The side neck turtle, also known as the side-necked turtle or sideneck turtle, is a common name for a group of turtles in the Chelidae family. This family consists of around 80 different species found in Australia, New Guinea, and South America. Side neck turtles get their name from their ability to bend their necks to the side and tuck their heads horizontally into their shells for protection. They are a highly diverse group of turtles that come in many different sizes, colors, and habits.
Key Facts About Side Neck Turtles
Here are some quick key facts about side neck turtles:
– There are around 80 different species in the Chelidae family of side neck turtles.
– They are found in Australia, New Guinea, and South America.
– Their necks can bend sideways into their shell, unlike most other turtles.
– They range greatly in size from just a few inches to over 2 feet long.
– They occupy diverse habitats including rivers, swamps, deserts and more.
– Their diets are omnivorous, eating plants, insects, fish, and carrion.
– They have reproductive behaviors unique among turtles.
– Many species are popular exotic pets.
– They face a variety of conservation threats in the wild.
Naming Conventions and Taxonomy
The side neck turtle family Chelidae is part of the larger turtle order Testudines. Within Chelidae, there are two subfamilies – Chelinae and Chelodininae. The diverse species within these subfamilies have a variety of common names depending on the region, but most contain the descriptor “side neck turtle” or “side-necked turtle”. Their scientific names follow standard taxonomic conventions.
Some examples include:
- Red-faced side-necked turtle – Emydura subglobosa
- White-throated snapping turtle – Elseya albagula
- Fitzroy River turtle – Rheodytes leukops
- Matamata turtle – Chelus fimbriata
The genus names like Emydura and Elseya represent the broader relatedness between species while the second part of the scientific name like subglobosa and albagula are unique descriptors for each species.
Major Categories of Side Neck Turtles
There are a few major subgroups within the side neck turtle family Chelidae:
Snake-necked Turtles
Snake-necked turtles belong to the Chelodina genus. They are named for their extremely long necks that can be fully extended to reach upwards, resembling a snake. There are around 10-12 species found in Australia and New Guinea. Some examples are the eastern snake-necked turtle (Chelodina longicollis) and the roti island snake-necked turtle (Chelodina mccordi).
Plateless Turtles
This diverse group lacks the upper shell plates that most turtles possess. They belong to genera like Elseya, Rheodytes, and Emydura. There are around 30 species. Some examples are the Fitzroy River turtle (Rheodytes leukops), northern snapping turtle (Elseya dentata), and the painted turtle (Emydura subglobosa).
Long-necked Turtles
Long-necked turtles have extremely long necks compared to their bodies but do not extend upwards like snake-necked turtles. They belong to genera like Chelodina and Macrochelodina. Examples include the eastern long-neck turtle (Chelodina longicollis) and the New Guinea long-neck turtle (Chelodina parkeri).
Short-necked Turtles
This group encompasses turtles with short, thick necks that cannot bend sideways. They belong to genera like Elseya and Emydura. The white-throated snapping turtle (Elseya albagula) and the Krefft’s river turtle (Emydura macquarii krefftii) are examples.
Pig-nosed Turtles
Pig-nosed turtles have an unusual upturned snout like a pig’s nose. There are just two species – the northern pig-nosed turtle (Carettochelys insculpta) and southern pig-nosed turtle (Carettochelys expansa) – both found in Australia and New Guinea.
Matamata Turtles
This group contains the single species matamata turtle (Chelus fimbriata), found in South America. It has a bizarre flattened head and carapace that resembles a gnarled tree stump as camouflage.
Geographic Ranges
Side neck turtles span three main regions – Australia, New Guinea, and South America:
Australia
Australia is home to around 48 species of side neck turtles from genera like Chelodina, Elseya, Emydura, and Rheodytes. They occupy diverse habitats across the continent from deserts to tropical rivers. The Fitzroy River turtle (Rheodytes leukops) is endemic to a single river system in Western Australia.
New Guinea
Around 29 species are found in New Guinea, several being endemics like the Fly River turtle (Carettochelys insculpta). They occupy the southern side of the island which belongs to the Australia/Oceania ecozone. Genera include Chelodina, Elseya, Emydura, and Carettochelys.
South America
Only 3 species are found in South America – the matamata turtle (Chelus fimbriata), the Argentine snake-necked turtle (Hydromedusa tectifera), and the South American snake-necked turtle (Hydromedusa maximiliani). Their disjointed range from other side neck turtles is a result of ancient continental drift.
Habitats
Side neck turtles occupy diverse freshwater, brackish, and terrestrial habitats:
- Rivers – Occupying both fast and slow-moving freshwater streams and rivers. Examples include the Mary River turtle (Elusor macrurus) of Queensland.
- Swamps – Inhabiting shallow, slow-moving, vegetated wetlands. The New Guinea snapping turtle (Elseya novaeguineae) occupies swamps.
- Lakes – Living in freshwater lakes of varying sizes. The black turtle (Emydura subglobosa) is found in lake habitats.
- Billabongs – Sheltered bodies of water left behind from diverted rivers. Important habitat for Chelodina species.
- Estuaries – Tolerant of brackish water where rivers meet the sea. Elseya dentata inhabits estuaries.
- Deserts – Adapted to ephemeral water sources in arid habitats. Chelodina steindachneri lives in desert areas.
They occupy both permanent and temporary wetland habitats ranging from frigid to tropical temperatures. Some species also spend significant time in terrestrial habitats.
Physical Characteristics
Side neck turtles vary greatly in size, shell morphology, coloration, and other physical features:
Size
They range from just a few inches like the Fly River turtle (Carettochelys insculpta) at 6-7 inches up to 2 feet for larger species like the matamata turtle (Chelus fimbriata). Most species are 8-12 inches long.
Shell
The upper shell or carapace comes in diverse shapes from oval to flattened. Many species are plateless while some have extensive plating. The lower shell (plastron) also varies greatly, from large and fixed to small and hinged.
Neck
As their name suggests, all species have necks that bend sideways into the shell. Neck length ranges from short stubby necks to extremely long snake-like necks over twice the shell length.
Head
Head shapes include short, blunt heads for species that feed on mollusks to long tubular snouts for piscivorous turtles. The matamata has a flattened hammer-shaped head.
Color
Coloration includes olive greens, browns, blacks, yellows, reds, and more. Patterns include spots, speckles, lines, and solid colors. Some have bright red, orange, or yellow heads.
Sexual Dimorphism
Males are generally smaller with longer, thicker tails. Their cloacal openings are beyond the shell edge while females’ openings are under the edge. Some species exhibit other head and shell differences.
Diet and Feeding
Side neck turtles are omnivores, feeding on a diverse range of plant and animal material:
- Aquatic plants – Feeding on underwater vegetation like seagrasses, algae, and leaves.
- Insects – Consuming aquatic insects and terrestrial insects that fall into the water.
- Spiders, worms, crustaceans – Eating invertebrates along shorelines and shallows.
- Mollusks – Crushing and eating snails, mussels, clams with strong jaws.
- Fish – Catching small fish, tadpoles, and eggs. Some species are specialized fish eaters.
- Fruit/Seeds – Many species supplementally consume fallen riparian fruits/seeds.
- Carrion – Feeding opportunistically on dead fish, frogs, reptiles and mammals.
Different species occupy various trophic levels from herbivorous grazers to carnivorous predators. Their powerful jaws allow them to feed on hard-shelled prey.
Unique Reproductive Behaviors
Side neck turtles exhibit some intriguing reproductive behaviors unique among turtles:
Cool-season nesting
Most species nest during the cooler dry season from May-September, unlike northern hemisphere turtles that nest in summer.
Terrestrial nesting
Females leave the water to dig nests and lay eggs terrestrially in soil, unlike most turtles that nest at the water’s edge.
Delayed fertilization
Females can store sperm inside oviducts/ovaries for months before eggs are fertilized and laid. This allows nesting to occur in optimal seasons.
Genetic sex determination
Sex is determined genetically at fertilization rather than by nest temperatures like other turtles. This allows greater reproductive flexibility.
Hatchling aestivation
Newly hatched turtles may aestivate underground until conditions are optimal for emergence. This improves survival in arid regions.
Conservation Status
Many side neck turtle species are threatened and have declining populations:
- IUCN Red List – Around 32 species are listed as endangered (EN), vulnerable (VU), or near threatened (NT).
- Habitat loss – Agricultural and urban development has destroyed wetland habitats.
- Invasive species – Cane toads, foxes, and feral pigs threaten native turtle populations.
- Overcollection – Exploited for the pet trade and human consumption in some regions.
- Climate change – Rising temperatures and drought impact semi-aquatic species.
- Disease – Various bacterial/fungal diseases pose a threat.
Conservation projects like headstarting, captive breeding, and habitat protection seek to restore at-risk side neck turtle populations. Further research into their ecology is needed.
Success story: Mary River Turtle
Native to one river in Queensland, the Mary River turtle (Elusor macrurus) declined severely until conservation efforts helped raise its status from Critically Endangered to Endangered. Protecting this unique species demonstrates the value of conservation programs.
Side Neck Turtles as Pets
A number of side neck turtle species are valued as exotic pets around the world:
- Red-eared slider – The most popular turtle pet due to bright coloration.
- Painted turtle – Small, attractive, and relatively easy to care for.
- Fitzroy River turtle – One of the most colorful species with orange markings.
- Snake-necked turtle – Unique elongated necks pique interest.
- Matamata – Prized for its bizarre appearance despite difficult care.
However, poaching wild turtles for the pet trade is contributing to declining populations. Only captive bred individuals should be kept as pets. They require extensive space and specialized care.
Key Takeaways
– Side neck turtles are a diverse family of about 80 species in Australia, New Guinea, and South America known for bending their necks sideways.
– They occupy varied habitats from rivers to deserts, have many different physical traits, and exhibit some unusual reproductive behaviors.
– Several species are popular as exotic pets but many are threatened by habitat loss, invasive species, and overcollection.
– Protecting wetland habitats and breeding programs are helping restore populations of endangered side neck turtles.
Conclusion
Side neck turtles represent a unique branch of turtles specialized for life in the Southern Hemisphere. Their great diversity across a range of habitats is still being uncovered by biologists. While valued by humans for food and pets, many side neck turtle populations are declining, underscoring the need for continued conservation. Their ability to thrive in both water and on land will likely ensure side neck turtles continue to inhabit Australia’s rivers and swamps for millions of years to come. With greater public awareness and habitat protection, future generations will be able to continue marveling at their distinctive sideways-bending necks.
