#Akmonistion

[bobnichollsart]

My 25 years of palaeoart chronology...

In 2010 I painted the Early Carboniferous shark, Akmonistion zangerli hunting Acanthodes fish. This was for Matt Dale and the famous Mr Wood's Fossils, in Edinburgh, Scotland: https://www.mrwoodsfossils.co.uk/

[hey-kid-can-i-info-dump]

Akmonistion/A. zangerli (Formerly Stethacanthus)

Name meaning: “akmon” = “anvil” & "istion” “sail” (both Ancient Greek) Lived from: 330-323 million years ago Stage/Age: Serpukhovian Epoch: Mississippian Period: Carboniferous Location: Bearsden Scotland Discovered by: Stan Wood Discovery date: 1982 Family: Stethacanthidae Genus: Stethacanthus Domain: Eukaryota Class: Chondrichthyes Order: Symmoriiformes Diet: Small fish and arthropods Akmonistion was a 60cm long shark with an anvil like specialized first dorsal fin called the "spine-brush complex" which is similar to the thoracic shield in placoderms and postparietals in catfish. This dorsal fin would've made it that the Akmonistion most likely couldn't swim fast. It is not confirmed what exactly the function of the spine-brush was but was most likely used to either used to scare away predators, attach to other large animals like a sharksucker, to mate or attract a mate. Its other dorsal fin is made of parallel rods with roots that have sharp ventral tips buried deep into it's skin. The Akmonistion was most likely a bottom feeder because of its small fins and teeth. The Akmonistion also had relatively large and had a pair of whip-like pectoral fin extensions possibly used during mating, with the male pelvic fin having a pair of pelvic claspers.

Note: We are always discovering things and making new scientific discoveries, this is the most accurate information as I am writing this but because of ques and us discovering new things information might not be completely correct during any period of time and if you catch something that's out of date please tell me

[newlabdakos]

Akmonistion zangerli

(temporal range: 330.9-323.2 mio. years ago)

[text from the Wikipedia article, see also link above]

Akmonistion is an extinct genus of holocephalian that lived in the Early Carboniferous. The genus contains a single species, A. zangerli, discovered by Stan Wood in 1982.[1] It is distinguished by an unusual enlarged formation of the dorsal fin, called a "spine-brush complex", of unknown function. This is also found in the better known genus Stethacanthus. Remains have only been found near Bearsden in Scotland.[2][3] The genus name is derived from the Ancient Greek “akmon” (“anvil”) + “istion” (“sail”) referring to the appearance of its first dorsal fin.[2] It reached 62 cm (24 in) in length.

[tojskfarnijler]

Apocalypse Jargon: So we're actually making this a series now?

The sky, an ultramarine blue, and the clouds, a rusty red. She saw two endless forces at each other's necks. Lightning and optics, mains hum. Pained wails and a bruising pain, taos hum. At some point it all turns into green noise, one she'd never heard before. Emergence in her dreamscapes, she saw objects in fractions of dimensions, peril with comfort.

Tall lycophytes filter the solar light. The buzz of a giant mayfly. Spoon on a boat made of trilobite shells, it's Basho. The swamp forest was rather shallow, Spoon could see the life beneath the boat. The ride was a first in a while, Spoon was relaxed.. until Lunae came running on water with a freshly caught akmonistion whilst being chased by a giant levitating psionic phantom nervous system. When it got close to Spoon's range, it immediately dissolved into the air. Following O'Donnell's first law, Lunae fell into the swamp's shallows and grabbed a couple extra lungfishes. They were really generous at giving Spoon more food, but always argues between each other on how much they should have. A carbon steel scythe interrupts their lunch. A lower elven deity of death has been mutated, and releases long threads of fate. The surrounding forest cut down in a sweep. Lunae tried to enclose it inside a cavitation bubble, but there isn't enough pressure difference. She grabbed a piece of loose trilobite shell and rocked the boat into the water, utilizing buoyancy to shoot the mutated reaper, cracking its skull. She repeated, but the reaper has tied its thread of fate on her, and she had lost control of her corporeal form. Attempting to drown herself, Basho scoffs at the idea, since she is already a Foraman, she is largely capable of absorbing oxygen in water. Basho realizes that the threads of fate means that it is a deterministic deity, which is his territory. He pulls out carved obsidian and schist coins, and prayed with it. The threads of fate begin to weaken to the point of tangling between trees, causing the reaper to get stuck. The physical tension releases the spiritual bind Lunae was in. Lunae climbed the swamp floor towards the reaper, slightly weakened from reverse osmosis. She yanked one of the threads of fate and began puppeteering the reaper around to smash into the trees and the ground. As she is closer to the ocean, the presence of beach sand become more apparent. She souldrives the sandy loam to crush the reaper's form. This demanifests the lower deity, and leaves behind mutivine bones. They repurposed the scythe into the world's first tumbler. The threads of fate and mutivine bones were perfect for making a soul lantern, Basho was very excited to perform improvised witchcraft for the first time, but Lunae seems to be rather curiojealous. Spoon has been mystified this entire time...

Despite that, her unconscience senses dread again, this time at the zenith. A dwarf planet has been transported here this entire time. Basho was extremely terrified and asked why Lunae did not warn him, she simply thought it was no big deal. The ocean is now visibly meniscus. They were then greeted by the sudden appearance of a Necrozoan knight, an armor made of coal, a body made of extracellular polymeric substance. They telepathically apologized for the inconvenience of the mutated reaper, and vanishes before Lunae can snatch more material. Basho found that habit of hers, impolite. They are now scrambling to find safety, but at this point, the dwarf planet will likely contact the earth in a matter of hours if not minutes. Spoon's electrozom brain has been on overdrive for enough time for her cancerous neurons to develop logic gates baked into her axons. Electroweak nerve cells allowing muonic transmission. This causes her to develop a pathway directly into her unconscience, allowing her to use a larger range of enermotion. While this situation is a checkmate, she found out that the same way she was brought through to here from the escher dimension, she could do the same now. The abundance of curse in the region coupled with her ragement and the untouched qi ocean surrounding them allows her to ignite and conduct a pathway in mid air to a random liminal dreamscape. Lunae and Basho says their goodbyes to that world of theirs, with a slight longing look.

They enter the realm of Child's Play. A favourite spot for witches and wizards to traverse to other dimensions due to ease of access. Paislefishes and Flakinons populate the marinile surfaces. Clocks, sextants, astrolabes, teddy bears, alphabet cubes, compasses, sundials, calendars, festival dolls, miniature houses... They walk across the many carpeted corridors littered with toys and antique items, sometimes meeting with windows of various designs to a sky peppered with clouds. Lunae hates the fuzzy textures, but Basho is in complete awe. They were then greeted by the witch of insanity, this time she promises she means no harm. It advises on the presence of paislesharks as they can deconfold you in a cinch, but also the extremely dense mixture of universe energies and entropies in the air. Lunae proved right, she feels an immense cold feeling, she complained to Basho as to why he didn't tell her of the turbulence, and he thought it was no big deal. They both fought each other as Spoon tuned in. The witch of insanity then grinned, cheshire. She... gave Spoon another problem in her unconscience. She is afflicted with the presence of aqueous mana and crystalline magic in her brain. A third ailment. Lunae and Basho were already at the witch's neck, but Spoon relieved in a better mental clarity. However, something began to rapidly transmute her electrozom skin to form patches of soulburnt blood skin. The witch clarified that such phenomenon is only natural as her body begins to evolve. Her grin is ominous, yet the three aren't able to feel the presence of ill intent. The witch then guides them through the endless corridors.

Spoon is dizzy.

[amnhnyc]

It’s time for Day 6 of 12 Days of Sharks! Meet Akmonistion, an extinct shark relative that lived about 329 million years ago—it went extinct millions of years before dinosaurs evolved. The bulky “brush” on its back was flat on top, like an ironing board, and covered with toothlike denticles. Denticles, which can still be found on sharks today, are hard, toothlike scales that cover the body. 🦈 Learn more about our special exhibition Sharks with the #linkinbio. Photo: D. Finnin/ © AMNH #sharks #naturalhistory #nyc #uws #marinelife #amnh #oceanlife (at American Museum of Natural History) https://www.instagram.com/p/CXryiZer8ze/?utm_medium=tumblr

[sirenemale]

🌻 :)

SMILE

You are going to hear about Eugenoeodontida cause they're my current fixation <3 They are an extremely strange group of shark like prehistoric cartilaginous fish, they have a lot of strange teeth and faces and shapes so I'm just going to list some off!

Helicoprion

Edestus

Sarcoprion

Hybodus

Akmonistion

Ornithoprion

They're funny. If you google any of them there's a huge range of how their tooth whorls or strange teeth are depicted and it's super neat! Helicoprion and Edestus especially have a huge range of how they're drawn and reconstructed.

[literalliterature]

top five carboniferous period animals (marine invertebrate bonus points)

First of all I was very disappointed to remember that kalligrammatids are from the Mesozoic rather than the Carboniferous and so I wouldn't be able to talk about the lacewings that tried so hard to be butterflies. Nevertheless:

1. Arthropleura

[ID: A museum model of an armored millipede several meters long, with grown people nearby for scale. End ID.]

A pedestrian choice? Perhaps. But I cannot deny my desire to sit on the back of one of these things and be carried very slowly through the forest like a child on one of those tiny trains they have in big malls.

2. Megarachne

[ID: An artistic interpretation of a eurypterid, an arthropod with four spindly legs and dot-like eyes. End ID.]

I like that some of the eurypterids during this period decided to branch off from looking at sea scorpions and decided to look like sea spiders instead.

3. Archaeothyris

[ID: A detailed, green-toned drawing of a creature that looks absurdly similar to a lizard but isn't. End ID.]

Oldest known synapsid. I appreciate the members of the mammal lineage who look indistinguishable from lizards. Good prelude to my beloved Permian.

4. Symmorium

[ID: A drawing of a dull purplish shark with large eyes and a wide mouth that appears to be grinning. End ID.]

"hehehehe"

5. Akmonistion

[ID: An illustration of a shark with bristles on its head and on its flat-topped dorsal fin. End ID.]

Tbh I just feel bad for it.

[fishteriously]

ok but. holocephalans do have denticles. along the lateral line canal, sometimes on the back esp in youngsters, and on the head and pelvic claspers! here's some pictures of them from a dissection i did of a Hydrolagus - left from the rim of the lateral line, right from a pelvic clasper.

Fossil holocephalans have even more and weirder denticles - see the spine brush complex & top of the head of Carboniferous holocephalans like Akmonistion or Stethacanthus:

Even Cladoselache, one of the best described early symmoriform holocephalans (close the the elasmobranch-holocephalan split) had denticles along the fin edges and lateral line. Point is, it goes deep. The common ancestor of elasmobranchs and holocephalans most likely had denticles, and their distribution was reduced (or lost, in some cases) in the chimeras. They don't look like your average selachian ("true shark") denticles:

but that's ok. denticles come in all shapes & sizes :3

Daily fish fact #402

Chimaeras!

Also called ghost sharks. They have interestingly lost the scales other sharks have, also known as denticles! Juvenile chimaeras have denticles on their back, but they lose them as they age.

[daily-mspaint-paleoart]

28/01/25 Akmonistion

[extinctanimals]

Akmonistion, a shark of the early Carboniferous.  Why does it have an anvil on its head, plz LMK.