Charonia

Etymology

The common name "Triton's trumpet" is derived from the Greek god Triton, who was the son of Poseidon, god of the sea. The god Triton is often portrayed blowing a large seashell horn similar to this species; such trumpets are also still occasionally made in modern times.

Fossil records

This genus is known in the fossil records from the Cretaceous to the Quaternary (age range: from 94.3 to 0.012 million years ago). Fossils are found in the marine strata throughout the world.

Description

Species within the genus Charonia have large fusiform shells, usually whithish with brown or yellow markings.

The shell of the giant triton Charonia tritonis (Linnaeus, 1758), which lives in the Indo-Pacific faunal zone, can grow to over half a metre (20 inches) in length.

One slightly smaller (shell size 100–385 millimetres (3.9–15.2 in) but still very large species, Charonia variegata (Lamarck, 1816), lives in the western Atlantic, from North Carolina to Brazil.

Distribution

Charonia species inhabit temperate and tropical waters worldwide.

Life habits

Unlike pulmonate and opistobranch gastropods, tritons are not hermaphrodites; they have separate sexes and undergo sexual reproduction with internal fertilization. The female deposits white capsules in clusters, each of which contains many developing larvae. The larvae emerge free-swimming and enter the plankton, where they drift in open water for up to three months.

Feeding behavior

Adult tritons are active predators and feed on other molluscs and starfish. The giant triton has gained fame for its ability to capture and eat crown-of-thorns starfish, a large species (up to 1 m in diameter) covered in venomous spikes an inch long. The Crown-Of-Thorns starfish has few other natural predators and has earned the enmity of humans in recent decades by proliferating and destroying large sections of coral reef, turning them into coral skeletons, empty husks of calcium carbonate.

Tritons can be observed to turn and give chase when the scent of prey is detected. Some starfish (including the crown-of-thorns starfish) appear to be able to detect the approach of the mollusc by means which are not clearly understood, and they will attempt flight before any physical contact has taken place. Tritons, however, are faster than starfish, and only large starfish have a reasonable hope of escape, and then only by abandoning whichever limb the snail seizes first.

The triton grips its prey with its muscular foot and uses its toothy radula (a serrated, scraping organ found in gastropods) to saw through the starfish's armoured skin. Once it has penetrated, a paralyzing saliva subdues the prey and the snail feeds at leisure, often beginning with the softest parts such as the gonads and gut.

Tritons ingest smaller prey animals whole without troubling to paralyse them, and will spit out any poisonous spines, shells, or other unwanted parts later.

Human use

Many people find triton shells attractive as a design object, and so they are collected and sold as part of the international shell trade. In recent years this has contributed to the animals' scarcity.

From ancient times, people of many different cultures have removed the tip of the shell, or drilled a hole in the tip, and then used the shell as a trumpet.

The Greco-Roman god Poseidon / Neptune is often depicted holding a triton shell, as is his son Triton.

Species and subspecies

Species and subspecies within the genus Charonia include: