Lecture 9: Order Chelonia - The Turtles

Flashcards covering the taxonomy, anatomy, reproduction, and specific species of turtles (Order Chelonia) based on Lecture 9.

Order Chelonia

The taxonomic order containing turtles, consisting of $14$ families and $361$ species distributed worldwide in tropical and temperate habitats.

Stupendemys

A freshwater turtle from Venezuela that arose during the late Triassic and could reach lengths of up to $4\,m$.

Archelon

A marine turtle from North America that reached up to $4\,m$ in length.

Carapace

The upper part of the turtle's unique bony shell that provides armor for the body.

Plastron

The bottom part of a turtle's bony shell.

Limb Girdles

Skeletal structures that, uniquely in turtles, lie within the rib cage.

Pleurodires

Side-necked turtles that wrap their necks around the side of the shell; they are considered the more primitive of the two great turtle groups and are largely Gondwanan in distribution.

Cryptodires

Hidden-necked turtles that withdraw their heads in a vertical, S-shaped curve; they are largely Laurasian in distribution and have more advanced shells.

Mesoplastron

A skeletal element in the plastron retained by some pleurodires but absent in cryptodires.

Sexual Dimorphism

Physical differences between sexes; in turtles, males typically have longer tails and a cloacal opening that exceeds the posterior rim of the carapace.

Arribada

A coordinated mass beach landing for breeding used by Ridley's turtles (genus Lepidochelys) involving thousands of individuals, generally occurring during the day.

Chelonia mydas

The Green Turtle, a strictly herbivorous species whose name is derived from the color of its body fat and can reach up to $204\,kg$.

Chelonia agassizi

The Black Turtle, often considered a subspecies of the green turtle, occurring primarily in the eastern Pacific with a shell notched above the hind flippers.

Natator depressus

The Flatback Turtle, which nests only in northern Australia and has a shell covered in soft leathery skin rather than hard scutes.

Eretmochelys imbricata

The Hawksbill turtle, a sponge specialist known for its tortoiseshell pattern and four imbricate costal scales.

Caretta caretta

The Loggerhead Turtle, distinguished by a large head, reddish-brown coloration, and five costal scutes; they feed primarily on shellfish.

Infaunal Mining

A feeding behavior used by Loggerheads where they use their mouths and fore-flippers to dig trenches to extract buried shellfish.

Lepidochelys kempii

Kemp’s Ridley, a relatively small sea turtle restricted to the Gulf of Mexico and Atlantic Ocean.

Dermochelys coriacea

The Leatherback Turtle, the largest living turtle (up to $907\,kg$) which lacks a normal shell, has seven longitudinal ridges, and feeds almost exclusively on jellyfish.

Bony Ossicles

Small internal bony elements found within the thick leathery shell of the Leatherback turtle.

Lonesome George

The last Pinta Island Tortoise, who hatched about $1910$ and died on June 24, $2012$.

Harriet

A Galapagos Tortoise believed to have been collected by Charles Darwin that reached the age of $175$ at the Australia Zoo.

Lingual Luring

A feeding strategy used by the alligator snapper involving a bright pink vermiform lure on the tongue to attract prey.