Herpetology: the Biology of Tetrapods BIOEE 470 and 472

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Herpetology the Biology of Tetrapods (BIOEE 470
and 472)
What about that midterm? And what about that
lab exam? What about GRADES??!! Are grades
curved in this class?
This is Harrys favorite lizard, Gerrhonotus
infernalis (Big Bend National Park, Texas,
photoH.W.Greene)
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Herpetology The Biology of Tetrapods
Tetrapoda (tetrapods) Amphibia (amphibians)
Gymnophiona Urodela
Anura Amniota (amniotes) Mammalia
(mammals) Reptilia (reptiles)
Testudines (turtles)
Lepidosauria (tuatara and lizards, including
snakes) Archosauria (archosaurs)
Crocodylia (alligators,
crocodiles, and gharials)
Aves (birds)
How much information can YOUusing lecture, text,
lab, TV, the web, etc.pack into this scheme?
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Regarding early eovlution of tetrapods
Aquatic origin, limbs provided support for a
creepy ambush lifestyle Later terrestrial,
perhaps for dispersal and feeding
Terrestriality associated with adaptations for
support, respiration, seizing (not sucking) prey,
and hearing Ancient divergence lead to two
surviving lineages, the Amphibia (or
Lissamphibia) and Amniota Each lineage
illustrates diverse examples of spectacular
descent with modification and convergent
evolution, from body elongation and limb loss to
viviparity and highly protrusible tongues
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More on early tetrapod evolution
One lineage of generally slow, clumsy animals
(limbs used as holdfasts) with inefficient
respiration, moist skin, small gelatinous eggs,
and secretive lifestyles includes extant
Amphibia And remember, there are more species
of frogs than of mammals! Wonder why that is?
Andrias japonicus (photoA.H.Savitzky)
Synapturanus mirandoriberioi (photoH.W.Greene)
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Still more on early tetrapod evolution
One lineage of generally fast, agile animals
(limbs used as levers) with rib-driven
ventilation, dry elaborated skin, large shelled
eggs, and obstreperous lifestyles includes extant
Amniota Reptiles are more closely related to
mammals than they are to amphibians so why have
mammals traditionally been excluded from
herpetology?
Upper Enyalius, Lower Conepatus semistriatus
(both Brazil, photosH.W.Greene)
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Regarding early evolution of amniotes
Amniotic membranes increased capacity for
exchange, storage, and support, while the shell
provided protection from desiccation they
permitted an egg gt10mm in diameter Larger egg
allowed larger hatchling and thus no larval
stage, and thus more freedom from water and
terrestrial feeding at an early life stage
Ancestral amniote were probably small, perhaps
associated with rise of insects as prey
Gerrhonotus infernalis (photosH.W.Greene)
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Why study mammals in herpetology?
More closely related to reptiles than are
Amphibia Fill out the tetrapod tree
Contemplate reptiles plus mammals versus
amphibians in terms of similarities and
differences, primitive and derived... Until
recently no Mammalogy course at Cornell but
now We are mammals!
Lion (Panthera leo, Africa, photoL.M.Chan)did
you know this species was widespread in North
America until about 100 centuries ago, and some
of us are trying to bring it back? Are we crazy?
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What is a mammal?
Viviparity is not diagnostic! Lactation (L.
lactis, milk mamma, breast) and mammary glands,
which are derived from skin glands No need for
external (seasonally variable) food source
Smaller fetal burden (lt20 versus lt50) Can
you think of an amphibian analog to lactation?
Longhorns (Bos taurinus, Wichita Mountains, OK
photosH.W.Greene)
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What is a mammal?
Endothermy (convergent in birds) associated
with hair, insulation, locomotion, and
respiration Jaw joint, dentition, secondary
palate Facial muscles for suckling, social
communication auditory sensitivity
Prairie Dogs (Cynomys ludovicianus, OK,
photosH.W.Greene)
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Who are the Synapsida?
Therapsids, and the incremental, sometimes
convergent attainment of mammal characters
Monotremes (3 species, 2-10 kg) Platypus and
echidnas, keep their eggs in pouch or burrows,
endemic to Australia and New Guinea Marsupials
(275 species, 5-90 kg) opossums, kangaroos,
etc. pouched young, 1 inch in a kangaroos the
size of a human female endemic to neotropics
and Australia marsupial "moles," "minks,"
"lions," "flying squirrels," etc.spectacular
examples of convergence possible independent
and alternate version of viviparity Eutherians
(4,165 species) placental mammals
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Most mammals are eutherians
Placenta for counter current fetal and maternal
blood flow as well as exchange of nutrients,
waste, gases Diversity highest in rodents,
next bats extremely varied lifestyles, more so
in the past (e.g, giant ground sloths) Blue
Whale, 120 tons, largest animal that ever lived,
with big brain etc. and now endangered...
Bison (Bison bison, Wichita Mtns, OK,
photosH.W.Greene)
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Eutherian Diversity(Approximate numbers of
species in parentheses)
Xenarthra (30) anteaters, sloths, armadillos
20 g-33 kg Insectivora (390) shrews, moles,
hedgehogs 2 g-1 kg Lagomorpha (69) pikas,
rabbits, hares 180 g-7 kg Rodentia (1814)
mice, squirrels, capybara, etc. 7 g-gt50kg
Artiodactyla (213) swine, hippos, deer, sheep,
cattle, etc. 2.5-3,600 kg Cetacea (80)
porpoises, toothed whales, baleen whales
20-200,000 kg
(PhotosH.W.Greene)
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Eutherian Diversity(Approximate numbers of
species in parentheses)
Primates (235) lemurs, monkeys, apes, humans
85 g-gt275 kg Chiroptera (986) bats 4 g-1.4
kg Carnivora (274) dogs, cats, bears,
raccoons, sea lions, etc. 70 g-760 kg
Perissodactyla (17) horses, tapirs, rhinos
200-3,600 kg Proboscidea (2 or 3) elephants
4,500-7,000 kg Sirenia (4) dugongs, manatees
140-gt1,000 kg
Zebra photographed in TX by H.W.Greenewhy am I
interested in TX Zebras?
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Herpetology The Biology of Tetrapods
Next reading assignment Pough et al., Ch. 4, pp.
97-111 and pp.169-173 New vocabulary carapace,
plastron, bridge, scutes, osteoderm, Pleurodira,
Cryptodira, Carettochelyidae, Ninjemys,
Chelydridae, Cheloniidae, Dermochelyidae,
Emydidae, Terrapene, Testudinidae, Gopherus,
Trionychidae, Kinosternidae, Alligatoridae,
Crocodylidae, Gavialidae, thecodont
Tetrapoda Amphibia Amniota
Mammalia Reptilia
Testudines Archosauria
Crocodylia Aves
Lepidosauria