#coelacanthiformes

(Sources - 1, 2)

Order: Coelacanthiformes

Common Name: “coelacanths”

Families: 1 - Latimeriidae (only two living species are known today, both from the genus Latimeria)

Anatomy: large, plump body; many lobed fins; tapetum lucidum in eyes; two nostrils and four other external openings

Diet: cuttlefish, squid, snipe eels, small sharks, and other fish

Habitat: reef and volcanic slope habitats between 90 to 200 m (300 to 660 ft) deep, in the western Indian Ocean around the Comoro Islands, Madagascar, and Mozambique (L. chalumnae) and in the waters of north Sulawesi, Papua, Southwest Papua, and North Maluku (L. menadoensis)

Evolved in: Middle Triassic

Propaganda under the cut:

Allenypterus montanus was an unusual early coelacanth that lived during the late Carboniferous, around 324 million years ago, in a tropical bay covering what is now central Montana, USA.

Up to about 15cm long (~6"), its tapering tadpole-like body plan somewhat resembled that of modern knifefishes and featherbacks, with the top part of its tail fin highly elongated into a ribbon-like shape and the rest of its tail fins being vestigial. The distinctive humped shape of its back was also much more pronounced in larger, more mature individuals.

It was probably a fairly slow swimmer, and preserved gut contents suggest it mainly ate small soft-bodied prey.

Its closest known relative seems to have been the eel-like Holopterygius – but since around 60 million years and different continents separated them both, this suggests the existence of a whole ghost lineage of other tapering coelacanths yet to be discovered.

———

NixIllustration.com | Tumblr | Patreon

Like tortoises, coelacanths are extremely long lived. Individuals don't reach sexual maturity until they're around 50, and most can live up to 100!

In fact, coelacanths take their time with just about everything- including pregnancy. Females gestate their young for 5 years, and can carry anywhere from 8 to 26 offspring.

Coelacanths are ovoviviparous, meaning they retain fertilized eggs inside their bodies until they hatch, and then give birth to live young!

Thanks to their three pairs of fins, which are extremely flexible, they can swim in almost any direction- including doing headstands and swimming upside down!

Coelacanths were thought to have gone extinct at the same time as the dinosaurs, around 65 million years ago

In 1938, they were re-discovered by a woman named Marjorie Courtenay-Latimer, who was the curator of the East London Museum in South Africa. Bonus fun fact: she finished writing the paper detailing the species' rediscovery only 4 days before giving birth to her son!

Although coelacanths can grow to be 1.8 m (5.9 ft) long, their brains only take up 2% of their cranial cavity!

Their large size also means that coelacanths have the largest eggs of any fish species, coming in at 9 centimeters (3.5 inches) in diameter and weighing over 325 g (0. 7lbs)!

Most fish have swim bladders filled with air, which helps them to float or sink as needed, but the swim bladders of coelacanths are filled with fat!

Two other characteristics that give the coelacanth the nickname 'living fossil' are the presence of a "rostral organ" in the snout that is part of the electrosensory system, and an intracranial joint or "hinge" in the skull that allows the top portion of the skull to swing upwards and the mouth to open much wider than other fish; neither feature is found in any other living vertebrate!

West Indian Ocean coelacanth (Latimeria chalumnae)

weki meki truly gave the lezzies a gift this yr! i really liked it! i wasnt expecting cool to be that....kinda dark nd sexy considering how light oopsy was but im not mad at the change. cool sounds like a bg song but in a good way like they took the only good things abt bg songs nd then improved on it. their voices sounded amazing they looked good i wanted yoojung to rip me in half. i need to watch the live performances nd look at the choreo bc weme honestly have some of the most interesting dances but they never get the hype. ANYWAYS final verdict:

Coelacanths are represented today by just two surviving species, one in East Africa and one in Indonesia, both very similar in appearance and ecology to each other.

For a long time their lineage was thought to be all "living fossils", retaining the same basic body plan for the last 400 million years – but more recent discoveries have revealed that these fish were actually much more diverse over the course of their evolutionary history.

Holopterygius nudus was a fairly early member of the group, living during the mid-Devonian about 385 million years ago. The only known fossil specimen was discovered in Germany in the 1970s, but it was originally thought to be a different type of fish entirely and wasn't identified as being a coelacanth until over 30 years later.

And compared to its living relatives it was tiny, just 7cm long (2.75"), with a distinctive tapering eel-like tail. Its convergent close resemblance to modern cusk-eels suggest it may have occupied a similar ecological niche, living near the sea floor and hiding in tight spaces like crevices and burrows.

———

here it is! and thank u so much, it means a lot!!! as a poc i only want to put out what i want to see :^) i feel so so honored ty <3