Home > Uncategorized > The Data Set (as it sits now)

The Data Set (as it sits now)

The ODP has accumulated a whole lot of data, and now we have to make some sense out of it. The first step was to pare it down from the original monstrous mass. Based on a very lively discussion (see this post and links therein), the data are pretty much trimmed. In addition to posting a link to those data (in response to this query by Hiro), I wanted to explain some of what I’ve done with the data.

The file, freely available as an Excel workbook, contains several spreadsheets. These are explained below, by spreadsheet:

  • To Analyze: Includes all of the data, minus highly incomplete or juvenile specimens. As you may recall, juveniles were rates as those listed as such in the literature, or individuals which were less than 2/3 the size of the largest individual for a species.
  • Deletion Candidates: The home for the highly incomplete or juvenile specimens mentioned above. We don’t want to throw them away, after all.
  • Fore Hind1 & ForeHind 2: Worksheets where I was just playing around with various ways of looking at the combined data.
  • Ratios: A whole bunch of ratios between various limb elements; it’s worth exploring. This will require a more detailed post in the not-so-distant future, to explain many of these.

You’ll probably notice the abbreviation “IM”. This refers to an intermembral index – basically, the ratio between forelimb and hind limb length. There are several ways to calculate it. These include:

  • IM1(U)=(Humerus+Ulna)/(Femur+Tibia)
  • IM2(U)=(Humerus+Ulna+MCIII)/(Femur+Tibia+MTIII)
  • IM1(R)=(Humerus+Radius)/(Femur+Tibia)
  • IM2(R)=(Humerus+Radius+MCIII)/(Femur+Tibia+MTIII)

There are several other possible ways to calculate this, but they often aren’t practical in terms of missing data (many more tibiae are known than fibulae). I would suggest that intermembral indices calculated with the radius are most desirable, for two reasons. First, the radius is a widely preserved and measured bone. Second, you don’t have to deal with the olecranon process, which exaggerates the functional length of the ulna in some animals.

There you have it! Comments?

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Categories: Uncategorized
  1. Jordan
    November 14, 2010 at 5:40 am

    Any plans to impute the missing data somehow?

  2. Andy Farke
    November 15, 2010 at 2:46 am

    Jordan :

    Any plans to impute the missing data somehow?

    Haven’t thought too much about that – anyone have thoughts? Although it would certainly help to round out the dataset, there are some animals (ankylosaurs and pachycephalosaurs and stegosaurs, for instance) for which there are so few measurements that imputation from distantly related animals would be rather hazardous!

  3. John Dziak
    December 15, 2010 at 8:50 pm

    I wondered whether the dataset was closed or whether you might want to include Koreanosaurus.

  4. John Dziak
    December 15, 2010 at 8:52 pm

    I thought Koreanosaurus might be an interesting newly discovered basal ornithopod, but the article is not easy to get and I couldn’t get it.
    http://www.ingentaconnect.com/content/schweiz/njbgeol/pre-prints/0102

  5. David W Dreisigmeyer
    February 11, 2011 at 3:06 pm

    Here’s a new paper which may be of interest:

    http://www.ncbi.nlm.nih.gov/pubmed/21308346

  1. November 16, 2010 at 4:52 am

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