HERP

Question 1

How snake skull compares to lizard skull?

Answer 1

-Snake skulls are more kinetic
->lost connection between quadrate & pterygoid
->very flexible articulation between quadrate & supratemporal
->2 mandibles attached by soft tissue
->bones of snout are loosely articulated in snakes, allowing greater movement of the maxilla

Question 2

How lizard skull compares to snake?

Answer 2

Lizard skull is very rigid
-stabilizing connection between quadrate & pterygoid
-mandibles rigidly joined by bony suture

Question 3

Snake vs Lizard differences

Answer 3

Snakes don’t have eyelids, don’t have scleral ossicles, instead they have a spectacle which sheds.

Question 4

Snakes Skull

Answer 4

-modified diapsid skull
-highly kinetic streptostylic skull allows mouth to open wider and for jaw to act as a ratchet
-protrusible trachea (in some species)
-No tympanum
-Spectacle instead of eyelid

Question 5

Typhlopidae

Answer 5

-cosmopolitan blind snake
-10 genera ; 252 species
-cosmopolitan in tropical areas
-fossorial

Question 6

Leptotyphidae

Answer 6

-slender blind snakes, thread snakes
-12 genera ; 117 species
-fossorial
-

Question 7

Pythonidae

Answer 7

-pythons
-9 genera ; 40 species
-non-protrusible tracheal tube
-cloacal spurs
-oviparous

Question 8

Boidae

Answer 8

-boas
-specialized infrared sensors
-cloacal spurs
-green anaconda = largest species

Question 9

Viperidae

Answer 9

-vipers and pit vipers
-37 genera; 328 species
-worldwide
-terrestrial, arboreal, semiaquatic
-venomous ->solenoglyphous fangs
-most viviparous, some oviparous

Question 10

Snake Body Morphology

Answer 10

-lack pectoral girdle & forelimbs
-derived & basal
-unique vertebrae
-reduction or absence of left lung
-scales

Question 11

Snake Scales

Answer 11

-body covered in epidermal scales
-ventral surface covered in rectangular scales (scutes)

Question 12

Snake Vertebrae

Answer 12

-increased # of vertebrae = elongated body
-each vertebrae has associated rib
-high number of vertebrae & ribs = increased flexibility
->undulatory locomotion

Question 13

Snake Tail Breakage

Answer 13

Tail breakage is rare in snakes
->intervertebral break

Question 14

Snake Evolution and Relation to Lizards

Answer 14

-evolved from lizards
-most closely related to varanid lizards
-> necks
->forked tongues
->similar jaw articulation

Question 15

Natricidae

Answer 15

-38 genera ; 211 species
-old world species : all oviparous
-new world species : all viviparous

Question 16

Dipsadidae

Answer 16

-96 genera ; 752 species
-mostly new world
-highly diverse group
-oviparity and viviparity

Question 17

Colubridae

Answer 17

-255 genera ; 1800 species
-common snakes
-worldwide distribution
-largest and most diverse family
-some are venomous
-some culubrias are opisthoglyphous
-oviparous and viviparous species

Question 18

Elapidae

Answer 18

-55 genera ; 353 species
-cobras, kraits, sea snakes, death adders, allies
-venomous ->proteroglyphous fangs
-oviparity and viviparity

Question 19

Two major groups of snakes

Answer 19

-scoleophidia (worm snakes)
->reduced bones
->akinetic skulls
->fossorial

-alethinophidia (the true snakes)
->all other snakes

Question 20

Solenoglyphous

Answer 20

-completely hollow

-movable maxilla

-viperidae

Question 21

Proteroglyphous

Answer 21

-front-fanged teeth
-static & immovable
-elapidae