Lecture 13 - Reptilia

1. 1. Amniotic eggs will calcareous or leathery shell that prevents desiccation while also used as a respiratory surface
   1. (amniotic fluid and allantois)
   2. 2. Scaly, water-tight skin preventing desiccation
      1. 3. Rotation of limbs to ventral side of body
         1. 4. Increased jaw mechanism to handle larger/harder insect prey

1. A. Oviparous, laying eggs on land
   1. B. 2 parts of bony shell, to which vertebrae are fused
      1. Carapace & Plastron
      2. Morphology reflects ecology
      3. C. Teeth absent, replaced by keratinized beak

1. Cryptodires - "hidden"-necked turtles

1. Lungs attached to top, sides of carapace
   1. Muscles force viscera (organs) upwards against lungs to compress; expand visceral cavity to decompress
      1. Exhale
         1. transverse abdominous; posterior limiting membrane
         2. pectoralis; shoulder girdle
      2. Inhale
         1. abdominal oblique
         2. serratus

1. Social Dominance
   1. a. ritualized head movements
      1. b. biting and ramming
2. Reproduction
   1. Courtship displays
      1. claw vibrating
   2. Nesting
      1. a. all species bury eggs
         1. b. typically 40-60 days to hatch
            1. c. some lay in fall; eggs exhibit diapause

1. Temperature-dependent gender determination
   1. - common among turtles
      1. - higher temperatures produce larger gender; female turtles
         1. - Ca. 3 - 4* C separates males, females
            1. Narrow temperature window, environmental variability ensure production of males, females
               1. Ex: sunny vs. shaded nest sites
                  1. Others?
                     1. ground temperature
                        1. rainy or humid
                           1. global warming

1. A. Oviparous, constructing terrestrial nests for eggs
   1. B. Thecodont teeth, well-developed palate
      1. C. Laterally-compressed tail
         1. D. 4-chambered heart
            1. E. 1st evidence of neocortex tissue in brain
               1. leads to complex behavior

1. - broad snouts
   1. - only upper teeth show when jaw closed
      1. - carnivorous.. but fruits/veggies too

1. - narrow snouts
   1. - 4th lower incisor protrudes when jaws closed
      1. - Largely piscivorous

1. - long narrow snouts
   1. - 4th lower incisor protrudes when jaws closed
      1. - carnivorous.. but fruits/veggies too

1. remain hidden while being able to see, breathe

1. separates nasal passage from mouth

1. bulges on upper, lower jaws
2. similar function to neuromast cells

1. right, left ventricle, atrium
2. variable blood flow when active, at rest, under water
3. when sunning, can "heat rapidly" by increasing flow to limbs

1. actively swallowed stones; "stomach stones"
2. Function(s):
   1. - help control buoyancy
      1. - digestion

1. second eyelid; closes front to back
2. facilitates underwater vision; improved eye protection

1. complex courtship behaviors; posturing, head-slapping, bellowing
2. females bury eggs in mound nests; defend eggs, young
3. temperature-dependent gender determination
   1. greater than or equal to 34*C = males
   2. less than or equal to 30*C = females
4. hatchlings call to parents before emerged from egg
5. stimulates male and/or female to excavate nest
6. adults of some species break open to assist hatchlings

1. "Alligator holes"
   1. disturb, clear muck, wetland vegetation with snout, limbs
   2. create depression with body, tail
   3. remains wet during drier seasons

1. pineal eye (unlensed dorsomedially placed)
   1. Acrodont teeth with 4 upper jaw rows, primarily insectivous

1. Paired kidneys placed posteriorly

1. push-ups, gulag (dewlap) fanning, and head bobs
   1. very similar regardless of situation; complex, responses matter
      1. Aggressive response = male Passive response = female
         1. Ex: Green Anoles
            1. A. assertion-challenge
            2. B. Aggressive posturing; if intruder is male
            3. C. Courtship; if intruder is female

Nota:

• - dropping of tail to escape predator - effective, but comes with a price     * loss of communication      * reduced fat storage - come skinks eat autotomized tails

1. Oviparity

   Nota:

   • - external development; eggs - ancestral form - low cost; multiple clutches possible
2. Viviparity

   Nota:

   • - internal development; eggs - derived form - high cost; single clutch only
3. Parthenogenesis
   1. all female populations
      1. typically originate from hybridization between bisexual species
         1. EX: Whiptails
            1. clone themselves; offspring are the same as her
      2. unisexual reproduction, no fertilization

1. b. elongated bony with annuli to facilitate bi-directional movement
   1. c. only 1 lung
      1. d. external ears absent
         1. e. skull entirely compact bones; with flattened snout

1. girdles extremely vestigial or absent, sternum absent
   1. urinary bladder absent, 1 lung
      1. mandibular symphysis absent, skull bones loosely connected

1. b. single carotid artery
   1. c. highly kinetic (moveable) skull
      1. d. most non-venomous

1. a. forked tongue; separated tips move independently
   1. b. projected, captures chemical stimuli; retracted, stimuli transferred to vomeronasal organs

Nota:

• - series of irregular curves, each pressing against object - lateral force canceled by subsequent curve

Nota:

• - rib muscles lift sections of body off ground, stretch forward - primarily heavy-bodied snakes; slow movement, but useful for stalking

Nota:

• - anchor posteriorly with "loops"; stretch forward; anchor anteriorly; draw rear forward - adapted for use in narrow passages -ex: rodent burrows, pipes in your house 

Nota:

• - raise sections of body in "loops", thrust forward and set on ground - force exerted downward  - primarily used by desert species

Nota:

• - sides move independently; complex; 3-dimensional

Nota:

• - permit taking of larger prey while minimizing risk of injury - shortened vertebrae, truck muscles permit tight lopping by constrictors     - cause of death for prey = suffocation Venom: mixture of enzymes, phosphates and other compounds

Nota:

• specialized, enlarged teeth associated with venom glands

1. Dentition/Placement of Fangs
   1. Aglyphous

      Nota:

      • no fangs, smaller teeth ex: constrictors
      1. Opisthoglyphous

         Nota:

         • fangs on posterior end of maxilla; smaller teeth in front fangs hollow or solid ex: boomslang, false viper
         1. Proteroglyphous

            Nota:

            • fangs on front of maxilla; smaller teeth behind fangs hollow; permanently erect ex: Coral snakes
            1. Solenoglyphous

               Nota:

               • fangs only teeth on maxilla fangs hollow; moveable; longer ex: viperids