Class Notes (922,334)
CA (542,800)
UTM (24,991)
Biology (2,327)
BIO356H5 (3)
Lecture 8

lecture 8

7 Pages
74 Views

Department
Biology
Course Code
BIO356H5
Professor
Michaelde Braga

This preview shows pages 1-2. Sign up to view the full 7 pages of the document.
Lecture 8- Lepospondyls and Lissamphibia
-When point is emphasized more (like stapes or evolution of the limb –look at pdf)->those are the things that need to
focus on; dont worry about memorizing all the taxa names or all the character traits (b/c theres so many listed) but
need to know some of the basic things (like interterygoid vacuity in temnospondyls). If theres 7 or 8 characters, not
going to ask to list all of them. As long as you have a sense of what character traits diagnose a particular group (like
one good character trait or something prof emphasized) then focus on that.
- Lissamphibia- if group is monophyletic, that means frogs, salamanders and caecilians have a
common ancestor but there is a lot of controversy because the modern amphibians today have
become so highly derived in their general appearance that its very hard to find direct links to any
fossil groups-> getting lucky w/ frogs and salamanders but so far, caecilians are a problem
- Lepospondyls- group that includes the microsaurs (recall: initially thought of as a reptile but
realized its not- just a specialized amphibian); will spend quite bit of time on lepospondyls
1.) Lepospondyls- appear in the Mississipian
united by a few characters (synapomorphy); most significant one is:
NO labyrinth infolding in teeth (the teeth are infolded, creating a labyrinth type structure
(like a maze) and has little grooves all around it)- no more of this grooving
Large cylindrical centra: centra associated w/ the vertebrate in most other groups tend to
be combinations of various elements. In lepospondyls, they look like a spool of thread
(very different)- still hollow
2.) Lepospondyl Diversity- fairly diverse; 3 major groups: Aistopoda, Nectridea and Microsauria;
Microsaur is probably paraphyletic
3.) Aistopods: wormlike, limbless creatures- not worms, they are proper vertebrates
Snake-like in appearance; quite small
appear in the Mississipian and continue to Permian; they disappear in the Lower Permian
(not sure why b/c it wasnt b/c of a mass extinction)
oldest known group member is Lethiscus
4.) Aistopod synapomorphies:
www.notesolution.com
skulls are very fenestrated- have lots of big holes and openings in skull; unlike the
temnospondyls which had very massive and heavily ossified skulls, aistopods have no
ornamentation of skulls, lots of big holes in skull; very fine and delicate bones
Very long bodies
No limbs (or even limb girdles); lost all indication of limbs
Intercentra are absent;
In tail region which tends in amphibians to be fairly flat, even in short tail amphibians. In these,
the tails have become cylindrical and pointy.
-Lost haemal arches (ventral extension of the tail)- from the tails shown before, have
neural spines on top of centrum and haemal spine at bottom; in aistopod amphibians,
haemal spines disappear and neural spines (arch) shortens so tails are not deep and are
very cylindrical-> very worm-like and tube-like in structure
5.)
Long body; Very fine, small bones- extremely delicate
Typical skull: huge openings all the way through, bones very fragile and delicate;
braincase totally open
aquatic or fossorial (live in burrows).They might have existed in burrows but b/c their
skulls are so fragile and delicate, wouldnt have dug the burrows themselves. More likely
to be swimmers.
6.) Nectrideans- also elongate but unlike the aistopods, they still retained limbs (very small but
still have limbs); extend from Lower Pensylvanian to Lower Permian ( so something existed in
Lower Permian to wipe out the leponspondyls at the time)
Important synapomorphies:
have flat, wide, short skulls-
Large tabular and squamosal (2 bones associated w/ the skull)
Have very pronounced tabular horn (extension of tabular) that gives boomerang-like
skull appearance
No intertemporal bone (bone had been lost independently in a few earlier taxa such as the
Ichthyostegids as well)
www.notesolution.com

Loved by over 2.2 million students

Over 90% improved by at least one letter grade.

Leah — University of Toronto

OneClass has been such a huge help in my studies at UofT especially since I am a transfer student. OneClass is the study buddy I never had before and definitely gives me the extra push to get from a B to an A!

Leah — University of Toronto
Saarim — University of Michigan

Balancing social life With academics can be difficult, that is why I'm so glad that OneClass is out there where I can find the top notes for all of my classes. Now I can be the all-star student I want to be.

Saarim — University of Michigan
Jenna — University of Wisconsin

As a college student living on a college budget, I love how easy it is to earn gift cards just by submitting my notes.

Jenna — University of Wisconsin
Anne — University of California

OneClass has allowed me to catch up with my most difficult course! #lifesaver

Anne — University of California
Description
Lecture 8- Lepospondyls and Lissamphibia -When point is emphasized more (like stapes or evolution of the limb look at pdf)->those are the things that need to focus on; dont worry about memorizing all the taxa names or all the character traits (bc theres so many listed) but need to know some of the basic things (like interterygoid vacuity in temnospondyls). If theres 7 or 8 characters, not going to ask to list all of them. As long as you have a sense of what character traits diagnose a particular group (like one good character trait or something prof emphasized) then focus on that. - Lissamphibia- if group is monophyletic, that means frogs, salamanders and caecilians have a common ancestor but there is a lot of controversy because the modern amphibians today have become so highly derived in their general appearance that its very hard to find direct links to any fossil groups-> getting lucky w frogs and salamanders but so far, caecilians are a problem - Lepospondyls- group that includes the microsaurs (recall: initially thought of as a reptile but realized its not- just a specialized amphibian); will spend quite bit of time on lepospondyls 1.) Lepospondyls- appear in the Mississipian united by a few characters (synapomorphy); most significant one is: NO labyrinth infolding in teeth (the teeth are infolded, creating a labyrinth type structure (like a maze) and has little grooves all around it)- no more of this grooving Large cylindrical centra: centra associated w the vertebrate in most other groups tend to be combinations of various elements. In lepospondyls, they look like a spool of thread (very different)- still hollow 2.) Lepospondyl Diversity- fairly diverse; 3 major groups: Aistopoda, Nectridea and Microsauria; Microsaur is probably paraphyletic 3.) Aistopods: wormlike, limbless creatures- not worms, they are proper vertebrates Snake-like in appearance; quite small appear in the Mississipian and continue to Permian; they disappear in the Lower Permian (not sure why bc it wasnt bc of a mass extinction) oldest known group member is Lethiscus 4.) Aistopod synapomorphies: www.notesolution.com
More Less
Unlock Document


Only pages 1-2 are available for preview. Some parts have been intentionally blurred.

Unlock Document
You're Reading a Preview

Unlock to view full version

Unlock Document

Log In


OR

Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit