Just an FWI to help out, (I reopened this thread to post it, but did not initially close it)
A peer reviewed article is generally any article in any scientific journal! They are not at all hard to find at the library. In the publication of a scientific article, in a reputable journal, the article is submitted, and sent off to colleagues for review. These reviewers submit suggested changes to the article, or, submit it for publication. This is the 'peer review' process.
Go to the library and search something like zoological records, or any paleo journal...there are, I AM SURE, loads of articles on this shark. You may not find them on the boards, and I am quite sure your prof did not intend online journals to be a source. These are usually frowned upon in the scientific community and are not typically peer reviewed. While you may find some background info, using or quoting online sources may not meet the assignment. Sometimes you can find the abstract of articles on line (some journals do this), but rarely the whole paper.
Here are some paleo journals with online links (though I don't know to what):
paleontology links
You are being asked to write a short paper with two references from scientific journals, from what I can tell (meaning, NOT the encyclopedia, online articles and the like, but a journal like Nature, Science, paleo journals, systematic biology, etc). This should not be difficult to find at the library, but you may need to go there, and not just search online.
They are trying to get you experience in going to use scientific sources. Some day, such an assignment will be a welcome easy little half hour project. FWIW, I suggest you go to the library to get these references, and not rely on others. FYI: this is a major peeve of mine (getting emails from students saying "send me your references on such and such"). It is a bad habit to get into. Really bad, so I don't suggest it! Go to the library, now that you have the name, and look up the journals. It is a very very very very very (infinity....) important skill to learn as a scientist (perhaps the most fundamental skill), and there are all sorts of computer software at the library to help you with this.
