Speculative Evolution -> COM #127: With Conical Teeth (2024)

Retreat to the Abyss - Conodonts of the Holocene

"The future is in the hands of those who explore... and from all the beauty they discover while crossing perpetually receding frontiers, they develop for nature and for humankind an infinite love."
- Jacques Yves Cousteau, Oceanographer

12:46 pm Local time, January 23, 1960, Somewhere off the coast of Guam, approx 6100 fathoms under the sea

The four and a half hour long journey has taken quite a toll on Piccard, with multiple measurements, rechecks, and consistent eyeing of the fathometer leaving him quite disoriented. Turning to Walsh, he carefully stretched his arms in the cramped compartment, making sure not to hit any equipment they have nearby. A brief yawn from his companion told him Walsh was feeling the effects as well.

Steeling himself, he once again made himself aware of his mission: he was to find the bottom of the trench, and the Trieste, the result of his family’s lifetime of work, shall be his most prized achievement. He had trained himself for this moment, he had piloted many bathyscaphes in the past, he wasn't going to get sleepiness get the better of him now. This time, he focused his gaze on the plexiglass window below, letting the calm flow of the exterior water empty his thoughts for just a moment.

Upon the window is a single crack, the result of a far too hasty descent from before. Though the window holds up, they would have to cut the expedition short to avoid the risk of a breach. To Piccard, the crack brings a certain amount of aesthetic into the small vessel, sparking the young adventurous self within him, the crack reminiscent of abandoned megastructures and lost temples that entranced his childhood with adventures and worlds of fantasy. Snaking through the glass like a torrential river cutting through a canyon the crack seems to point and twist, grooves from the cracking shimmering in the spotlight. In the background, marine snow paints the darkness with an omnipresent downfall, and further beyond lies nothing more than the vast domain of shadows. One could spend hours staring at the scene, but work needs to be done, and he couldn’t have Walsh do all the work. Cracking his knuckles, he hunched back to the surrounding machinery and began recording the measurement, absorbed into the maintenance of the submarine.

Some time later, a light thump echoed through the chamber as the Trieste reached the seafloor. Walsh had already notified Piccard to help him visually record the scene onto the radio as he noted the readings down on a notepad, the former scrambling on the radio button. Calming his breath, he began describing the scene outside; Marine snow still fell, but this time onto a soft, shifting sediment that was the seafloor. To the distance was a vague strip of light, which Piccard interpreted as refraction from the ship’s spotlight, but what most interested him was directly below the window: what appears to be a flatfish has been startled out of it’s resting place, lazily half-lifting itself from the sediment in a slow and ungainly stride. Despite the slow retreat, the two men were well aware of the significance of this event. A teleost fish, deep within the trench of the Mariana. This was definite proof that life existed past 5000 fathoms! Smiling, they turned to each other to shake hands.

Little did they know how quickly it would disappear.

The strip of lights, which the duo had neglected to take full notice of, suddenly lunged onto the flatfish, unsheathing flashes of silver and ramming the fish with several stabbings of the pickaxe-like protrusions. The flatfish, now revealed to be a sea cucumber, was startled by the presence of an assailant, and quickly attempted to escape. Curved knives that snapped in from the sides held it in place. The hapless cucumber was lifted upwards, grinded like pulverized meat by the now visible teeth of the eel-like creature, flashing a final display of light across the window as it dragged its prey up past the bathyscaphe, disappearing into the darkness beyond.

Stunned, the two men looked at each other, both arms still gripped in a handshake. Neither seemed to know what to make of the strange encounter, but one thing seemed to hover in the air above the two of them: What monster had they just bore witness?

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Many marine scientists have disproved, and some outright not believing Picard’s accounts that any such life even exists that deep, simply dismissing the sightings as mere mirages from fatigue and the bending of light by the window. But as more dove into the depths they are confronted with the undeniable truth that life, not only survives, but even thriving in a near undisturbed time capsule where refugees from extinctions seek shelter from the tumultuous seas above. Coelacanths, Chimeras, Vampire Squids, and so many others persist as the last of their lineage, in a world cut off from our own. Perhaps one of the most intriguing denizens of the deep are the deep sea conodonts, a grouping of jawless fish that have produced some of the strangest creatures to emerge from the cradle of life.

It is believed that the ancestors of the deep sea conodonts were derived bottom feeders that were the only group to survive into the Jurassic, and while speciation occurred they were quickly driven into the deep sea during the mid Jurassic, as fossils slowly disappeared from sedimentary beds. Although there are no answers to why they disappeared from shallow waters, several theories exist, ranging from the rising competitiveness of rays to the presence of a sudden anoxic and acidification event that was known to occur during the Toarcian. Nevertheless, they disappeared from fossil records, seeming to only be present in the deep sea from then on.

Today, The order of surviving Conodonts can be separated into two distinct families, and contain upwards of nearly thirty species, with undescribed species possibly reaching the hundreds. They can be found in a near cosmopolitan range across the ocean, but only within deep sea habitats and trenches. The ancestral species of all living conodonts is believed to be surprisingly similar to the Silteels, a good basal example to derive all other conodonts from.

Common Silteels live on the continental shelves and abyssal plains of oceans worldwide besides the arctic and antarctic, and are known to shift through the sediment in a sweep-feeding manner, raking through a variety of annelids, microorganisms, copepods, amphipods, and detritus across the bathypelagic zone. Their bodies, while flattened, are not to the severity of a ray or a flatfish, rather more akin to that of a highly elongated loach. Two pairs of barbels extend from their snout, and their eyes are little more than reflective lenses that only sense light and movement. Their mouths have migrated to the bottom of their body, where layers of contracting and expanding teeth collect and upturn large amounts of sediment in search of food. After raking a large amount of sediment in their mouth, they use their tongue to push and stir the sediment, forcing the fine silt and sand out through a set of stiff, baleen like teeth. Prey is captured and gulped down, and from there the process begins anew. Common Silteels are believed to be some of the most primitive conodonts, with the exception of increased specialization towards a benthic life. Subspecies worldwide specialize their diet across the various microorganisms within their localized environment, but the highly generalistic Silteels are the most common depiction of conodonts when one is brought to mind.

Not every conodont is a gentle filter feeder. The Neon Charybdis (not to be confused with Charybdis the crab) is a deep-sea predatory conodont that inhabits the ridges and trenches across the pacific ocean, being found only past the abyssopelagic zone and beyond. This was the specimen that was observed by the diving crew of the Trieste, the first of many deep-sea monsters that would become popularized in the late 20th century. In this vein, it is the deepest known vertebrate to have ever been discovered, having first been sighted at over 10,000 meters within Challenger deep. An ambush predator that floats across the sea column, they drift across the water column in search of prey in perpetual darkness. Despite their relatively small size, Neon Charybdis are able to fully swallow prey twice as big as themselves, using an expandable stomach in their abdomen that has the dual ability to hold both food and spawn. Despite the lack of jaws that most other deep sea predatory fish possess, the Neon Charybdis has fashioned a unique weapon of their own: A complex system grasping teeth.

Prey would first approach the conodont from flashing bioluminescent dots that illuminate their back. Waiting until the prey approaches to a sufficient distance, the Charybdis would quickly lunge forward, piercing their prey with a row of short circular, pointed teeth in a flash. Then comes a pair of mandible teeth snaps in from the sides, keeping wriggling prey from escaping the first volley. Finally, the inner rows of teeth thugs the prey inwards, eventually swallowing it whole as the prey dies from their multiple puncture wounds and partial mincing from the inner teeth.

Neon Charybdis are extremely solitary creatures, attacking any one of their kind should two ever cross paths with another. It is only at the end of their three year life cycle would they gather in rocky outcrops across the seabed to mate aggressively. Interestingly, they are semelparous, and males would spend all their energy producing larvae before death. These larvae would in turn gain more nutrients to mature, growing at an accelerated rate within egg sacks in their mother. This would deprive the mother extensively, who is forced to seek a refuge within the rocks to rest. In a mere day or two, the larvae would burst out of their eggs internally, and consume the already deprived mother with a vortex of fangs. The mother puts up no fight, instead allowing herself to become the fuel for the next generation. Once every strip of edible meat has been stripped from the bones, the juvenile larvae disperse into the ocean, never to meet another of it’s kind until it is their turn to become parents.

Finally, there is one extreme outlier that stands out even among the highly diverged conodonts, one so extreme that no vertebrate has ever once adopted such a lifestyle: A fish that lives off energy produced by internal, symbiotic, chemosynthetic bacteria.

The Gratefish, named after the shape of their teeth, is a chemosynthetic conodont that resides around hydrothermal vents, cold seeps, brine pools, and even mud volcanoes within the abyssal plains, commonly seen slowly circulating in shoals of 60-200 around the source. Though only reaching sizes between 28-80 cm, compared to other denizens they share their habitat with, they are considered to be the most efficient in terms of energy production and conservation. Gratefish, being the most mobile grazer of the chemosynthetic nutrients, has devised multiple adaptations to meet the high competitive requirements of chemosynthetic life. Firstly, a pair of large organs can be found occupying the entire underbelly of the fish, taking up nearly half of the entire body. These are specialized organs that are used to store bacteria that, for simplicity's sake, will be referred to as a trophosome. Theorized to have evolved from a fusion of between the liver, stomach, and the sphincter muscle, veins and arteries snake through the interior in increasingly branching formations, dispersing chemicals within the blood and regaining nutrients and energy from organized layers of endosymbiotic bacteria, each densely packed in rows along the trophosome. Add multiple layers stretching across the half the fish and you have a good idea how much energy would be processed in a matter of minutes.

In addition to this, they would gather in slow swimming, circulating shoals around sites of high nutrient concentrations, mainly relying on their cartilage skeleton to stay afloat. They would beat their tails in a curving, rhythmic pattern, creating complex wakes that wastes much less energy while keeping themselves suspended. An array of outer brushy, filament-like teeth would concentrate nutrients around their mouth, where grate-like inner teeth would filter the nutrients inwards and through a highly modified pharynx and gill system, finally dissolving the chemicals into the blood, where they would be taken through the trophosome and muscles, before finally returning to the pharynx and gills to collect more. All individuals are hermaphrodite, their reproductive organs relatively small and relegated near the tail end of their body. During spawning season, individuals within a shoal would vehemently reproduce, and upon spawning would disperse part of their larvae into the ocean currents or the backs of visiting larger fauna, such as octopuses and rays. With luck, a few would make it to a new nesting site, and from there a new colony would be born. When the current vent/seep begins to run dry, the shoals would be forced to make a dangerous migration in search of a new site of nutrients, where as much as a third of the Gratefish perish before a new site is reached. Due to their lifestyle, they are one of the rarer inhabitants of hydrothermal vents and the like, found in lesser abundance than yeti crabs or tube worms. Regardless, Gratefish are some of the most distinctive creatures to call these alien underworlds home, due to their extensive coverage in both popular media and scientific research.

For in this reality, Conodonts never went extinct, allowing humanity to bear witness to some of the most fascinating life forms in Earth’s history.

It’s a shame they died in ours.

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Source for the Challenger deep story:
https://library.ucsd.edu/speccoll/DigitalArchives/smc0028/Dives_Bathyscaph_Trieste_Dictabelts.pdf