>One of the trends in fish evolution is the reduction of the scales. in
>the fish I work with for my senior thesis they are about 300my old. they
>guys have incredibly thick scales. as the fish become more refined the
>scales get thinner and thinner. by reducing the number of layers in the
>scale. the end point of this is the total lost of scales in certian
>groups of fish.
>
>one of the best books on fish. Nelson 1994 "fishes of the world".
>coveres mostly extnt fish with some fossils. It is an excellent refrence
>for all the fish at the family level. out of all the fish books this is
>one of my favorites. For classification this is the bible of
>dealing with fish. "Fishes: An Introduction to Ichthyology" by Moyle et
>al, 1999, is also a good book, it is a bit dry though, When I took
>Ichthyology we used "the diversity of Fishes" Helfman, 1997. both of
>these last two books are good. I own both of them and use them often as a
>starting place when dealing with live fishes. if you guys are intrested
>in fossil fish, most of the good books are out of print, I am still
>trying to get copies of alot of them, besides using the xerox machine.
>
>Sally
>
>On Wed, 11 Oct 2000, Sajjad Lateef wrote:
>
>>
>> Thanks. I was curious about the second type (fish that have lost
>> scales altogether) like Catfish.
>>
>> I think I ought to obtain a basic Ichthyology/Zoology book
>> (Zoology 101 college text) sometime. Any recomendations?
>>
>> Sajjad
>>
>> On Wed, 11 Oct 2000, Paleofish wrote:
>>
>> >
>> > The presence and absence of scales is a trait used to distinguis fish
>> > usually with in a family but there are numerous fish that have lost scales
>> > all together. off the top of my head I can think of several groups that
>> > have lost scales. most notably some catfish,specifically of the family
>> > arriidae another gropu of fish is leptoleips espicilly <i>Todiltia
>> > schoewei</i>. these are some middle jurassic fish that I have done some
>> > work on. These two groups are only distantly related. Better ways of
>> > classifing fish are based on skull morphology and the shape of the bones
>> > in the pelvic and pectoral girdles.
>> >
>> > Sally
>> >
>> > On Wed, 11 Oct 2000, Sajjad Lateef wrote:
>> >
>> > >
>> > > I was discussing swordfish with a friend. We were wondering if
>> > > that fish had scales or not. Does anyone know?
>> > >
>> > > Are fishes classified based on whether they have scales or not?
>> > > Are all scaleless fish classified under one class, family or
>>order? ( Or
>> > > is there an identifiable collection of fish which do not have scales? )
>> > >
>> > > Thanks in advance,
>> > > Sajjad
>> > >
>> > >
>> > >
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>> >
>> > ~~Sally Johnson~~~<}}><~~~www.unm.edu/~sbuna~~~~~~~~~~~~~~~~~~~~~~~~
>> > "Nice boy, but about as sharp as a sack of wet mice."
>> > - Foghorn Leghorn
>> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> >
>> >
>> >
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>
>
>~~Sally Johnson~~~<}}><~~~www.unm.edu/~sbuna~~~~~~~~~~~~~~~~~~~~~~~~
>"Nice boy, but about as sharp as a sack of wet mice."
> - Foghorn Leghorn
>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>
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