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Herpetology: the Biology of Tetrapods (BIOEE 470 and 472). • Do we need to order more Pough et al. (a copy is on reserve in Mann Library)? • If you are going to drop the lab, please do so ASAP... • Thanks for your feedback… Any questions about the last lecture?.

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Herpetology: the Biology of Tetrapods (BIOEE 470 and 472)

• Do we need to order more Pough et al. (a copy is on reserve in Mann Library)?

• If you are going to drop the lab, please do so ASAP...

• Thanks for your feedback… Any questions about the last lecture?

Calling male leaf rog (Phyllomedusa sauvagii)

Photo:H.W.Greene

Course website: www.eeb.cornell.edu/herpetology/index.html


Phylogenetic classification of living salamanders*…

Urodela

Sirenidae (2 genera/4 species)

Neocaudata

Cryptobranchoidea

Cryptobranchidae (2/3)

Hynobiidae (9/43)

Salamandroidea* *

Ambystomatidae (1/30)

Amphiuma (1/3)

Dicamptodontidae (1/4)

Plethodontidae (27/360)

Proteiidae (2/6)

Rhyacotriton (1/4)

Salamandridae (15/62)

*salamanders, newts, etc.

* * unresolved polytomy

(Andrias japonicus, Cryptobranchidae, photo:A.Savitzky)

(Pseudoeurycea bellii, Plethodontidae, photo:J.Sigala)


Herpetology: the Biology of Tetrapods

• A spectacular book: James W. Petranka, Salamanders of the United States and Canada, Smithsonian Institution Press

• Reading assignment: Pough et al., Chapter 8 (for now concentrate on the sections that pertain to salamanders), Chapter 11 (pp. 385-388, 400-403), and Chapter 13 (pp. 465-471)… You should also browse this excellent textbook for things that catch your eye, or just look up some topic or kind of organism that especially fascinates you. Perhaps first skim the text of a particular chapter, then look at the figures and their legends, then read the text, and finally seek the vocabulary and answers to assigned questions.


“Typical” or primitive amphibian complex life cycle …

Aquatic eggs and carnivorous larvae, metamorphosis, carnivorous terrestrial adults (here Pacific giant salamanders, Dicamptodon)

Photo: E.D.Brodie Jr.

Photo: H.W.Greene

Photo: S.Deban


Major innovations in salamander evolution…

Internal fertilization: females have spermathecae, males deposit spermatophores

Photos:L. Houck & S. J. Arnold


Cryptobranchidae

Dicamptodontidae

Rhyacotritonidae

Ambystomatidae

Gymnophiona

Salamandridae

Amphiumidae

Plethodontidae

Hynobiidae

Sirenidae

Proteiidae

Anura

Innovations and trends in salamander evolution…

• Internal fertilization, spermatophores, and spermathecae

• Hey, how am I getting these trees and how is character evolution inferred?

• Can you name these nodes?

• Caecilians have a phalloideum!

• Problematic sirenids and proteiids…


Dicamptodontidae

Cryptobranchidae

Ambystomatidae

Rhyacotritonidae

Plethodontidae

Salamandridae

Gymnophiona

Amphiumidae

Hynobiidae

Proteiidae

Sirenidae

Anura

A revolution in amphibian biology?

• D. Frost et al., 2006, The Amphibian tree of life. Bulletin of the Amer. Mus. Nat. Hist. 297:1-370 (free from AMNH website)

• ca. 5,000 base pairs for >500 species representing major amphibian taxa

• Controversial, stay tuned!

• Cryptobranchoidea and Salamandroidea

• Sirenidae and Proteiidae

• Dicamptodon in Ambystomatidae

• Ambystomatidae and Salamandridae

• Rhacotritonidae, Amphiumidae, Plethodontidae


Living cryptobranchids…

• Content and biogeography

• Size and feeding biology

• Social system: “den masters”

• Esthetic and conservation issues

Japanese Giant Salamander

(Andrias japonicus)

(Photos:A.H.Savitzky)


Fossil cryptobranchids…

K. Gao and N. H. Shubin, 2003, Earliest known crown-group salamanders. Nature 422:424-428

Chunerpeton tianyiensis (“early creeping animal from Tianyi”), Late Jurassic (161 mya)


What about the other living cryptobranchoids?

Hynobiidae:

• Asian land salamanders

• Modest diversity of form and ecology, all fairly small

• External fertilization

• Does this one remind you of any U. S. salamanders?

Hynobius leechii (Hynobiidae, photo:H.W.Greene)


Morphological diversity in salamandroids…

Body elongation and limb reduction or loss:

• Accomplished by longer vertebrae or more vertebrae, even within Plethodontidae…

• How many times in the U.S.?

Oedipina poeltzi (Plethodontidae, photo: M.&P.Fogden)


More morphological diversity in salamandroids: eye loss

• How many times in the U.S., in which taxa (see Field Guide)?

• How many times elsewhere, in which taxa (see Pough et al.)?

• Associated with particular natural histories?

• Where could a herp ecotourist see a blind cave salamander?

Texas Blind Salamander (Eurycea [Typhlomolge] rathbuni, Plethodontidae, photo:D.Sessler


Where to see blind cave salamanders in the U.S.

“The best public site for Grotto Salamanders is Round Spring Cavern, Shannon Co., operated by the Ozark National Scenic Riverways, National Park Service… they conduct electric lantern tours on a trail through the cave. In recent years 1 to 4 might be seen in shallow pools or the cave stream, along with Cave Salamanders and Eastern Pipistrelle bats. It's very educational, and the lack of trail lights allows it to remain pretty natural. The cave has many speleothems (formations), so it's good all-around… visit my website (www.utexas.edu/depts/tnhc/.www/biospeleology) to find photos of Grotto Salamanders and other cave life.” (email 2/8/05 from Bill Elliott, Cave Biologist for the MO Department of Conservation)


Life history diversity: paedomorphosis

• Retention of embryonic, larval, or juvenile traits in reproductive adults

• A subset of heterochrony, evolutionary changes in the timing of developmental events

• Widespread to varying degrees in salamanders, and they have played a prominent role in understanding heterochrony and paedomorphosis

• Reproduction as larvae occurs in a few ambystomatids, dicamptodontids, plethodontids, and salamandrids, as well as in all proteiids and sirenids

Tiger Salamander (Ambystoma tigrinum, Ambystomatidae, photo:H.W.Greene)

Axolotl (Ambystoma mexicanum, Ambystomatidae, photo:N.W.Cohen)


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