Amphibians PART II VERTEBRATE ZOOLOGY (VZ Lecture13 – Fall 2012 Althoff - reference PJH Chapter...

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Amphibians PART II VERTEBRATE ZOOLOGY (VZ Lecture13 – Fall 2012 Althoff - reference PJH Chapter 10)

Transcript of Amphibians PART II VERTEBRATE ZOOLOGY (VZ Lecture13 – Fall 2012 Althoff - reference PJH Chapter...

Amphibians

PART II

VERTEBRATE ZOOLOGY (VZ Lecture13 – Fall 2012 Althoff - reference PJH Chapter 10)

Classification of Amphibia

CLASS Amphibia

SUBCLASS Labryinthodonotia*

Leposondyl*

Lissamphibia

ORDER Urodela

Anura

Gymnophiona

* = extinct

(salamanders)

(frogs)

(caecilians)

Focus on Frogs• ORDER: ________ (Greek: “an” = without, “uro”= tail)

• 29 familes, ~4,800 species(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

2

2a

3 3a

4 4a

Primitive vs. Derived Skeletal Characters

Reduction number of toes on front feet

Reduction in presacral vertebrae

Pelvic girdle changes

Hind limbs & toes

5

14

short ilium,no urostyle

short

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

Fig. 10-8 p231 PJH

HINDLIMBLENGTH(longer)

FORELIMB LENGTH(longer)

walker-hopperwalker-jumper

jumperhopper-burrower

walker-hopper-burrower

hopper

swimmer

Frog Natural History & Locomotion

• ________-legged species that move by hopping frequently are wide-ranging predators

a) more vulnerable to predatorsb) shorter legs prevent rapid escapec) 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 projectionswhich 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….

• Bottomline: diversity in structure and form among anurans is considerable if one looks at the finer points!

…… is the process whereby organisms notclosely related (not monophyletic), independently evolvesimilar traits as a result of having to adapt to similarenvironments or ecological niches

Ohio – 4 families represented

• Family Pelobatidae - ___________________

• 1 species – southeast Ohio…____________ _____________________

eastern spadefoot

Ohio – 4 families represented

• Family Bufonidae - ___________________

• 2 species in Ohio eastern American toad

Ohio – 4 families represented

• Family Hylidae - ___________________

• 6 species in Ohiogray tree frog

Ohio – 4 families represented

• Family Ranidae - _____________________

• 6 species in Ohiopickerel frog