Living in America: Part 2, Boneless Locals

This entry is Part 2 in a three-part series on organisms found in the United States in celebration of the country’s 240th birthday. Part 1, which featured some of the U.S.’s less widely-familiar vertebrate inhabitants, can be found here. This entry will go over some of the invertebrate fauna (bugs, slugs, and the like) that call the U.S. home.

There is plenty of biodiversity to celebrate in the U.S.A. that doesn’t come with an internal skeleton. Vertebrates, a single subsection of a single phylum (Chordata), represent a infinitesimal sliver of total animal diversity. How tiny? Really damn tiny. Like less than 3% of all animal species tiny. The vast majority of animal species in the U.S.A. and elsewhere are of the creepy-crawly, backbone-bereft, squiggly-wiggly variety, yet they are collectively ignored as much as anything David Faustino did after Married with Children. A bizarre and attractive example of this American mini-fauna is the eastern ox beetle (Dynastes tityus) (photo above), a type of rhinoceros beetle (Dynastinae) endemic to the eastern U.S., from Texas north to New York. Males, like the one above, have intimidating horns that they use in dominance bouts with other burly dude beetles…like tiny, six-legged bull elk…all in the aim of landing access to a mate. A close relative of this species, the Hercules beetle (Dynastes hercules), found in Central and South America, is among the largest beetles (and insects) in the world, with some males reaching the size of a Big Mac, starting off their lives as grubs that look like an albino bratwurst from Hell.

Now that we here in the good ol’ U.S. of A. have just finished the star-spangled clusterfuck that is our quadrennial duo of major political party conventions (and the 2016 Summer Olympics have started up) it seems like as good a time as any to continue to the next part of this Ameri-centric post series. I will also refrain from making any tired “spineless invertebrates” jokes in regards to politicians, tempting as it may be. Take a gander below at a selection of the underappreciated boneless beasties that make their home in the States.

Echinoderm

Echinoderms are animals in the Phylum Echinodermata, which includes things like sea stars, sea cucumbers, sea urchins, and sea lilies. With their round or spoked, faceless bodies, weird little hydraulic tube feet, and slow, deliberate movements, they seem like the kinds of things that would crawl out from a meteorite crater, slither across the Heartland in the dead of night, and gobble up clueless second string high school football players and expendable town drunks in an extraterrestrial feeding frenzy. However, despite their alien appearance, outside of our own phylum (Chordata), echinoderms are essentially our closest relatives.

The sunflower seastar (Pycnopodia helianthoides) is a spectacular representative of this group. This purple (or sometimes red or pink) powerhouse is a relatively common member of the subtidal kelp forest community that runs along the stupefyingly majestic western coast of North America, in particular between southern California and Alaska. Sunflower seastars are among the largest sea stars in the world, with many individuals wide enough to wrap fully around the waist of an average-sized adult like a wet, salty wrestling title belt. In terms of mass, this 24-armed critter can reach the heft of a well-fed house cat.

The sunflower seastar’s hulking aspect belies another superlative up its many sleeves. This real-life Starmie is the Usain Bolt of the sea star world. With all fifteen thousand of its tube feet pumping on its underside, the sunflower seastar can glide across the seafloor at a rate of about three feet per minute (sprinting at six feet per minute), which is just about as fast as any species of sea star can move. That may not seem like much to you or I, but for snails, sea urchins, and other slow, bottom-dwelling invertebrates, this speediness is a big deal….a big deal because the sunflower seastar is basically an ever-hungry, predatory Roomba, omnomnom-ing its way over the lives of everything unlucky enough to be caught in its path. The sunflower seastar can run down and overtake anything its radially symmetrical gut desires, enveloping its victims like a mauve blanket of death.

Arachnid

The lovely lady with the long, tan legs above is a photogenic representative of a very special species of spider found only in the U.S. Not only is this species found only within U.S. borders, it is known from a single, rural corner of one U.S. state: Oregon.

Meet Trogloraptor marchingtoni, a unique arachnid found only in a handful of deep caves in the thick, mountainous forests of Josephine County, Oregon, near the city of Grants Pass in the southwestern corner of the state. This spider was completely unknown to science until 2010, when the first specimens were collected far down in the black, twisted caverns that wind through the folded marble of the Klamath Mountains. Trogloraptor marchingtoni is the first discovered member of its genus, but is also distinct enough from other spiders that is has been placed in its own family (Trogloraptoridae), which is significant, considering that these days it’s exceptionally rare to stumble upon a family of spiders that have yet to be cataloged by science. It is also remarkable how long it took for these spiders to be discovered when you see how goddamn big they are; with a leg span of three inches, large females of the species can sit on the top of a soda can with all eight feet dangling off the rim.

So what makes this species so special? There are a number of seemingly primitive features of its biology, and based on its genetics, it doesn’t seem to be closely related to the only spiders on the planet that seem outwardly similar. But the real kicker is what sits at the end of its kickers: Big. Ass. Claws. The last segment of their legs are tipped with a set of long, curved hooks, each liberally flourished on the bottom edge with gripping teeth.

Yes, when Trogloraptor gives you a hug, it’s a long-term engagement.


Hey! Crampons! Just what spiders needed.

Very few other varieties of spider have anything like this, and given that when it does show up in spider groups many times the spiders are cave-dwelling specialists, it is likely these claws have evolved to cope with the extreme subterranean environment. Trogloraptor appears to only spin a half-assed web, so it’s currently thought that the spider hunts by dangling upside down with legs potentially outstretched, just waiting for something to fly just a liiiiittle too close….then BAM, Ms. Velcro Hands snags din-din. The few live specimens that have been collected so far haven’t ever been seen feeding, so at this point, it’s not really definitively known if the claws are used in this way.

But the notion of giant spiders that cling to their prey like deadly bur seeds in the blind, inky depths of the Earth certainly has impact. Hell, this even directly inspired their badass scientific name: “troglo-” refers to cave-dwelling, and “raptor” means “plunderer”, a nod to their insidious talons. Despairingly, this species, like an acolyte in the House of Black and White, has no common name. I find this unacceptable for such an interesting animal, even as a new introduction to zoological knowledge, so I’ve drafted a few monikers for this group of spiders, which I will now share even though I’m pretty sure they are not in any way wanted. How about the “Stygian grapplespider”? Or the “Oregonian caveclaw”? Perhaps the “Josephine eighthook”? No?

Insect

The beetle above, decorated in its Halloween best, is the American burying beetle (Nicrophorus americanus). This living candy corn was once found all over the United States east of the Rockies, but its numbers have declined dramatically over the last century or so, and it is now an endangered species with wild populations only occurring in a band of Midwestern states.

American burying beetles, and their relatives in the family Silphidae (which includes all the burying and carrion beetles), have a strange and specialized life cycle among insects. During the colder half of the year, American burying beetles hibernate in the soil, but once surface temperatures become amenable in the spring, they climb up through the dirt and get to work on making baby beetles. Adult burying beetles are strong fliers, and in the middle of the night, patrol the skies for miles at a time using their keen sense of smell to track down a recently deceased animal. But not just any ol’ bit of fetid roadkill will do. The beetles are picky, and the corpse has to be small, about the size of a songbird or a rodent. Once the stinky treasure is located it’s usually a mad dash for dominance among all the other burying beetles that have arrived on the scene. After some scuffling, the biggest and strongest male and female representatives lay claim to the spoils, presumably right before locking their compound eyes and realizing that someone in their lives finally gets them.

This macabre meet cute turns the dial up to eleven on the creepy, Buffalo Bill-style, serial killer bullshit right quick once foreplay commences. Before consummating their reeking relationship, the new lovers have to prepare their nest. And by “prepare their nest” I mean they have to dress and entomb their precious fuck-carcass so that the rate of decay is slowed enough for their imminent offspring to feed on the remains while underground. So, after taking care to cover the body in soil, they, like a couple of the world’s tiniest, horniest taxidermists, painstakingly pluck away all fur or feathers, roll the body into a neat ball, and slick it up all nicely with spit and ass juices…both of which have anti-bacterial and anti-fungal properties. With the au naturale embalming procedure complete, the two beetles can finally cozy up in subterranean privacy, and make the beast with two backs on the back of a beast that’s been shellacked….probably with Berlin’s “Take My Breath Away” playing loudly in the background.

The female soon lays eggs in a separate, nearby dirt chamber, and while the eggs incubate, both parents process the partially preserved flesh and regurgitate it back up into a liquid slush that is collected in a small pit carved into the top of the corpse. It’s like a bread bowl, but instead of hearty chowder and sourdough, everything is made out of decaying flesh. Mammals give milk to their young. Some birds store pre-digested food in their crop for their nestlings. And burying beetles make a crypt-themed baby room, lovingly outfitted with a feeding trough full of rotten chipmunk bisque.

As the grubs grow, mommy and daddy beetle stay behind to provide care for them, which is a truly unique level of parental investment by insect standards, perhaps only exceeded by the eusocial hymenopterans (bees, wasps, ants, etc.). Grubs “beg” for food, and their doting parents barf up partially broken down flesh for them on demand. It isn’t long until the young have matured enough to feed themselves, and once the carcass has been stripped down to the bone and the larvae are ready to pupate, the parental beetles give each other a knowing nod on a job well done, emerge from the soil, and die a short time afterwards, their life cycle now complete. Their young bust out of their pupal shells in nearby soil about a month later, and patiently overwinter as fully-formed adults, waiting until the next spring to go about finding a little fixer-upper cadaver of their own.

It is precisely this corpse-centered reproductive cycle that is at the root of the decline of the American burying beetle. While the increased use of potent pesticides in the 20th century is certainly a contributing factor to this species’ conservation woes, a bigger issue has been the dramatic shift in land use in the Midwest and Eastern U.S. during the past century. The effect of an increasing proportion of agricultural and developed land can take several forms. For one, as more and more land has been developed for crops and human habitation, habitat for small animals (many of them “pests”) has been obliterated, and their bodies are no longer as readily available to burying beetles. With dwindling natural spaces, there is potentially more competition for carrion from larger, scavenging vertebrates (think foxes, raccoons, etc.), which are feeling the pinch from their own habitat and resource loss. As suburbs have sprawled out away from urban hubs in the past several decades, light pollution has invaded even relatively untouched habitats, which can interfere with the nocturnal body-hunting habitats of burying beetles.

Whatever the ultimate cause of their decline, the way things stand today, American burying beetles are critically endangered. Efforts for increasing their numbers are on-going, with reintroduced colonies started in Ohio and Massachusetts.

Myriapod

“Myriapods” are arthropods in the subphylum Myriapoda, and refer to centipedes, millipedes, and their lesser known, closest cousins (symphylans and pauropods). Myriapods are often lumped in together with insects and spiders in a creepy-crawly catchall bucket, but they are equally distinct from both groups. Insects are a single class within a separate arthropod subphylum (Hexapoda), and spiders are arachnids, a class within the subphylum Chelicerata (a subphylum which also includes weird things like sea “spiders” and horseshoe “crabs”).

The two big subdivisions within the Myriapoda are the centipedes (Chilopoda) – which are highly-carnivorous, armed with electrifying venom, athletic, with a single pair of legs per body segment – and the millipedes (Diplopoda) – which are generally slow-moving, vegetarian, often protected with toxins or other chemical deterrents, and have two pairs of legs per body segment. While the names “centipede” and “millipede” evoke specific numbers of legs (centipede and millipede literally mean ‘hundred foot’ and ‘thousand foot’, respectively), the number varies radically between species. Centipedes can have as few as thirty legs, to over three hundred in some species. While millipedes do tend to have more legs than their centipede cousins, no known species has as many as 1,000 legs. But one species, with far more legs than the average diplopod, comes pretty close.

Behold Illacme plenipes, which is not only the leggiest millipede in the world, but the leggiest animal, period. How many legs does it have? Most individuals have more than six hundred goddamn legs, but some have many more than that still. The count tops out at some seven hundred fifty legs. To put that in perspective, that’s roughly the same number of legs present on a huge Airbus A340 commercial aircraft at maximum passenger capacity…all on one animal.

Illacme plenipes may spend enough money on pairs of jeans and sneakers to fund a small country, but that doesn’t mean everything else about it has scaled appropriately. This species of millipede only reaches about one inch in length, making its long, thin, pale body look more wormy than anything, really. With such ridiculous proportions it looks like a far-along game of Snake come to life:

Illacme plenipes is the only known member of its genus, and is a U.S. endemic species, found only in central coastal California, primarily near the Santa Cruz/Monterey/San Simeon area, as well as Big Sur. This species is almost exclusively found below the surface of the soil in moist, fog-heavy areas, and while the reason for the millipede’s excessively multitudinous gams is not definitively known, it has been suggested that they may be of assistance in the burrowing lifestyle of the animal, allowing a higher cumulative pushing force as it bores through the dirt, seeking rotting vegetative matter to chew on.

This blind, cream-colored species, much like Trogloraptor marchingtoni – the clingy cave spider outlined at the beginning of this blog post – does not have a common name. This needs to be fixed right now, goddamnit, especially considering this miraculous animal looks exactly like a panoramic photo fuck up and somehow, sure enough, it really does exist. How about the bleached thread-ipede? Monterey worm-of-many-feet? Californian single-file-army millipede?


Somehow I feel “leggy blond” will be an unacceptable choice as well

Crustacean

There is a wealth of crustacean diversity in the United States. In particular, crayfish diversity is high, especially in the eastern and southeastern parts of the country. With Australasia, the boggier, riverine areas of the U.S. are considered the global hotspots for crayfish diversity.

One species found only in the U.S. is Procambarus alleni, also known as the electric blue crayfish or the Florida cray. It is found in the wild only in streams in the southern and eastern regions of the State of Florida (including the Florida Keys), where it is plentiful. However, it can be found worldwide in the aquarium trade as a popular and attractive pet. Wild populations vary in color, ranging from the typical “crayfishy” red-brown, to a deep or vibrant, cobalt blue (much more rarely). Humans, being the crafty little tinkerers we are, have selectively bred, in captivity, distinct strains of P. alleni that are predominantly super blue in color.

Other than that, it’s a fairly standard, North American crayfish, biologically-speaking. Endemic crayfish. Some are blue as hell. Moving on.

Annelid worm

Annelids are members of the phylum Annelida and are generally considered one of the many groups of “worms”, given their overall body shape. The term “worm” doesn’t really have any taxonomic validity, as the animals called “worms” are not more closely related to one another than they are to other phyla of animals. If anything, “worm” is just a descriptor of a specific body type: long, often cylindrical, and often without obvious appendages. Within the phylum Annelida are many familiar groups of ‘segmented worms’: leeches, ragworms, marine Christmas tree worms, and of course, the garden-frequenting earthworms.

One species of earthworm, found only in the Pacific Northwest, is an idiosyncratic representative of the group due to its rarity. Also, its size. Did I mention that it’s really fucking big? Because yeah, slowly tunneling beneath the windswept grasslands of eastern Washington and parts of Idaho is Driloleirus americanum, the giant Palouse earthworm – and it can reach lengths of over three feet, looking more like that pallid monstrosity in Prometheus than something you’d throw on a fish hook.

Before you get your heart pounding about real-life Graboids bursting up through your manicured, Pullman, Washington front lawn and dragging you into the soft loess by your taint, know that 1) these are still just earthworms we’re talking about here, and 2) you’re almost guaranteed to never see one, because they are either exceptionally rare, or so hard to find that they may as well barely exist. In the 1980s, sightings were so non-existent that it was thought that they had gone extinct. Over the next thirty years, only a handful of additional sightings had been confirmed, and in 2010, researchers were finally able to collect a couple of specimens from the wild, effectively “re-discovering” the giant Palouse earthworm. In the several years since then, only a few additional worms have been encountered. So, this isn’t a creature you’re going to just find splayed out on the sidewalk after a rainy weekend.

It was said in older accounts that this species, and its only known close relative, the Oregon giant worm (Driloleirus macelfreshi) of the Willamette Valley, were able to spit a substance in defense while being handled, and that they gave off a lily-like scent (hence the genus name “driloleirus”, which means “lily worm”). Although, when the most recent live specimens of the giant Palouse earthworm were yanked out of the ground, they didn’t exactly smell like a bar of nice, artisanal soap. They smelled like….well….soil. And they sure as hell didn’t spit.

When it was first described in the late 19th century, the white worm (“Moby Dirt”, I call it) was supposedly quite common in the bunchgrass prairie that once covered the rolling, hilly Palouse region of eastern Washington State. But the growth of agriculture in the region has turned the Palouse prairie into one of the most threatened native grasslands in the United States, with much of the prairie now converted into cropland. It is possible that dramatic population reduction caused by the decline of the Palouse prairie is why the giant Palouse earthworm is so uncommonly seen in modern times; again, a native species potentially done in by habitat loss.

Mollusk

Mollusks are members of the phylum Mollusca, and are a group that includes soft-bodied, muscular animals that may or may not have some kind of shell, like clams, snails, octopus, and abalone, among many others. They are ubiquitous in marine, freshwater, and terrestrial environments. The U.S., in a similar manner to its relationship with crayfish, has a high degree of mollusk diversity. This is particularly true when it comes to bivalves like freshwater mussels, which are as diverse in the Midwest as fried cheese-based dishes, grocery stores that sell “pop”, and camouflage apparel choices.

But the U.S. has some unique molluscan inhabitants that are of the gastropod variety as well. Gastropods (“stomach foot”) are a taxonomic class of mollusk that includes the familiar snails and slugs; the vaguely turd-shaped, slimy animals that scoot around on a muscular “foot” running beneath their bodies. One group of these gastropods are the taildropper slugs, genus Prophysaon. They are in the roundback slug family (Arionidae), and are thus close relatives of the typical slugs you’re likely to find laying waste to everything green in your garden in the dead of night. Taildropper slugs are found across western North America, but one species in particular, the blue-gray taildropper (Prophysaon coeruleum) is found only in the wet forests that run from southern Vancouver Island and Washington’s Olympic Peninsula, through the Oregon Cascades, and into far northern California. There is an isolated population holding out in the moist woods of northern Idaho, and the slugs inhabiting the drier forests of southern Oregon and northern California are morphologically and genetically distinct, and may constitute a separate species or subspecies. The blue-gray taildropper is easily identifiable among its closest taildropper relatives, as it is the only one with the pleasant, glaucous coloration that makes it look like a booger made out of granite.

Blue-gray taildroppers, like all members of their genus, have the peculiar ability to sever their tail region from their bodies when being assaulted by a predator, serving as a distraction and satisfying their attacker long enough for them to make an escape….albeit a very, very slow escape. A barely discernible crease or perforation line can be seen across their tail, marking an area of structural weakness where the tail can be easily ripped off. This defensive strategy (often called “autonomy” or “self amputation”) is common in the animal world. Skinks and other lizards can regularly shed their tails to keep their assailant preoccupied; the tail thrashes on the ground, the lizard gets the fuck out of there, and the tail eventually grows back. Octopuses routinely will discard an arm to a predator. Crabs and lobsters often loose claws or legs in much the same manner.

Cnidarian

Cnidarians are animals found in the phylum Cnidaria. These are very primitive animals with limited tissue layers and loads of venomous stinging cells; think jellyfish, sea anemones, and corals.

One spectacular member of this group that is found in U.S. waters is the sand-rose anemone (Urticina columbiana). This isn’t a species that can be found up in tidepools like many other types of anemone, but it frequents sandy or soft mud bottoms from the highest subtidal (the depth just below the lowest low tide mark) down to a few tens of meters down, so this is a species that can be encountered by SCUBA divers rather than beach walkers and waders. Its range encompasses a long swath of Pacific coastline, from Vancouver Island south to Baja California.

With its brilliant, red, central color contrasting with white or peach-colored tentacles, it’s a sight to behold. Doubly so because some individuals can reach stupendous sizes, sometimes with the oral disc reaching diameters as wide as the door to your house. Sand-rose anemones are among the largest anemones on the planet, and if you live on the West Coast, and have an inclination to take up SCUBA diving, you can strap on a tank, jump in, and see them for yourself.

At this point, this ‘Mericuh-centric post series has only examined the animals that live within the borders of the country. But of course, much of the diversity of life is not of the faunal variety, so there is still much to say about American flora and other organisms…

This post series will continue with fungi and plants in Part 3.

Image credits: Eastern ox beetle, sunflower seastar, Trogloraptor marchingtoni, Trogloraptor clawAmerican burying beetle, Illacme plenipes #1, Illacme plenipes #2, electric blue crayfish, giant Palouse earthworm, blue-gray taildropper, sand-rose anemone

© Jacob Buehler and “Shit You Didn’t Know About Biology”, 2012-2016. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Jacob Buehler and “Shit You Didn’t Know About Biology” with appropriate and specific direction to the original content.

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4 thoughts on “Living in America: Part 2, Boneless Locals

  1. I love that you started this post with that beetle – I have a specimen at my desk at work! I had identified it as an Eastern Hercules Beetle (same species name – I had not see this called an “ox beetle” before). The one I have was already dead, and a fairly dark color when I found it near my office in VA. As it dried, it became lighter and greener, with the same dark spots, so that it now looks like the photo above.

    I have a couple more at home that I picked up in Chattanooga TN. I’m always on the lookout for them in late summer now, they are some of my favorites.

    • Yup! Same species! I was going to call it by the more widely used common name (Eastern Hercules beetle), but I thought that it might be confusing, considering that the giant, neotropical representative of the genus is also simply called the “Hercules beetle.”
      They really are cool critters. Never seen one in the flesh though, as I’ve spent most of my life living in the American West, where they don’t occur.

      • They’re certainly impressive. The ones I have are about an inch and a half long, one of the largest beetles I’ve seen. I’ve only found dead ones so far, though.

  2. Pingback: Living in America: Part 3, The Fruited Plain | Shit You Didn't Know About Biology

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