Transcript MAMMALOGY AS A SCIENCE

VERTEBRATE ZOOLOGY
(VZ Lecture13 – Fall 2012 Althoff - reference PJH Chapter 10)
Amphibians
PART II
Classification of Amphibia
CLASS
SUBCLASS
Amphibia
Labryinthodonotia*
Leposondyl*
Lissamphibia
ORDER
Urodela
(salamanders)
Anura (frogs)
Gymnophiona
* = extinct
(caecilians)
Focus on Frogs
• ORDER: ________ (Greek:
• 29 familes, ~4,800 species
“an” = without, “uro”= tail)
(compare to 10 families, ~515 species for salamanders)
• Found on all continents except Antarctica
• Body form is more compact, clearly specialized for
jumping. Jumping aided by hind limb-muscle
arrangement form lever-like action that can
catapult them into the air
a) powerful pelvis
b) pelvis strongly fastened to vertebral column
c) posterior vertebrate fused into solid rod
forming ___________
d) hind legs elongate, tibia and fibula fused
Triassic fossil PRIMITIVE
Modern day DERIVED
1
1a
2a
2
3a
3
4
4a
Primitive vs. Derived Skeletal Characters
5
14
short ilium,
no urostyle
short
Reduction number of
toes on front feet
Reduction in presacral
vertebrae
Pelvic girdle changes
Hind limbs & toes
Closer look at “rear” end “adjustments”
• Hind legs elongate, ____________________ = 1
•
•
•
bone
Stronger attachment of a stronger, __________
________ to the vertebral column
_________ (part of pelvis) is elongate and
reaches far anteriorly.
Urostyle (part of pelvis) is what was vertebrae—
now all fused into a solid rod
Closer look at “midway” adjustments
• Reduction in number of ____________ vertebrae
• Presacral vertebrae are strongly braced by
_________________ that restrict lateral bending
Closer look at “frontend” adjustments
• ________ forelimbs
• ________ pectoral girdle
Goliath frog
Eye Structure & Placement
• Large
• Placed well forward on the head
• Result  __________________
Specialization of Locomotor Systems
FORELIMB LENGTH
(longer)
walker-hopper
walker-jumper
jumper
hopper-burrower
hopper
HINDLIMB
LENGTH
(longer)
walker-hopper-burrower
swimmer
Fig. 10-8 p231 PJH
Frog Natural History & Locomotion
• ________-legged species that move by hopping
•
frequently are wide-ranging predators
a) more vulnerable to predators
b) shorter legs prevent rapid escape
c) result  most have potent defensive
chemical released from glands in
skin when attacked
________-legged species that move by jumping
usually are sedentary predators (“ambush”
predators)
a) cryptically colored
b) usually lack chemical defenses
c) result  escape w/ rapid series of leaps
Webbing & Toe Specializations
• _______________ species have webbed feet
•
•
vs.
Most _____________ based frogs (including
those referred to as toads) usually have little
webbing between the toes
Spadefoot toads (NA) have keratinized structure
on hindfoot that aids digging backward into the
soil
Tree Frog Toe Surfaces
• Many tree frogs have enlarged toe disks
a) epidermal layer has peg-like projections
which has mucus gland that secretes
a viscous solution
b) canals in between
c) result  ____________ & __________
hold toe pad and surface together
Fig. 10-10 p233 PJH
Toe Disks – Found in Several Lineages
• Toe disks are not a “tree frog” exclusive…some
•
terrestrial species (vs. the “arboreal” tree frog
species) also have expanded toe disks
Toe disks have evolved independently in several
lineages….a specific example of convergence in
structure. This, in a more general sense, is
known as _____________________ which….
…… is the process whereby organisms not
closely related (not monophyletic), independently evolve
similar traits as a result of having to adapt to similar
environments or ecological niches
• Bottomline:
diversity in structure and form
among anurans is considerable if one looks at
the finer points!
Ohio – 4 families represented
• Family Pelobatidae - ___________________
eastern spadefoot
• 1 species – southeast Ohio…____________
_____________________
Ohio – 4 families represented
• Family Bufonidae - ___________________
• 2 species in Ohio
eastern American toad
Ohio – 4 families represented
• Family Hylidae - ___________________
• 6 species
in Ohio
gray tree frog
Ohio – 4 families represented
• Family Ranidae - _____________________
• 6 species
in Ohio
pickerel frog