Impurest's Guide to Animals #156 Buoy Barnacle

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Edited By ImpurestCheese

Thunder Snow?! Yeah I’d never heard of it before either, at least not until it dropped an ice cold surprise on my home and car. Luckily memories of last week’s issue the Bearded Fireworm (and multiple cups of coffee) were enough to keep me warm through the night. This week we’re drifting along the ocean surface, hope you guys enjoy…

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Issue #156 – Buoy Barnacle

[1]
[1]

Kingdom – Animalia

Phylum – Arthropoda

Class – Maxillopoda

Order – Pedunctula

Family – Lepadidae

Genus – Dosima

Species – fascicularus

Related Species - Buoy Barnacles are members of the Goose Barnacle Order (1)

Range - Buoy Barnacles are found in temperate and tropical marine waters around the world, often floating just under the ocean’s surface

Bobbing Along…

Buoy Barnacles are medium sized goose barnacles, with a capitulum, which in effect is the animals ‘shell’ and is formed of five large blue plates. Unlike the more familiar acorn barnacles found on rocky shores, the goose barnacles, sometimes also called goose necked barnacles, have their capitulum on the end of a stalk with the other end anchored to a rock, or in the case of the Buoy Barnacle, a float formed out of a natural spongey cement created from glands, and designed to keep the creature afloat. This cement is the same chemical that keeps shore dwelling barnacles attached to rocks, and is designed to withstand long term submersion in sea water (2). Within the barnacle shell, the animal’s actual body resembled a shrimp, with the animal shedding its skin within its casing, rather than expanding the protective plates around it.

[2]
[2]

The legs of this internal form are one of the few organs that emerge from the tip of the capitulum where they are used to fan oxygenated water over its body. These legs are also used to filter the plankton the barnacle feeds into its shell. It’s access to food that led the Buoy Barnacle out into open water since the species is a ‘fugitive organism’ and can’t effectively compete with other species in similar niches in the habitat it evolved in, effectively forcing it into a new habitat. As the only pelagic barnacle and with little predation, the Buoy Barnacle has managed to avoid competing with other filter feeding animals on the shore line, and had thrived in its new environment.

Buoy Barnacles mature rapidly, and within fifty days of either creating a float or colonising an existing floating object, are able to reproduce. Since barnacles are not broadcast spawners, the Buoy Barnacle has to rely on other barnacles of the same species attaching to the same float, something that can lead to massive clumps of barnacles floating along together. Once reproduction has completed the eggs are released into the water stream. Upon hatching the larval barnacle known as a Naupilus drifts in the plankton for up to a half a year before maturing into a Cyprid larvae (3). This larval form of barnacle doesn’t feed, instead relaying on the resources it accumulated earlier to swim around and find a floating object to mature into an adult barnacle on.

Five Bizarre Barnacle Facts

Goose Barnacles were long thought to be the plants whose tips grew into Barnacle Geese (Branta leucopsis), possibly due to the bird like appearance of their stalks and that they were often found growing on driftwood. It wasn’t until 1456 that this was debunked on the orders of the Holy Roman Emperor Fredrick the II, who was well known for having great tolerance and a thirst for knowledge.

Even after this suffered from misclassification, often being grouped with molluscs simply because they had shells. It wasn’t until observations made by Charles Darwin in 1854, that he concluded that they were crustaceans, and thus more closely related to crabs then snails and clams.

It was barnacle reproduction that attracted Darwin to barnacles (4). While most species are hermaphrodites, barnacles can’t self-fertilise, and instead use an elongated penis to pass sperm to one another. Relative to the size of its owner, these penises are the longest in the animal kingdom, which can be up to fifty time longer than the animal it is attached to.

The penis of one of the 'Acorn Barnacles'
The penis of one of the 'Acorn Barnacles'

Barnacles sometimes grown in other animals, most notably Humpback Whales (Megaptera novaeangliae). While painful looking, most barnacles don’t harm their ‘hosts’ since they don’t rely on roots to keep them attached, but rather a natural cement as mentioned earlier.

Despite this there are parasitic barnacles, as mentioned in a previous issue that infect crabs, but some species also infest vertebrate prey. First descrubed by Charles Darwin (he really liked barnacles) in 1851, the parasitic barnacle Anelasma squalicola has been discovered growing on lantern sharks (Etompterus sp) and unlike the majority of its relatives, feeds on the nutrients using a root like anchor. This ‘theft’ of nutrients effects the shark’s reproduction system, effectively chemically castrating them for the rest of their lives.

[4]
[4]

Bibliography

1 -www.arkive.org

2 - E. Bourget (1987).Barnacle shells: composition, structure, and growth. pp. 267–285

3 - Donald Thomas Anderson (1994). "Larval development and metamorphosis". Barnacles: Structure, Function, Development and Evolution. Springer. pp. 197–246

4 - http://mentalfloss.com/article/83887/darwins-obsession-barnacle-penises-makes-lot-sense-now

5 - https://sharkdevocean.wordpress.com/2015/10/23/shark-eating-barnacles/

Picture References

1 - http://www.marlin.ac.uk/assets/images/marlin/species/web/o_dosfas.jpg

2 - https://scientistinlimbo.files.wordpress.com/2015/07/dscn6917.jpg

3 - http://boingboing.net/filesroot/080206150703-large.jpg

4 - http://phenomena.nationalgeographic.com/files/2014/06/Shark_barnacle.jpg

I like barnacles more than I like snow, well I like most of them more anyway. Next week we look under the ‘rug’ at an often overlooked animal, but until then make sure to critic, comment and suggest future issues as well as making sure you check past issues in Impurest’s Bestiary.

Many Thanks

Impurest Cheese

Want more IGTA? We’ve covered floating animals before and they are always really cool! For a true seaman, click here to meet the ‘By the Wind Sailor’. Or for another nautical navigator click here to see the Greater Argonaut.

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mrmonster

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Awesome. Thanks for tagging me.

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wildvine

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#3 wildvine  Moderator

Yeah buoy! Haha. Sorry

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tparks

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Neat!

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ImpurestCheese

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pipxeroth

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That is an... interesting shape.

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FicOPedia

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@impurestcheese: Looks like a cross between a jellyfish and a dead dandelion. :)

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ImpurestCheese

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@ficopedia: @pipxeroth: Not going to lie I can see exactly where you both are coming from with this. Thanks for the comment(s)

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laflux

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This takes me back to my Wales ecology field trip. We had to do a presentation about Barnacles, and I was the one that said that if a human has a barnacle proportioned member it would be the size of Nelson's column :p.

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ImpurestCheese

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@laflux: Ah the inocence of Wales Field Trips. Mine involved drinking too much wine, climing Y Gern with a hangover and chasing a wolf spider on some sand dunes in Mona.

(To be 20 again...)

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deactivated-097092725

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Well, then. Barnacles are quite the creature. From chemically castrating another living thing through parasitic behaviour to being in possession of (ahem) such a nightmarish "member".