Update and a Mini-Tutorial
The project is really rolling now – we have 46 project volunteers, 128 132 verified data entries and 46 56 unverified entries. Around 12 of the volunteers (representing several different countries) have submitted data, thus qualifying them for authorship. Thank you to everyone for your assistance, and your patience as we work the kinks out of the system. Several people have written in with some very helpful suggestions and requests for clarification, and some of those will be the topic of this post. Don’t be afraid to speak up, by email to me or in the comment threads! Unless we know there’s a problem or bit of confusion (no matter how slight), we can’t take steps to fix it. Really, our feelings won’t be hurt. And there’s no such thing as a stupid question.
Clarifying Some Measurements
Although we’ll have a larger tutorial on the forelimb in just a few days, I wanted to briefly discuss the scapula, coracoid, and scapulocoracoid (illustrated below). The scapula is the shoulder blade, and the coracoid is a bone that attaches to it. When the two bones fuse up (as often happens in dinosaurs), this single element is called a “scapulocoracoid.” Now, we have entries for scapula length (a maximum length of the element) and scapulocoracoid length (another maximum length), but not coracoid length. The reason for this is that almost nobody measures coracoid length the same way – some measure along the long axis, some along the axis parallel to the scapula. Because the consistency of measurements is especially questionable, we have elected not to include the coracoid in our measurement list.
Also, scapulocoracoid length is NOT the same as adding the lengths of the scapula and coracoid. See the diagram below for a reason why. In the example shown here, adding scapula and coracoid lengths together would slightly exceed the true measurement of scapulocoracoid length.
Our second point of clarification concerns the femoral measurements. On the spreadsheet as it was originally posted, we have length (L), minimum (or midshaft) circumference (Circ), mediolateral width at midshaft (Shaft W), and antero-posterior width at midshaft (Shaft L). Of course, the last two measurements in particular were very confusing as named. My bad. In particular, Shaft L implied a measurement very close to just plain-old length. These measurements are patterned after measurements taken by Matt Carrano, for documenting changes in femoral anatomy through dinosaur evolution. In order to avoid confusion in the future, I have now changed the column labels to Midshaft ML W and Midshaft AP L. Does this work for everyone?
For Those Who Are Measuring Specimens Directly
A brief note on this now, and we’ll hopefully have a more formal tutorial later. Whenever possible, we want maximum lengths of elements. Yes, we realize that this may mean slightly different anatomical landmarks on different taxa. For the present purposes of the study (and given the relative lack of standardization in overall anatomical measurements for dinosaurs), it is presumably just easier this way. Perhaps there is an interesting discussion to be had on standardizing morphometric measurements for archosaurs, though! Thinking out loud (this is an open project, after all), that would be a pretty darned cool product from the ODP. I know that some studies (Chinnery’s work on ceratopsians, for instance) have developed standard landmarks for a subset of archosaurs. . .has anyone attempted this for archosaurs as a whole? Or attempted to develop measurements that could be compared adequately with mammals?
And Don’t Forget
When you submit data, please make sure to provide a full reference for the paper in PLoS ONE format (see here for info), and include the page number for the data that you are transcribing. This will make it easier to check or double-check entries if there is a problem. Thanks!
Also, please make sure that someone hasn’t entered or re-entered the data you have your eye on. Always use the latest versions of the verification list and task list.
Looking For References? Check out the Polyglot Paleontologist! They’ve got lots of translations of dinosaur-related papers.