Prehistoric Turtle Pictures and Profiles

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Meet the Turtles of the Mesozoic and Cenozoic Eras

Wikimedia Commons

Ancestral turtles and tortoises branched off from the mainstream of reptile evolution hundreds of millions of years ago, and have persisted pretty much unchanged down to the present day. On the following slides, you'll find pictures and detailed profiles of over a dozen prehistoric turtles of the Mesozoic and Cenozoic Eras, ranging from Allaeochelys to Stupendemys.

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Allaeochelys. Wikimedia Commons

Name: Allaeochelys; pronounced AL-ah-ee-OCK-ell-iss

Habitat: Swamps of Western Europe

Historical Epoch: Middle Eocene (47 million years ago)

Size and Weight: About one foot long and 1-2 pounds

Diet: Fish and small marine organisms

Distinguishing Characteristics: Moderate size; semi-hard shells

Over the last few hundred years, naturalists, paleontologists, and amateur enthusiasts have identified millions of fossils spanning the entire history of vertebrate life on earth, from the earliest fish to the precursors of humans. In all that time, only a single species has been found preserved in the act of mating: Allaeochelys crassesculptata, a difficult-to-pronounce, foot-long Eocene turtle that, roughly speaking, was somewhere between hard-shelled and soft-shelled varieties. Scientists have identified no less than nine conjoined male-female Allaeochelys pairs from German's Messel deposits; this wasn't some kind of Eocene orgy, however, since the duos died at different times.

How did Allaeochelys wind up being fossilized in flagrante delicto? Well, being a turtle certainly helped, since carapaces have a better chance of persisting over millions of years in the fossil record; also, this particular species of turtle may have needed a longer time than usual to consummate its relationships. What happened, it seems, is that the male and female Allaeochelys hooked up in fresh water, and then became so consumed and/or entangled in the act of mating that they drifted off into poisonous parts of the prehistoric pond, and perished.

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Archelon. Wikimedia Commons

The giant Archelon differed significantly from modern turtles in two ways. First, this two-ton testudine's shell wasn't hard, but leathery, and supported by a skeletal framework underneath; and second, it possessed unusually wide flipper-like arms and legs.

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Carbonemys. Wikimedia Commons

The one-ton prehistoric turtle Carbonemys shared its South American habitat with the one-ton prehistoric snake Titanoboa, a mere five million years after the dinosaurs went extinct—and these two reptiles may occasionally have engaged in combat.

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Colossochelys. American Museum of Natural History

Name: Colossochelys (Greek for "colossal shell"); pronounced coe-LAH-so-KELL-iss

Habitat: Shores of central Asia, India and Indochina

Historical Epoch: Pleistocene (2 million years ago)

Size and Weight: About eight feet long and one ton

Diet: Plants

Distinguishing Characteristics: Large size; thick, stumpy legs

As huge as it was, the eight-foot-long, one-ton Colossochelys (formerly designated as a species of Testudo) wasn't the biggest prehistoric turtle that ever lived; that honor belongs to the ocean-dwelling Archelon and Protostega (both of which preceded Colossochelys by tens of millions of years). The Pleistocene Colossochelys seems to have made its living much like a modern-day Galapagos tortoise, a slow, lumbering, plant-eating turtle the adults of which are virtually immune to predation. (For comparison, modern Galapagos tortoises weigh about 500 pounds, making them one-quarter the size of Colossochelys.)

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Cyamodus (Wikimedia Commons).

Name: Cyamodus; pronounced SIGH-ah-MOE-duss

Habitat: Shores of western Europe

Historical Period: Early Triassic (240 million years ago)

Size and Weight: About 3-4 feet long and 10 pounds

Diet: Crustaceans

Distinguishing Characteristics: Long tail; prominent shell

When Cyamodus was named, by the famous paleontologist Hermann von Meyer in 1863, this marine reptile was widely considered to be an ancestral turtle, thanks to its testudine-like head and large, bifurcated carapace. On further investigation, though, it turned out that Cyamodus was in fact a type of creature known as a placodont, and thus closely related to other turtle-like reptiles of the Triassic period such as Henodus and Psephoderma. Like these other placodonts, Cyamodus made its living by hovering close to the sea floor, vacuuming up bottom-feeding crustaceans and grinding them between its blunt teeth.

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Eileanchelys. Wikimedia Commons

Name: Eileanchelys (Gaelic/Greek for "island shell"); pronounced EYE-lee-ann-KELL-iss

Habitat: Ponds of western Europe

Historical Period: Late Jurassic (165-160 million years ago)

Size and Weight: About two feet long and 5-10 pounds

Diet: Marine plants

Distinguishing Characteristics: Moderate size; webbed claws

The prehistoric turtle Eileanchelys is a case study in the shifting fortunes of paleontology. When this late Jurassic reptile was announced to the world, in 2008, it was touted as the earliest marine turtle that ever lived, and thus a crucial "missing link" between the terrestrial proto-turtles of the Triassic and early Jurassic periods and later, bigger, fully marine turtles like the end-Cretaceous Protostega. Wouldn't you know it, though, only a few weeks after the debut of Eileanchelys, Chinese researchers announced a marine turtle that lived a whopping 50 million years earlier, Odontochelys. Of course, Eileanchelys remains important from an evolutionary standpoint, but its time in the limelight was definitely over.

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Eunotosaurus. Wikimedia Commons

The striking thing about Eunotosaurus is that it possessed wide, elongated ribs that curved around its back, a kind of "proto-shell" that one can easily imagine evolving (over the course of tens of millions of years) into the giant carapaces of true turtles.

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Henodus. Getty Images

Name: Henodus (Greek for "single tooth"); pronounced HEE-no-dus

Habitat: Lagoons of western Europe

Historical Period: Middle Triassic (235-225 million years ago)

Size and Weight: About three feet long and 10-20 pounds

Diet: Shellfish

Distinguishing Characteristics: Broad, flat shell; toothless mouth with beak

Henodus is an excellent example of how nature tends to produce similar shapes among creatures with similar lifestyles. This marine reptile of the Triassic period looked uncannily like a prehistoric turtle, with a broad, flat shell covering most of its body, short, clawed feet poking out the front, and a small, blunt, turtle-like head; it probably lived like a modern turtle, too, plucking shellfish out of the water with its knobby beak. However, Henodus was very unlike modern turtles in terms of its anatomy and physiology; it's actually classified as a placodont, a family of prehistoric reptiles typified by Placodus.

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Meiolania. Lord Howe Island Museum

Name: Meiolania (Greek for "little wanderer"); pronounced MY-oh-LAY-nee-ah

Habitat: Swamps of Australia

Historical Epoch: Pleistocene-Modern (2 million-2,000 years ago)

Size and Weight: About eight feet long and 1,000 pounds

Diet: Probably fish and small animals

Distinguishing Characteristics: Large size; strangely armored head

Meiolania was one of the largest, and one of the most bizarre, prehistoric turtles in earth's history: this slow-moving denizen of Pleistocene Australia not only sported a huge, hard shell, but its strangely armored head and spiked tail seem to have been borrowed from the ankylosaur dinosaurs that predated it by tens of millions of years. In turtle terms, Meiolania has proven difficult to classify, because as far as experts can tell it neither retracted its head into its shell (like one major type of turtle) nor swung it back and forth (like the other major type). 

When its remains were first discovered, Meiolania was mistaken for a prehistoric species of monitor lizard. That's why its Greek name, which means "little wanderer," echoes Megalania ("great wanderer"), the giant monitor lizard that lived in Australia around the same time. Perhaps Meiolania evolved its impressive armor to avoid being eaten by its larger reptile cousin.

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Odontochelys. Nobu Tamura

Name: Odontochelys (Greek for "toothed shell"); pronounced oh-DON-toe-KELL-iss

Habitat: Shallow waters of eastern Asia

Historical Period: Late Triassic (220 million years ago)

Size and Weight: About 16 inches long and a few pounds

Diet: Small marine animals

Distinguishing Features: Small size; toothed beak; soft shell

When it was announced to the world in 2008, Odontochelys caused a sensation: a prehistoric turtle that preceded the earliest known turtle ancestor, Proganochelys, by 10 million years. As you might expect in such an ancient turtle, the late Triassic Odontochelys possessed some "transitional" features intermediate between later turtles and the obscure prehistoric reptiles of the Permian period from which it evolved. Most notably, Odontochelys had a well-toothed beak (hence its name, Greek for "toothed shell") and a semi-soft carapace, analysis of which has provided valuable clues about the evolution of turtle shells in general. Judging by its anatomy, this turtle probably spent most of its time in the water, a sign that it may have evolved from a marine ancestor.

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Pappochelys (Rainer Schoch).

Pappochelys fills an important gap in turtle evolution: this lizard-like creature lived during the early Triassic period, halfway between Eunotosaurus and Odontochelys, and while it had no shell, its broad, curved ribs were clearly heading in that direction.

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The skull of Placochelys. Wikimedia Commons

Name: Placochelys (Greek for "flat shell"); pronounced PLACK-oh-KELL-iss

Habitat: Swamps of Western Europe

Historical Period: Late Triassic (230-200 million years ago)

Size and Weight: About three feet long and 10-20 pounds

Diet: Shellfish

Distinguishing Characteristics: Flat shell; long arms and legs; powerful jaws

Despite its uncanny resemblance, Placochelys wasn't a true prehistoric turtle, but a member of the family of marine reptiles known as placodonts (other turtle-like examples including Henodus and Psephoderma). Still, animals that pursue similar lifestyles tend to evolve similar shapes, and for all intents and purposes, Placochelys filled the "turtle" niche in the swamps of late Triassic western Europe. In case you were wondering, the first true turtles didn't evolve from placodonts (which went extinct as a group 200 million years ago) but most likely from a family of ancient reptiles known as pareiosaurs; as for the placodonts themselves, they seem to have occupied an early branch of the plesiosaur family tree.

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Proganochelys. American Museum of Natural History

Name: Proganochelys (Greek for "early turtle"); pronounced pro-GAN-oh-KELL-iss

Habitat: Swamps of western Europe

Historical Period: Late Triassic (210 million years ago)

Size and Weight: About three feet long and 50-100 pounds

Diet: Plants

Distinguishing Characteristics: Medium size; spiked neck and tail

Until the recent discovery of Odontochelys, Proganochelys was the earliest prehistoric turtle yet identified in the fossil record—a three-foot-long, well-carapaced reptile that lumbered across the swamplands of late Triassic western Europe (and probably North America and Asia as well). Startlingly for such an ancient creature, Proganochelys was almost indistinguishable from a modern turtle, with the exception of its spiked neck and tail (which meant, of course, that it couldn't retract its head into its shell and needed some other form of defense against predators). Proganochelys also possessed very few teeth; modern turtles are completely toothless, so you shouldn't be surprised that the even earlier Odontochelys ("toothed shell") was well-supplied on the dental front.

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Protostega. Wikimedia Commons

Name: Protostega (Greek for "first roof"); pronounced PRO-toe-STAY-ga

Habitat: Shorelines of North America

Historical Period: Late Cretaceous (70-65 million years ago)

Size and Weight: About 10 feet long and two tons

Diet: Probably omnivorous

Distinguishing Characteristics: Large size; strong front flippers

Dinosaurs weren't the only plus-sized reptiles to dominate the late Cretaceous period; there were also huge, sea-dwelling prehistoric turtles, one of the most common of which was the North American Protostega. This 10-foot-long, two-ton turtle (second in size only to its close contemporary Archelon) was an accomplished swimmer, as evidenced by its powerful front flippers, and Protostega females were probably capable of swimming for hundreds of miles in order to lay their eggs on land. Befitting its size, Protostega was an opportunistic feeder, snacking on everything from seaweed to mollusks to (perhaps) the corpses of drowned dinosaurs.

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Psephoderma. Nobu Tamura

Like its fellow placodonts, Psephoderma doesn't appear to have been a very fast swimmer or especially well suited to a full-time marine lifestyle—which may be the reason all of these turtle-like reptiles went extinct at the end of the Triassic period.

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Puentemys. Edwin Cadena

Name: Puentemys (Spanish/Greek for "La Puente turtle"); pronounced PWEN-teh-miss

Habitat: Swamps of South America

Historical Epoch: Middle Paleocene (60 million years ago)

Size and Weight: About eight feet long and 1,000-2,000 pounds

Diet: Meat

Distinguishing Characteristics: Large size; unusually round shell

Every week, it seems, paleontologists discover a new plus-sized reptile that prowled the warm, wet swamps of middle Paleocene South America. The latest entry (hot on the heels of the even bigger Carbonemys) is Puentemys, a prehistoric turtle that was distinguished not only by its enormous size but by its unusually large, round shell. Like Carbonemys, Puentemys shared its habitat with the biggest prehistoric snake yet identified, the 50-foot-long Titanoboa. (Oddly enough, all of these one- and two-ton reptiles thrived only five million years after the dinosaurs went extinct, a good argument that size alone was not the cause of the dinosaurs' demise.)

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Puppigerus. Wikimedia Commons

Name: Puppigerus (Greek derivation uncertain); pronounced PUP-ee-GEH-russ

Habitat: Shallow seas of North America and Eurasia

Historical Epoch: Early Eocene (50 million years ago)

Size and Weight: About three feet long and 20-30 pounds

Diet: Plants

Distinguishing Characteristics: Large eyes; flippered front legs

Although Puppigerus was far from the biggest prehistoric turtle that ever lived, it was one of the best-adapted to its habitat, with unusually large eyes (to gather in as much light as possible) and a jaw structure that prevented it from inhaling water. As you may already have guessed, this early Eocene turtle subsisted on marine vegetation; its relatively undeveloped hind limbs (its front legs were much more flipper-like) indicate that it spent a significant amount of time on dry land, where females laid their eggs.

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Stupendemys. Wikimedia Commons

Name: Stupendemys (Greek for "astonishing turtle"); pronounced stu-PEND-eh-miss

Habitat: Rivers of South America

Historical Epoch: Early Pliocene (5 million years ago)

Size and Weight: About nine feet long and two tons

Diet: Marine plants

Distinguishing Characteristics: Large size; six-foot-long carapace

The largest freshwater prehistoric turtle that ever lived—as opposed to slightly bigger saltwater turtles like Archelon and Protostega—the aptly named Stupendemys possessed a six-foot-long shell, the weight of which helped it to hover below the surface of rivers and feast on aquatic plants. To judge by its oversized anatomy, Stupendemys wasn't the most accomplished swimmer of the Pliocene epoch, a clue that the tributaries it lived in were broad, flat, and slow (like stretches of the modern Amazon) rather than fast and churning.

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Strauss, Bob. "Prehistoric Turtle Pictures and Profiles." ThoughtCo, Apr. 5, 2023, Strauss, Bob. (2023, April 5). Prehistoric Turtle Pictures and Profiles. Retrieved from Strauss, Bob. "Prehistoric Turtle Pictures and Profiles." ThoughtCo. (accessed June 6, 2023).