Flamingo Tongue (Cyphoma gibbosum)
By Diane Okpala
and
James B. Wood (Ed)
James B. Wood (Ed)
|
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Flamingo Tongue (Cyphoma gibbosum)
By Diane Okpala
and
James B. Wood (Ed) |
Abstract
Cyphoma gibbosum, or Flamingo Tongue, is an ovulid prosobranch gastropod and belongs to a family of snails called "false cowries" (Ovulidae). Its small, snail-like body is about one inch long and is covered with a fleshy colorful mantle, which are large flaps that cover most of their pure ivory shell. They are common throughout the Caribbean Sea on soft corals, such as sea fans. Cyphoma gibbosum is a gregarious animal and is found to live in colonies. They move along the substrate from gorgonian to gorgonian to feed on their axial tissues and polyps. By ingesting the tissue, Cyphoma gibbosum is capable of incorporate chemicals used for defense by gorgonians into it's body. They are also, in turn, toxic for other fishes to eat. The flaps of their brightly colored mantle, like many nudibranchs, contain distasteful chemicals that deter fish from eating them. Cyphoma gibbosum is gonochoric and reproduces sexually. They lay their fertilized eggs in mucus nets that hatch within a couple of days. Their planktonic larva must metamorphose before becoming an adult snail. New research is studying the movement and density aggregation behaviors of the Flamingo Tongue.
Taxonomy
Phylum: Mollusca
Class: Gastropoda
Order: Neotaenioglossa
Family: Ovulidae
Habitat
Cyphoma gibbosum is a common species on coral reefs in the shallow waters of the Western Atlantic Ocean (Rosenberg 1989). They can be found in the Caribbean, the Bahamas, Florida, Belize and the Grenadines (Harvell et al. 1989; Humann et al. 1992). C. gibbosum lives and feeds on gorgonian soft corals especially on colonies of sea fans such as Pseudopterogorgia spp., Pseudoplexaura spp., and Plexaura homomalla (Lasker et al. 1988). The gorgonian corals serve as sites for protection, mating, egg deposition and most importantly, food sources. C. gibbosum live in colonies whose densities range from two to thirty snails every 100 squared meters (Lasker et al. 1988) but are more often found to be in groups of two or three (Bandel 1973). They are not distributed randomly, but are clumped into small, gregarious groups. This could be because some colonies of gorgonians are more acceptable to these snails (Harvell et al. 1989).
Ecology
Morphology
The shell of the Cyphoma gibbosum can range from reddish-cream to salmon to white (Humann et al. 1992; Rosenberg 1989; Bandel 1973; Ghiselin et al. 1966). The shell of C. gibbosum is elongated, thick and heavy and has a narrow opening. The earliest whorls on the shell of a juvenile C. gibbosum are quite fragile and transparent and take on the color of the gorgonian (Ghiselin et al. 1966). The long and shallow mantle normally extends over the length of the shell (Humann et al. 1992; Ghiselin et al. 1966). The translucent and opaque mantle is usually cream-white with dark orange spots surrounded by a brown rim (Bandel 1973; Sterrer 1986; Rosenberg 1989; Sterrer 1992). This living tissue acts like a fish's gills through which oxygen and carbon dioxide can be exchanged through the water so that the snail can breathe (Sterrer 1992). The foot of C. gibbosum is ivory white, with detached irregular black lines radiating toward the black-edged margin (Sterrer 1986). The coloration of the entire snail makes the animal conspicuous on the monochromatic host gorgonians and warns predators that they are toxic (Rosenberg 1989).
Feeding Behavior
Cyphoma gibbosum is an ectoparasite that feeds exclusively on gorgonians and spends 99% of its time on its host (Rosenberg 1989; Gerhert 1986). They are diurnally active, so they feed predominantly during the day (Harvell et al. 1989). They have a long, narrow aperture without teeth and a thick, inflected outer lip (Sterrer 1986). C. gibbosum chews off the purple parts of the sea-fan branches, leaving only the internal black skeleton (Bandel 1973). It preferentially consumes axial tissues near the base of colonies such as Pseudopterogorgia (Harvell et al. 1989). In lab experiments, C. gibbosum was found to eat the polyps of the gorgon if all of the axial tissue had already been stripped off (Harvell et al. 1989). C. gibbosum appears capable of tolerating unusually high levels of gorgonian terpenes which are various unsaturated hydrocarbons. They may also sequester these compounds from the gorgonians for chemical defenses used in its mantle (Harvell et al. 1989).
Defense Mechanisms
Cyphoma gibbosum have unusually thick shells for ovulids, potentially allowing them to survive attacks by predators that reject them as prey items (Rosenberg 1989). Juvenile C. gibbosum have thin shells that are often the same color as their host gorgonians and are cryptic and nocturnal in habits. They do not have aposematic coloration since that would make them conspicuous and easily injured/preyed upon (Rosenberg 1989). The brightly colored mantle of C. gibbosum covers its plain white shell with a fleshy lobes which can be retracted back into its shell when disturbed. The mantle tissue of C. gibbosum is distasteful to many different predators such as the bluehead wrasses, Thalassoma bifasciatum, whereas its foot tissue is palatable. C. gibbosum has sterols and prostagladins that are ingested from the host gorgonians (Harvell et al. 1989). This is the reason why C. gibbosum is distasteful and unappealing to predators. C. gibbosum keeps its mantle extended, which ensures that predators come in contact with their distasteful tissues. This is unlike other gastropods that immediately retract into their shells when handled (Harvell et al. 1989). One of the only animals able to eat this snail is the grouper (Sterrer 1992). This is because they are indiscriminate feeders.
Gregariousness may lead to decreased susceptibility to predators (Gerhert 1986). C. gibbosum does not prefer to be on a colony where other C. gibbosum used to be. This could be due to the gorgon increasing its defenses of the lessened availability of tissue to eat. C. gibbosum clump together in colonies so predators can recognize that they are bad to eat. If they lived solitary, they would be surrounded by naïve predators who would try to eat them, thus injuring them. Gregariousness helps decrease the number of predator attacks. C. gibbosum does not immediately retract its mantle when handled, but keeps it extended. At the same time, C. gibbosum curls its foot along the longitudinal axis, so that the sole is protected and only the outer surface is exposed. The outer part of the mantle is covered with mantle tissue, and possesses a pattern of brown, zebra-style stripes on an orange background. If handling continues, the mantle and foot are withdrawn (Gerhert 1986).
Locomotion
The Cyphoma gibbosum moves along the substrate “tasting” different sea fans (Lasker et al. 1988). They leave a trail of mucus in their wake that other C. gibbosum can follow to find a colony other members of this species (Lasker et al. 1988). Previous studies proposed that the clumped distribution of C. gibbosum could be due to intracolony variation in secondary metabolite content of gorgonians while others proposed that gregariousness of C. gibbosum is due to mucus trail following (Chiappone et al. 2003). Whichever is true, the fact remains that the movement of C. gibbosum among different gorgonians is not random.
Reproduction
Cyphoma gibbosum reproduces sexually. Copulation begins with the male approaching the female from the rear. He will then crawl onto her dorsal surface and insert his penis into her mantle cavity. This will last for 3.5 hours, during which there is little movement, except for the occasional action by the buccal mass of the female (Ghiselin et al. 1966). Well fed C. gibbosum specimens in the aquaria spawn occasionally. A single male can fertilize other females in a single aquarium to spawn thus producing one or more communal egg masses. Egg masses are attached to walls or dead and living sea fans. The eggs (or ootheca) are arranged in lines and nets. The ootheca are transparent, colorless, and smooth and have a rim membrane that helps them attach to the substrate. Inside each capsule are the embryos concentrated in curved rows (Bandel 1973). After 10-11 days the capsule in which the eggs are encased disintegrates and discharges several hundred long-term planktotrophic veligers (Rosenberg 1989). Siblings very rarely metamorphose near each other because the veligers are dispersed over long distances by currents when they are in the wild (Rosenberg 1989). This reduces the amount of inbreeding between these snails.
Recent
Research
Recent studies on Cyphoma gibbosum have focused on assessing on a large scale the density and gorgonian host-occupation patterns of the ovulid, gastropod C. gibbosum. This research was carried out in the Florida Keys in different geological areas. The scientists concluded that the mean densities of C. gibbosum were not significantly different between habitat types. The distribution patterns of C. gibbosum were affected by many factors such as predation pressures, larval recruitment, post-settlement survival, and patchy gorgonian patterns.
Commercial
Importance
There is no commercial importance for Cyphoma gibbosum although they are over-collected for their shiny, ivory-white shells.
Bermuda Laws
Cyphoma gibbosum does not have specific Bermudian Law protecting it. Bermuda does have 29 marine-protected areas that fall under the Fisheries Act of 1972 that states that within the Bermudian marine-protected areas, all marine life including C. gibbosum are not allowed to be collected (Wood and Jackson 2005).
Personal Interest
I first became interested in the flamingo tongue snail when completing my first research assignment for Marine Invertebrate Zoology. We had to find a symbiotic relationship between two Bermudian species. I never realized that a snail could be considered a parasite. I also really enjoyed the coloration of the snail and its defensive techniques against predators. I knew I wanted to do my research on a mollusk, so I was able to find a species I liked from there. I truly think that the Flamingo Tongue snail is a fascinating creature.
References
Bandel, Klaus. 1973. Notes on Cyprae cinerea Gmelin and Cyphoma gibbosum (Linnaeus) from the Caribbean Sea and Description of their Spawn. The Veliger. 15:4, 335-339.
Chiappone, Mark, Dienes, Helga, Swanson, D.W. and Miller, S.L. 2003. Density and Gorgonian Host-occupation Patterns by Flamingo Tongue Snails (Cyphoma gibbosum) in the Florida Keys. Caribbean Journal of Science. 39:1, 116-127.
Gerhert, D.J. 1986. Gregariousness in the gorgonian-eating gastropod Cyphoma gibbosum: tests of several possible causes. Marine Ecology-Progress Series. 31, 255-263.
Ghiselin, M.T. and Barry R. Wilson. 1966. On the anatomy, natural history, and reproduction of Cyphoma, a marine prosobranch gastropod. Bulletin of Marine Science. 16:1, 132-141.
Harvell, C.D. and William Fenical. 1989. Chemical and structural defenses of Caribbean gorgonians (Pseudopterogorgia spp.): Intra colony localization of defense. Limnology and Oceanography. 34:2, 382-389.
Humann, Paul. 1992. Reef Creature Idenification: Florida, Caribbean, Bahamas. New World Publications. 214.
Lasker, H. R., Coffroth, M. A. and Fitzgerald, L. M. 1988. Foraging Patterns of Cyphoma gibbosum on Octocorals: the Role of Host Choice and Feeding Preference. Biological Bulletin. 174, 254-266.
Rosenberg, Gary. 1989. Aposematism evolves by individual selection: evidence from marine gastropods with pelagic larvae. Evolution. 43:8, 1811-1813.
Sterrer, Wolfgang. 1992. Bermuda’s Marine Life. Bermuda: Island Press, 133.
Sterrer, Wolfgang. 1986. Marine Fauna and Flora of Bermuda: A Systematic Guide to the Identification of Marine Organisms. New York: John Wiley and Sons, 422.
Wood, J.B. and K.J. Jackson. 2005. Bermuda In: Caribbean Marine Biodiversity: The Known and the Unknown. Miloslavich, P. and E. Klein eds. DEStech Publications, Inc. 19-36.
Links
Integrated Taxonomic Information System
Bermuda Institute of Ocean Sciences