Catalog Number: CG-0055

Petalodus ohioensis tooth number 10 is a beautiful specimen. It’s well-shaped, well colored, and has a solid root. I worked the specimen with an air scribe for some time, removing the matrix from a perimeter slowly, before uncovering the tooth itself. Air scribes are useful but troublesome to work with. They are loud and vibrate heavily. When removing rock, you have to take your time and be careful you don’t mark up or break the specimen.

Petalodus ohioensis
Tooth before right side root exposure
Petalodus ohioensis
Petalodus ohioensis before right side root and crown exposure
Petalodus ohioensis
Petalodus ohioensis

Further work with the scribe removed the crown from the matrix. I recovered the blade and a piece of root. The plan is to reattach it to the base with Paraloid B-72. It will be removable with acetone later.

Petalodus matrix base
Base with crown removed and leftover roof pieces.
Labial view of tooth crown
Lingual view of tooth crown. This will be hidden once the crown is reattached.

Lingual Side of Crown

Before I glued the lingual side of the crown back to the rock, I created a panoramic focus-stacked image from 18 different photos through a microscope. I only added Paraloid B-72 adhesive to the crown by the broken portion, and it could be removed again simply using acetone. The lingual side of the crown is the flat to concave side. The labial side of the crown is convex.

Petalodus ohioensis, labial side of tooth.
Labial side of specimen CG-0058

Crown Interior Microscopic Detail

Below is a simple focus-stacked image of three photos made through a microscope. You can see what appears to be another layer of enamel buried further in. A polished section would provide a better view.

Petalodus ohioensis inner crown microscopic detail
Detail of broken crown cross-section.

Crown with scale

Petalodus ohioensis. Contrast heightened with ammonium chloride.
CG-0055 – Petalodus ohioensis. Contrast heightened with ammonium chloride. Scale bar = 1 cm.

Catalog of Petalodus ohioensis specimens found to date

We keep a running list of found specimens and dimensions. This specimen has a medium-sized crown. The labial side of the crown measures 11 mm tall, while the lingual side measures 13 mm. The lingual side measures longer as its concave nature increases the distance from the cutting edge to the distal crown tongue. It also naturally sits further down into the tooth profile than the backside.

Catalog IDSpecimen NameCrown HeightCrown Width
CG-0015Petalodus I6mm23mm
CG-0016Petalodus II9.5mm24mm*
CG-0029Petalodus III8mm28mm*
CG-0027Petalodus IV10.5mm**
CG-0034Petalodus V14mm27mm*
CG-0038Petalodus VI5.5mm*****
CG-0045Petalodus VII10mm25mm
CG-0047Petalodus VIII13mm31mm
CG-0048Petalodus IX******
CG-0055Petalodus X11mm†28mm
CG-0058Petalodus XI8mm†27mm
CG-0070Petalodus XII******
CG-0087Petalodus XIII9mm23mm
CG-0102Petalodus XIVComing SoonComing Soon
CG-0107Petalodus XVComing SoonComing Soon
Current specimens found and metric measurements. Crown height measured from start of root on the lingual side. This includes a dark band that was originally covered by the distal crown tongue.
* – Measured based on symmetry. One side broken/obscured.
** – Unable to measure, both sides were broken.
*** – From the top of the distal crown tongue.
**** – Unable to measure, crown broken.
† – Measured from the labial side.
CG-0055, Petalodus ohioensis
CG-0055, Petalodus ohioensis