Erratum for The Age of Fishes Part 1.

As several readers have pointed out, this fish:

is actually Climatius klimti, not Climatius reticulatus as I claimed in the previous post.

Here is the true, open water-dwelling, plankton-eating C. reticulatus:

C. klimti, on the other hand, is actually a bottom-dwelling species. It inhabits algae praires where its dappled pattern provides perfect camouflage as it hunts the tiny gastropods, caprellids, amphipods and hyoliths that make up the majority of its diet.

The Age of Fishes Part 1.

First in a long series.

There’s good reason that the Devonian is called “the age of fishes”, since this is the first major radiation of aquatic vertebrates. Although nearly all of the creatures swimming the waters around Opitz Station are unlike anything you’d see in Present Time.

I should point out that the term “fish” is actually not as scientifically precise as you’d think. Really it’s more of a type term, designating aquatic vertebrates that obtain oxygen by filtering it from the water with gills. It’s kind of like the term “vehicle”, which could refer to a car, bus, airplane, helicopter, boat, tank or really any device that transports people and goods from one place to another.

See, many creatures that we’d call “fish” are only distantly related. For example, a Present Time salmon is actually more closely related to a human being than a hammerhead shark. This is because both humans and salmons are part of the class Osteichthyes—fish with skeletons made of bone (and yes, that does mean that, technically, we Homo sapiens could be considered a highly, highly derived type of “fish”) whereas sharks and their relatives-- skates, rays and chimaeras-- are part of the class Chondrichthyes, which are fish with skeletons made of cartilage.

Yet even sharks and salmon are more closely related to each other than either is to lampreys (Petromyzontiformes) or hagfish (Myxini)—the latter of which are not even considered proper vertebrates since they don’t actually have hardened spinal columns (though they do have spinal nerve cords).

As if that weren’t complicated enough, the Devonian snarls up the concept of “fish” even further with all manner of delightful oddballs such as Thelodonts, Galeaspids, Osteostaracans, Heterostracan Acanthodian “Spiny Sharks”, armor-headed Placoderms and the bizarre, trap-jawed Conodonts.

I’ll have a detailed chart of all these fish-groups in a later post once I talk with Dr. Alonso and tease out all the groups. But for now enjoy a few of of the weirdo Devonian fishes from around our Station.

SPINY SHARK
Climatius reticulatus

Acanthodians or “spiny sharks” (which are only distantly related to true sharks—the name comes from their overall shape) are the most abundant schooling fish around Opitz Station. As their name suggests, the bodies of spiny sharks are studded with up to fifteen stout spines to protect them against predators and to act as stabilizing fins. Spiny sharks are believed to have been the first vertebrates to evolve jaws—which derived from the bony arches supporting its ancestors’ first set of gills.

Climatius reticulates, our most common acanthodian, congregate in massive schools to feast upon plankton. They’re rather bold, curious fish and will frequently swim up to check out a diving researcher. We haven’t yet figured out what the massive eyespot on the gill cover is for, though Dr. Alonso suspects it may be used to distract smaller predators away from the animal’s sensitive eyes.

GREEN ARROWNOSE
Pteraspis queeni

Heterostracans are tadpole-shaped fish covered in a mosaic of large armored plates and smaller pebble-like scales. These provide ample protection from predators such as placoderms, eurypterids, squids, ammonites, nautiloids, the more aggressive trilobites and the dreaded Emperor Death Shrimp-- a critter that even we humans are a little afraid of (more on that in a future post).

In addition to their head armor, heterostracans are also distinguished by the possession of a large gill opening on either side of the body. Most groups can shoot water from these openings to create a kind of jet propulsion.

Heterostracans don’t have any jaw bones. Their mouths are just armored openings that can’t be closed, though they do have muscles that seal off the end of the throat to prevent prey from escaping.

Pteraspis is a genus of heterostracans distinguished by a long snout or rostrum (though a few comparatively snub-nosed species are known) and a large spine on the back that serves as a dorsal fin. All of the species we encountered around Opitz station were open-water swimmers that hunted the huge schools of crustaceans and trilobites hanging out near the ocean surface. Pteraspis' heavy armor coupled with their lack of swim bladders means they are very negatively buoyant. Thus they must swim constantly to stay up in the water column.

Since many Present Time fossils are fragmentary, our researchers frequently have a hard time matching up fossil species with the creatures swiming through our Devonian waters. In such cases, they give the living specimens their own distinct species name. The creature pictured here, for example, is Pteraspis queeni, the Green Arrownose. Dr. Alonso named it. Apparently its emerald coloring reminds him of some sort of super Robin-Hood character from a comic he reads.

FRYING-PAN FISH
Drepanaspis gemuendensis

So nicknamed due to its flattened body, this heterostracan hangs out on the sea bottom camouflaged amongst the rocks and debris. It uses its upturned eyes to spy out small invertebrates swimming just above the ocean floor, which it slurps up with a quick lunge of its equally upturned mouth.

At Opitz station, the Drepanaspis are highly attracted to the overhead lights on the docks. Well, more accurately, they’re attracted to the abundant swarms of trilobites, ostracods and other arthropods that gather under the lights.

As you may have noticed, our Expedition Seal is a Drepanaspis. Specifically, this is our team pet, “Salty”, who Marisa and Healani rescued from a tide pool in our first few days at the Station.

Salty was more than half-dead when they found him , having suffered through several hours of excruciating heat, depleted oxygen levels and high salinity (hence the name) in the shallow, sun-exposed, rapidly-evaporating pool. Luckily they were able to get him to the Station in time and nurse him back to health in one of our sea-tables. He recovered quite well, though we think his brain got a little fried since he developed a weird habit of hanging out upside-down at the surface of his tank (not an easy task, mind you, since Drepanaspis are negatively-buoyant and bottom-heavy). Oddly, Salty was avocado-green instead of the usual mottled-brown of his fellow frying-pans. We haven’t been able to figure out if this was just a random mutation or an effect of his experience in the tide pool.

The Devonian Night, part 1

Here’re a few constellations from the Devonian night sky. There’re a lot more than these hiding out amongst my notes (I really gotta’ organize these portfolios better), so I’ll put the other ones up as I find them.

In addition to constellations, we’ve also named a few of the more prominent stars (quite a few astronomy nuts on staff). I should point out that, technically, the names we’ve given to the Devonian night aren’t official since they weren’t registered with the International Astronomical Union. But so far TEI hasn’t had the time (or money) to send an IAU representative back yet, so the names stay for now.

THE ANOMALOCARIS

The red star (actually a red giant near the end of its life) forming its left eye is Yama, named after the Buddhist judge of the dead.

The star forming the right eye is called Nash (short for Nashville-- you’ll see why in a second). Notice from this star there’s a crooked line of stars leading through the first and second body segments of the anomalocaris, down through the third flipper to point at a yellow star in the lower left. We dubbed this the “Natchez Trace” after the historical trail running from Nashville, Tennesse all the way to Natchez, Mississippi (a name we’ve given to the yellow star). The other stars along the “Trace” are named for aspects of the real Natchez trail.

Choctaw is named for the largest Native American First Nation originally found along the trail.

Pharr refers to a complex of eight Middle Woodland Indian burial mounds approximately 23 miles northeast of Tupelo, Mississippi.

Kaintuck is the nickname for boatmen from the Ohio River Valley who floated merchandise down the Ohio and Mississippi rivers to sell in Natchez and New Orleans during the late 18th and early 19tth centuries. Since they obviously couldn’t take their rafts back up the river, they usually sold their boats for lumber and walked home along the Natchez.

THE HELMIT URCHIN AND THE HORNET

Helmet urchins (Colobocentrotus atratus) are a bizarre, flattened species of urchin often found in intertidal zones throughout the tropical Pacific.

The Hornet is, well, a hornet. Not much of a story there. Might have something to do with the fact that Art Yamaguchi is from Charlotte (and really seems to dislike New Orleans for some reason).

The only star we’ve name in this area is Acanthoptera, which joins these two constellations together.

MAUI'S FISH HOOK

Named after the Polynesian folk hero. Near the base of the Hook is an open star cluster called the Balistidae Cluster, after the family name for triggerfish.
The star at the tip of the hook is called Horkheimer, after the late Jack Horkheimer, host of Star Hustler—later called Star Gazer (you remember that show, don’t you?) and executive director of the Miami Space Transit Planetarium at the Miami Science Museum. Not sure if that one will stick if IAU gets out here since Present Time already has 11409 Horkheimer, a main-belt asteroid.

(Note that the modern-day constellation Scorpius is also sometimes called Maui’s Fishhook. Personally, I like ours better.)

QUETZALCOATL

Named after the feathered serpent deity of the Aztec, Teotihuacan and other Mesoamerican peoples.

The star in the eye of Quetzalcoatl is named Pegasi-51, in reference to our modern day 51-Pegasi, which was the first sun-like star discovered to have an extra-solar planet. Though we have no idea if our Pegasi-51 has planets around it.

In the crown of Quetzalcoatl is another star cluster called the Toltec Cluster, after the legendary (and partially mythological) cultural precursors to the Aztecs.

Below Quetzalcoatl is the brightest star in the Devonian night. As I mentioned in the first entry, we went through several different names for this star before finally deciding on Amaterasu, after the Japanese Sun Goddess. Latrice—the biggest astronomy nut out of all of us—was the one who discovered that Amaterasu is actually a binary system (two stars orbiting around each other—Amaterasu A and Amaterasu B). More precisely, it’s an eclipsing binary system wherein the stars’ plane of orbit is parallel to the observer’s line of sight. In other words, as they orbit, one star passes directly in front of the other with respect to the viewer. As a result, Amaterasu grows dimmer when the smaller of the two stars is hidden behind its larger partner.

THE KIWI

Named after the flightless New Zealand bird. Reese dubbed the bright blue star at the base of its foot Orakei Korako after a particularly active geothermal hot springs located near his hometown of Taupo.

The Glowworm Nautilus and her Passengers

As promised, here's a more detailed discussion of some of the critters we caught on our way to Opitz Station

GLOWWORM NAUTILUS

(Velabrachius lucifer)

The female of this species possesses two extra-long arms with sail-like flaps called vela (the name is singular and plural), which she clamps along the sides of her loosely- coiled shell to form a chamber. Eggs are deposited into this chamber, and the larvae remain within until they are large enough to survive on their own. Males are similar in size, though they do not possess the long arms nor the vela.

Both male female V. lucifer possess bioluminescent organs, called photophores, along their arms. Glowworm Nautili can "wink" their lights on and off, producing flashing patterns, probably as a form of communication.

For more details, see: Irvine, Gene The Luminous Sea: A Bioluminescent Nautiloid from the Middle Devonian (2011) Journal of Cephalopod Studies 134:45 pgs. 345-362

PASSENGERS

In addition to young V. lucifer (b), several other organisms frequently take up residence in the Nautilus' brood chamber. Copepods (A.), Ostracods (E.) and pelagic trilobites (D.) are abundant, as are planktonic crustacean larvae such as this crab zoea (C.). The identity of (F.) remained a mystery for quite some time. Clearly it was some sort of larvae, but we couldn't identify the adult form until Dr. Alonso successfully managed to raise a few to adulthood in his lab tanks. It turns out this spiny critter is actually the young of the anomalocarid Schinderhannes bartelsi! I'll have a lot more on Schinderhannes in a later post.

ECHIDNA SHRIMP

(Echinodorsus gladiocaudus)

In addition to Glowworm Nautili, we also find an abundance of this prickly-backed shrimp in the Glowing Sea. Despite its name, the Echidna Shrimp is actually a phyllocarid (a primitive group believed to be ancestral to crabs, lobsters and true shrimp). While most phyllocarids are bottom-dwellers, E. gladiocaudus is entirely pelagic.

Echidna shrimp are frequently preyed upon by Glowworm Nautili. Though the shrimp's prickly carapace protects it from most predators, the V. lucifer gets around this difficulty by grasping the shrimp's tail and stripping off the shell with its tentacles before consuming the hapless prey.

Arrival

My first Jump through time is kind of disappointing. I expect there to be lots of crackling and blue lightning. A swirling vortex shredding time and space. Maybe my stomach leaping up through my skull. But I don’t even realize when the Jump begins. I expect an angry ramjet-roar when the Temporal-Displacement Field engine kicks in, but I don’t even realize it’s going until Dr. Zhang points out the low whir barely audible under the thrum of the Walcott’s four lift-fans. I feel it buzz in the plastic-leather of my seat and my heart thunders as I wait for the sky to open up and suck us in. I crane to look out the tiny porthole window, staring off into bright blue noon.

Then there’s a pop like a fuse blowing and suddenly it’s nighttime. The TDF engine fades to nothing. Captain Troughton comes on and says we’re now in the Early Middle Devonian, approximately 380 million years from when we started, and reminds us to clip on our seat belts as she takes us down.
Aside from the night sky, the scenery down below hasn’t even changed. Just ocean all the way to the horizon.

I’m not the only one who’s disappointed. “That’s it,” asks Latrice, our computer gal.

“You should be glad,” says Dr. Zhang, “first unmanned probe they sent through ended up embedded inside a mountain.” She peers out her starboard window then scoots across the seat to check the port. She hits the intercom. “Marie, where is Opitz Station?”

“Looks like we had a little spatial shift when we went back,” Captain Troughton replies, “I got a fix on their beacon to the west.”

We touch down on the sea and the lift-fans go quiet. Soon there’s another buzz as the Walcott’s marine screw comes to life. I wonder why Marie doesn’t just fly us straight to Opitz. Later she explains to me that the lift-fans use a lot more fuel than the screw— and we’re going to need lots of gas if we’re going to make it back into the air again; the Sawyer Effect* makes it way too dangerous to Jump on the ground.

Once the time-ship is moving along at an even pace, Marie tells us we can go check out the view on deck.

I should probably pause here a moment to mention the other folks who’re on this ship with me.

Professor Zhang Jingfei, the head of this expedition, is a Paleontologist specializing in Devonian biota. She’s originally from Yunnan University, though at the moment she’s one of the chairs at the Temporal Exploration Institute at Cape Canaveral. She’s not exactly what you’d expect from her name and occupation, seeing as how she’s got to be at least six feet tall and wears that white Stetson everywhere (seriously, I swear she had it on during the mission briefing at TEI headquarters last week).

Doctors Juan-Carlos Alonso and Gene Irvine are both marine researchers out of Woods’ Hole. Dr. Alonso is an ichthyologist while Dr. Irvine is an invertebrate zoologist specializing in echinoderms. They brought their senior-most grad students along—Mariska Newlin for Dr. Alonso and Art Yamaguchi for Dr. Irvine.

Dr. Carla Dixon’s a phycologist from the University of Auckland. Her grad student, Reese Mohi, is more of a botanist, so together they’ve got the land and sea pretty well covered when it comes to photosynthesizing organisms.

Professor Kale Kaupali is a parasitologist from the University of Hawai’I (first name’s pronounced “kah-lei”, by the way, not “kale” like the vegetable. He’ll give you a hard time if you screw that up). He’s also brought along his own grad student, Healani Nguyen.

Latrice Anderson is our computer technician. She’s going to be relieving the tech guy who came in with the engineering team about an hour ago to set up Opitz Station (hour by Present Time. In Devonian Time, they’ve been here about a month).

Then, of course, there’s our captain, Marie Troughton and her co-pilot Phil Leach. In addition to piloting the Walcott, they’ll also be in charge of the smaller vessels at the station.

Anyway, back to the narration:

Everybody’s eager to go outside and have a look at the Devonian night. We stop in the airlock to put on atmospheric-scrubber masks since there’s a lot more CO2 in this atmosphere than we’re used to, along with extra sulfur and a few other trace gases our lungs won’t like. Before we exit, Reese and I unfold a portable ramp so Doc Dixon can get her wheelchair up over the three steps leading to the deck.

Although the passenger cabin is cramped, the Walcott itself is huge. It has to be to accommodate all our scientific equipment, creature comforts and food for several months (Jumps get expensive fast, so the Institute tries to minimize the number of trips). As such, there’s plenty of deck space for us to spread out.

The sky is strange. In college I worked as a planetarium operator, so I instinctively look for the familiar constellations. But where there used to be (or rather, will be) patterns in the sky, there’s just a scattering of pale blue sand against a beach of obsidian glass, bisected by the soft smear of the Milky Way. The moon’s bigger, too. Not huge, but enough that you notice. I’m curious to see what effect it’ll have on the intertidal zone once we hit land. To the east there’s a blue star brighter even than Sirius in our time.

We take turns naming the sky. Doc Zhang’s apparently a big Precolumbian Mesoamerica nerd, so she picks out The Plumed Serpent Quetzalcoatl, The Giant Olmec Head and the Ahuizotl (some kind of water-monster, it seems). Reese names the Fish Hook of Maui, the Kiwi bird and Bird’s Saxaphone. Dr. Irvine picks out a Lion’s-Mane Jellyfish and an Outrigger Canoe with Crab-Claw Sail. Art sees a Hornet and an Aardvaark. I pick out an Anomalocaris. Latrice names a new Orion and a new Big Dipper. Healani names the Humumunukunukuapua’a and the Helmet Urchin.

No one can agree on what to call the new, bright star. Healani wants to call it Amaterasu after the Japanese sun goddess. Mariska wants the Gorgon’s Eye. Latrice likes Eastern Blue. I suggest Yuggoth. We decide to table the discussion for now.

We encounter the Glowing Sea about an hour after arrival. It starts off as a sprinkling of lights in the water, scattered enough that you’d mistake them for reflections from the moon or the ship’s own lamps. Soon the sprinklings grow into patches as big as a man. Then a truck. Then a plane. Suddenly the sea all around is filled with a soft ice-blue light. We send down a trawl net that comes up full of bioluminescent nautiloids (Doc Irvine later names them Glowworm Nautiluses, Velabrachius lucifer).

We speculate on why they congregate in such huge numbers. Dr. Alonso thinks it’s probably a mass spawning, although Dr. Irvine suspects they may be feeding. Possibly on all the Echidna Shrimp (Echinodorsus gladiocaudus) we bring up as well. We also catch a predator—a six foot long placoderm that resembles Dunkleosteus. Its entire head is smeared with bioluminescent slime-- ink from the nautiloids, maybe? It’s later described officially as a Bulletskull (Calvichthys triodon). Clinging to its fins are a couple of tiny, colorless, parasitic trilobites.

(I’ll post more on V. Lucifer, C. triodon and the other things we caught in the next entry.)

As we travel, one of the horizon stars grows steadily brighter. It’s a while before I realize that’s the light from Opitz Station. Soon a thin band of darkness forms above it, marking the higher land of the approaching continent. It’s strange to see that one light against the black. The only piece of human civilization on the planet. The Glowing Sea fragments and scatters around us, although the hull of the ship still glows for nearly half an hour after we pass the last of the swarm.

As we get closer to shore, buildings resolve out of the night. First is the long, plastiwood pier. It extends a long way out into the water, since the Walcott’s size means it can’t go into the shallows. There’s a square metal shack perched on the shore (the supply shack for the inflatable Zodiac motorboats, I later find out). Farther upland is the high dome of the main research laboratory, its base girdled by windows like the skirt of a deep-sea jellyfish. Coming off its sides are eight long metal arms that remind me of those 1950’s diners made from boxcars. These are the dormitories, engineering workshops and recreational rooms, as well as a few extra labs.

The land here looks odd. Manmade almost. Like sheets of corrugated metal. The ground seems to be tiled. I realize then that it’s columnar basalt. The whole shore, as far as the lights illuminate. Nothing but hexagonal pillars of dusty black rock. At the water line are bands of pink, white, green and orange-brown. Algae and barnacles (or a barnacle-equivalent).

As the Walcott glides in along the pier, the engineering team emerges from the laboratory dome to help us in.

Latrice points to the water. Dark shapes move against the sandy bottom. One enters the boat’s light field and we see that it’s a small, flat fish shaped like an armored frying pan. Later, Doc Zhang identifies these as Drepanaspis gemuendenensis, a species of jawless heterostracan fish.

There’re a couple hours of unloading and greetings to go around, but I won’t bore you with that. Check back in a few days for more reports.

*For those not up on their Time-Jump terminology, the Sawyer Effect is the tendency of a vessel traveling through time to maintain the exact same position with respect to the planet’s core. In other words, it usually stays at the same latitude, longitude and distance from the core as it travels along the time dimension. As any high school geology class will tell you, though, land shifts over millions of years, so the ship runs the risk of ending its Jump inside a mountain (as happened to the first unmanned time probe—the Jacques Cartier I), under the sea (as happened to the Jacques Cartier III), or high in the air. To avoid this, time ships are elevated at least a kilometer into the air when they Jump. Even then, as our Jump clearly illustrates, there’s still occasionally a bit of a shift in position.