#carrier shell

Don't ask me why they call in the AUSTRALIAN Carrier Shell when the specific epithet clearly indicates it's an Aotearoan species. The generic mean 'stranger-bearer'. AKA as Onustus neozelanicus and Phorus corrugatus.

One of about 15 currently accepted species in the genus, which has been around since the Late Cretaceous. They're best known for their habit of reinforcing, disguising and extending the shell with other shell, bits of dead coral, and small rocks. Each piece takes about 90 minutes to position and glue into place.

Xenophora neozelanica was successfully kept alive in captivity by New Zealand marine biologist, scholar, theologian, and conservationist Dr. John Morton in 1971. He found that they were unselective mud feeders, and travel across the seafloor with a “one-legged stomp” motion.

Carrier Snail

These sea-snails really like to decorate. As they grow, they grab things from their surroundings, living or dead, and hold them in place while their shell grows around them, and cements them into place.

These remarkable gastropods are in the genus Xenophora (from latin: xeno = 'foreign', phora = 'carrier'), and are found in deep tropical waters throughout the Indo-Pacific, from East Africa, all the way to New Zealand and Japan. The specimen in this photo is Xenophora pallidula, or 'pale carrier snail'.

Why do they do this? In simple terms, to make themselves bigger. Larger, spikier objects are harder for predators to get their jaws or claws around. Many gastropods, like the spectacular Murex 'comb shells' (https://goo.gl/SnxuZW), do this by physically growing a complex network of spines. However, this takes a lot of time and energy. The Xenophora have found an efficient short cut, by collecting rocks and shells to act as makeshift spines.

They're not too fussy about what they pick up. Their decorations depend mostly on what's around them - this one, it seems, was living around a lot of smaller sea shells. Some pick up living sponges, which grow to several times their size, providing the ultimate mega-spine. A few in East Africa have developed a symbiotic relationship with a barnacle (Paralepas).

IMPORTANT: You'll find these spectacular shells for sale in various places on the internet. PLEASE DO NOT BUY THEM. They are usually caught live, and by buying them you'll be creating a market for unsustainable fishing in delicate ecosystems.

OB

Image Credit: http://goo.gl/Hl4Awx (with permission)

Further reading: - More about Carrier Shells: http://goo.gl/RcTpev

Xenophora pallidula from the Comotes Sea in the Philippines. Photo and shell are from C.R. McClain. Bottom view The carrier shells of the family Xenophoridae are the most remarkable bunch of snails.  Both their common name and their Latin name give away their uniqueness.  Xenophoridae in Latin a...