#nautiloidea

[alphynix]

Although the only nautiloids living today have characteristic tightly coiled shells, earlier in their evolutionary history these cephalopods were much more diverse.

And Glossoceras gracile here is an example of one of the more unusual groups of nautloids: the ascocerids.

Living during the Late Silurian, about 422 million years ago, in wheat is now Gotland, Sweden, Glossoceras was only around 5cm long as an adult (~2"). Like other ascocerids it started out its life looking like a fairly standard early nautiloid, with a long straight shell that curved slightly upwards, but as it approached maturity things got weird – the front part of the shell grew out into a much more bulbous flask-like shape, and the old juvenile section broke off entirely.

The gas-filled buoyancy chambers of its adult shell were positioned directly above its body chamber rather than behind like in other nautiloids, giving it very good stability in the water. The shell walls were also very thin and lightweight, which would have made it a much more maneuverable swimmer.

———

NixIllustration.com | Tumblr | Patreon

[sina-man]

Umbeloceras

[totally-not-a-raccoon-thief]

Why does he look like an orthocereas nautiloidea from the ordovician

[bestanimal]

Round 3 - Cephalopoda - Nautilida

(Sources - 1, 2, 3, 4)

Order: Nautilida

Common Name: “nautilus” (pl: “nautiluses” or “nautili”)

Families: 1 - Nautilidae

Anatomy: Smooth external shells with internal chambers, 50-90+ tentacles, toothed radula within parrotlike beak

Diet: crustacean molts, hermit crabs, carrion

Habitat/Range: Indo-Pacific ocean, at depths of several hundred metres

Evolved in: Order Nautilida in the Devonian, Family Nautilidae in the Triassic (230 million years ago)

Propaganda under the cut:

During the Middle Devonian, Nautilus species were more diverse, and their shells were more varied than those found in species of living Nautilus, ranging from curved (cyrtoconic), through loosely coiled (gyroconic), to tightly coiled forms, represented by the Rutoceratidae, Tetragonoceratidae, and Centroceratidae. Only a single genus, Cenoceras, with a shell similar to that of the modern nautilus, survived the Triassic extinction, at which time the entire Nautiloidea almost became extinct. They diversified again, but never reached the extent of diversity they had before the Triassic extinction. The nautilids were not as affected by the end Cretaceous mass extinction as the Ammonoids that became entirely extinct, possibly because their larger eggs were better suited to survive the conditions of that environment-changing event.

Nautiluses are the sole living cephalopods to have external shells. They can withdraw completely into their shell and close the opening with a leathery hood formed from two specially folded tentacles.

The nautilus has the extremely rare ability to withstand being brought to the surface from its deep natural habitat without suffering any apparent damage from the experience. Where fish or crustaceans brought up from such depths inevitably arrive dead, a nautilus will be unfazed despite the pressure change of as much as 80 standard atmospheres (1,200 psi).

Nautiluses have a seemingly simple brain, lacking the large complex brains of octopus, cuttlefish and squid, and had long been assumed to lack intelligence. But recent experiments have shown not only memory, but a changing response to the same event over time.

In a study in 2008, a group of Chambered Nautiluses (Nautilus pompilius) were given food as a bright blue light flashed until they began to associate the light with food, extending their tentacles every time the blue light was flashed. The blue light was again flashed without the food 3 minutes, 30 minutes, 1 hour, 6 hours, 12 hours, and 24 hours later. The nautiluses continued to respond excitedly to the blue light for up to 30 minutes after the experiment. An hour later they showed no reaction to the blue light. However, between 6 and 12 hours after the training, they again responded to the blue light, but more tentatively. The researchers concluded that nautiluses had memory capabilities similar to the "short-term" and "long-term memories" of the more advanced cephalopods, despite having different brain structures.

Female nautiluses spawn once per year and regenerate their gonads, making nautiluses the only cephalopods to be able to breed more than once in their lifetime.

Nautiluses may live for more than 20 years, which is exceptionally lengthy for a cephalopod, many of whom live less than 3 even in captivity and under ideal living conditions. However, nautiluses typically do not reach sexual maturity until they are about 15 years old, limiting their reproductive lifespan to often less than five years.

The osmeña pearl is not actually a pearl, but a jewellery product derived from the iridescent inner layer of the nautilus shell. Nautilus shells are also sold whole, carved as souvenirs, or historically used to make items such as lamps and cups. However, these are not simply shells that wash ashore; the animals are killed for the shell. The low fecundity, late maturity, long gestation period, and long life-span of nautiluses make them vulnerable to overexploitation, and high demand for their ornamental shells is causing population declines. In 2016 all species in the family Nautilidae were added to CITES Appendix II, regulating international trade, though in some places they can still openly be found for sale in tourist areas. The best way to combat nautilus population decline is to stop the demand for these shells.

[captainswaglord500]

Totlohô

Kingdom: Animalia

Phylum: Mollusca

Class: Cephalopoda

Subclass: Nautiloidea

Superorder: Alysidaceratoidea

Order: Paratetrapoda

Superfamily: Cotylopodoidea

Family: Cotylopodidae

Subfamily: Anomaloteuthiinae

Genus: Anomaloteuthis

Species: A. magnificus (”magnificent unusual squid”)

Ancestral species: possibly Plectronoceras cambria

Temporal range: Early Jurassic (Toarcian) to Early Cretaceous (Hauterivian) (180 - 130 mya)

Information:

While humans have long seen themselves as the first and only sapient species to inhabit their planet, in all truth, there existed another in Xenogaea several hundreds of millions of years ago, one whose legacy can still be felt throughout the region untold eons later in their bizarre ruins and artifacts: the Totlohô-tu-Tẋusko/Tẋusko-tu-Totlohô (IPA: /to̞t͡ɬo̞hɔ tu t͡ʃusko̞/ OR /t͡ʃusko̞ tu to̞t͡ɬo̞hɔ/, meaning "ancestor of (the) architect"), better known as simply the Totlohô (/to̞t͡ɬo̞hɔ/, simply meaning "architect").

As soft tissues of this species have only rarely been preserved, and hard tissues consist only of armor plating and beaks, their size and general appearance alone must be inferred purely based on known proportions from living relatives, other members of the aberrant nautiloid clade Alysidaceratoidea, known more colloquially as the shrikehounds. The most reliable size estimate places them at around 12 feet long, 6-7 feet tall, and weighing close to 600 lbs. The appearance of these creatures, based on ancient stone murals, would seem to suggest that they were centaur-like in build, sporting six main limbs along with a menagerie of smaller tentacles around the face, which housed a long, narrow beak with a noticeable underbite. The exact coloration of this species isn’t known, though as murals exist which depict them, it can be inferred that they might have had a similar coloration pattern to living nautili, with a creamy-colored body and eyes with an earthy red shell and head piece.

Living shrikehound species are not particularly vocal, with only the paratetrapods having an analogue to proper vocal cords. This species was presumably vocal in some capacity, though the exact vocalizations cannot be deduced. It has been suggested that like their living relatives, they might have been able to produce clicks, grunts, warbles, rumbles, belches, screeches, and shrieks. It has been suggested, however, that they may have convergently evolved chromatophores like some of their living relatives and may have had a primarily visual language instead, one which has not, as of yet, been decoded.

Much of these organism's general biology is not known conclusively. Most evidence points to a carnivorous diet, consisting mainly of small dinosaurs/paravians, but also other terrestrial nautiloids, small mammals, and a bizarre group of terrestrial acanthodians known as coelospondyls. Though the exact place where they first evolved has yet to be conclusively found, fossilized beaks first appear in the Matansitra Formation in the southwest of the Isle of Perils, though later formations across the entire archipelago show that almost every habitable landmass sported a population of these creatures at one point. Dubious material from areas outside the archipelago, including what is now China and Australia, suggests they may have eventually left the archipelago at some point as well. At their peak during the Kimmeridgian age of the Late Jurassic epoch roughly 150 millions years ago, their population size was likely upwards of 40 million. Very little (if anything) can be inferred about their reproductive biology, though murals would seem to suggest that courtship and copulation was a very long, drawn-out process, treated almost as an art form unto itself. From their closest relatives, it can be inferred that the males, using a modified tentacle, deposited sperm into a small groove on the female’s underside, where it could be absorbed and used to fertilize the eggs. Their clutch size is believed to have been anomalously small compared to other species in their clade, possibly no more than 10 eggs at a time. The young appear to have matured at a similar rate to human young, if not slightly faster. Sexual dimorphism does not appear to be a prominent trait within their species.

Not much can be inferred about the behavior of this species from what remnants have been found, though it can be inferred that they were likely highly social creatures with complex social structures. They appear to have engaged in agrarianism and the farming of other animals in their later stages of societal development, as evidenced by a high correlation in dump beak remains found near dump sites for animal bones and shell, and even built cities. Murals would seem to suggest Totlohô society was ruled by a class of elders, the oldest respective members of their society, while the youngest members formed the work force. Song and dance appear to have been ways to bond with one another, and spirituality played a large part in their society’s function. Warfare appears to have been an isolated phenomenon in their society and frequently on a much smaller scale than as seen in humanity, though there exists some evidence of widespread warfare in the later years of existence. Even in their later stages, when they evidently had significantly advanced technology (or, as the more conspiracy-minded would suggest, magic of some kind), the Totlohô still preferred to build their homes out of stone.

During the later stages of their existence, the Totlohô appear to have dabbled in what appears to be highly-advanced technology or potentially even magic of some kind, as evidenced by massive, seemingly Totlhômade, carved, levitating stones covered in glyphs. In a place known as the Square Chasm (picture below, artwork by Dipfruit), a reportedly supernatural space some weary jungle travelers have stumbled upon near a triple-forked river, one of these stones appears to have formed a perfectly square-shaped pocket dimension around itself, where gravity itself appears to bend to the stone’s whim.

Fossilized beaks and hard shells are really the only physical parts of these creatures to have been preserved, and they are the only indication of their existence outside of aforementioned ruins and murals. Their written languages have yet to be decoded, and there are believed to have been several thousand at a given time. What exactly led to their extinction has yet to be conclusively revealed, though murals seem to suggest that, from their perspective, supernatural forces may have been at play, with recurrent imagery of what appears to be demonic figures showing up across several murals. Another recurrent image in these murals is a white bird-like creature with horns, which some have suggested may be related to the mythical white bird seen in Xenogaean mythology, which was said to herald the apocalypse. While some have suggested that these murals may have been painted by one of the last Totlohô, who had simply gone insane from isolation and began painting their hallucinations, others suggest that there might be a grain of truth in these murals, perhaps a war of apocalyptic scale which engulfed the entire species, the demagogues fueling it being portrayed as demonic figures. What this doesn’t explain, however, are the high number of artifacts which appear to be made from an unknown metallic substance, one which is highly durable and in near-pristine condition hundreds of millions of years later. This substance, referred to colloquially as “anomalous tungsten”, is paradoxically lightweight yet durable with a high melting point, seemingly higher than almost any other known metal or metalloid. As this metal has not been found anywhere on Earth or even in any known compounds on Earth or another planet, this begs the question of how and where the Totlohô obtained this substance, leading to a wide menagerie of conspiracy theories, with everything from extraterrestrials to divine beings being suggested as the source from which they obtained this material. Whatever the case, those who have studied the artifacts have claimed to have had vivid dreams where they spoke to the Totlohô shortly after contact. Perhaps this is just a form of confabulation or merely even group hysteria, but nonetheless, it would appear that even long after the Totlohô have left this world, their legacy still manages to touch the human spirit. Finally, they appear to have domesticated a species of coelospondyl, Platycephale aridus, the so-called “flat-faced coelospondyl” (1st picture below, artwork by me), and another species of shrikehound, which is currently unnamed (2nd picture below, artwork by me). These appear to have been utilized as livestock animals.

[theremaybetears]

Micrographs of radulae of recent cephalopods a) Radula of Nautilus pompilius (Nautilidae, Nautiloidea). UMUT unregistered specimen. From off Suva, Fiji. b) Radula of Japetella diaphana (Octopoda, Amphitretidae). c) Radula of Loligo pealei (Loliginidae, Coleoidea). d) Radula of Dosidicus gigas (Humboldt squid, Ommastrephinae, Coleoidea)

From Isabelle Kruta, Neil H. Landman and Kazushige Tanabe's "Ammonoid Radula" via ResearchGate

[uk-fossils]

RARE Fossil NAUTILUS - NAUTILUS SICULUS – Toarcian, Jurassic – Ilminster, UK – Genuine + COA!

RARE Fossil NAUTILUS - NAUTILUS SICULUS – Toarcian, Jurassic – Ilminster, UK

📜 From the Prestigious Alice Purnell Collection! 📜

✅ 100% Genuine Specimen – Comes with a Certificate of Authenticity (COA)

📏 Scale Rule / Cube = 1cm (Full sizing details in photos)

📸 You will receive the exact fossil shown in the images

⭐ Fossil Overview:

This is a rare and well-preserved nautilus fossil of Nautilus siculus, dating back to the Toarcian Stage of the Jurassic Period (~180 million years ago). It was discovered in Ilminster, United Kingdom, an area renowned for its exceptional fossil specimens from ancient Jurassic seas.

Nautiluses are extinct marine mollusks related to modern-day nautiluses, squids, and octopuses. Unlike ammonites, nautiloids have a simpler, more streamlined shell structure. This particular specimen boasts well-defined whorls, fine preservation, and a stunning natural display.

This fossil originates from the Alice Purnell Collection, one of the largest and most prestigious fossil collections in the world. Fossils from this collection are highly sought after and hold significant paleontological value.

🦖 Geological & Scientific Details:

Species: Nautilus siculus

Group: Cephalopoda (Nautiloidea)

Age: Toarcian, Early Jurassic (~180 Million Years Ago)

Location: Ilminster, United Kingdom

Formation: Toarcian deposits

Preservation: Excellent, with visible shell structure and natural details

This fossil offers a fascinating glimpse into prehistoric marine life, showcasing the evolution of nautiloids during the Jurassic seas.

🛒 Why Buy This Fossil?

✔ RARE Nautilus Fossil – Sourced from Ilminster, UK

✔ Prestigious Alice Purnell Collection provenance – Highly collectible

✔ Authentic Jurassic Fossil – 180-million-year-old prehistoric relic

✔ Perfect for Collectors, Museums, and Educational Displays

✔ 100% Genuine & Certified Fossil – Comes with a Certificate of Authenticity (COA)

✔ Great Investment Piece – Fossils of this rarity and quality are only increasing in value

📦 Shipping & Packaging:

Securely packed to ensure safe arrival

Tracked & insured shipping for peace of mind

Worldwide shipping available! 🌍

🔬 Don’t miss out on this scientifically significant, rare fossil! Perfect for serious collectors, museums, or as a unique display piece.

📥 Buy with confidence – 100% authentic, fully certified, and ready to ship!

🔎 Check out our other fossils & rare specimens!

🔥 RARE Nautilus siculus Fossil – Once it’s gone, it’s gone! 🔥

[o-craven-canto]

Since the numbers are readable, I'll try to reconstruct a caption, too. Mind that many of these relations were later disproven. † marks extinct organisms.

A. Single unspecialized cell B. Morula (a collection of unspecialized cells sticking together) C. Blastula (morula with the formation of an hollow space) D. Gastrula (invagination of the morula to form a proto-gut and proto-mouth) E. Opening of pores in the walls of a gastrula, leading to a proto-sponge F. Gastrula with tentacles, forming a polyp G. Formation of a coelom (organ-containing cavity) in a gastrula from masses of cells, proto-mouth forming the mouth H. Trochophora ciliate larva I. Formation of a coelom from gut pouches, proto-mouth forming the anus J. Dipleurula ciliate larva

Some simple protist that I can't quite recognize

Unicellular flagellate, possibly the parasite Giardia

Paramecium (ciliate)

Naked amoeba

Thecate amoeba

Foraminiferan

Heliozoan

Radiolarian (or maybe 7. Radiolarian and 8. Heliozoan? Not sure)

Flagellate alga, something like Chlamydomonas

Volvox (colonial alga) (the other arrow from 9 goes to plants)

Sponge, probably a Calcarean sponge

Sponge, probably a Demospongian

Sponge, probably a "glassy" Hexactinellid sponge

(I don't recognize this one)

†Archaeocyatha, an extinct sponge-like organism

Colonial hydroid

Probably a Siphonophoran related to the Portuguese man-o'-war? (Looks more like a Graptolith, but that should be closer to starfish)

Jellyfish

†Tabulate coral

Colonial coral (either Octocorallia or Hexacorallia)

Solitary coral, possibly †Rugose coral

Colonial coral (the other type than 20)

Ctenophoran (comb jelly)

Probably a Turbellarian flatworm

Cestoda (tapeworm)

Probably Nematoda (roudworm)

Hirudinea (leech)

Polychaeta (ragworm)

Oligochaeta (earthworm)

Rotifera

†Trilobite

†Chasmataspidida

†Eurypterida (sea scorpion)

Xiphosura (horseshoe crab)

Scorpiones (scorpion)

Araneae (spider)

Acari (mite)

Anostraca (fairy shrimp)

Copepoda

Ostracoda (clam shrimp)

Cirripedia (barnacle)

Phyllocarida

Syncarid

Decapoda (lobster)

Amphipoda (sandhopper)

Isopoda (wood louse)

†Aysheaia

Onychophora (velvet worm)

Myriapoda (centipede)

Thysanura (silverfish)

†Palaeodictyoptera

Hemiptera? ("true bugs")

Orthoptera (grasshopper)

Phthiraptera (louse)

Lepidoptera (butterfly)

Coleoptera (beetle)

Hymenoptera (wasp)

Siphonaptera (flea)

Diptera (fly)

Polyplacophora (chiton)

Bivalvia (clam)

Prosobranchia (sea slug)

I don't recognize this one

Nudibranchia (sea slug)

Pulmonata (snail)

†Orthoceratida

Nautiloidea

†Ammonoidea

Coleoidea (squid)

Inarticulate brachiopod (Lingula)

†A presumably extinct brachiopod I don't recognize

Articulate brachiopod (Terabratula?)

Phoronida or Bryozoa

†Homalozoa (Cothurnocystis)

†Another Homalozoa

Crinoidea (sea lily)

Asteroidea (starfish)

Echinoidea (sea urchin)

Holothuroidea (sea cucumber)

Hemichordata (acorn worm)

Chaetognatha (arrow worm)

Tunicata (sea squirt)

Cephalochordata (lancelet)

†Pteraspidomorphi (Anglaspis)

Cyclostomata (lamprey)

†Placodermi (Bothriolepis)

Chodrichthyes (shark)

†Early Actinopterygian

Chondrostei (sturgeon)

Holostei (alligator gar)

Teleostei (mackerel)

†Eusthenopteron

Dipnoi (lungfish)

†Temnospondyli

Lissamphibia (newt)

Anura (frog)

Testudinata (tortoise)

†Ichthyosauria

Crocdylia (crocodyle)

Squamata (lizard)

Squamata (snake)

†Dinosauria (Triceratops)

†Pterosauria

†Therapsida (Biarmosuchus?)

Aves (seagull)

Monotremata (platypus)

Marsupialia (kangaroo)

Chiroptera (bat)

Rodentia (squirrel)

Artiodactyla (gazelle)

Carnivora (jaguar)

Cetacea (orca whale)

†Plesiadapis

Hominidae (chimpanzee)

Hominidae (human)

"Chart of Evolution" by Borgny Bay (1937), Paleontological Museum, University of Oslo.

[silurfilur-blog]

Phragmoceras

Look at the darker spots, could it be pigment telling us about this creatures original pattern?

The shell doesn’t seem to be intact on the other side so my guess is that this side was preserved thanks to  being buried in sediment.

Found this one in Ireviken, Gotland, Sweden

[jaubaius]

Having survived relatively unchanged for hundreds of millions of years, nautiluses represent the only living members of the subclass nautiloidea, and are often considered "living fossils".

[shaanjeevanecofarm]

The Nautilus. The Sailor. The nautilus is a cephalopod, a distant cousin to squids, octopus, and cuttlefish. Unlike its color-changing cousins, though, the soft-bodied nautilus lives inside its hard external shell. The shell itself has many closed interior chambers or “compartments.” The nautilus uses jet propulsion to roam the ocean deep.

Having survived relatively unchanged for hundreds of millions of years, nautiluses represent the only living members of the subclass nautiloidea, and are often considered "living fossils". We found the shell on our little mangrove beach and feel so immensely lucky and fortunate to been able to see back in time.

[alphynix]

Almost-Living Fossils Month #12 -- The Other Nautiluses

Nautiloids are represented today by just two living genera (Nautilus and Allonautilus), but they have a lengthy evolutionary history going back almost 500 million years.

The peak of their diversity was during the first half of the Paleozoic, with many different shapes of shells from coiled to straight, then they began to decline when their relatives the ammonites and coleoids appeared and began to compete for similar ecological niches. Although a few groups of nautiloids survived through the end-Permian mass extinction, most of them had disappeared by the end of the Triassic, leaving just one major remaining lineage known as the Nautilina (or Nautilaceae).

During the mid-to-late Jurassic (~165 mya) two new groups split away from the ancestors of the modern nautiluses -- the cymatoceratids and the hercoglossids.

Cymatoceratids such as Cymatoceras sakalavum here had shells with a ribbed texture. Living during the Early Cretaceous, about 112-109 million years ago, this particular species is known from Japan and Madagascar and could reach a shell diameter of over 15cm (6″).

Hercoglossids, meanwhile, were much more smooth in appearance, but both groups also had more complex undulating sutures between their internal chambers than modern nautiluses do.

These nautiluses made it through the end-Cretaceous mass extinction and had a brief period of renewed success, filling the ecological roles left vacant by the extinct ammonites. But by the end of the Oligocene (~23 mya) both the cymatoceratids and hercoglossids vanished, possibly unable to deal with cooling oceans and the evolution of new predators.

Some of the hercoglossids’ Cenozoic descendants, the aturiids, managed to last a little longer into the Early Pliocene (~5 mya) before another period of cooling seems to have finished them off. Past that point, all that was left of the once-massive nautiloid lineage were their cousins the nautilids, who gave rise to today’s few living representatives.

(It’s also worth noting that the classification of the cymatoceratids seems to be in flux right now. Some paleontologists currently don’t consider Cymatoceras itself to actually be part of the group, instead being a nautilid much closer related to modern nautiluses. If this is the case then the cymatoceratids may not have actually survived past the Late Cretaceous -- but the Cymatoceras genus alone still counts as an “almost-living” fossil since its various species ranged from the Late Jurassic to the Late Oligocene.)

[sina-man]

Cymatoceras paralibanoticum

[encyclopika]

Animal Crossing Fish - Explained #91

Brought to you by a marine biologist with another one of her faves…

CLICK HERE FOR THE AC FISH EXPLAINED MASTERPOST

This was also requested by my good friend @pandoramusicbox09​! If you would like to see something specific, please send me an ask! :D

I don’t know if its obvious, but I love weird, unique animals. I have a vivid memory of my grandmother buying me a stuffed frilled lizard because she, and I quote, “think[s] it’s scary, so I know you would love it.” The Chambered Nautilus isn’t so scary as it’s just a blast-from-the-past kind of animal. Weird, Unique. Demonstrably beautiful. We’ve actually briefly spoken about the nautilus and how its kind survived the extinctions that wiped out the very similar Ammonites. Now, today, we’ll talk about how different they are from other Cephalopods, the octopuses, squid, and friends.

This one is kind of rare. Like the Vampire Squid, you may have to stay in the water for an extended period of time to catch this. It’s not ridiculously fast, so at least you have that going for you. 

Nautilids are cephalopods, part of the Mollusks, but are very far removed from the others in their own subclass Nautiloidea. In the past, they were much more diverse, with over 2000 species across time that we know about. Nowadays, most nautilids inhabit great depths (which explains why they are put into the deep-sea tank in the museum) and carry out vertical migrations for food and for escaping predators. Vertical migrations, in which animals in the sea travel up from depth and then back down again, typically over the course of a day, are seen across species that use the deep, dark depths as a cover from predators found in the euphotic (always light) depth range of the ocean. The best known nautilid, and perhaps the most common, is the Chambered Nautilus, Nautilus pompilius, native to much of the South Pacific. They are mainly scavengers, but have no problem hunting crustaceans.

By Profberger at English Wikipedia, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=6428108

How the nautilus moves up and down on its vertical migration is simply amazing, because it doesn’t swim - it floats! The shell is where this magic happens. The animal actually doesn’t occupy most of it’s shell. As it grows, it moves all of its internal organs into the very last, open chamber where its eyes, mouth, siphon, and tentacles (up to 90!!!) stick out for more familiar processes, like feeding. The rest of the chambers are for buoyancy. Take a look at the picture below for reference to what I’m talking about.

By Chris 73 / Wikimedia Commons, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=19711

Those other chambers are filled with fluid. The nautilus can change the density of the fluid inside, as well as fill them with gases by ways of an organ called the siphuncle that extends into the chambers for this function (and if you want to know the exact science of how that’s done, this website does a better job of explaining it than I can). Doing this effectively allows the nautilus to float up towards the surface, or sink down into the depths effortlessly and at will. 

I really can’t think of any other animal that does this, so again, Mollusks, man. Diverse and cool af. 

Of course, you can guess with such a beautiful and unique shell, humans have taken notice. All nautilus species are considered Vulnerable due to collection for their shells to make into jewelry and decoration. Nautilus shells are often seen in historical artifact collections from the Renaissance, and they have been the subject of a number of art pieces through history.  

And there you have it. Fascinating stuff, no?

[rjzimmerman]

Some weird shit in this article. Here, I pick on three of these creatures and post the photo and the story. Click/tap on the caption to learn about the rest.

Nautilus

The nautilus represents the only living member of the subclass Nautiloidea. The nautiluses are cephalopods that retain an outer shell unlike other distantly related animals such as squid and octopus.

Their beautiful shells have inspired many artists over the centuries, and they are also among the finest natural examples of a logarithmic spiral or the golden ratio.

Because of their shells, the fossils of nautiluses are easier to come by than remains of other cephalopods, and fossil hunters have discovered ancient shells dating back at least 500 million years.

Purple frog

Discovered as recently as 2003, this living fossil has been described by researchers as a "bloated doughnut with stubby legs and a pointy snout." Looking at this portly purple creature, it's hard to disagree with that assessment. Even more bizarre, its cry sounds like that of a chicken.

Though found in India, its closest living relatives can only be found on the Seychelles islands, meaning these frogs have been around for at least 100 million years, when India, Madagascar and Seychelles were connected as a single land mass.

Hoatzin

These odd-looking, pheasant-sized birds are arguably the most debated living birds because their evolutionary tree is missing so many branches.

It is the only member of its family (Opisthocomidae), though some taxonomists also place them in their own order. They retain some characteristics that are not found in any other birds. For instance, as chicks they still retain claws on the ends of their wings, which aid them in climbing and clinging to trees.

Regardless of how they fit into the evolutionary picture, they are stunning ancient animals.

[uk-fossils]

RARE Fossil NAUTILUS PSEUDOLEGANS – Upper Toarcian, Jurassic – Byfield, Northants, UK – Genuine + COA!

RARE: Fossil Nautilus Pseudolegans – Upper Toarcian, Jurassic – Byfield, Northants, UK

📜 From the Prestigious Alice Purnell Collection! 📜

✅ 100% Genuine Specimen – Comes with a Certificate of Authenticity (COA)

📏 Scale Rule / Cube = 1cm (Full sizing details in photos)

📸 You will receive the exact fossil shown in the images

⭐ Fossil Overview:

This is a RARE and exceptionally preserved Nautilus pseudolegans fossil, dating back to the Upper Toarcian Stage of the Early Jurassic Period (~180 million years ago). It was discovered in Byfield, Northants, United Kingdom, a well-known site for exceptional Jurassic fossil discoveries.

Nautilus pseudolegans is a species of nautiloid, an ancient cephalopod closely related to modern nautiluses and ammonites. Unlike ammonites, nautiloids have a more simple, less intricate shell structure, but their evolutionary success has allowed their lineage to persist into the present day. This fossil displays remarkable preservation with distinct shell patterns, offering a rare glimpse into the marine life of the Jurassic seas.

This fossil originates from the Alice Purnell Collection, one of the largest and most prestigious fossil collections in the world. Fossils from this collection are highly collectible and hold significant paleontological value.

🦖 Geological & Scientific Details:

Species: Nautilus pseudolegans

Group: Nautiloidea (Cephalopoda)

Age: Upper Toarcian, Early Jurassic (~180 Million Years Ago)

Location: Byfield, Northants, United Kingdom

Fossil Features: Well-preserved shell structure with clear growth lines

Preservation: Outstanding condition with intricate natural details

This fossil provides invaluable insight into the Jurassic marine environment, shedding light on the survival and adaptation of early cephalopods.

🛒 Why Buy This Fossil?

✔ RARE Nautilus Pseudolegans Fossil – Sourced from Byfield, Northants, UK

✔ Prestigious Alice Purnell Collection provenance – Highly collectible

✔ Authentic Jurassic Fossil – 180-million-year-old prehistoric relic

✔ Perfect for Collectors, Museums, and Educational Displays

✔ 100% Genuine & Certified Fossil – Comes with a Certificate of Authenticity (COA)

✔ Great Investment Piece – Fossils of this rarity and quality are only increasing in value

📦 Shipping & Packaging:

Securely packed to ensure safe arrival

Tracked & insured shipping for peace of mind

Worldwide shipping available! 🌍

🔬 Don’t miss out on this scientifically significant, rare fossil! Perfect for serious collectors, museums, or as a unique display piece.

📥 Buy with confidence – 100% authentic, fully certified, and ready to ship!

🔎 Check out our other fossils & rare specimens!

🔥 RARE Nautilus Pseudolegans Fossil – Once it’s gone, it’s gone! 🔥