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January 7, 2009

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Shark Teeth

New species??...

New species??

1/19/2003 5:10:48 AM

legacyForum

725 posts

New species??

I was just reading a book about Megalodon and shark evolution, and not being a scientist, I started wondering how and why new species are defined. It seemed odd that (according to the book) there were a bunch of species defined in the progression of Otodus obliquus to megalodon, especially early on when Otodus started developing serrations. Yet for teeth like P. benedeni, even though the teeth went through some relatively big changes, there has only been one species defined over the millions and millions of years during which the changes occurred. Just seems odd to me. Any comments?

1/19/2003 7:11:27 PM

legacyForum

725 posts

Re: New species??

Well, I don't know the specifics of the species you mentioned but a species is defined as a group of animals which can mate with each other to reproduce fertile offspring(creatures that produce Asexually are tricky, Im not sure what the criterea are for them). For example, a donkey and a horse can mate to produce a mule but as mules are always sterill, the donkey and horse are considered seperate species. Drew

1/21/2003 6:08:15 AM

legacyForum

725 posts

Re: New species??

Thanks for the response, but I guess my question is more geared toward the shark species I mentioned. It just seems inconsistent to have in one case so many Carcharocles species defined along the evolutionary line, where it seems a new species is defined when each slight change (ie, serrations get a little less coarse) occurs. Yet on other hand, as discussed on this forum, P. benedeni went, over 30 or so million years, from being relatively small and side cusped to being large and lacking side cusps without being separated into different species. I guess maybe it has more to do with how much interest scientists have in a particular evolutionary line. So I guess my question is, at what point does someone say, "Hey, this is not a C. auriculatus tooth but neither is it a C. angustidens; it's an new, intermediate species that I will name after myself."?

1/26/2003 3:19:18 PM

ditchweezil

347 posts

Re: New species??

I think the reason is because more people have studied the carcharocles / carcharodon lineage so more is known. I have looked all over the place for information on parotodus but next to nothing is known. Clearly there are diffferences in the oligocene species not present in the miocene/pliocene species. I've heard from different things reputable sources, and that makes it more difficult. One source says that the oligocene variety is the same genus but a different species. Others say there is no difference at all. This may have to be one of those "personal preference" kind of things until someone out there with the answer either writes a book or comes across this forum!

2/9/2003 2:19:09 PM

legacyForum

725 posts

Re: New species??

It's in human nature to want to put a name on every tooth and a different name on anything that deviates from the visible norm. This clashes sometimes with science. There's still a lot to be researched about fossil sharks. Think about all synonyms too and evolution names... In Russia p. ex. they divided Otodus-Carcharocles evolution in much more names than in the USA, For me they're only names to know what we're talking about check the excellent work of Lutz Andrez here : http://www.fossilguy.com/topics/megshark/evolution_lines.htm For me the names are less important then the knowledge how a certain species evolved... In situ fossils are very important here...

2/10/2004 11:09:10 AM

legacyForum

725 posts

Re: New species??

This is carcharocles subserrata?; and Carcharocles auriculatus var. disauris; and carcharocles sokolowi (very C. auiuculatus; Carcharocles debray;Procacharodon (very auriculatus); Carcharocles ¿askuaticus?. bye

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