Post on 05-Apr-2018
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 1/562
Venomous
snakes in Illinois
and elsewhere.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 2/562
The early evolution of venomous snakes is notwell understood because of the variety of tooth
types and a dearth of fossil material showingmaxillary bones with fangs in place.
The oldest fossils I have located are from the
Early Miocene (ca 5 my BP), which is not toolong ago. Both viperids and elapids are known,but they are very similar to living forms, so onecould presume they have had an extended
earlier history.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 3/562
Venomous Snakes
There are three major types of venomous snakes in the world, if
mildly venomous types, such as Heterodon, are excluded.Categorization has mainly been based on the shapes of theirmaxillary bones and the positions of the fang-like teeth on themaxillaries. Se below for those considered more ancestral(Opisthogyphous) to those believed more specialized (Protero. &
Soleno.) :
Opisthoglyphous (Rear-fanged snakes)
Proteroglyphous (Front-fanged snakes: cobras, sea snakes,coral snakes, mambas, kraits)
Solenoglyphous (Moveable-fanged snakes: (vipers, pitvipers) rattlesnakes, copperheads, cottonmouths,bushmasters)
:
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 4/562
Rear-fanged snakes are generally believed
to have been be the earliest venomous
snakes, but there is no fossil evidence for
this. However, if we assume this to be the
case, then the following slide shows how
this might have happened.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 5/562
Rear-fanged
snakeMaxilla is movable
and rotates on this
surface
To change to asolenogyphus snake
would need to
shorten maxilla
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 6/562
We have three rear-fanged snakes in
Illinois, the 1) Ring-necks, the 2) Flat-headed, and 3) the Hognoses. None of
these are known to bite people, so they
are not considered dangerous. Seebelow.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 7/562
Few people in this area know that Ringneck
snakes are rear-fanged. The genus Diadophis
occurs over much of the eastern U. S. (see
map below), but I don’t think a bite from this
snake has ever been reported. It never gets
more than about 15 inches long, and usuallyis quite common, especially in rocky,
limestone regions. There are two subspecies
in Illinois, the Prairie Ringneck, D. punctatusarnyi and the Northern Ringneck, D. p.
edwardsii.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 8/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 9/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 10/562
Diadophis skullshowing slightlyenlarged rear fang
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 11/562
Northern
Prairie
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 12/562
The rear-fanged snakes of the genus
Tantilla include a very large group, butmost of the species are found to the
southern and western U. S. They are all
small snakes not known to bite, so theycan be easily handled without fear. Only
one species occurs in IIIinois, and it is on
the endangered species list, so it is a rarity
in the state.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 13/562
Flathead snake: Tantilla gracilis
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 14/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 15/562
The Hognosed snakes of the genus Heterodon,
are known colloquially as “Puff Adders,” because
they can flatten their neck somewhat like a
cobra. There are two species in the state, one
that used to be common in this area (H.
platyrhinos), and the other which is found only in
very sandy areas (H. nasicus). Both species haveenlarged rear “fangs” (see below) with which
they puncture their toad prey. Again, this is a
snake that rarely bites, so it usually can be
handled with impunity. Very few bites have beenreported for either species, and those that have
been bitten indicate that the venom is not very
toxic.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 16/562
Eastern hognose snake: Heterodon platyrhinos
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 17/562
Eastern hognose snake: Heterodon platyrhinos
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 18/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 19/562
Heterodon nasicus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 20/562
Western hognose snake: Heterodon nasicus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 21/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 22/562
Serpentes
Scolecophidia
Alethinophidia
Macrostomata
Caenophidia
Colubroidia
Living snake
families
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 23/562
Solenoglyphous snakes in
IllinoisCopperheads
Cottonmouth
Massasauga
Timber Rattlesnake
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 24/562
Northern Copperhead: Agkitrodon contortrix mokasen
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 25/562
Southern Copperhead : Agkistrodon contortrix contortrix
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 26/562
A. c. mokasen A. c.contortrix
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 27/562
There are five copperheadsubspecies in the U.S. Only twoof which occur in Illinois:
Agkistrodon contortrix contortrix and A. c. mokasen. Interestingly,the females of all the subspecies
are more colorful than the males.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 28/562
Cottonmouth: Agkistrodon piscivorus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 29/562
Cottonmouth: Agkistrodon piscivorus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 30/562
A juvenile cottonmouth with yellow tail..
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 31/562
Note: None inMadison Co.
Monroe Co., nrFults. Now gone?
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 32/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 33/562
Note the 9enlarged head
scales in the genus
Sistrurus.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 34/562
9 enlarged head scales in genus Sistrurus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 35/562
Eastern Massasauga: Sistrurus catenatus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 36/562
Clinton Co.,near. CarlyleLake
Used to be in Madison
Co.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 37/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 38/562
Timber rattlesnake: Crotalus horridus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 39/562
Still in Effingham area
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 40/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 41/562
Illinois Snakes
Worm snakes
Mud snake
Racers
Kingsnakes
Rat snakes
Green snakes
Bull snake
Colubrine Snakes
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 42/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 43/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 44/562
C. a. helenae
nr Chester
C. a. vermis
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 45/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 46/562
Black Racer: Coluber constrictor priapus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 47/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 48/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 49/562
C. c. flaviventris
C. c. priapus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 50/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 51/562
Monroe Co.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 52/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 53/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 54/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 55/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 56/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 57/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 58/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 59/562
E. o. spiloides
Now Pantherophis, not Elaphe
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 60/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 61/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 62/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 63/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 64/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 65/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 66/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 67/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 68/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 69/562
Now Liochlorophis vernalis
N t i i snakes
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 70/562
Natricine snakesGarder snakes (2)
Ribbon snakes (2)
Water snakes (6)
Queen snake
Crayfish snake
Brown snake
Redbelly snake
Lined snake
Earth snake
Kirtland‟s snake
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 71/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 72/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 73/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 74/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 75/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 76/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 77/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 78/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 79/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 80/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 81/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 82/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 83/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 84/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 85/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 86/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 87/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 88/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 89/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 90/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 91/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 92/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 93/562
Mississippi Green water snake: Nerodia cyclopion
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 94/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 95/562
Kirtland‟s snake: Clonophis kirtlandi
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 96/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 97/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 98/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 99/562
Venomoussnakes in
Illinois
Scolecophidia
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 100/562
Serpentes
Alethinophidia
Macrostomata
Caenophidia
Colubroidia
Living snake
families
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 101/562
Rear-fanged
snakeMaxilla is movableand rotates on this
surface
To change to a
solenogyphus snake
would need to
shorten maxilla
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 102/562
Hognosed snakesor
Puff “adders”
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 103/562
Eastern hognose snake: Heterodon platyrhinos
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 104/562
Eastern hognose snake: Heterodon platyrhinos
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 105/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 106/562
Northern Copperhead: Agkitrodon contortrix mokasen
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 107/562
Southern Copperhead : Agkistrodon contortrix contortrix
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 108/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 109/562
There are five copperheadsubspecies in the U.S. Only twoof which occur in Illinois:Agkistrodon contortrix contortrix
and A. c. mokasen. Interestingly,the females of all the subspeciesare more colorful than the males.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 110/562
Cottonmouth: Agkistrodon piscivorus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 111/562
Cottonmouth: Agkistrodon piscivorus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 112/562
A juvenile cottonmouth with yellow tail..
Note: None inMadison Co
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 113/562
Madison Co.
Monroe Co., nrFults. Now gone?
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 114/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 115/562
Note the 9enlarged head
scales in the genus
Sistrurus.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 116/562
9 enlarged head scales in genus Sistrurus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 117/562
Eastern Massasauga: Sistrurus catenatus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 118/562
Clinton Co.,near. CarlyleLake
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 119/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 120/562
Timber rattlesnake: Crotalus horridus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 121/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 122/562
Rear-fanged
snakeMaxilla is movableand rotates on this
surface
To change to a
solenogyphus snake
would need to
shorten maxilla
Class Reptilia
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 123/562
Class Reptilia
Sublass DiapsidaInfraclass Lepidosaurimorpha
Superorder Lepidosauria
(Includes Rhynchocephalians)
Order Squamata
(includes lizards, amphisbaenids, and snakes)
Suborder Serpentes or Ophidia
(Incudes only snakes)
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 124/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 125/562
A principle adaptation in snakes
is their ability to feed on largeprey. Everything we see in snakeanatomy seems pointed toward
this end. Because they cannotchew, their prey must beswallowed whole. Note the slides
below which shows how they dothis.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 126/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 127/562
Note that cartilaginous rings surround
the trachea so that it remains open
for inhalation and exhalation duringthe swallowing process. Snake lungsare very elongate and internally
diverse.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 128/562
ectopterygoid
supratemporal
The major changes we see in snakes when compared with lizards are
associated with large-sized food objects which must be swallowed whole.
Starting anteriorly and moving posteriorly we see:
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 129/562
Starting anteriorly and moving posteriorly we see:
1) The two mandibles are not fused medially, but are attached by a stretchable
symphysial ligament so the mouth can be opened widely.
2) The premaxillae are fused medially and are not rigidly attached to the rostrum as
in lizards.
3) The maxillaries, palatines, and pterygoids are all movable and have teeth.
4) The teeth are longer, curved posteriorly (to embed more deeply when the prey
attempts to escape), and are on movable bones (to increase contact with prey
when in the mouth).
5) The braincase is completely surrounded by bone (for isolation from the prey as it
moves down the anterior esophageal area).
6) Elongate supratemporal bones with quadrate bones attached posteriorly (forshifting the gape farther back and increasing its size).
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 130/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 131/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 132/562
vomeronasal organ = Jackobson’s
Palate
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 133/562
symphysial
ligament
Lizards
Lower jaw
Developmentally, snakes are similar to
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 134/562
p y,other vertebrates, but as time passes
they begin to coil and lengthen (seenext slide). During this lengtheningphase the viscera in the body cavityalso lengthens, so when snake viscera
is examined it appears quite elongated,and different from what lizard viscerawould look like (see below).
Stage 18 Stage 20 Stage 26
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 135/562
Trunk starts short, thenincreases in length.
Somite
Snake viscera in
two parts.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 136/562
Nerodia ?
anterior posteriorHeart
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 137/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 138/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 139/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 140/562
How snakes move
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 141/562
How snakes move
Lateral undulation
concertina
sidewinding
rectilinear
(See below)
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 142/562
Lateral undulatory
locomotion
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 143/562
Concertina locomotion
Sidewinding
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 144/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 145/562
In heavy-bodied snakes such as boas,pythons, and vipers.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 146/562
Rectilinear locomotion
interscutali
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 147/562
superior costo-cutaneous
Ventral scale
inferior costo-cutaneous
Gliding snake from East Indies
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 148/562
Hind limb vestiges in living snakes
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 149/562
Hind limb vestiges in living snakes
A considerable number of living snakes havevestiges of hind limbs. When this character ispresent, systematists generally consider it anancestral trait, and thus, those snakes that
have it as more primitive. See the slide belowfor two examples of this.
Eyelash boa
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 150/562
3 wormsnakes
pubis
ilium
femur
Immovable
maxilla
Braincase only
partly covered
posteriorly
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 151/562
maxilla
Immovable
palatines &
pterygoids
mostly without
teeth
Teeth not
recurved
Primitive skullroof
Epipterygoid present
Supratemporals thin
sheets on lateral edge
parietals
Tegu lizard
Tupinambis
nigropunctatus
Teeth on maxilla
Teeth on palatines
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 152/562
Teeth on pterygoids
supratemporalquadrate
recurved teeth
Python argus
Enclosed braincase
Maxilla, palatines,and pterygoids all
movable.
No epipterygoid
Intramandibular joint
Fossil snakesPachyrhachis problematicus (late Cretaceous of Israel)
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 153/562
Pachyrhachis problematicus (late Cretaceous of Israel)
Hassiophis terrasanctus (late Cretaceous of Israel)
Yurlunggur camfieldensis (Late Oligo. to E. Mio. Australia)
Wonambi naracoortensis (Pleistocene of Australia;Eocene rest of world)
Dinilysia patagonica (late Cretaceous of S. America)
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 154/562
Living
snakes
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 155/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 156/562
Pachyrhachis problematicus (Late Cretaceous of Israel)
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 157/562
Pachyrhachis , another interpretation
Dinilysia
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 158/562
yFrom late Cretaceous (± 70 my BP)
of South AmericaA primitive snake
No recurved maxillary teeth ?
Maxillaries not moveable
Supratemporals in lizard-
like position
Palatines and pterygoidsnot moveable, but
toothed
dorsal view
ventral view
Late Oligoceneto early
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 159/562
Miocene of
Australia
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 160/562
Yurlunggur camfieldensis (E Miocene of Queensland Australia
SynapomorphyIf a shared homologue is found in (or inferred to occur in) a
common ancestor, and if it is thought to have originated in that
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 161/562
common ancestor, and if it is thought to have originated in that
ancestor and not in an earlier ancestor, then the shared
homologue is termed a synapomorphy.
According to cladistics, only synapomorphic characters can be
used in phylogenetic reconstruction.
Symplesiomorphy
If the shared homologue is found in (or inferred to occur in) the
common ancestor of the subject taxon, but is thought to have
originated as an evolutionary novelty in an earlier ancestor, then
the homologue is termed a symplesiomorphy.
According to cladistics, symplesiomorphic characters cannot be
used in phylogenetic reconstruction.
Serpentes Scolecophidia
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 162/562
Alethinophidia
Macrostomata
Caenophidia
Colubroidia
Living
snakefamilies
S l hid G l
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 163/562
Scolecophidea: Gr. s colec +
ophidea = worm + snake
Alethinophidea: Gr. aleth +
ophidea = real or authentic +
snake .
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 164/562
ScolecophidiaBlind or Worm Snakes
Includes three families:
Anomalepididae
Leptotyphlopidae
Typhlopidae
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 165/562
The “worm” snakes are very
specialized, and probably are not
ancestral (although they are touted
as such by some) to the
Alethinophidia (or normal snakes)
Most of the fossil snakes found do
not show any of the scolecophidianspecializations.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 166/562
Typhiophis squamosus
QuadrateWorm Snake
Very specializedskull
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 167/562
A Scolecophidian skull
Scolecophidae
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 168/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 169/562
Anomochilidae
1) No teeth on premaxilla, palatines, or pterygoids.
Synapomorphies
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 170/562
2) Dentary and maxillary teeth short, with stout bases.
3) Ectopterygoid element reduced to a small splint within the
pterygo-maxillary ligament.
These are derived, not primitive snake characters!
So I disagree with the phylogeny in the text.Content: Two Species.- Anomochilus leonardi (Malaysia
and Sabah in Borneo) and
A. weberi (Sumatra and Kalimantan
in Borneo)
A very specialized skull
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 171/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 172/562
Anomochilus weberi
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 173/562
Aniliidae1) Angular and splenial elements of lower jaw absent.
Synapomorphies
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 174/562
2) Tips of hemipenial lobes dicoidal.
3) Eye reduced in size and covered by a transparent scale.
4) Posterior superficial palate strongly bilobed and turned dorsally into
orbitonasal trough.
5) Lacrimal foramen entirely within posterior wall of prefrontal.
Content: One species.- Anilius scytale (A burrowing snake that is a
specialized feeder) Feeds on elongate vertebrates, primarily caecilians,
amphisbaenians, eels, and other snakes.
Distribution: See map below
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 175/562
Anilius scytale
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 176/562
Uropeltidae
Synapomorphies
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 177/562
1) Hemipenis undivided (?).
2) Sulcus spermaticus unforked.
3) Premaxillary teeth absent.
4) Broadened cultriform process of basisphenoid.
5) Vomerine processes of premaxilla reduced.
6) Fovea dentis of occipital condyle reduced or absent.
Content: 2 subfamilies, 9 genera and ca 55 species.
Distribution: See map below
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 178/562
Cylindrophis rufus
This is a lizard-like
Quadrate and
supratemporalMaxilla not loose
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 179/562
supratemporal
Palatines and
pterygoids not
movable
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 180/562
Uropeltis m. macrolepis
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 181/562
Boidae1) Supraorbital element present.
2) Levator anguli oris muscle lost
Synapomorphies
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 182/562
2) Levator anguli oris muscle lost.
Content: 3 subfamilies, ca 20 genera, and ca 74 species
Subfamilies: Boinae (9 genera, 33 species)
Pythoninae (ca 8 genera, 26 species) Southern Africa,southern Asia from India, eastward throughout the Indoaustralian
Archipeligo and Australia.
Erycinae (3 genera, 15 species) Central and northern Africa,
southern Europe, and southwestern Asia
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 183/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 184/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 185/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 186/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 187/562
Jaw articulation far
back.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 188/562
Elongate quadrate
widens gape by moving
jaw articulation
posteriorly..
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 189/562
posterior
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 190/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 191/562
Young copperhead using wiggling tail
as a lure (Can you ID the anuran?).
Areas where snakes are not
found.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 192/562
There are no colubrid snakes in
Greenland, Iceland, Ireland, New
Zealand, Tasmania, or southern SouthAmerica.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 193/562
Illinois SnakesColubrine Snakes
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 194/562
Worm snakes
Mud snake
RacersKingsnakes
Rat snakes
Green snakes
Bull snake
Colubrine Snakes
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 195/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 196/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 197/562
C. a. helenae
nr Chester
C. a. vermis
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 198/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 199/562
Black Racer: Coluber constrictor priapus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 200/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 201/562
C. c. flaviventris
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 202/562
C. c. priapus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 203/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 204/562
Monroe Co.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 205/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 206/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 207/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 208/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 209/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 210/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 211/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 212/562
E. o. spiloides
Now Pantherophis, not Elaphe
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 213/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 214/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 215/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 216/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 217/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 218/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 219/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 220/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 221/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 222/562
Now Liochlorophis vernalis
Natricine snakesGarder snakes (2)
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 223/562
Ribbon snakes (2)Water snakes (6)
Queen snake
Crayfish snake
Brown snake
Redbelly snake
Lined snake
Earth snake
Kirtland‟s snake
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 224/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 225/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 226/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 227/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 228/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 229/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 230/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 231/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 232/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 233/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 234/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 235/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 236/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 237/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 238/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 239/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 240/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 241/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 242/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 243/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 244/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 245/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 246/562
Mississippi Green water snake: Nerodia cyclopion
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 247/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 248/562
Kirtland‟s snake: Clonophis kirtlandi
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 249/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 250/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 251/562
RINGNECK SNAKES
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 252/562
RINGNECK SNAKES
Genus Diadophis
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 253/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 254/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 255/562
Diadophis skullshowing slightlyenlarged rear fang
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 256/562
The Hognosed snakes of the genus Heterodon, are
known colloquially as “Puff Adders,” because they
can flatten their neck somewhat like a cobra.
There are two species in the state one that used
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 257/562
There are two species in the state, one that usedto be common in this area (H. platyrhinos), and
the other which is found only in very sandy areas
(H. nasicus). Both species have enlarged rear
“fangs” (see below) with which they puncture
their toad prey. Again, this is a snake that rarely
bites, so it usually can be handled with impunity.
Very few bites have been reported for either
species, and those that have indicate that the
venom is not very toxic.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 258/562
Eastern hognose snake: Heterodon platyrhinos
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 259/562
Eastern hognose snake: Heterodon platyrhinos
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 260/562
Heterodon nasicus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 261/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 262/562
Western hognose snake: Heterodon nasicus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 263/562
Serpentes
Scolecophidia
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 264/562
Alethinophidia
Macrostomata
Caenophidia
Colubroidia
Living snakefamilies
Solenoglyphous snakes in
Illinois
Copperheads
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 265/562
Copperheads
Cottonmouth
Massasauga
Timber Rattlesnake
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 266/562
Northern Copperhead: Agkitrodon contortrix mokasen
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 267/562
Southern Copperhead : Agkistrodon contortrix contortrix
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 268/562
A. c. mokasen A. c.
contortrix
There are five copperhead
subspecies in the U S Only two
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 269/562
subspecies in the U.S. Only twoof which occur in Illinois:Agkistrodon contortrix contortrix
and A. c. mokasen. Interestingly,the females of all the subspeciesare more colorful than the males.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 270/562
Cottonmouth: Agkistrodon piscivorus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 271/562
Cottonmouth: Agkistrodon piscivorus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 272/562
A juvenile cottonmouth with yellow tail..
Note: None inMadison Co.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 273/562
Monroe Co., nrFults. Now gone?
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 274/562
Note the 9
l d h d
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 275/562
enlarged head
scales in the genus
Sistrurus.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 276/562
9 enlarged head scales in genus Sistrurus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 277/562
Eastern Massasauga: Sistrurus catenatus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 278/562
Clinton Co.,
near. CarlyleLake
Used to be in Madison
Co.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 279/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 280/562
Timber rattlesnake: Crotalus horridus
Still in Effingham area
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 281/562
Still in Effingham area
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 282/562
Illinois Snakes
Worm snakes
Colubrine Snakes
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 283/562
Worm snakes
Mud snake
Racers
Kingsnakes
Rat snakes
Green snakes
Bull snake
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 284/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 285/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 286/562
C. a. helenae
nr Chester
C. a. vermis
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 287/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 288/562
Black Racer: Coluber constrictor priapus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 289/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 290/562
C. c. flaviventris
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 291/562
C. c. priapus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 292/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 293/562
Monroe Co.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 294/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 295/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 296/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 297/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 298/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 299/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 300/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 301/562
E. o. spiloides
Now Pantherophis, not Elaphe
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 302/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 303/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 304/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 305/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 306/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 307/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 308/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 309/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 310/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 311/562
Now Liochlorophis vernalis
Natricine snakesGarder snakes (2)
Ribbon snakes (2)
Water snakes (6)
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 312/562
Queen snake
Crayfish snake
Brown snake
Redbelly snake
Lined snake
Earth snake
Kirtland‟s snake
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 313/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 314/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 315/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 316/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 317/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 318/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 319/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 320/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 321/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 322/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 323/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 324/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 325/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 326/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 327/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 328/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 329/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 330/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 331/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 332/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 333/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 334/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 335/562
Mississippi Green water snake: Nerodia cyclopion
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 336/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 337/562
Kirtland‟s snake: Clonophis kirtlandi
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 338/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 339/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 340/562
Venomous
snakes in
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 341/562
snakes in
Illinois
Serpentes
Scolecophidia
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 342/562
Alethinophidia
Macrostomata
Caenophidia
Colubroidia
Living snakefamilies
To change to a
solenogyphus snake
would need toshorten maxilla
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 343/562
Rear-fanged
snakeMaxilla is movable
and rotates on thissurface
Hognosed snakes
or
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 344/562
or
Puff “adders”
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 345/562
Eastern hognose snake: Heterodon platyrhinos
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 346/562
Eastern hognose snake: Heterodon platyrhinos
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 347/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 348/562
Northern Copperhead: Agkitrodon contortrix mokasen
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 349/562
Southern Copperhead : Agkistrodon contortrix contortrix
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 350/562
There are five copperheadsubspecies in the U.S. Only twoof which occur in Illinois:A ki t d t t i t t i
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 351/562
Agkistrodon contortrix contortrix
and A. c. mokasen. Interestingly,the females of all the subspeciesare more colorful than the males.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 352/562
Cottonmouth: Agkistrodon piscivorus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 353/562
Cottonmouth: Agkistrodon piscivorus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 354/562
A juvenile cottonmouth with yellow tail..
Note: None inMadison Co.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 355/562
Monroe Co., nr
Fults. Now gone?
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 356/562
Note the 9
enlarged head
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 357/562
g
scales in the genusSistrurus.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 358/562
9 enlarged head scales in genus Sistrurus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 359/562
Eastern Massasauga: Sistrurus catenatus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 360/562
Clinton Co.,near. Carlyle
Lake
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 361/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 362/562
Timber rattlesnake: Crotalus horridus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 363/562
To change to a
solenogyphus snake
would need toshorten maxilla
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 364/562
Rear-fanged
snakeMaxilla is movable
and rotates on this
surface
Class ReptiliaSublass Diapsida
Infraclass Lepidosaurimorpha
Superorder Lepidosauria
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 365/562
(Includes Rhynchocephalians)
Order Squamata
(includes lizards, amphisbaenids, and snakes)
Suborder Serpentes or Ophidia(Incudes only snakes)
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 366/562
A principle adaptation in snakesis their ability to feed on large
prey. Everything we see in snakeanatomy seems pointed toward
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 367/562
anatomy seems pointed towardthis end. Because they cannotchew, their prey must beswallowed whole. Note the slidesbelow which shows how they dothis.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 368/562
Note that cartilaginous rings surroundthe trachea so that it remains open
f i h l ti d h l ti d i
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 369/562
for inhalation and exhalation during
the swallowing process. Snake lungsare very elongate and internally
diverse.
ectopterygoid
supratemporal
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 370/562
The major changes we see in snakes when compared with lizards are
associated with large-sized food objects which must be swallowed whole.Starting anteriorly and moving posteriorly we see:
1) The two mandibles are not fused medially, but are attached by a stretchable
symphysial ligament so the mouth can be opened widely.
2) The premaxillae are fused medially and are not rigidly attached to the rostrum as
in lizards.
3) The maxillaries, palatines, and pterygoids are all movable and have teeth.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 371/562
4) The teeth are longer, curved posteriorly (to embed more deeply when the prey
attempts to escape), and are on movable bones (to increase contact with prey
when in the mouth).5) The braincase is completely surrounded by bone (for isolation from the prey as it
moves down the anterior esophageal area).
6) Elongate supratemporal bones with quadrate bones attached posteriorly (for
shifting the gape farther back and increasing its size).
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 372/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 373/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 374/562
vomeronasal organ = Jackobson’s
symphysial
Palate
Lizards
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 375/562
y p yligament
Lizards
Lower jaw
Developmentally, snakes are similar toother vertebrates, but as time passesthey begin to coil and lengthen (see
next slide). During this lengtheningphase the viscera in the body cavityalso lengthens, so when snake viscera
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 376/562
g ,is examined it appears quite elongated,
and different from what lizard viscerawould look like (see below).
Stage 18 Stage 20 Stage 26
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 377/562
Trunk starts short, then
increases in length.
Somite
Snake viscera intwo parts.
Nerodia ?
anterior posteriorHeart
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 378/562
Snake vertebrae are only slightly different from lizardvertebrae, but with lengthening there’s a lot more of
them. Two additional processes, the zygosphene
and zygantrum have been added to stabilize the
long vertebral column dorso-ventrally. When a snaket d it k b d t l t h
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 379/562
extends its neck or body out a long way to reachanother purchase, the two above processes keep it
from sagging too much in the middle.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 380/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 381/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 382/562
How snakes move
Lateral undulation
concertina
(See below)
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 383/562
sidewinding
rectilinear
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 384/562
Lateral undulatorylocomotion
Concertina locomotion
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 385/562
Sidewinding
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 386/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 387/562
In heavy-bodied snakes such as boas,
pythons, and vipers.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 388/562
Rectilinear locomotion
superior costo-cutaneous
Ventral scale
inferior costo-cutaneous
interscutali
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 389/562
Gliding snake from East Indies
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 390/562
Hind limb vestiges in living snakes
A considerable number of living snakes have
vestiges of hind limbs. When this character ispresent, systematists generally consider it anancestral trait, and thus, those snakes that
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 391/562
, ,have it as more primitive. See the slide below
for two examples of this.
Eyelash boa
pubis
ilium
femur
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 392/562
3 wormsnakes
Immovable
maxilla
Braincase only
partly covered
posteriorly
Teeth not
recurved
Primitive skull
Epipterygoid present
Supratemporals thin
sheets on lateral edgeparietals
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 393/562
Immovable
palatines &
pterygoids
mostly without
teeth
Primitive skull
roof Tegu lizard
Tupinambisnigropunctatus
Teeth on maxilla
Teeth on pterygoids
Teeth on palatines
supratemporal
Enclosed braincase
Maxilla, palatines,
and pterygoids all
movable.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 394/562
supratemporal
quadraterecurved teeth
Python argus
No epipterygoid
Intramandibular
joint
Fossil snakesPachyrhachis problematicus (late Cretaceous of Israel)
Hassiophis terrasanctus (late Cretaceous of Israel)
Yurlunggur camfieldensis (Late Oligo to E Mio Australia)
Dinilysia patagonica (late Cretaceous of S. America)
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 395/562
Yurlunggur camfieldensis (Late Oligo. to E. Mio. Australia)
Wonambi naracoortensis (Pleistocene of Australia;Eocene rest of world)
Living
k
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 396/562
snakes
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 397/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 398/562
Pachyrhachis problematicus (Late Cretaceous of Israel)
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 399/562
Pachyrhachis , another interpretation
DinilysiaFrom late Cretaceous (± 70 my BP)of South America
A primitive snakeSupratemporals in lizard-
like position
dorsal view
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 400/562
No recurved maxillary teeth ?
Maxillaries not moveable
Palatines and pterygoidsnot moveable, buttoothed
ventral view
Late Oligoceneto earlyMiocene ofAustralia
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 401/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 402/562
Yurlunggur camfieldensis (E Miocene of Queensland, Australia
Synapomorphy
If a shared homologue is found in (or inferred to occur in) a
common ancestor, and if it is thought to have originated in that
ancestor and not in an earlier ancestor, then the shared
homologue is termed a synapomorphy.
According to cladistics, only synapomorphic characters can be
used in phylogenetic reconstruction.
S l i h
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 403/562
Symplesiomorphy
If the shared homologue is found in (or inferred to occur in) the
common ancestor of the subject taxon, but is thought to have
originated as an evolutionary novelty in an earlier ancestor, then
the homologue is termed a symplesiomorphy.
According to cladistics, symplesiomorphic characters cannot be
used in phylogenetic reconstruction.
Serpentes Scolecophidia
AlethinophidiaLiving
k
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 404/562
Macrostomata
Caenophidia
Colubroidia
snake
families
Scolecophidea: Gr. s colec +
ophidea = worm + snake
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 405/562
Alethinophidea: Gr. aleth +
ophidea = real or authentic +
snake .
ScolecophidiaBlind or Worm Snakes
Includes three families:
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 406/562
AnomalepididaeLeptotyphlopidae
Typhlopidae
The “worm” snakes are very
specialized, and probably are not
ancestral (although they are touted
as such by some) to the
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 407/562
y
Alethinophidia (or normal snakes)Most of the fossil snakes found do
not show any of the scolecophidian
specializations.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 408/562
Typhiophis squamosus
Quadrate
Worm SnakeVery specializedskull
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 409/562
A Scolecophidian skull
Scolecophidae
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 410/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 411/562
Anomochilidae
1) No teeth on premaxilla, palatines, or pterygoids.
2) Dentary and maxillary teeth short, with stout bases.
3) Ectopterygoid element reduced to a small splint within the
pterygo-maxillary ligament.
These are derived, not primitive snake characters!
So I disagree with the phylogeny in the text
Synapomorphies
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 412/562
So I disagree with the phylogeny in the text.
Content: Two Species.- Anomochilus leonardi (Malaysiaand Sabah in Borneo) and
A. weberi (Sumatra and Kalimantan
in Borneo)
A very specialized skull
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 413/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 414/562
Anomochilus weberi
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 415/562
Aniliidae1) Angular and splenial elements of lower jaw absent.
2) Tips of hemipenial lobes dicoidal.
3) Eye reduced in size and covered by a transparent scale.
4) Posterior superficial palate strongly bilobed and turned dorsally into
orbitonasal trough.
5) Lacrimal foramen entirely within posterior wall of prefrontal.
Synapomorphies
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 416/562
Content: One species.- Anilius scytale (A burrowing snake that is a
specialized feeder) Feeds on elongate vertebrates, primarily caecilians,
amphisbaenians, eels, and other snakes.
Distribution: See map below
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 417/562
Anilius scytale
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 418/562
Uropeltidae1) Hemipenis undivided (?).
2) Sulcus spermaticus unforked.
3) Premaxillary teeth absent.
4) Broadened cultriform process of basisphenoid.
5) Vomerine processes of premaxilla reduced.
6) F d ti f i it l d l d d b t
Synapomorphies
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 419/562
6) Fovea dentis of occipital condyle reduced or absent.
Content: 2 subfamilies, 9 genera and ca 55 species.
Distribution: See map below
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 420/562
Cylindrophis rufus
This is a lizard-like
Quadrate and
supratemporalMaxilla not loose
Palatines and
pterygoids not
movable
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 421/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 422/562
Uropeltis m. macrolepis
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 423/562
Boidae1) Supraorbital element present.
2) Levator anguli oris muscle lost.
Content: 3 subfamilies, ca 20 genera, and ca 74 species
Subfamilies: Boinae (9 genera, 33 species)
Pythoninae (ca 8 genera, 26 species) Southern Africa,
Synapomorphies
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 424/562
y g p
southern Asia from India, eastward throughout the Indoaustralian
Archipeligo and Australia.
Erycinae (3 genera, 15 species) Central and northern Africa,
southern Europe, and southwestern Asia
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 425/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 426/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 427/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 428/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 429/562
Elongate quadrate
Jaw articulation far
back.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 430/562
Elongate quadrate
widens gape by moving jaw articulation
posteriorly..
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 431/562
posterior
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 432/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 433/562
Young copperhead using wiggling tail
as a lure (Can you ID the anuran?).
There are no colubrid snakes in
Greenland, Iceland, Ireland, New
Zealand, Tasmania, or southern South
Areas where snakes are notfound.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 434/562
America.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 435/562
Illinois Snakes
Worm snakesMud snake
Racers
Colubrine Snakes
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 436/562
Kingsnakes
Rat snakes
Green snakes
Bull snake
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 437/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 438/562
C. a. vermis
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 439/562
C. a. helenae
nr Chester
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 440/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 441/562
Black Racer: Coluber constrictor priapus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 442/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 443/562
C. c. flaviventris
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 444/562
C. c. priapus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 445/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 446/562
Monroe Co.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 447/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 448/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 449/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 450/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 451/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 452/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 453/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 454/562
E. o. spiloides
Now Pantherophis, not Elaphe
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 455/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 456/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 457/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 458/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 459/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 460/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 461/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 462/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 463/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 464/562
Now Liochlorophis vernalis
Natricine snakesGarder snakes (2)
Ribbon snakes (2)
Water snakes (6)
Queen snake
Crayfish snake
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 465/562
Brown snake
Redbelly snake
Lined snake
Earth snake
Kirtland‟s snake
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 466/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 467/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 468/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 469/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 470/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 471/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 472/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 473/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 474/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 475/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 476/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 477/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 478/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 479/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 480/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 481/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 482/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 483/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 484/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 485/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 486/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 487/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 488/562
Mississippi Green water snake: Nerodia cyclopion
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 489/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 490/562
Kirtland‟s snake: Clonophis kirtlandi
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 491/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 492/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 493/562
RINGNECK SNAKES
Genus Diadophis
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 494/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 495/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 496/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 497/562
Diadophis skullshowing slightlyenlarged rear fang
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 498/562
The Hognosed snakes of the genus Heterodon, areknown colloquially as “Puff Adders,” because they
can flatten their neck somewhat like a cobra.
There are two species in the state, one that used
to be common in this area (H. platyrhinos), andthe other which is found only in very sandy areas
(H. nasicus). Both species have enlarged rear
“fangs” (see below) with which they puncture
their toad prey Again this is a snake that rarely
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 499/562
their toad prey. Again, this is a snake that rarelybites, so it usually can be handled with impunity.
Very few bites have been reported for either
species, and those that have indicate that the
venom is not very toxic.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 500/562
Eastern hognose snake: Heterodon platyrhinos
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 501/562
Eastern hognose snake: Heterodon platyrhinos
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 502/562
Heterodon nasicus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 503/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 504/562
Western hognose snake: Heterodon nasicus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 505/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 506/562
Coral snakes are proteroglyphous (front-fanged
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 507/562
Coral snakes are notfound near Illinois, but
as Milk snakes are oftenbanded with red, sothey have been
f d i h d
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 508/562
confused with andconsidered coral snakes
by some.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 509/562
Texas Coral Snake: Micrurus fulvius tener
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 510/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 511/562
Rear-fanged snakes
(Opisthoglyphous)
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 512/562
Rattlesnake striking. Note mouth is wide open
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 513/562
Fangs are pointing almost straight at prey
canal
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 514/562
Proteroglyphous
snake
Fixed-fanged snake
(maxilla does not move)
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 515/562
African Spitting Cobra
Naja nigricollis
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 516/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 517/562
Mozambique spitting cobra: Naja ??
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 518/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 519/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 520/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 521/562
Australian Death „adder‟: Acanthophis antarcticus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 522/562
Australian Tiger-Snake: Notechis niger
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 523/562
Pelagic Sea Snake: Pelamis platurus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 524/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 525/562
Azemiops feae
The most primitve living viper
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 526/562
The pit vipers are different from the true vipers
in having a heat (infrared) sensitive pit (or hole)
between the eye and the nostril (see slide
below). The group occurs in both the old and
new worlds (see map below). Old world genera
have been considered more ancestral than New
World because they are still oviparous, whereas
all New World members (except theb shmaster) are i iparo s There are fe
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 527/562
( pbushmaster) are viviparous. There are few
other additional ancestral features to separate
the two groups.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 528/562
Bushmaster mouth: long fangs!
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 529/562
Solenoglyphous
snake
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 530/562
Crotalus ruber ruber
Red Diamond Rattlesnake
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 531/562
30 Rattlesnake SpeciesFrom the New World (North, Central and South America)
2 genera:
Crotalus and Sistrurus
plus
51
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 532/562
subspecies (if you recognize)
For a total of 81 taxa in all
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 533/562
Ridge-nosed Rattlesnake: Crotalus willardi
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 534/562
Eastern Diamondback rattlesnake: Crotalus adamanteus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 535/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 536/562
Western diamondback rattlesnake: Crotalus atrox
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 537/562
Rock Rattlesnake: Crotalus lepidus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 538/562
The Bushmaster is the onlyNew World pit viper
(Crotalinae) that lays eggs.
All others (rattlesnakes,
copperheads, cottonmouths),
are viviparous However,
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 539/562
are viviparous. However,most Old World pit vipers
still lay eggs.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 540/562
Bushmaster mouth: long fangs!
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 541/562
Bushmaster: Lachesis muta ssp
The fangs of venomous snakesare never bare as shone in
many commercialpublications. They are covered
with a thin epithelial
membrane which is a part of
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 542/562
membrane which is a part of
the oral cavity.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 543/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 544/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 545/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 546/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 547/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 548/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 549/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 550/562
Rhinoceros viper: Bitis nasicornus
from Africa
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 551/562
Horned viper: Bitis nasicornus
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 552/562
The Burrowing Asps: genusAtractaspis, appears to be a groupof solenoglyphus snakes not very
closely related to the true vipers.They don’t have a viper -like head,and they don’t look very viper -like.
They have very elongate venomglands which apparently are not
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 553/562
glands which apparently are notconsidered homologous toDuvernoy’s glands.
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 554/562
Burrowing asps: Atractaspis
Family Atractaspidae
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 555/562
Burrowing asps: genusAtractaspis
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 556/562
Mole viper: Atractaspis engaddensis
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 557/562
Burrowing asp: Atractaspis microlepidota
Heat sensitive organsin snakes
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 558/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 559/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 560/562
8/2/2019 016 Fanged + Venomous Snakes
http://slidepdf.com/reader/full/016-fanged-venomous-snakes 561/562