From the creepiest Cambrian critters to huge marine reptiles, splendidly bizarre sea creatures have inhabited our oceans for over half a billion years. We have put collectively a listing of 25 of the strangest historical sea monsters ever to have lived, all of which went extinct lengthy earlier than people got here alongside.
The one cause we all know that these evolutionary marvels existed is as a result of some left behind fossilized stays in rocks. Trendy researchers are nonetheless deciphering these fossils and making recent discoveries on a regular basis, so make sure you sustain with the newest Dwell Science fossil information.
Plesiosaurs
Plesiosaurs had been a bunch of marine reptiles with boat-like our bodies and 4 flippers. There have been long-necked plesiosaurs (assume historical Loch Ness monster) and short-necked plesiosaurs (think about a Loch Ness monster with a brief neck and an enormous head). Plesiosaurs lived from the Triassic interval (251.9 million to 201.4 million years in the past) till they went extinct alongside the non-avian dinosaurs on the finish of the Cretaceous interval (145 million to 66 million years in the past). They lived the world over’s oceans.Â
“Not solely had been these animals odd in comparison with issues that we have now alive as we speak, however they had been additionally globally distributed and really, very numerous,” Michael Caldwell (opens in new tab), a vertebrate paleontologist on the College of Alberta in Canada, informed Dwell Science. Â
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Tanystropheus hydroides
Michael Caldwell is a professor within the departments of Organic Sciences and Earth & Atmospheric Sciences on the College of Alberta. His analysis profession has broadly focussed on marine reptile evolution, and consists of research on mosasaurs, dolichosaurs, ichthyosaurs, plesiosaurs and extinct snakes.
Tanystropheus hydroides lived within the Tethys Sea off the traditional supercontinent Pangaea, when the entire continents had been joined collectively, throughout the Triassic interval round 242 million years in the past. Researchers recognized these historical marine reptiles from weird fossils positioned on what’s now the border between Switzerland and Italy. That they had bizarre, broomstick-like necks that stretched to 10 toes (3 meters) in size — thrice the size of their torsos.
“Like [long-necked] plesiosaurs, tanystropheids have small heads on the entrance and these tiny, bizarre little our bodies means behind this gigantic neck,” Caldwell mentioned. “They’re ungainly and awkward.”
Helicoprion
Helicoprion, or the “buzz noticed sharks,” was a bunch of shark-like fish with a spiral jaw that made their tooth resemble the sting of a buzz noticed. They inhabited Earth’s oceans from the Devonian interval (419.2 million to 358.9 million years in the past) to the Triassic interval, in keeping with the Australian Museum (opens in new tab). Fossil information point out that these fish grew as much as round 25 toes (7.7 m) lengthy, making them 5 toes (1.5 m) longer than the most important identified fashionable nice white sharks (Carcharodon carcharias). Â Â
Habelia optataÂ
Habelia optata was extra of a mini monster, with a physique size of as much as 1.6 inches (4.1 centimeters). These tiny sea predators had helmet-like heads and creepy mouth appendages for catching and ripping aside their prey. H. optata fossils may be present in British Columbia, Canada, and date again round 505 million years to the Cambrian interval (538.8 million to 485.4 million years in the past), in keeping with the Royal Ontario Museum (opens in new tab).Â
Lyrarapax unguispinus
The Cambrian interval additionally noticed the reign of a claw-faced sea monster that was completely not like something swimming in our oceans as we speak. Lyrarapax unguispinus was one among many weird arthropods that lived throughout the Cambrian interval, however even for its time, this species was unusual. It grew as much as 3.2 toes (1 m) lengthy and had a claw-shaped appendage on the entrance of its head to understand prey. This killer arthropod was one of many world’s first apex predators.Â
Mosasaurs
Mosasaurs is probably not the strangest animals on this listing, however they’re actually worthy of the title “sea monster.” Earlier than they fell to the identical destiny because the nonavian dinosaurs, this group of marine reptiles roamed the world’s oceans, chowing down on nearly something that moved, together with different mosasaurs. A 2014 examine within the journal Proceedings of the Zoological Institute RAS (opens in new tab) estimated that the mosasaur Mosasaurus hoffmanni grew to be round 56 toes (17 m) lengthy.
Associated: This historical sea monster may do the breaststroke
Placodonts
Placodonts had been an order of turtle-like Triassic marine reptiles that lived in what’s now Europe, the Center East and China. Caldwell informed Dwell Science that placodonts “had extremely unhealthy buck tooth that they might have picked apples by way of a picket fence with.” They used their entrance tooth to pluck shells and mollusks off reefs or the ocean ground, and so they had flat crushing plates on the backs of their mouths for munching.Â
Sea scorpionsÂ
Sea scorpions, or eurypterids, had been a bunch of ocean-dwelling arthropods that resembled modern-day scorpions. What made them unusual? Properly, some had been huge in contrast with scorpions dwelling as we speak. For instance, one eurypterid fossil present in New York is estimated to have come from a sea scorpion bigger than a human. Members of this group may exceed 8 toes (2.5 m) in size, in keeping with the Yale Peabody Museum of Pure Historical past (opens in new tab) in Connecticut. Sea scorpions terrorized the seas for greater than 200 million years, till they went extinct on the finish of the Permian interval (298.9 million to 251.9 million years in the past).Â
 Saccorhytus coronarius
Saccorhytus coronarius was primarily a wrinkly sac with no anus (opens in new tab). These weirdos lived throughout the Cambrian interval round 500 million years in the past and are identified from microfossils found in China. The Minion-like creatures might have spent their days catching prey in seafloor sediment, however researchers’ understanding of the animals’ lives is proscribed. They’re believed to be associated to penis worms and dust dragons.Â
Ichthyosaurs
Attempt to image a reptilian model of a dolphin, and you will not be far off the looks of an ichthyosaur. This numerous group of pointed-nose predators advanced to have dolphin- or fish-like our bodies, however they appeared way more menacing. Ichthyosaurs advanced round 250 million years in the past and went extinct round 90 million years in the past. Whereas there have been ichthyosaur species as small as 1 foot (0.3 m) lengthy, the group was dwelling to a number of giants within the late Triassic interval. In 2018, researchers estimated {that a} fossilized jawbone from the U.Ok. belonged to an ichthyosaur that was greater than 85 toes (26 m) lengthy, which is practically the dimensions of a blue whale (Balaenoptera musculus).Â
Tully monsters
The Tully monster (Tullimonstrum gregarium) was a soft-bodied species with primitive eyes on stalks and an extended, skinny appendage that resulted in a claw-like function. These mysterious creatures had been so unusual that researchers as we speak have had bother agreeing on the animals’ place on the tree of life. No matter they had been, these monsters hunted in marine coastal environments 300 million years in the past and are discovered solely in fossils from Illinois, in keeping with the Illinois State Museum (opens in new tab). Â
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Odontochelys semitestaceaÂ
Odontochelys semitestacea swam within the Triassic coastal waters of what’s now China 220 million years in the past. The species was one of many first identified turtles, nevertheless it appeared very completely different from its fashionable family members. Â
“These most historical turtles have gotten the chest piece, or the plastron, however they do not have the carapace on the again,” Caldwell mentioned. “So, right here we have now early variations of turtles which might be missing the turtle shell, the carapace, and are nonetheless toothed.”
Typhloesus wellsi
Typhloesus wellsi left behind such unusual fossils that Simon Conway Morris (opens in new tab), an emeritus professor of paleobiology on the College of Cambridge within the U.Ok., gave them the nickname “alien goldfish” in a 2005 article revealed within the journal Astronomy & Geophysics (opens in new tab). Morris joked that they might have been dropped at Earth by a visiting intergalactic commodore who grew bored with holding them as pets and dumped them right here throughout the Carboniferous interval (358.9 million to 298.9 million years in the past). The species shot a toothy “tongue” out of its intestine to catch prey and will have been an early gastropod.Â
Basilosaurus
Basilosaurus swam by way of the ocean like an enormous sea serpent from 37.8 million to 33.9 million years in the past, with a slender physique that stretched as much as 59 toes (18 m) in size. The title Basilosaurus interprets to “king lizard” as a result of the researchers who named it mistook the large life-form for a marine reptile, like a mosasaur or ichthyosaur. However the species wasn’t a serpent or a lizard; it was a mammal, and a relative of recent whales, in keeping with the College of Michigan’s Museum of Paleontology (opens in new tab).
Fanjingshania renovata
This shark-like fish was heralded as being not like any vertebrate ever found when it was unveiled in 2022. Lined in spiny fins with teeth-like scales and bony armor, Fanjingshania renovata is someplace between a bony fish and a shark on the fish household tree. It lived in what’s now southern China throughout the Silurian interval (443.8 million to 419.2 million years in the past).Â
Opabinia regalis
When paleontologist Harry Blackmore Whittington offered an early reconstruction of Opabinia regalis to a gathering of fellow paleontologists in 1972, everybody within the room laughed, in keeping with the Royal Ontario Museum (opens in new tab). One other small, British Columbian beasty from the center Cambrian, O. regalis had 5 eyes and claws on its lengthy, versatile snout to catch prey. The species swam by way of historical oceans round 505 million years in the past utilizing lateral lobes and a tail fan to steer.
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Archelon ischyros
There’s nothing significantly unusual concerning the sea turtles we see as we speak, however what in the event that they had been larger — like, a lot larger? That may be somewhat odd, proper? Flip again the clock 65 million years, and the ocean featured 15-foot-long (4.6 m) supersize turtles named Archelon ischyros. They might have dwarfed the most important turtles alive as we speak — leatherback turtles (Dermochelys coriacea), which max out at round 5.9 toes (1.8 m) lengthy.
Megalodon
Megalodon (Otodus megalodon) was one other supersize model of a contemporary animal. Fossilized tooth recommend that megalodon, which reigned over ocean ecosystems between round 23 million and a couple of.6 million years in the past, was at the least thrice longer than a contemporary nice white shark, and the largest shark on report. The beast’s precise dimension is disputed in scientific circles, nevertheless it may have been as much as 60 toes (18 m), and even 80 toes (24 m), lengthy. This shark was so large, it may have devoured a contemporary orca (Orcinus orca) in only a few bites.
Titanokorys gainesi
Titanokorys gainesi might have been solely 2 toes (0.6 m) lengthy, nevertheless it was one of many largest predators throughout the Cambrian interval. The early arthropod swam throughout the ocean ground, hoovering up prey like a Roomba and devouring it with a toothy, round mouth. Half-a-billion-year-old fossils from British Columbia reveal that the creature’s helmeted head was disproportionately massive, making up round two-thirds of its complete physique size.
Websteroprion armstrongi
Websteroprion armstrongi was a mighty worm of the Devonian interval and extinct relative of recent marine worms. The carnivore dwarfed its fellow historical worms, with an estimated physique size of as much as 6.6 toes (2 m). It was so massive, in actual fact, that when researchers described the species from Canadian fossils in 2017, it instantly turned the most important marine jawed worm on report. And if an enormous worm weren’t already metallic sufficient, the researchers named its genus Websteroprion after death-metal guitarist Alex Webster from the band Cannibal Corpse.
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Dunkleosteus terrelli
Dunkleosteus terrelli, or “Dunk” for brief, was a bus-size armored fish that lived throughout the Devonian interval. When researchers began discovering Dunk skulls in Cleveland 150 years in the past, they estimated that the creature was 30 toes (9.1 m) lengthy. Nevertheless, a 2023 examine revealed within the journal Range (opens in new tab) discovered that the creatures had been truly extra like 13 toes (4 m) lengthy, however tremendous chunky. D. terrelli was a superpredator, with blade-like jaws for slicing by way of any animal it may digest.Â
Nothosaurs
A 2014 examine revealed within the journal Scientific Reviews (opens in new tab) described a nothosaur species, Nothosaurus zhangi, that had a 26-inch-long (65 cm) decrease jaw and an estimated complete physique size of as much as 23 toes (7 m). These predators propelled themselves by way of the water with their forelimbs and snatched prey with fang-like tooth. N. zhangi lived round 245 million years in the past in what’s now southwestern China.
Dolichosaurs
Dolichosaurs had been slender, serpent-like lizards with small limbs that snaked by way of the water, chasing prey. They lived throughout the Cretaceaous interval and had been found in English fossils within the mid nineteenth century. Caldwell mentioned the most important dolichosaurs he encountered within the fossil report had been solely round 2 toes lengthy, however their necks had been longer than these of recent lizards, and so they contained many extra cervical vertebrae. “That they had this fiendishly lengthy neck, which is weird amongst lizards,” Caldwell mentioned.Â
Diplocaulus magnicornis
Diplocaulus magnicornis stands out amongst even the strangest creatures of the traditional aquatics due to its boomerang-shaped cranium. Researchers aren’t certain why this amphibian advanced such a weird head, nevertheless it most likely performed a job in how the species swam. D. magnicornis lived about 275 million years in the past, throughout the Permian interval, in keeping with the American Museum of Pure Historical past (opens in new tab). The fossils left behind by this species are present in modern-day Texas.Â
Shell-dwelling penis worms
And eventually, there are the ferocious penis worms of the Cambrian interval. Do not let their comical connotations idiot you; these marine worms had been mighty predators 500 million years in the past, with teeth-lined mouths for devouring prey all throughout the ocean. To keep away from turning into prey within the aggressive Cambrian seas, penis worms suited up for defense. A 2021 examine within the journal Present Biology (opens in new tab) discovered that these animals inhabited cone-shaped shells like hermit crabs do. The shell-dwelling penis worm fossils belong to the priapulida group, which incorporates their shell-less dwelling descendants. The title of this group honors the well-endowed Greek god Priapus. Â