Transcript Lecture 22 January 2015

Amphibians
Amphibian diversity
• Anura (frogs, ~4000 sp.); Caudata (salamanders,
~450 sp.); Gymnophiona (caecilians, ~175 sp.)
Amphibian characteristics
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Skin
– permeable
– respiration
– mucous glands
– poison glands
biphasic lifestyle
second hearing system
unique retinal cells
skull
– paired occipital condyles
– reduction/loss of bones
– orientation of stapes
short ribs
declining populations
Caecilian characteristics
• No limbs, reduced or
absent girdles
• Annuli
• Solidified skull with
– Eyes reduced/absent
– Fusion of bones
– Roofed, few/no fossa
• Tentacle
• Phallodeum
Siphonops annulatus
Salamander characteristics
• Tailed, most with four limbs, four digits on front limbs, five
digits on hindlimbs
• Aquatic, terrestrial/fossorial, arboreal
• Breathe through lungs, gills, and/or skin
• Sprawling gait
• Large genome
– 15-90 pg (humans: 3pg)
• Diverse life cycles,
reproductive modes
--mostly internal fertilization
Frog characteristics
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Squat, tailless body
Fused limb bones
Hindlimbs > forelimbs
Few vertebrae
Terrestrial, arboreal, aquatic
Great diversity of reproductive
modes
– Mostly external fertilization
• Many species with protrusible
tongue for feeding
Reptile diversity
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Turtles (Chelonia) 300 species
Crocodiles, alligators, caimans (Crocodylia) 27 species
Tuatara (Sphenodon) 1-2 species
Lizards, snakes, amphisbaenids (Squamata) 6000 species
Birds (Aves) 9000 species
Reptile characteristics
• Dry, scaly outer covering
• Shelled eggs laid on land
• Ectotherms
Turtle characteristics
• Shell
• Fused to ribs
• Fused to vertebrae
• Terrestrial or aquatic
• Limb girdles lie inside
ribcage
• Jaws lack teeth
Crocodylian characteristics
• Alligators, caimans,
crocodiles, gavials
• Large
– 1-8 meters
• Complex parental care
• Top-end predators
Lizard characteristics
• 6000+ species
• 2 or 4 limbs, or limbless
• Oviparous, viviparous,
ovoviviparous
• Terrestrial, semiaquatic,
arboreal, fossorial
What is Herpetology?
• The study of amphibians and reptiles
• Greek root
– Herpein: to creep
– Herpeton: creeping animal
• "To herp" (verb): to look for herps
• "Herps"
– Amphibians: frogs, salamanders, caecilians
– "Reptiles": lizards, amphisbaenids, snakes,
crocodylians, tuataras, turtles
Why study amphibians and "reptiles"
together as a single group?
• An evolutionary grouping?
– Amphibians and reptiles closest relatives?
• Shared characteristics?
– E.g., ectothermy?
• Tradition?
– History
Diapsida
Why study amphibians and reptiles together as a
single group?
• An evolutionary grouping?
– Amphibians and reptiles are not closest relatives
• Shared characteristics?
– E.g., ectothermy?
• Tradition?
– History
Shared characteristics of reptiles and
amphibians
• Ectothermy
– Thermoregulation
– Energy requirements
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Body size and shape
Lay eggs (most)
Terrestrial (most)
Lack fur and feathers…
Differences between reptiles and
amphibians
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Amniotic egg
Integument
Claws
Heart
Skull
Fertilization
Moisture environment
Why study amphibians and reptiles together as a
single group?
• An evolutionary grouping?
– Amphibians and reptiles are not close relatives
• Shared characteristics?
– Amphibians and reptiles differ greatly in anatomy
and physiology
• Tradition?
– History
Why study amphibians and reptiles
together? Tradition!
"Most amphibia are abhorrent
because of their cold body,
pale colour, cartilaginous
skeleton, filthy skin, fierce
aspect, calculating eye,
offensive smell, harsh voice,
squalid habitation, and
terrible venom; and so their
Creator has not exerted his
powers to make many of
them."
Linnaeus (1750)
History of Herpetology
Contributions to the History of Herpetology
Kraig Adler; ssarherps.org
• Aristotle (384-322 BC): blood, locomotion, limbs, eggs
• Carol Linnaeus (1707-1778): Systema Naturae (1735+)
• 1700s-1800s: France is center
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G. Buffon: Histoire Naturelle (1749-88)
B. Lacepede: Histoire des Quadrupedes Ovipares et des Serpientes (1789)
A. Brongniart (1799): Separation of Batrachians (amphibians)
F. Daudin: Histoire Naturelle des Reptiles (1802)
A. Dumeril and G. Bibron: Erpetologie Generale (1834-54)
History of Herpetology
• Mid-1800s: Great Britain (J. Gray, A. Gunther, G.
Boulenger)
• Late 1800s: North America emerges
– J. Holbrook: North American Herpetology (1836-42)
– E. D. Cope: The Crocodilians, Lizards, and Snakes of North
America (1900)
– L. Stejneger: Herpetology of Puerto Rico (1904)
Doris Cochran 1898-1968
Curator of Herpetology, Smithsonian 1942-1968
Herpetology in the US today
• UC Berkeley
– C Camp, R Stebbins, D Wake, M Wake, H Greene, C Moritz, J Mc Guire
• U of Kansas
– E Taylor, J Tihen, H Smith, H Fitch, W Duellman, L Trueb, R Brown, R Glor
• USNM (Smithsonian)
– D Cochran, J Peters, G Zug, R McDiarmid, R Heyer, K de Queiroz
• UT Austin
– F Blair, D Cannatella, D Hillis, E Pianka, M Ryan, C Gans
• Harvard
– T Barbour, A Romer, A Loveridge, E Williams, P Alberch, J Cadle, J Hanken, J Losos
• American Museum of Natural History
– M Dickerson, G Noble, C Bogart, C Myers, C Cole, D Frost
Herpetological societies
• American Society of Ichthyologists and
Herpetologists (ASIH; 1913; Copeia)
• Herpetologists’ League (HL; 1946;
Herpetologica, Herpetological Monographs)
• Society for the Study of Amphibians and
Reptiles (SSAR; 1958; Journal of Herpetology,
Herpetological Review)
Web resources
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Amphibiaweb.org
reptile-database.org
ssarherps.org
asih.org
herpetologistsleague.org
Journals
• Journal of Herpetology, Copeia,
Herpetologica, Amphibia-Reptilia,
Herpetological Conservation &Biology,
Herpetology Notes, Phyllomedusa, Journal
of Mesoamerican Herpetology, African
Journal of Herpetology, Salamandra,
Herpetological Monographs,
Chelonian Conservation &Biology…
Systematics
• Phylogenetics
• Taxonomy
– Classification
– Nomenclature
• Species and higher level taxa
Species concepts
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Phenetic species concept: A species is a set of organisms that look similar to each
other and distinct from other sets (Ridley, 1993).
Species concepts
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Phenetic species concept: A species is a set of organisms that look similar to each
other and distinct from other sets (Ridley, 1993).
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Ecological species concept: A species is a set of organisms exploiting (or adapted
to) a single niche (Ridley 1993).
Species concepts
•
Phenetic species concept: A species is a set of organisms that look similar to each
other and distinct from other sets (Ridley, 1993).
•
Ecological species concept: A species is a set of organisms exploiting (or adapted
to) a single niche (Ridley 1993).
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Biological species concept: Species are groups of actually or potentially
interbreeding natural populations, which are reproductively isolated from other
such groups (Mayr, 1940).
Species concepts
•
Phenetic species concept: A species is a set of organisms that look similar to each
other and distinct from other sets (Ridley, 1993).
•
Ecological species concept: A species is a set of organisms exploiting (or adapted
to) a single niche (Ridley 1993).
•
Biological species concept: Species are groups of actually or potentially
interbreeding natural populations, which are reproductively isolated from other
such groups (Mayr, 1940).
•
Evolutionary species concept: A species is a single lineage of ancestor-descendant
populations which maintain its identity from other such lineages and which has its
own evolutionary tendencies and historical fate (Wiley, 1981).
Species concepts
•
Phenetic species concept: A species is a set of organisms that look similar to each
other and distinct from other sets (Ridley, 1993).
•
Ecological species concept: A species is a set of organisms exploiting (or adapted
to) a single niche (Ridley 1993).
•
Biological species concept: Species are groups of actually or potentially
interbreeding natural populations, which are reproductively isolated from other
such groups (Mayr, 1940).
•
Evolutionary species concept: A species is a single lineage of ancestor-descendant
populations which maintain its identity from other such lineages and which has its
own evolutionary tendencies and historical fate (Wiley, 1981).
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Phylogenetic species concept: A species is the smallest diagnosable cluster of
individual organisms within which there is a parental pattern of ancestry and
descent (Cracraft 1983).
Species concepts: History
• Pre-1942
– Typology
– Key reading: Aristotle
• 1940s-1990s
– Operationalism
– Interbreeding
– Key reading: Mayr 1942
• 1990s-now
– Species = evolutionary lineages (Simpson1961)
– Operational/conceptual distinction
– Key reading: Wiley 1981, de Queiroz 1998, Frost and Kluge 1994