Identification of Ceratosaurus Teeth

[Troodon]

Ceratosaurus is one of my favorite Jurassic theropod Dinosaurs found in the Morrison Formation.

Teeth of this and other theropods are commonly sold through online Dealers, Auction Houses and at Fossil shows. Just because a site/dealer sells Jurassic material does not guarantee the are accurately identified.   Variation of the teeth in the jaw also adds to the complexity.  Isolated teeth from the Morrison Formation are very difficult to diagnose and all require an understanding of additional characteristics than normal, in hopes of properly identifying them.   Some publications describe the anterior teeth which is shown below..  This Latest edit is driven by C Hendrickx 2019 paper which shows some data on these teeth which I present in this edit.

 

The following information is needed to identify these teeth: 

 

1)Photo of tooth all sides and base and one of the mesial edge

2)Serration density of both edges, 5 mm wide at midline

3)Dimensions: CBL, CBW, CH

4)Locality: State and County

 

 

 

Premaxillary Position (From Morrison Fm) (Data from 10 Teeth Hendrickx study)

 

Crown height ratio CH÷CBL        CHR : 1.2 to 1.9 (Avg 1.7)

Crown base ratio CBW÷CBL        CBR : 0.57 to 0.78 (Avg 0.66)

 

Serration Density:

DSDI  0.9 to 1.8 (Avg 1.35) 

Distal :  7 to 9 / 5 mm

Mesial:  9 to 12.5 / 5 mm

 

Other Characteristics

Cross-section base : Subcircular 

Mesial Carina NOT reaching the base in most crowns

Lingual grooves (flutes) are diagnostic and on the lingual side only.   

Transverse Undulations:  May be present on the lingual side

Interdental Sulci:  Weak to absent

 

Lateral Dentary Positions (From Morrison Fm) (Data from 9 Teeth Hendrickx study)

 

Crown height ratio CH÷CBL        CHR : 1.7 - 1.9 (Avg 1.8)

Crown base ratio CBW÷CBL        CBR :  .035 to 0.5 (Avg  0.44)

 

Serration Density:

DSDI .09 to 1.1 (Avg 1) 

Distal :  11.5 to 13 / 5 mm

Mesial:  10 to 12.5 / 5 mm

 

Other Characteristics

Mesial serrations extend to the base on most crowns

Transverse Undulations: light present on distal teeth

Interdental Sulci: unknown

 

Anterior Dentary Positions

 

Gooves are present on the lingual side of the three anterior teeth

 

 

Lateral Maxillary Positions (From Morrison Fm) (Data from 11  Teeth Hendrickx study)

 

 

Crown height ratio CH÷CBL         CHR : 1.8 - 2.3 (Avg 2)

Crown base ratio CBW÷CBL         CBR :  .032 to 0.6 (Avg  0.42)

 

Serration Density:

DSDI .097 to 1.2 (Avg 1.06) 

Distal :  9 to 12 / 5 mm

Mesial:  9 to 12.8 / 5 mm

 

Oher Characteristics

Mesial carina extend to the base on most crowns

Transverse Undulations: can be light present 

Interdental Sulci: can be present

 

 

If you would like to learn more about Ceratosaurs, bones and teeth there is a great soft covered printing.

Ceratosaurs

(Dinosauria, Theropoda)

A Revised Osteology by Madsen and Welles

by the Utah Geological Survey

Its also available on PDF but the book is cheap and a great reference guide.

If anyone has additional information to add to this please post it.

 

Reconstruction  Skull of Ceratosaurus from Utah Museum of Natural History.

So you can see variation of the teeth in jaw

 

Reference

1)Journal of Iberian Geology

June 2017, Volume 43, Issue 2 , pp 257-291

Analysis of diversity, stratigraphic and geographical distribution of isolated theropod teeth from the Upper Jurassic of the Lusitanian Basin, Portugal

 

2)Multivariate and Cladistic Analyses of Isolated Teeth Reveal Sympatry of Theropod Dinosaurs in the Late Jurassic of Northern Germany

Oliver Gerke, Oliver Wings

Published: July 6, 2016

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0158334

 

3) Taxonomic identification of isolated theropod teeth: The case of the shed tooth crown associated with Aerosteon (Theropoda: Megaraptora) and the dentition of Abelisauridae

ChristopheHendrickx, EmanuelTschopp, Martín d.Ezcurra

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0158334

[Runner64]

What should the shape of the tooth look like? Is there a characteristic form?

[Troodon]

Good question should have addressed that. The tooth in my post is an anterior tooth in the dentary. I wish I had detailed pictures of the other teeth but I dont and none exist in my publications. Actually I do not know how much of the dentary has been discovered. Maybe someone can provide additional info. The publication I noted has great plates with images like these two. The largest tooth in the maxilla is 3 1/2"

Edit: I don't have all of the answers just posting what I aware of

Edited August 24, 2015 by Troodon

[Troodon]

Attached is a skull from the Utah Museum of NH in SLC. Not sure how much is real real.

[Runner64]

Ok cool, just trying to make sure I have a ceratosaurus tooth.

[zekky]

These teeth are very hard to ID unless they have the lingual grooves. The main issue with identifying Ceratosaurus teeth is the crazy variation in Allosaurus teeth. 

[Jesuslover340]

@Troodon, This thread has been quite informative...I have a couple of dinosaur 'teeth' I have recently obtained, and was wondering if you could help ascertain a tentative identification for them? I have been unable to message you, so you may have to pm me. Thanks!

[Troodon]

Just post them in the forum ID section so that way everyone will learn @Jesuslover340

[Troodon]

Completely updated first page based on obtaining published information versus my personal collection

[Haravex]

Good post highly informative 

[zekky]

One thing I have found is that Cerzatosaurus' Lateral teeth are symmetrical. While not diagnostic by itself, most Allosaurus  teeth are not symmetrical. 

[Troodon]

Little has been published on Maxillary teeth of Ceratosaurus.   A museum quality replica jaw consisting of the a partial maxilla and pre-maxilla was made available at the Tucson show this past year so I picked it up so I could examine its teeth.   The serrations are pristine so its a good opportunity to get some data on them. 

 

Morrison Fm. of  Colorado 

The jaw is 9.5" (24 cm) long by 3" (7.6 cm) wide.

 

Pre-maxillary teeth (6 present):  the key diagnostic feature were the lingual grooves on all the teeth as seen on the illustrations at the very top of this page.   The grooves were not has strong on the outer teeth.

 

Maxillary teeth #1 through #5

( in mm )

CH: Crown Height #1: 56, #2: 64, #3: 68, #4: 69, #5 64

BL: Base Length   #1: 24, #2: 27, #3: 28, #4: 29, #5 28

BW: Base Width all were around 11

 

Density (Mid-line 5 mm wide)

Serration Density:  #1 Distal 11, Mesial 13, #2 through #5  Distal and Mesial 11 to 11.5 

DSDI of 1 on #2 through #5 and 1.2 on #1 so most teeth NOT ALL had similar densities on both carina.

The average number of serrations per mm was around 2.2

 

Mesial Carina extends to the base (cervix)

 

CBR (Crown Base Ratio) range of .37 to .45 which describes a narrow crown.

CHR (Crown Height Ratio) range of 2.28 to 2.43 which describes a moderately elongated crown

 

                            

 

 

 

@paulyb135

[paulyb135]

11 hours ago, Troodon said:

Little has been published on Maxillary teeth of Ceratosaurus.   A museum quality replica jaw consisting of the a partial maxilla and pre-maxilla was made available at the Tucson show this past year so I picked it up so I could examine its teeth.   The serrations are pristine so its a good opportunity to get some data on them. 

 

Morrison Fm. of  Colorado 

The jaw is 9.5" (24 cm) by 3" (7.6 cm) wide.

 

Pre-maxillary teeth (6 present):  the key diagnostic feature were the lingual grooves on all the teeth as seen on the illustrations at the very top of this page.   The grooves were not has strong on the outer teeth.

 

Maxillary teeth #1 through #5

( in mm )

CH: Crown Height #1: 56, #2: 64, #3: 68, #4: 69, #5 64

BL: Base Length   #1: 24, #2: 27, #3: 28, #4: 29, #5 28

BW: Base Width all were around 11

 

Density (Mid-line 5 mm wide)

Serration Density:  #1 Distal 11, Mesial 13, #2 through #5  Distal and Mesial 11 to 11.5 

DSDI of 1 on #2 through #5 and 1.2 on #1 so most teeth NOT ALL had similar densities on both carina.

The average number of serrations per mm was around 2.2

 

Mesial Carina extends to the base (cervix)

 

CBR (Crown Base Ratio) range of .37 to .45 which describes a narrow crown.

CHR (Crown Height Ratio) range of 2.28 to 2.43 which describes a moderately elongated crown

 

                            

 

 

 

@paulyb135

 

Thanks! I’ll try to use this for my Lourinhã tooth and also any Morrison cerato teeth I hopefully get offered in the future 

[Troodon]

4 hours ago, paulyb135 said:

 

Thanks! I’ll try to use this for my Lourinhã tooth and also any Morrison cerato teeth I hopefully get offered in the future 

 I actually think the teeth from Germany that I show above a more representative of those from Portugal

[paulyb135]

1 hour ago, Troodon said:

 I actually think the teeth from Germany that I show above a more representative of those from Portugal

Interesting! 

 

Hopefully i can own a confirmed one one day. They’re definitely one of the coolest looking dinosaurs to have roamed the earth