| BARNACLES! |
Of all the sea-life we can view with the naked eye, the barnacles or Cirripedia are
simultaneously among the most plentiful and the most overlooked. They gradually build up
on almost any submerged object, the tell-tale fingerprints of the sea's briny clutches. Seldom
do people stop to realize that these crusty little lumps, peppered over every rusty anchor
and waterlogged pier, are just a whole bunch of incredibly bizarre bugs. Crustaceans,
specifically; just like crabs, lobsters and shrimp.
"Acorn" barnacles like the ones above are usually the barnacles that first spring to mind,
and to begin our understanding of these weirdos, we're going to go over how an acorn
barnacle develops. From there, we'll take a look at progressively more peculiar features of
the group.
simultaneously among the most plentiful and the most overlooked. They gradually build up
on almost any submerged object, the tell-tale fingerprints of the sea's briny clutches. Seldom
do people stop to realize that these crusty little lumps, peppered over every rusty anchor
and waterlogged pier, are just a whole bunch of incredibly bizarre bugs. Crustaceans,
specifically; just like crabs, lobsters and shrimp.
"Acorn" barnacles like the ones above are usually the barnacles that first spring to mind,
and to begin our understanding of these weirdos, we're going to go over how an acorn
barnacle develops. From there, we'll take a look at progressively more peculiar features of
the group.
| Photo by modomatic |
| photo by Michelle Kroll |
| photo by Ben Amstutz |
Perhaps a bit odder than the acorns are the stalked or "goose" barnacles, many of which
prefer to grow on floating objects such as seaweed, driftwood and man-made objects such
as boats or lengths of rope. These barnacles are so named not merely for their
appearance, but for the bizarre medieval-era misconception that they were the eggs or
young of actual geese. This was so readily accepted that goose flesh was recognized as
fish by the Catholic church, and thus acceptable to eat on a Friday when red meats and
poultry were forbidden.
Unlike acorn barnacles, some goose-necked species have two distinct sexes; but the adult
males may be little more than tiny tubes of sperm, parasitically attached to the females.
prefer to grow on floating objects such as seaweed, driftwood and man-made objects such
as boats or lengths of rope. These barnacles are so named not merely for their
appearance, but for the bizarre medieval-era misconception that they were the eggs or
young of actual geese. This was so readily accepted that goose flesh was recognized as
fish by the Catholic church, and thus acceptable to eat on a Friday when red meats and
poultry were forbidden.
Unlike acorn barnacles, some goose-necked species have two distinct sexes; but the adult
males may be little more than tiny tubes of sperm, parasitically attached to the females.
While "buoy" barnacles otherwise resemble their goosey cousins, they've adapted a bit
further by simply growing their own flotation device, a spongy mass at the end of their neck.
These little cheaters may merge together in communal rafts and even find themselves
colonized by other freeloading barnacle species; could full-fledged swimming be in their
evolutionary future? Barnacles go through all that trouble to be sedentary and these little
surfer-bums are totally wussing out!
further by simply growing their own flotation device, a spongy mass at the end of their neck.
These little cheaters may merge together in communal rafts and even find themselves
colonized by other freeloading barnacle species; could full-fledged swimming be in their
evolutionary future? Barnacles go through all that trouble to be sedentary and these little
surfer-bums are totally wussing out!
Like all Crustaceans, Cirripedia begin their lives as microscopic plankton. The first stage,
characterized by a single eye, is called the Nauplius, and is a form shared by all
Crustaceans at some point in their development, whether as a larva or in early embryonic
stages.
characterized by a single eye, is called the Nauplius, and is a form shared by all
Crustaceans at some point in their development, whether as a larva or in early embryonic
stages.
After up to six months as a Nauplius, the barnacle begins to deviate from other
Crustaceans by becoming a Cyprid. This stage is enclosed in a clam-like set of hinged
shells, and it exists only to seek out a resting place; a rock, a seashell, a whale, another
barnacle, anything solid will do, though most species will follow pheromone trails and
settle alongside their own kind. Once it finds a suitable location, it secretes an adhesive
from its antennae and anchors in place upside-down.
Crustaceans by becoming a Cyprid. This stage is enclosed in a clam-like set of hinged
shells, and it exists only to seek out a resting place; a rock, a seashell, a whale, another
barnacle, anything solid will do, though most species will follow pheromone trails and
settle alongside their own kind. Once it finds a suitable location, it secretes an adhesive
from its antennae and anchors in place upside-down.
On the outside, our barnacle will rapidly grow into the armored fortress we all know and
love, but on the inside, it still follows a shrimp-like body plan. Our squishy bug will spend
the rest of its life rooted inside its spacious exoskeleton, employing its feathery legs as a
net to collect plankton and other nutrients from the water's current.
Of course, reproduction can be a bit of a problem for animals that don't move around.
Some, like the corals and sponges, solve it by pumping sperm and eggs into the water.
Some just clone themselves. Acorn barnacles are a little more sophisticated than that; as
arthropods, they're more complex animals with an anatomy closer to you or I than to a
coral polyp. What I'm saying is that barnacles have penises, and since they can't walk
around, they have really, really long, prehensile penises.
love, but on the inside, it still follows a shrimp-like body plan. Our squishy bug will spend
the rest of its life rooted inside its spacious exoskeleton, employing its feathery legs as a
net to collect plankton and other nutrients from the water's current.
Of course, reproduction can be a bit of a problem for animals that don't move around.
Some, like the corals and sponges, solve it by pumping sperm and eggs into the water.
Some just clone themselves. Acorn barnacles are a little more sophisticated than that; as
arthropods, they're more complex animals with an anatomy closer to you or I than to a
coral polyp. What I'm saying is that barnacles have penises, and since they can't walk
around, they have really, really long, prehensile penises.
| Free-floating barnacles |
On more than one occasion, goose barnacles have been mistaken for "sea monsters" when
thousands congregate on a single massive object, often completely hidden by their writhing
bodies. However, not all are content to wait around for a log to float by...
thousands congregate on a single massive object, often completely hidden by their writhing
bodies. However, not all are content to wait around for a log to float by...
| Barnacles in the deep |
Largely barren of plankton, our beloved abyssal zone is generally inhospitable to
filter-feeders, but some barnacles, such as this beautiful Vulcanolepis species, find their
niche near hydrothermal vents; the boiling, highly toxic underwater volcanos where bacteria
happen to thrive like nowhere else on Earth. Rather than catch food from the water, these
guys grow a fuzzy, white garden of bacteria on their legs, eating a small portion when they
draw their legs inside.
filter-feeders, but some barnacles, such as this beautiful Vulcanolepis species, find their
niche near hydrothermal vents; the boiling, highly toxic underwater volcanos where bacteria
happen to thrive like nowhere else on Earth. Rather than catch food from the water, these
guys grow a fuzzy, white garden of bacteria on their legs, eating a small portion when they
draw their legs inside.
| Boring Barnacles |
Not boring in the "how long will he talk about all these damn barnacles" sense, but boring in
the "tunnels through soft flesh" sense, which is almost the exact polar opposite of the other
type of boring. The drawing above portrays an adult female Lithoglyptis mitis, one of the
Acrothoracica. These extremely tiny barnacles burrow their way into snails, clams or other
barnacle species to live parasitically, never developing the thick armor of their relatives.
Males are always tinier than the females, and may in turn live in or on the bodies of their
mates.
the "tunnels through soft flesh" sense, which is almost the exact polar opposite of the other
type of boring. The drawing above portrays an adult female Lithoglyptis mitis, one of the
Acrothoracica. These extremely tiny barnacles burrow their way into snails, clams or other
barnacle species to live parasitically, never developing the thick armor of their relatives.
Males are always tinier than the females, and may in turn live in or on the bodies of their
mates.
| Barnacles as a mind-warping crab disease |
We now come to one of my favorite monstrosities of the deep blue sea; parasitic barnacles
of the Sacculina genus. I talk about these wonders under parasitic crustaceans, but it would
be criminal not to include them here.
At that point in life where other barnacles attach to a rock or a sea-turtle, Sacculina instead
opts to find itself a crab, insert a needle-like appendage into the crab's body and inject a
tiny clump of cells, a simple blob of tissue. The rest of it will die...the blob is the adult stage,
and it begins to grow as filaments throughout the crab's body. For generations, these
organisms were mistaken for a type of fungus. They metamorphose into what is more or
less crab cancer, and they only get weirder from there, manipulating their host in downright
disturbing ways. If you haven't already, go read all about it.
of the Sacculina genus. I talk about these wonders under parasitic crustaceans, but it would
be criminal not to include them here.
At that point in life where other barnacles attach to a rock or a sea-turtle, Sacculina instead
opts to find itself a crab, insert a needle-like appendage into the crab's body and inject a
tiny clump of cells, a simple blob of tissue. The rest of it will die...the blob is the adult stage,
and it begins to grow as filaments throughout the crab's body. For generations, these
organisms were mistaken for a type of fungus. They metamorphose into what is more or
less crab cancer, and they only get weirder from there, manipulating their host in downright
disturbing ways. If you haven't already, go read all about it.
| Charles Darwin and Mr. Arthrobalanus |
In 1835, Charles Darwin (king of the animals) collected a tiny parasite from the shell of a
conch, a creature very similar to one of the boring barnacles. It intrigued him, but would be
filed away for over a decade before he would settle down and examine it. At the time,
barnacles were understood quite poorly, and had even been considered mollusks only
years prior.
Darwin affectionately nicknamed his discovery "Mr. Arthrobalanus" or "Mister Jointed
Barnacle," and began comparing its anatomy to various other barnacle species. He
intended to spend a few months studying the animals before returning to the subject of
natural selection. Instead, faced with a wealth of unexplored territory and pressured by
colleagues, barnacle research would consume the aging naturalist for eight grueling years,
his health severely deteriorating as he spent day after day dissecting and comparing
thousands of specimens from all over the world, living and fossilized, before completing four
entire volumes on barnacles alone.
Through these studies, Darwin found answers to many of his deepest questions on the
processes of adaptation, and to this day his writing is among the most extensive and
valuable research ever done on a particular animal group. The discovery of Mr.
Arthrobalanus - whom Darwin would later dub Cryptophialus - was almost certainly one of
the most life-changing and influential finds of the man's entire career as a naturalist, and
Darwin allegedly had this to say on the matter:
-"I hate a Barnacle as no man ever did before."
conch, a creature very similar to one of the boring barnacles. It intrigued him, but would be
filed away for over a decade before he would settle down and examine it. At the time,
barnacles were understood quite poorly, and had even been considered mollusks only
years prior.
Darwin affectionately nicknamed his discovery "Mr. Arthrobalanus" or "Mister Jointed
Barnacle," and began comparing its anatomy to various other barnacle species. He
intended to spend a few months studying the animals before returning to the subject of
natural selection. Instead, faced with a wealth of unexplored territory and pressured by
colleagues, barnacle research would consume the aging naturalist for eight grueling years,
his health severely deteriorating as he spent day after day dissecting and comparing
thousands of specimens from all over the world, living and fossilized, before completing four
entire volumes on barnacles alone.
Through these studies, Darwin found answers to many of his deepest questions on the
processes of adaptation, and to this day his writing is among the most extensive and
valuable research ever done on a particular animal group. The discovery of Mr.
Arthrobalanus - whom Darwin would later dub Cryptophialus - was almost certainly one of
the most life-changing and influential finds of the man's entire career as a naturalist, and
Darwin allegedly had this to say on the matter:
-"I hate a Barnacle as no man ever did before."
The penis of the barnacle is considered one of the largest in the entire animal
kingdom, and allows the animal to simply reach over and fertilize its neighbors. To
add to the convenience, all acorn barnacles are hermaphroditic, so each individual
can both conceive and bear young.
kingdom, and allows the animal to simply reach over and fertilize its neighbors. To
add to the convenience, all acorn barnacles are hermaphroditic, so each individual
can both conceive and bear young.
| wooooooooooOOP! |
| Barnacles as vertebrate parasites |
Sacculina is a favorite of mine and definitely the strangest (what beats a bug that turns into
a fungoid mass?) but if you're having trouble relating to the crab host, here's a barnacle
that parasitizes your vertebrate cousins; small sharks (dogfish) of the deep sea. Many
ordinary barnacles will attach to other animals, but they're only harmless hitch-hikers, still
feeding from the surrounding seawater. Anelasma squalicola is the exception, and you're
looking at one deeply anchored in a shark's back. It closely resembles a goose barnacle,
but has no feeding legs and buries its bulbous stem inside the host's body, drawing
nutrients through dozens of thin tendrils.
If that doesn't weird you out enough, this is also one of the few parasites on Earth to
castrate a vertebrate, just like Sacculina does to its crab. The entire development of the
dogfish's reproductive system is inhibited by the presence of this life-sucking, limbless bug.
a fungoid mass?) but if you're having trouble relating to the crab host, here's a barnacle
that parasitizes your vertebrate cousins; small sharks (dogfish) of the deep sea. Many
ordinary barnacles will attach to other animals, but they're only harmless hitch-hikers, still
feeding from the surrounding seawater. Anelasma squalicola is the exception, and you're
looking at one deeply anchored in a shark's back. It closely resembles a goose barnacle,
but has no feeding legs and buries its bulbous stem inside the host's body, drawing
nutrients through dozens of thin tendrils.
If that doesn't weird you out enough, this is also one of the few parasites on Earth to
castrate a vertebrate, just like Sacculina does to its crab. The entire development of the
dogfish's reproductive system is inhibited by the presence of this life-sucking, limbless bug.