If You Don’t Know What It Is, Keep It! by Bob Simon

Often when digging in the bone bed, we encounter numerous dinosaur bone fragments and partial specimens. The difficulty arises when you try to identify a specimen in the field - especially when it is covered in matrix and looks to be too fragile to remove any of the enclosing rock to determine its ‘ID’.

When left with such a puzzle, we always ‘bag and tag’ bones with locality information and dates to keep accurate records, regardless of their current state. Tentative IDs are sometimes “UDO” (Unidentified Dinosaur Object), “rib section” (good fall-back option for thin, elongate bone pieces) or simply a big question mark.

The key is to SAVE EVERYTHING, as you never know what might be lurking in the matrix. 

One such mystery bone was placed in a flat of bone pieces found in a pocket that appeared to contain many broken or partial bones or fragments. Thankfully the flat was labeled as to site locality and date! It came back home with me and I stored the flat on a shelf.

Often when I prep - having worked long, hard hours on difficult specimens - I rest my arm by checking out these flats of miscellaneous bone pieces. This bone was in a large chunk of matrix and looked to be a rib piece, except the shape was not quite right. After a bit of careful air scribing, it became apparent this was not a rib, but rather a small dentary (lower jaw bone) of an Ornithopod dinosaur, most likely Camptosaurus.

As you can see in the photos, two unerupted teeth have been exposed so far. Full preparation will many more hours to delicately remove more of the rock to expose the jaw and hopefully, more teeth.

Unexpected specimens like this are exciting to find when I’m back in the lab. It just goes to show: If you are careful and save everything at the digsite, you may be rewarded years later with some really great specimens!

Below: Partially-prepped Ornithopod dentary with prepped Camptosaurus dentary! Go to Camptosaurus Gallery.