Herpetology: Chelonians

Testudines

Order containing all extinct and extant turtles and tortoises

Anapsid

amniote whose skull lacks fenestration, or holes in the skull near temples. Most basal lineage of amniote.

Diapsid

Amniote with two temporal fenestrae in skull.

Testudines: Anapsid or Diapsid?

Turtles lack fenestration, morphologically appearing to be anapsids, but molecular data indicates that they are of diapsid lineage. (Secondary loss of fenestration in skull)

label the given phylogeny with the turtle families, placing an asterisk next to families found in north america and a carat next to families found in florida.

Name the significant testudine fossils mentioned in class

• Odontochelys

• proganochelys

Odontochelys: time period, significance, characteristics

Proganochelys: time period, significance, characteristics

Describe the evolution of the turtle’s shell

dorsal ribs and ventral ribs widen, pelvic and pectoral girdles become tucked in, plastron fuses, then carapace fuses.

describe the way turtles respire

absorption of oxygen via lungs and to a lesser extent cloaca. Air pumped to lungs via buccal pumping, and contraction of posterior abdominal pockets in rear leg pocket imitates a diaphragm

Chelidae

Common name: Australo-American side-necked/snake-necked turtles

Distribution: Australia, new guinea, SA

Genera: 12

morphology: flattened skulls/shells

Habitat: mostly aquatic

Characteristics: omnivorous, during drought, bury in mud for extended periods (aestivation)

Pelomedusidae

Common name: African side-necked turtles

Distribution: Africa, madagacar, seychelles

Genera: 2

morphology: convergent with Kinosternidae; rounded shells

Habitat: mostly aquatic; slow water bottom walkers

Characteristics: carnivorous, aestivate

Podocnemidae

Common name: Madagascan big-necked turtles, american side-neck river turtles

Distribution: Madagascar, NE SA

Genera: 3

morphology: broad, domed shells for swimming in current

Habitat: rivers

Characteristics: herbivorous

Carettochelyidae

Common name: pig-nosed turtle

Distribution: Australia, new guinea

Genera: 1

morphology: streamlined shell with epidermal skin, flipper forelimb, webbed hindlimbs

Habitat: rivers, estuaries

Characteristics: omnivorous, eggs hatch when exposed to water

Trionychidae

Common name: Softshell turtles

Distribution: NA, Africa, asia, New Guinea

Genera: 13, NA Apalone

morphology: flat, flexible shells with leathery skin

Habitat: Rivers, lakes

Characteristics: reduced carapace and plastron bones, omnivorous, fast swimmers

Kinosternidae

Common name:mud, musk turtles

Distribution: NA, SA

Genera: 4, NA Kinosternon, Sternotherus

morphology: convergent with pelomedusidae

Habitat: mostly aquatic, bottom walkers

Characteristics: mostly carnivorous, some specialization on mollusks, musk glands that secrete foul substance when disturbed

Dermatemydidae

Common name: mesoamerican river turtles

Distribution: Central america (Gulf)

Genera: on species, Dermatemys mawii

morphology: oblong, slightly domed shell

Habitat: slow moving rivers and lakes

Characteristics: herbivorous, highly endangered due to human predation

Chelydridae

Common name: snapping turtles

Distribution: NA, SA, central america

Genera: 2, north american Chelydra serpentina and Macrochelys temminckii

morphology: large head and jaws, reduced plastron, long tail

Habitat: aquatic

Characteristics: omnivorous, ambush/active predator

Cheloniidae

Common name: Hard-shelled sea turtles

Distribution: worldwide in tropical/temperate seas

Genera: 5, NA caretta, chelonia, eretmochelys, lepidochelys

morphology: flattened, streamlined shells and flippers

Habitat: marine, nest on coastline

Characteristics: omnivores when young, specialize when adult.

• chelonia - marine grasses/algae

• caretta - crustaceans and mollusks

• eretmochelys - sponges and corals

dermochelyidae

Common name: leatherback

Distribution: worldwide

Genera: 1 species, dermochelys coriacea

morphology: lack epidermal scutes, have leathery skin

Habitat: marine

Characteristics: specialized on jellyfish and other inverts, endothermal, large

Emydidae

Common name: Cooters, sliders, box turtles, etc

Distribution: NA, SA, CA, EU, north africa

Genera: 10 genera, all can be found in NA

morphology: variable

Habitat: aquatic or terrestrial

Characteristics: diet variation; carnivorous, omnivorous, herbivorous

Platysternidae

Common name: Big-headed turtle

Distribution: Asia

Genera: 1 species, platysternon megacephalum

morphology: large head and jaws

Habitat: high elevation rocky streams

Characteristics: can climb trees

Geoemydidae

Common name: asian river turtles, leaf and roofed turtles, asian box turtles, etc

Distribution: EU, Asia, africa, SA, NA

Genera: 23 genera

morphology: variable

Habitat: aquatic or terrestrial

Characteristics: diet variable, most highly endangered due to human predation in asia

Testudinidae

Common name: tortoises

Distribution: NA, SA, EU, africa, asia

Genera: 15, NA gopherus

morphology: high domed shells

Habitat: terrestrial, many desert adapted

Characteristics: most herbivorous, some omnivorous, columnar hindlimbs, size highly variable