Strombus

Lore & Background

True conches have long eye stalks with colorful ring-marked eyes at the tips. The shell has a long and narrow aperture, a short siphonal canal, and a stromboid notch near the anterior end through which one eye stalk protrudes. The foot ends in a pointed, sickle-shaped operculum used in an unusual leaping locomotion. Conches lay eggs in long strands contained in twisted, gelatinous tubes. True conches grow a flared lip on their shells only upon reaching sexual maturity, called an alated outer lip or alation. Like almost all shelled gastropods, conches have spirally constructed shells, usually right-handed but very rarely left-handed. Most living species are in the Indian and Pacific Oceans, and many live on sandy bottoms among beds of sea grass in tropical waters, eating algae. Worldwide, several larger species are economically important as food sources, including the endangered queen conch, which very rarely also produces a pink, gem-quality pearl. In the geological past, a much larger number of species existed, with fossils found all over the world in sediments from Cretaceous to Quaternary.

Reader's Guide

The genus Strombus has been central to the study of conch taxonomy and phylogeny. In a 2005 monograph, Simone proposed a cladogram based on morphoanatomical analysis that placed only Strombus gracilior, Strombus alatus, and Strombus pugilis within Strombus, elevating former subgenera to genus level. In a different approach, Latiolais and colleagues (2006) proposed a cladogram based on DNA sequences of nuclear histone H3 and mitochondrial cytochrome-c oxidase I, showing Strombus pugilis, Strombus alatus, Strombus granulatus, and Strombus gracilior as closely related and sharing a common ancestor. The genus originally comprised about 50 species, 38 in the Indo-Pacific region. Many species originally placed in Strombus have since been moved to other genera, as reflected in extensive synonymy lists. The queen conch, once Strombus gigas, is now often assigned to Eustrombus, Lobatus, or Aliger gigas. The West Indian fighting conch, Strombus pugilis, remains a key species. The economic importance of larger species, especially as food, and the rarity of the queen conch's pink pearl, have made Strombus a notable genus both commercially and scientifically.

Did You Know?

• The genus Strombus was named by Carl Linnaeus in 1758.
• True conches use a sickle-shaped operculum for leaping locomotion.
• The queen conch, once Strombus gigas, very rarely produces a pink, gem-quality pearl.
• Fossils of Strombus have been found in sediments from the Cretaceous to the Quaternary.