MARGIN SHELLS OF THE TROPICS

MARGIN SHELLS

Marginellidae, or the margin shells, are a taxonomic family of small, often colorful, sea snails, marine gastropod molluscs in the clade Neogastropoda

Margin Shells are found in most tropical seas. A few species exceed 2 inches but most are under 1/4 inch in size. All Margin Shells are smooth and glossy ending in a short siphonal notch. They dwell in sand, under rocks or sometimes found in algae fields. Margins feed on other mollusks. Margin Shells belong to the family Marginellidae.

The higher classification of the family Marginellidae has long been in a state of confusion. Many popular works still treat all members of this family under the single genus Marginella, basing them primarily on superficial similarities of the shell.

The confusion over the classification stems from the fact that the earlier classifications were based rather crudely on shell characters. Although many good differential shell characters do exist within this group, those characters were generally misinterpreted or not recognized as significant. Such information as did exist on the radulae and the external anatomy of the living animals was widely scattered in the scientific literature, and internal anatomical descriptions were not available until fairly recently.

In 2019 a new molecular phylogeny (A phylogenetic tree (also phylogeny or evolutionary tree) is a branching diagram or a tree showing the evolutionary relationships among various biological species or other entities based upon similarities and differences in their physical or genetic characteristics. All life on Earth is part of a single phylogenetic tree, indicating common ancestry.) of marginelliform gastropods has been established by Fedosov A.E., Caballer Gutierrez M., Buge B., Sorokin P.V., Puillandre N., Bouchet P.

The shell of Marginellidae is usually small, but varies in different species from minute to medium-sized. The external color of the shell can be white, cream, yellow, orange, red, or brown, and can be uniformly colored, or patterned in various ways. The protoconch is paucispiral. The lip of the shell is thickened, and can be smooth or denticulate. An external varix may be present or absent, a siphonal notch may be present or absent. The columella may have 2-6 plications. The operculum is absent in this family.

Scientific classification

Domain: Eukaryota

Kingdom: Animalia

Phylum: Mollusca

Class: Gastropoda

Subclass: Caenogastropoda

Order: Neogastropoda

Superfamily: Volutoidea

Family: Marginellidae

Fleming, 1828

Brown Marginellas Shells

Brown Marginellas Shells

Y1-10

One Brown Marginellas Shell 5/8 to 1 inch ..... .03



Marginatus Shell

Marginatus Shell

US0-9

One Marginatus Shell 2 to 2 3/8 inches ..... .13



Tan Marginellas Shells

Tan Marginellas Shells

01-8

One Tan Marginellas Shell 3/8 to 1 inch ...... .04



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