herpetology chapter 4 pt 5 (exam 1)

relationship among major clades

1. pleurodira
2. cryptodira

pleurodira

side necked

cryptodira

hidden necked

defining features of chelidae (1)

austro-american side necked turtles (pleurodira)

\

1. extensive emargination of the cheekbones

defining features of trionchidae (5)

softshell turtles (cryptodira)

\

1. flattened body and reduced bony portions of shell
2. carapace lacks peripheral series of bones
3. costal bones reduced distally in most species
4. leathery skin that has no keratinous scutes, soft to touch
5. fleshy proboscis and lips

defining features of carettochelyidae (3)

pig nosed turtle (cryptodira)

\

1. elongated nostrils
2. limbs are elongate paddles, clawed
3. has bony carapace with soft skin

defining features of emydidae (2)

pond and box turtles (cryptodira)

\

1. plastrons like some species are hinged
2. red eared slider is invasive species

defining features of testudinidae (3)

tortoises (cryptodira)

\

1. terrestrial, usually have a high domed shell
2. stout limbs, feet are not webbed
3. gigantism has evolved independently in many oceanic island populations

defining features of chelydridae (2)

snapping turtles (cryptodira)

\

1. plastron reduced
2. alligator snapping turtle: bifurcate fleshy projection on tongue to lure fish (prey)

defining features of cheloniidae (4)

sea turtles (cryptodira)

\

1. strongly developed forelimbs modified into elongate, fully webbed paddles
2. totally marine (except to lay eggs)
3. egg laying occurs only on tropical or warm temperate beaches
4. extensive migration

defining features of dermochelyidae (4)

leatherback sea turtle (cryptodira)

\

1. strongly developed forelimbs modified into elongate, fully webbed paddles
2. totally marine (except to lay eggs)
3. egg laying occurs only on tropical or warm temperate beaches
4. extensive migration

skeleton

unique features (4)

1. vertebrae (except cervicals) fused together and to ribs
2. flattened ribs form bony core of carapace
3. cervical vertebrae have ball and socket articulation with first shell vertebra
4. pectoral and pelvic girdles inside shell

shell carapace (3)

1. scutes
2. dermal bones
3. ribs

scutes and dermal bone alignment

do not overlap identically for protection purposes

ribs

follow shell shape

shell plastron (2)

1. scutes
2. dermal bones

what families have a reduced bony shell (3)

1. dermochelyidae
2. trionychidae
3. carettochelyidae

skull features (3)

1. lack temporal fenestrae (anapsid: secondarily derived)
2. back of skull greatly emarginated (notched) from the posterior end
3. no teeth (tough, keratinous beak)

locomotor adaptations (3)

1. terrestrial (tortoise)
2. aquatic
3. sea (sea turtles)

reproduction

penis

all taxa features (4)

1. internal fertilization
2. direct development
3. oviparous
4. variety of sex determination mechanisms