Turtle Biology and Taxonomy 낱말 카드

Chelidae

Australian side-necked turtles; freshwater turtles that retract their heads sideways beneath the shell

Carettochelyidae

Pig-nosed turtles; freshwater turtles with a distinctive pig-like snout, leathery skin, and flipper-like limbs

Cheloniidae

Hard-shelled sea turtles; marine turtles with keratinous scutes covering their shells

Dermochelyidae

Leatherback turtles; marine turtles with leathery skin covering a mosaic of small bony plates rather than a conventional hard shell

Eastern long-necked turtle

Chelodina longicollis; example of Chelidae

Macquarie turtle

Emydura macquarii; example of Chelidae

Pig-nosed turtle

Carettochelys insculpta; example of Carettochelyidae

Green turtle

Chelonia mydas; example of Cheloniidae

Loggerhead turtle

Caretta caretta; example of Cheloniidae

Hawksbill turtle

Eretmochelys imbricata; example of Cheloniidae

Leatherback turtle

Dermochelys coriacea; example of Dermochelyidae and the largest living turtle species

Carapace

Upper shell of a turtle, typically covering the back

Plastron

Lower shell of a turtle, covering the underside

Scutes

Keratinous plates covering the shell of many turtles

Keratinous scutes

Protective plates made of keratin that cover the bony shell in hard-shelled turtles

Bony plates

Ossified structures forming the internal framework of a turtle's shell

Carapace ridges

Raised longitudinal structures on the upper shell; leatherbacks have seven prominent ridges

Vertebral scutes

Central row of scutes running along the carapace

Costal scutes

Paired scutes located on either side of the vertebral scutes

Hydrodynamic shell

Streamlined shell shape that reduces resistance while swimming

Leathery shell

Flexible outer covering found in leatherbacks and pig-nosed turtles rather than conventional external keratinous scutes

Rigid shell

Hard, relatively inflexible shell supported by bony plates

Reduced plastron

Smaller or less-developed lower shell, allowing greater flexibility or streamlined movement

Side-necked turtle

Turtle that retracts its neck sideways beneath the shell rather than vertically

Pleurodira

Turtle suborder containing side-necked turtles that retract their necks horizontally

Cryptodira

Turtle suborder containing turtles that retract their necks vertically into the shell

Neck retraction

Ability to withdraw the head and neck into or beneath the shell for protection

Beak

Toothless, keratin-covered mouth structure used to bite and process food in turtles

Keratinous beak

Hard, keratin-covered jaws that replace teeth in turtles

Serrated jaw edges

Saw-like cutting edges along the jaws that help process food

Snout

Forward-projecting region of the head containing the mouth and nostrils

Pig-like snout

Distinctive fleshy, protruding snout of pig-nosed turtles, with nostrils at the tip

Flippers

Flattened, paddle-like limbs adapted for swimming

Foreflippers

Front flippers that provide most of the propulsion in marine turtles

Hindflippers

Rear flippers that assist with steering and maneuvering in marine turtles

Propulsion

Movement generated by pushing against water or another surface

Steering

Controlling the direction of movement

Webbed feet

Feet with skin connecting the digits to increase surface area for swimming

Sexual dimorphism

Physical differences between male and female turtles, including differences in tail length and claw length

Salt glands

Specialized glands near the eyes of marine turtles that excrete excess salt

Salt excretion

Removal of excess salt from the body, especially important for marine organisms

Chelidae diagnostic features

Long necks, sideways neck retraction, hard shells, webbed feet, and freshwater habitats

Carettochelyidae diagnostic features

Pig-like snout, leathery skin, flipper-like limbs, reduced plastron, and freshwater lifestyle

Cheloniidae diagnostic features

Hard streamlined shell with keratinous scutes, paddle-like flippers, and marine lifestyle

Dermochelyidae diagnostic features

Leathery shell without external scutes, seven longitudinal ridges, large streamlined body, and powerful flippers

Chelidae vs. Cryptodira

Chelidae belong to Pleurodira and retract their necks sideways; Cryptodira retract their necks vertically

Hard-shelled vs. leatherback turtles

Hard-shelled turtles have keratinous scutes over a rigid bony shell; leatherbacks have leathery skin over a mosaic of small bony plates

Green turtle diet

Primarily seagrass and algae as adults

Loggerhead diet

Primarily crustaceans and molluscs

Hawksbill diet

Primarily marine sponges

Leatherback diet

Primarily jellyfish and other gelatinous organisms

Pig-nosed turtle diet

Omnivorous; aquatic plants, fruits, molluscs, crustaceans, and fish

Side-necked turtle diet

Mostly carnivorous; fish, frogs, crustaceans, insects, and molluscs

Marine turtle

Turtle adapted to life in the ocean, with flippers and streamlined bodies

Freshwater turtle

Turtle that lives primarily in rivers, lakes, ponds, and wetlands

Open-ocean habitat

Marine environment far from coastlines, used by species such as leatherback turtles

Coastal feeding area

Nearshore marine habitat where sea turtles forage for food

Nesting beach

Sandy coastal habitat where female sea turtles come ashore to lay eggs

Long-distance migration

Seasonal or reproductive movement over large distances between feeding and nesting habitats