Stefen (2014) Cranial morphology of the Oligocene beaver Capacikala gradatus…

Homepage Forums Open Access Papers Stefen (2014) Cranial morphology of the Oligocene beaver Capacikala gradatus…

Viewing 3 posts - 1 through 3 (of 3 total)
  • Author
  • #28861
    Lisa Lundgren

    Here’s the second paper in our weekly series on open access paleontology. Click on the link to read it yourself:

    The main point of the journal article:  

    Some key terms and their definitions might be helpful here:

    Castorids: the scientific family to which beavers belong. “Palaeocastorine” is a subfamily, and refers to ancient beavers of North America. (paleo=ancient).

    Phylogeny: a hypothesis about the evolutionary relationships among organisms. Usually, phylogenies are represented by a “tree” like diagram. Scientists use computer programs to construct phylogenies.

    Some key questions I ask myself when I read scientific papers: who, what, where, when?

    Who: A small beaver, which goes by the scientific name Capacikala gradatus

    What: Stefen, the author of the paper, studied the skull of the beaver, looking for similarities and differences in the beaver’s skull to compare it to other ancient beavers. Stefen compares the nearly complete skull to others found from the species, and indicates that it’s very challenging to tell what is what because the descriptions of these skulls are incomplete, which points to a key piece for paleontological research: always take extensive notes and draw out (or work with a paleoartist!) specimens as it could greatly benefit future researchers.

    Where: The John Day Fossil Beds in eastern Oregon. 

    When: The specimen was dated to the Oligocene, specifically, between 28.7 and 27.89 million years old.

    To summarize the paper with the main goals and findings:

    • Goal: To compare Capacikala gradatus to recent and ancient beavers because a skull that is this complete had not been described yet. The complete skull could help paleontologists determine if the beaver is actually its own species or if it belongs to a different species.
      • FINDINGS: The phylogenetic analysis showed that Capacikala gradatus is within a “sister group” of other ancient North American beavers.

    Questions we have: 

    What does it mean that the beaver is in a “sister group”? Is this important?

    There’s a lot of information about the skull and its anatomy here, maybe someone like @taorminalepore would be able to help us understand it more!

    This is more about open access publishing, but, I ‘ve noticed that on some open access journal sites, there are instances of papers that have just been “published” but in the citation, you find out that it was actually published in 2014. Can @bmacfadden or @kcrippen shed some light on what’s going on there?

    Citation: Stefen, Clara. 2014. Cranial morphology of the Oligocene beaver Capacikala gradatus from the John Day Basin and comments on the genus. Palaeontologia Electronica Vol. 17, Issue 1;25A; 29p.



    Hey all!

    Thanks for including me in this discussion, I love this topic and I’m excited to see a sort of amalgamation of all sorts of open access journals!

    Whenever I’m discussing an academic paper with my students, I’ll pull up the paper on my projector screen and walk through it, showing them that even I have to stop and make sure I understand a particular piece of jargon, or to interpret a graph. I think this kind of modeling is critical because it helps students understand that it’s really like learning another language, to sift through scientific terminology that’s relatively unfamiliar; they shouldn’t expect themselves to just dive in and understand every facet of the information!

    That being said, I really love the methods you’ve shared, @llundgren and all, on breaking a paper down into manageable chunks.

    I’m pretty sure I found this image through a thread on myFOSSIL, but here it is anyway (see attached) – Jennifer Raff has some great tips on how to begin deciphering an academic paper, and I’ve used this graphic with my students with some pretty good success, as a baseline.

    As far as the anatomy goes – man, there’s the other language, and in this case it really is learning to decipher Latin and Greek, of course…so I’d start students with a diagram of a modern beaver skull, like this one: 

    …So they can become familiar with the “map” of a skull, and I’d probably lead them through it by translating most of the words into something a bit clearer. Though, I’ve found with a lot of my ESL students, especially Spanish-speaking students, that the Latin terms often help them remember what each feature is.

    Whew! Happy to chat more about this. (Also, if I may gush for a moment – what a freaking cool beaver paper! :D)

    Best wishes, all.



    You must be logged in to view attached files.
    Sadie Mills

    Thanks @llundgren for the summary, and @taorminalepore for the great overview of the skull anatomy terms!

    Like Lisa wrote in her summary, I wondered what a “sister group” means? It had been a while since my college evolutionary biology classes, so I did some Googling to review and found a great, short phylogeny overview from UC Berkeley, including a simple sister group diagram:

    The authors mention that their phylogenetic conclusions should be viewed with caution, however, due to low bootstrap support.  @jbokor, @bmacfadden, @smoran – you were all recommended as people with phylogenetic knowledge, can anyone help explain what that means? Thanks!

    You must be logged in to view attached files.
Viewing 3 posts - 1 through 3 (of 3 total)

You must be logged in to reply to this topic.