1. HERPETOLOGY (BIOL/AECL 457) LAB
Reptiles Part I: Intro, Rhynchocephalia, Crododylia, & Squamates (part I)
HERPETOLOGY (BIOL/AECL 457) LAB

2. Today’s Agenda Return Lab Exam #2
Introduction to Reptiles, Rhynchocephalia, Crocodylia, & Squamata
Begin “Snakes” Lecture
Examine croc, lizard, and snake specimens

3. Lab Exam #2: Discussion Spadefoot toad family: Formerly Pelobatidae
Changed to Scaphiopodidae (2003)
Book wrongly says Scaphiophidae
- OLD

4. Reptiles Ectothermic vertebrates (amniote tetrapods)
Paraphyletic group – With respect to what?
Found on every continent except Antarctica
Characteristics
Heart with a single ventricle
Except for Crocodilians
Amniotic egg
Young are miniature replicas of
parents
Skin covered in scales/scutes
Mainly breathe via lungs

5. Gymnophiona (Caecilians)
Caudata (Salamanders)
Anura (Frogs)
Mammals
Squamata (Snakes + Lizards)
Rhynchocephalia (Tuatara)
Testudines (Turtles)
Birds
Crocodilia

6. Scleroglossan lizards (skinks, monitors, snakes, amphisbaenians, etc.)
Mammals
Scleroglossan lizards (skinks, monitors, snakes, amphisbaenians, etc.)
Rhynchocephalia (Tuatara)
Testudines (Turtles)
Aves (Birds)
Squamates
Lepidosaurs
Iguanian lizards (iguanas, chamaeleons, etc.)
Sauropods (Extinct)
Main points:
--Rhynchocephalia sister to squamates
--Snakes are lizards
--Turtles sister to arhosaurs
--Birds are dinosaurs
--Crocs sister to birds (among extant groups)
Archelosaurs
Dinosaurs
Other Therapods (Extinct)
Archosaurs
Ornithischians (Extinct)
Crocodilia

7. Overview: Extant Reptiles
Rhynchocephalia (Tuatara, 2 extant spp)
Crocodylia (Crocodilians, 24 extant spp)
Testudines (Turtles, 300+ extant spp)
Squamata (Lizards and Snakes, extant spp)

8. Rhynchocephalia (not in Iowa)
Tuatara
“spines on the back”
2 spp confined to New Zealand
Most active at night
Burrowing
Primarily insectivorous
Jaw teeth (acrodont)
Primitive
Diapsid skull
No male copulatory organ
Morphology
Lizard-like in appearance
Lack external ear
Can reach 30 cm in body length
Parietal eye

9. Reptile teeth
Crocodilians: Thecodont Snakes: Mostly acrodont Tuatara: Acrodont Lizards: Mostly pleurodont (but many exceptions)

10. Skull fenestration in amniote tetrapods

11. Crocodylia (not in Iowa)
3 Families
Gavialidae
Alligatoridae
Crocodylidae
Most are threatened or endangered
Occur in warm parts of the world
Heavy armored, elongated bodies, with long snouts

12. Gavialidae Gavials or gharials Elongated narrow snouts 2 species
Primarily consume fish
Ghara or ‘pot’ on end of male’s snout
Gavials

13. Alligatoridae Alligators and Caimans 4 extant genera
Teeth of lower jaw fit into pits of upper jaw
Alligator
Caiman

15. Crocodylidae Crocodiles 2 genera
4th tooth in lower jaw is accommodated in a notch in the upper jaw; visible when mouth is closed
Saltwater crocodile (Crocodylus porosus) is largest living reptile
Crocodile

16. Squamata Lizards and Snakes Largest group of Reptiles (9000+ species)
Snakes are specialized lizards
“Lizards” are paraphyletic with respect to snakes
Largest group of Reptiles (9000+ species)
Morphology
Pair of copulatory organs (hemipenes)
Loss of limbs in multiple lineages
Tail
Snake hemipenes on the radio!

17. Lacertilia Families (26, including…)
Chamaeleonidae
Iguanidae
Gekkonidae
Teiidae (IA)
Scincidae (IA)
Anguidae (IA)
These are the families we have specimens for.

18. Veiled Chameleon (Chamaeleo calyptratus)
Chamaeleonidae
Zygodactyl feet
Casques, horns, & crests on heads of most species
Extremely extensile tongues
Change color easily & quickly
Eyes can move independently of one
Arboreal species have prehensile tails
Most species have laterally flattened bodies
Acrodont teeth 
Veiled Chameleon (Chamaeleo calyptratus)

19. Iguanidae 8 genera Males have dewlaps in many genera
Many have dorsal spines
Pleurodont teeth
Also have bicuspid teeth
Parietal eye
Adult green iguana (Iguana iguana)
Dan Warner
Adult brown anoles (Anolis sagrei) basking

20. Tokay gecko (Gekko gecko)
Gekkonidae
Habitats include warm tropical locales
Most are nocturnal and have very large eyes
Some have specialized scales under the toes that enable them to scale vertical surfaces and even walk upside down
Pads are called lamellae, which are composed of micro hair-like setae
Tokay gecko (Gekko gecko)

22. Teiidae (IA) “Racerunners” Active diurnal lizards
Diverse sandy habitats
Oviparous
Parthenogenetic in some spp.
Whip-like tail
Rings of square scales on tail
Rectangular belly scales

23. Aspidoscelis sexlineatus
Cnemidophorus sexlineatus (before 2002)
SIX-LINED RACERUNNER
Pointed noses
Large scales on top of the head
Rectangular belly plates
Tan, yellow, or greenish stripes that extend from the head to the tip of the tail

24. Scincidae (IA) Iowa species changed to Plestidiodon (2005)
Most are diurnal
Diverse habitats
Oviparous or viviparous
Smooth, shiny cycloid scales
Body form varies
Limb reduction observed in some spp.
Tails break very easily

25. Plestiodon septentrionalis
NORTHERN PRAIRIE SKINK
Three wide tan stripes run dorsally neck to tail
Separated by two narrow dark lines
Stripes less distinct on tail
Three dark bands running the length of sides
Separated by two narrow light stripes
Seven light bands altogether

26. Plestiodon fasciatus FIVE-LINED SKINK
Superficially similar to prairie skinks
Five light color stripes run snout to tail on dorsum
Light stripes separated by much wider dark bands.
Central or mid-dorsal stripe forks at the neck, forming an upside-down V on top of head
Remember: V is Roman numeral 5
Sexually dimorphic
Adult females retain lined pattern on back, but often have a blue-gray tail

27. Plestiodon obsoletus GREAT PLAINS SKINK Largest skink species in Iowa
Gray or tan
Edges of the dorsal scales are often dark, giving the appearance of spotting
Lateral scales are oblique rather than parallel

28. Comparison of lateral scales
Plestiodon septentrionalis
Plestiodon obsoletus
Images from inaturalist.org and University of Lincoln-Nebraska

29. Anguidae (IA) “Alligator and glass lizards” Diurnal Diverse habitats
Mostly fossorial or arboreal
Oviparous or viviparous
Limb reduction or loss in some spp.
Long, fragile tail
Lateral fold

30. Ophisaurus attenuatus
SLENDER GLASS LIZARD
Long and slender snake-like body
2/3 of its total length is tail (*notice position of cloaca!)
Legless
Has lateral fold
Distinguished from snakes:
Lizard-like head
Presence of eyelids
External ear openings

31. Anatomy and head scales of a snake
Know:
Rostral scale
Labial scales
(important for garter snakes)
Scale row numbers

32. Serpentes Families Anomalepididae Typhlopidae Leptotyphlopidae
Anomochilidae
Aniliidae
Uropeltidae
Xenopeltidae
Loxocemidae
Boidae
Xenophidiidae
Tropidophiidae
Boyeriidae
Acrochoridae
Viperidae
Elapidae
Atractaspididae
Colubridae

33. Serpentes Families Anomalepididae Typhlopidae Leptotyphlopidae
Anomochilidae
Aniliidae
Uropeltidae
Xenopeltidae
Loxocemidae
Boidae
Xenophidiidae
Tropidophiidae
Boyeriidae
Acrochoridae
Viperidae (IA)
Elapidae
Atractaspididae
Colubridae (IA)
Red ones are those we have specimens for.

34. Snake fangs Aglyphous: many small teeth, no fangs
Most colubrids
Opisthoglyphous: Rear-fanged
Hognose snake & some other colubrids
Proteroglyphous: Hollow, immobile fang
Elapids
Solenoglyphous: Hollow, hinged fang
Vipers

35. Colubridae (IA) Includes ~63% of all extant snake species
Might be paraphyletic with respect to Elapidae
Several species are venomous
Systematics poorly understood
Spp. vary in form and size
Aglyphous and
opisthoglyphous
WILL COVER THESE NEXT WEEK!
Photo credit: Andrew Kramer

36. Green Anaconda (Eunectes murinus) is the heaviest extant spp of snake.
Boidae
“Pythons & Boas”
2 Subfamilies--8 genera
Overpower prey by constriction
Asphyxiate, not crush, prey
Females larger than males
Rigid lower jaw
Palatal teeth
Many have functional left lung
Vestigial pelvic girdle
Most are viviparous
Pythons are oviparous
Green Anaconda (Eunectes murinus) is the heaviest extant spp of snake.

37. CT scan showing ventral view of the skull of Boa constrictor.
palatal teeth
marginal teeth
CT scan showing ventral view of the skull of Boa constrictor.
(From Mahler & Kearney 2006)

38. Elapidae Variety of habitats 61 genera Head has large shield scale
Habits range from arboreal to marine
61 genera
Head has large shield scale
Round pupils
Proteroglyphous
Smooth scales
Usually long and slender bodies
Most are oviparous
At up to 18.5ft the king cobra (Ophiophagus hannah) is the largest venomous snake

39. Viperidae (IA) Arboreal and terrestrial Most are viviparous
Solenoglyphous
Facial/heat pit (=sensory organ)
Most have keeled scales
Tail scales are in one row
Triangular head is wider than neck
Vertically elliptical pupil

40. Crotalus horridus TIMBER RATTLESNAKE Large and heavy-bodied
Head usually unmarked
Strongly keeled scales
Color varies
Dark, chevron-shaped bands cross the back
Bands bordered by lighter-colored scales
Black tail
Undivided anal plate
Photo credit: Brooke Bodensteiner

41. Crotalus viridis PRAIRIE RATTLESNAKE
Light postocular line passes above corner of mouth
Tan or green dorsum
Dark dorsal blotches outlined with white
Smaller blotches run laterally
Tail is ringed
Keeled scales
Undivided anal plate
Rattle on end of tail

42. Sistrurus catenatus MASSASAUGA Small, robust rattlesnake Keeled scales
Row of dark blotches extend down back
Thick black bar connects eye to jaw
Dirty white chin
Keeled scales
Black venter with light mottling
Undivided anal plate
Rattle on end of tail
Photo credit: Mitch Barazowski

43. Agkistrodon contortrix
COPPERHEAD
Medium-sized & heavy bodied
Orange to bronze ground color
Distinct rust or dark orange bands down the back shaped like hourglasses
Weakly keeled scales
Undivided anal plate
No tail rattle

44. For next three labs…
Next week: continue squamates Week after break: Turtles Reptile study guide assignment is due the Tuesday after break Two weeks after break: Reptile practical exam

45. Questions?