Young DK and MW Young. 1977. Community structure of the macrobenthos
associated with seagrass of the Indian River estuary, Florida, p. 359- 381
in: B. C. Coull (ed.). Ecology of Marine Benthos. University of South
Carolina Press. Columbia, South Carolina.