Explore reptiles including turtles, snakes, lizards, and crocodilians, with species profiles covering size, habitat, lifespan, traits, and IUCN status.
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Testudinata is commonly known as turtles, and all its members are the oldest reptiles in existence. They are characterized by a very strong shell on their bodies. When attacked, the turtle can retract its head, tail and limbs into the shell. Most turtles are carnivorous. Turtles can usually live on land and in water, and there are also sea turtles that live in the sea for a long time. Turtles are also long-lived animals, and some live for more than a hundred years in the natural environment.
Taxonomic Placement
Testudines (also referred to as Chelonia in some classifications) is an order of Reptilia (reptiles) that includes all extant and extinct turtles, tortoises, and terrapins. With around 350 living species, they inhabit freshwater, marine, and terrestrial environments in tropical, temperate, and even high-elevation regions worldwide.
Prominent Morphological Features
Carapace and Plastron: The most distinctive attribute is the hard shell composed of an upper carapace (formed by expanded ribs and vertebrae) and a lower plastron, often covered by horny scutes or leathery skin.
Neck Retraction: Based on how the neck is retracted or bent sideways, turtles are divided into two main suborders: Cryptodira (hidden-necked turtles) and Pleurodira (side-necked turtles).
Toothless Jaws: Turtles lack true teeth, instead bearing sharp, horn-like beaks for feeding.
Longevity and Growth: Many Testudines species exhibit long lifespans and slow growth rates; some sea turtles and giant tortoises can live for decades or even over a century.
Ecological Habits
Habitat Range: Includes marine (e.g., sea turtles), freshwater (e.g., softshell turtles, pond turtles), and terrestrial (e.g., tortoises) habitats.
Varied Diets: Some are strictly herbivorous (many tortoises), others are omnivorous (certain freshwater turtles), and some are carnivorous (softshells, snapping turtles, leatherback turtles, etc.).
Reproduction: All are oviparous, laying eggs on land or sandy beaches. The hatchlings receive no parental care post-hatching.
Role in Food Webs
Freshwater and marine turtles often act as mid-level predators, scavengers, or algae grazers, helping maintain aquatic ecosystems. Tortoises can be influential herbivores in grasslands and deserts, aiding seed dispersal and soil turnover.
Economic and Cultural Value
Fisheries and Medicinal Use: Some turtles (like softshell turtles, certain freshwater species) are harvested for food or used in traditional medicine.
Pets and Ornamental Species: Many species (e.g., red-eared sliders, Asian box turtles, sulcata tortoises) appear in the pet trade, which can raise concerns regarding invasive species or illegal trafficking.
Cultural Symbol: Turtles often symbolize longevity and resilience in various cultures, while sea turtles hold important roles in marine ecotourism and folklore.
Fossil Record and Early Origins
Turtles emerged as early as the Late Triassic (over 200 million years ago), as evidenced by fossils like Odontochelys, which had partly formed shells.
By the Jurassic, stem turtles like Proganochelys displayed a more complete shell, although retaining some primitive traits. These fossils illustrate the evolutionary path from thickened ribs and dermal plates to the robust shells we see today.
Division into Hidden-necked and Side-necked Turtles
The difference in neck retraction strategy leads to two main lineages:
Cryptodira: The majority of modern turtles (sea turtles, tortoises, freshwater turtles) retract their necks straight back into the shell.
Pleurodira: Fewer species found mainly in the Southern Hemisphere (snake-necked and side-necked turtles) bend their necks sideways to tuck it under the shell margin.
This divergence dates back to the Late Jurassic or mid-Cretaceous, with each lineage evolving extensively on different continents.
Modern Diversity and Distribution
Through subsequent geological periods, tectonic shifts and climatic changes allowed turtles to expand into marine, riverine, wetland, and desert habitats.
Human activities (hunting, habitat destruction, global trade) and climatic changes now pose significant threats to many turtle populations, placing numerous species under endangered or protected status.
| Family | Representative Genus | Example Species | Distribution & Notes |
|---|---|---|---|
| Chelidae (Austro-American Side-necked Turtles) | Chelus (Mata mata), Chelodina (Long-necked turtles), etc. | Mata mata (Chelus fimbriata), Australian long-necked turtle (Chelodina longicollis), etc. | Found in South America and Australia; notably long necks that fold sideways, some have very unusual appearances. |
| Pelomedusidae (Afro-American Sideneck Turtles) | Pelomedusa (African Helmeted Turtle), Pelusios, etc. | African helmeted turtle (Pelomedusa subrufa), etc. | Mostly in Africa, parts of South America and Madagascar; neck folds to the side rather than fully retracting. |
| Podocnemididae (River Turtles) | Podocnemis (South American River Turtles), etc. | Yellow-spotted river turtle (Podocnemis unifilis), etc. | Large, riverine turtles found in South American basins and Madagascar; many species are big-bodied and aquatic. |
| Family | Representative Genus | Example Species | Distribution & Notes |
|---|---|---|---|
| Cheloniidae (Sea Turtles) | Chelonia (Green Sea Turtle), Eretmochelys (Hawksbill), Caretta (Loggerhead), etc. | Green sea turtle (Chelonia mydas), Hawksbill (Eretmochelys imbricata), Loggerhead (Caretta caretta), etc. | Occupy tropical/subtropical oceans worldwide; threatened by fisheries bycatch, marine pollution, coastal habitat loss. |
| Dermochelyidae (Leatherback Sea Turtle) | Dermochelys (Leatherback Turtle) | Leatherback turtle (Dermochelys coriacea) | The largest sea turtle; unique leathery shell instead of horny scutes; jellyfish specialist; also endangered globally. |
| Chelydridae (Snapping Turtles) | Macrochelys (Alligator Snapping Turtle), Chelydra (Common Snapping Turtle) | Alligator snapping turtle (Macrochelys temminckii), Common snapping turtle (Chelydra serpentina) | Native to North America; large freshwater turtles with strong bites and aggressive temperament. |
| Trionychidae (Softshell Turtles) | Pelodiscus (Chinese Softshell), Apalone (American Softshell), Rafetus, etc. | Chinese softshell turtle (Pelodiscus sinensis), Spiny softshell (Apalone spinifera), etc. | Soft, leathery carapace; well-adapted for ambush hunting and burrowing; found in Asia, Africa, North America. |
| Emydidae (Pond and Box Turtles) | Trachemys (Sliders), Emys (European Pond Turtle), Graptemys (Map Turtles), etc. | Red-eared slider (Trachemys scripta elegans), European pond turtle (Emys orbicularis), etc. | Mostly in North America and parts of Europe/North Africa/Asia; popular in pet trade. Red-eared sliders can be invasive. |
| Testudinidae (Tortoises) | Testudo (Mediterranean tortoises), Geochelone (Giant tortoises), Gopherus (Gopher tortoises), etc. | Sulcata tortoise (Centrochelys sulcata), Galápagos tortoise (Chelonoidis niger), etc. | Terrestrial species with strong, columnar limbs; found in arid/semi-arid regions worldwide; some are extremely long-lived. |
| Geoemydidae (Leaf and Pond Turtles) | Mauremys (Asian Pond Turtle), Cuora (Asian Box Turtle), Sacalia, Chinemys, etc. | Asian leaf turtle (Mauremys mutica), Yellow-margined box turtle (Cuora flavomarginata), etc. | Mostly Asian distribution; many species threatened by habitat loss and over-collection for food or medicine. |
| Dermatemydidae (Mesoamerican River Turtle) | Dermatemys (Giant River Turtle) | Central American river turtle (Dermatemys mawii) | Endemic to river systems in Central America; extremely endangered due to limited distribution and exploitation. |
Multiple Evolutionary Events Shaping Global Distribution
The fossil record of turtles dates back to the Late Triassic, revealing the earliest shells and subsequent division into the hidden-neck (Cryptodira) and side-neck (Pleurodira) lineages.
These lineages diversified into marine, freshwater, and terrestrial habitats on different continents across geological time.
Ecology and Human Interaction
Turtles play vital roles in marine and freshwater ecosystems (e.g., sea turtles controlling jellyfish populations, softshells scavenging organic matter). Tortoises are key herbivores in deserts/grasslands.
Overexploitation (hunting, trade), habitat loss, and pollution threaten many turtle species, making conservation efforts vital.
Conservation and the Future
Many sea turtles and numerous freshwater/terrestrial turtles are listed under international conventions or on endangered species lists. Conservation efforts include protected areas, nesting beach patrols, captive breeding, and release programs.
Ongoing genetic and phylogenetic research refines our understanding of turtle relationships, guiding taxonomy, conservation priorities, and strategies.
This overview analyzes the historical evolution, main classifications, and roles of the order Testudines in ecology and human society. If you need to get more detailed information on the morphology, distribution, and conservation status of specific species, you can refer to local herpetological records, reports from wildlife conservation organizations, and the latest molecular systematics research. I hope this "Classification of Testudines" can provide you with easy-to-understand and informative popular science.
Search the animals shown on this page or narrow them by IUCN conservation code.
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Dermochelys coriacea，Leatherback Turtle，Leatherback turtle, seven-winged turtle, sampan turtle, swallow turtle, leatherback turtle
The leatherback turtle is large and is the largest turtle in the world. It has a large head, short neck and tail, paddle-shaped li···
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Lepidochelys olivacea,Olive Ridley, Pacific Ridley,Ridley du Pacifique, Tortue Bâtarde, Tortue Olivâtre, Tartaruga-comum, Tartaruga-oliva, Tartaruga-pequena,Tortue de Ridley,Tortuga Carpintera, Tortug
The Olive Ridley is marine and little is known about its behavior other than its regular annual trips to nesting beaches. It feeds···
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Eretmochelys imbricata, Hawksbill Turtle,Caret, Tortue Caret, Tortue imbriquée, Tortue à bec faucon, Tortue à écailles,Tortuga de Carey,سلحفاة صقرية المنقار
Hawksbill turtles are an animal that often migrates. They are highly mobile and swim fast. They are large and fierce carnivorous a···
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Chelonia mydas,Green Turtle,Sea turtle, black turtle, stone turtle
The green turtle, also known as the sea turtle, is one of the larger species of sea turtles. It is named because its body fat is r···
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Caretta,Loggerhead turtle, loggerhead sea turtle, loggerhead sea turtle, loggerhead sea turtle, loggerhead sea turtle, loggerhead sea turtle
The loggerhead sea turtle is a single species worldwide that spends most of its life in the open ocean and shallow waters. It rare···
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Sacalia bealei,Beal's eyed turtle,Spotted turtle
The spotted turtle is aquatic, mainly living in streams with slow and clear water flow and gravel bottom in hilly areas below 400 ···
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Geoemyda spengleri,Black－breatsed Leaf Turtle,Golden turtle, twelve-horned turtle, maple leaf turtle, black-breasted leaf turtle, twelve-winged turtle
The ground tortoise lives in the shaded and moist areas near streams in the mountain jungle at an altitude of about 700 meters, an···
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Cuora,Broken plate turtle, snake turtle, snake-claw turtle, Asian box turtle
The genus Cuora (scientific name: Cuora) is a genus of Testudinata, Testudinidae, commonly known as box turtles. They are distribu···
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Mauremys mutica,Stone turtle, stone golden coin turtle, water turtle, yellow turtle, fragrant turtle
The yellow-throated water turtle lives in the waters of hilly areas, mountain basins in semi-mountainous areas, and river valleys.···
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Mauremys sinensis,Chinese Stripe-necked Turtle,Ocadia sinensis Gray，1834,Chinese turtle, spotted turtle, pearl turtle, long-tailed turtle, Taiwan turtle
The flower turtle is an aquatic turtle. It is water-loving and has the habit of going ashore to bask in the sun. When the temperat···
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Mauremys nigricans,Red-necked pond turtle,Painted turtle, black-necked painted turtle, three-lined turtle, Guangdong grass turtle, black-necked terrapin
The black-necked turtle is large in size and lives in streams in subtropical hilly and mountainous forests. The black-necked turtl···
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Cyclemys oldhamii,Snake-catching turtle, snake-catch turtle, snake-killing turtle
The European turtle is a wild animal of the order Testudinata and family Geochelone. In the wild, it often hides near dead trees t···
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Testudo horsfieldii,Afghan Tortoise Central Asian Tortoise Four-toed Tortoise Horsfield's Tortoise Steppe Tortoise,Land turtle, taspaha, prairie tortoise, land tortoise, turtle
In the Yili River Valley in Xinjiang, China, there is a small creature called "Tasipaka". "Tasipaka" means &qu···
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Manouria impressa,Impressed Tortoise, Kirin tortoise
Concave-shelled tortoise lives in tropical and subtropical mountainous areas. Adults live on the banks of mountain streams, and yo···
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Indotestudo elongata,Elongated Tortoise,Yellow elephant turtle, pillow turtle, dry turtle, Burma land, dragon claw turtle and so on
Burmese tortoises are subtropical terrestrial tortoises, living in mountains, hills and bush forests, active at night, warm and af···
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Platysternon megacephalum，Big-headed Turtle，Hawk-billed turtle, big-headed flat-chested turtle, eagle turtle, etc
Flat chest turtle like Yin fear of high temperature, fierce temperament, rock climbing and tree climbing ability is very strong. I···
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Tortoise, golden turtle, grass turtle, mud turtle, mountain turtle, black turtle, flower turtle
In a broad sense, turtle refers to the general term for animals of the order Testudinata, and in a narrow sense, refers to species···
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Aldabra giant tortoise, Seychelles giant tortoise, Darding giant tortoise, Arnold's giant tortoise
This tortoise was discovered by humans more than 400 years ago. At that time, people did not realize that it was a long-lived anim···
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Sulcata tortoise, Sulcata tortoise, African spurred tortoise, spurred tortoise, hairy-clawed tortoise
The Sulcata tortoise is a tortoise reptile that lives on land. It originally belonged to the family Testudinidae and the genus Tes···
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green sea turtle,Green turtle, blue turtle, stone turtle, tsio̍h-ku,ku-piah,ku-phi̍ah
Turtles are one of the oldest animals on Earth. These creatures have existed in the world for more than 200 million years, but the···