Reptile Families

Which of the following is NOT true of reptiles?

a

They have scales

b

They are homeothermic

c

If they have legs, they have claws

d

They have 4 legs or no legs

Which of the following is a morphological difference between Anapsids and Diapsids?

a

Different number of legs

b

Different number of heart chambers

c

Different type of scales

d

Different number of holes in the skull

Snakes with ___________ scales are better at climbing. 

a

smooth

b

keeled 

c

shedding

d

shell 

What's attached to precaudal vertebrae in snakes? 

a

rattle

b

skull

c

ribs

d

feet

Members of which group of reptiles sometimes have a parietal eye?

a

lizards

b

turtles

c

venomous snakes

d

non-venomous snakes

Synapsids and Sauropsids

  • First amniotes—340MYA

    • reptiles very different from current reptiles

  • Two lines diverged soon after

  • Extant Sauropsids= turtles, reptiles, crocodiles, birds

  • Extant Synapsids = mammals

Anapsids, Synapsids, and Diapsids

  • Based on number of temporal openings (fenetra)

    • jaw muscle attachment

  • Anapsid: no temporal openings

    • turtles

  • Synapsid: single temporal opening

    • mammals

  • Diapsid: 2 temporal openings

    • reptiles including birds

Reptile Classification

Order Testudines

  • Cheloniidae

  • Chelydridae

  • Kinostemidae

  • Emydidae

  • Characteristics

    • shell, modified ribcage

    • keratin beak

    • pelvic and pectoral girdles within ribcage

Cheloniidae—Sea Turtles

  • 4 spp. in NC, 7 species worldwide

    • 6 of 7 threatened or endangered, 3 critically endangered

  • limbs modified into flippers

  • mostly aquatic

Trionychidae—Softshell Turtles

  • 25 species worldwide, 1 in NC

    • more than half are at risk, 5 endangered

  • buried in mud, not baskers

  • slow moving water with soft bottom

Chelydridae: Snapping Turtles

  • Big headed turtles—cannot fully retract into shell

  • 3 spp worldwide, 1 in NC

  • None are at risk

  • large, mostly aquatic turtles

    • heavy carapace, reduced plastron

  • strong jaws

Kinosternidae—Mud and Musk Turtles

  • 25 species worldwide, 4 spp. in NC

    • most species not at risk

  • related to snapping turtles

    • much smaller

  • fixed or hinged plastrons

Emydidae—Box and Basking Turtles

  • 95 species worldwide, 10 spp. in NC

    • bog turtle endangered

  • occupy a wide variety of habitats

    • most are aquatic

    • some even are salt-water tolerant

Testudinidae—Tortoises

  • 40-50 species

  • fully terrestrial, warm climates

  • domed carapace, herbivores

  • 13 species in US

  • gopher tortoise is the only tortoise in the Southeast—listed as threatened

Order Crocodylia

  • only extant members of Archosauria—all dinosaurs and other reptiles of the Mesozoic 245-65MYA

  • 3 families, 23 species worldwide

  • non-overlapping scales and bony scutes

  • 4-chambered heart with a pore

  • super acidic stomach

Crocodylidade

  • 3 genera, 14 species worldwide

  • American Crocodile is endangered

  • True crocodiles

  • long, narrow heads

  • lower jaw teeth outside mouth

Alligatoridae

  • true alligators—4 genera and 8 species worldwide

  • American Alligators were listed as endangered in 1967, now they are least concern and even hunted in some places

  • broad heads

  • lower jaw teeth inside mouth

Order Squamata

  • largest order of reptiles, over 7000 species worldwide

  • lizards, snakes, tuataras

  • tuataras are the only surviving member of the group that gave rise to all of Squamata

Phrynosomatidae—horned and fence lizards

  • more than 120 species worldwide, 1 sp. (+1 introduced) in NC (greater diversity in West)

    • eastern fence lizard is least concern

  • rough scales

Polychrotidae—Anoles

  • more than 600 species worldwide, 1 sp. in NC (several others in US, mostly introduced)

  • Carolina Anole=least concern

  • granular scales

  • good climbers

Scincidae—skinks

  • more than 1000 species worldwide, 5 spp in NC

  • 3 species on our list = least concern

  • All members of Plestiodon in NC have blue tails as juveniles (Scincella tails are always brown)

  • short neck

  • relatively small legs

Viperidae—pit vipers

  • 364 species worldwide, 5 spp in NC, 26 worldwide are vulnerable, at risk, or endangered

  • All NC members have heat-sensing pits, moveable front fangs, and give live birth

  • Venom=hemotoxin

Elapidae—cobras, coral snakes, and kraits

  • 1 sp in NC (+2 spp, further west), over 300 species worldwide

  • Eastern coral snake is least concern

  • diverse family, but one species very rarely occurs in NC

  • fixed front fangs, egg-laying

  • venom = neurotoxin

Colubridae—non venomous snakes

  • 31 spp in NC, almost 2000 species worldwide!

  • Indigo snake is threatened

  • egg-layers and live-bearers—ovoviviparous

  • smooth or keeled scales