G is for Gastropod


As a part of the A-Z Photographic Glossary of Biological Terms challenge, today it is G for Gastropod, as illustrated by this Flamingo Tongue Snail (Cyphoma gibbosum) from Bonaire in the Dutch Caribbean.

Gastropods are one of the most diverse groups of animals including snails and slugs of all sizes from the microscopic to the relatively large (conchs). They are by far the largest group of molluscs, with more than 62,000 described living species occupying all marine habitats ranging from the deepest ocean basins to the supralittoral (the area above the high tide line, on coastlines that is regularly splashed, but not submerged by ocean water), as well as freshwater habitats, and other inland aquatic habitats including salt lakes. They are also the only terrestrial molluscs, being found in virtually all habitats ranging from high mountains to deserts and rainforest, and from the tropics to high latitudes.

With the exception of slugs, gastropods tend to have a coiled or spiral-shaped shell and a single foot which is usually rather large and is typically used for crawling although in some species it has be modified for burrowing, leaping (as in conchs), swimming, or clamping (as in limpets).

In our example today, at approximately 25mm the Flamingo Tongue Snail is a rather small marine gastropod mollusc in the family Ovulidae, an ally to the cowries. The orange-yellow coloring is not the shell, but live mantle tissue which can be retracted exposing the shell, but this usually only happens when it is threatened or attacked. The spots on this fleshy mantle vary from individual to individual and as with spotted cats, can be recognised as such!

They feed by browsing on the living tissues of the soft corals on which they live with common prey including Briareum spp., Gorgonia spp., Plexaura spp., and Plexaurella spp. but these corals can regrow their polyps, therefore predation by the snail is generally not lethal; however, soft corals do contain noxious and toxic compounds and by obtaining these secondary chemicals, these gastropods are distasteful and therefore less susceptible to predation themselves, although mistaking the colorful mantle for the shell (which is actually a neutral brown), they have become increasingly scarce due to overcollecting.

19406871769_d0125c2ee8_oFemales will attach their eggs to the coral upon which they have recently fed and after about 10 days, the larvae will hatch and float in the water column as plankton eventually settling onto other gorgonian corals.

Further examples of gastropods include:

23478695165_29fdede46e_oMangrove Periwinkle (Littoraria angulifera), Sittee River Wildlife Reserve, Belize

20821034618_1634262c0a_oFour-toothed Nerite snail (Nerita versicolor), Sanctuary Caye, Belize

17208811329_f56f663887_oBleeding Tooth Nerite (Nerita peloronta), Onima, Bonaire, Dutch Caribbean

15385720783_b61f28b908_othe critically endangered Catalina Mountain Snail (Radiocentrum avalonense), Catalina Island, California


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