Lance fm. Potential Varanoid Tooth?

[PaleoNoel]

Hi everyone, I found this small tooth over the summer in a Lance formation channel deposit in Wyoming. In the field I didn't know what to make of it, too recurved and compressed to be croc, no visible serrations either so probably not a non avian theropod. Months later I took a closer look at it and continued to search for its potential identity. I thought to myself could it be a mammal canine. After some online browsing I couldn't find a match for anything in the Hell Creek/Lance fauna. However, after posting it on an instagram story, I got a few suggestions. One of the more intriguing of those suggestions came from @Mioplosus_Lover24 who believed it was probably a varanoid lizard, potentially Palaeosaniwa. I looked for any images of Palaeosaniwa teeth online and came up empty handed, but I did find some similarities between my tooth and that of the Cretaceous Mongolian varanoid Estesia and a modern example of a monitor teeth. The length is approximately 6 mm and the width at the base is 2 mm.

 

monitor skull I found online

Estesia mongoliensis skull described in a 2013 paper by Norell & Yi

[jpc]

Look for illustrations of Paleosaniwa.  I think this is a mammal canine.  But tough to tell from pix alone.  

[siteseer]

I have read there are at least ten taxa of lizards from the Hell Creek Formation so I assume there could be at least that many in the Lance as well.  You might have to dig into some technical papers for help.  You might start with articles by Laurie Bryant and J. David Archibald.

[PaleoNoel]

2 hours ago, jpc said:

Look for illustrations of Paleosaniwa.  I think this is a mammal canine.  But tough to tell from pix alone.  

 

13 minutes ago, siteseer said:

I have read there are at least ten taxa of lizards from the Hell Creek Formation so I assume there could be at least that many in the Lance as well.  You might have to dig into some technical papers for help.  You might start with articles by Laurie Bryant and J. David Archibald.

Thanks!

[jpc]

Estesia and the modern monitors have teeth that are very narrow (antero-posteriorly), yours looks more rotund than theirs.  Also, monitor teeth are not rooted like this.  They glom onto the jaw bone rather than fit into it, and have a striated base. 

 

PS... nice tooth.   

[Troodon]

I've seen this referred to as Paleosaniwa

 

Nice find

 

[Troodon]

No help but some from the late cretaceous 

 

 

 

Mass extinction of lizards and snakes at the
Cretaceous–Paleogene boundary
Nicholas R. Longrich, Bhart-Anjan S. Bhullarb and Jacques A. Gauthiera

[jpc]

53 minutes ago, Troodon said:

 

Mass extinction of lizards and snakes at the
Cretaceous–Paleogene boundary
Nicholas R. Longricha, Bhart-Anjan S. Bhullarb and Jacques A. Gauthiera

Thanks for bringing this paper to my attention. 

[PaleoNoel]

12 hours ago, jpc said:

Estesia and the modern monitors have teeth that are very narrow (antero-posteriorly), yours looks more rotund than theirs.  Also, monitor teeth are not rooted like this.  They glom onto the jaw bone rather than fit into it, and have a striated base. 

PS... nice tooth.   

 

11 hours ago, Troodon said:

I've seen this referred to as Paleosaniwa

Nice find

 

11 hours ago, Troodon said:

No help but some from the late cretaceous 

Mass extinction of lizards and snakes at the
Cretaceous–Paleogene boundary
Nicholas R. Longrich, Bhart-Anjan S. Bhullarb and Jacques A. Gauthiera

Thanks for your help guys. Certainly an odd tooth and does not seem to fit any particular group that well.

@jpc If you can find any pictures of mammal canines with a curvature similar to my tooth it would be greatly appreciated as I can't seem to find a match for it online.

Is there any chance it's avian? I remember in my searches online I found that hesperornis was vaguely similar, but had this bizarre lingual bend and what appear to be enamel ridges.

 

[jpc]

bird teeth from the late K have a pinched base, as I understand it.  There are not many published reports of Lance (or Hell Creek) mammal canines as most of the speices are known from partial jaws (no canines) and isolated teeth.

[PaleoNoel]

11 minutes ago, jpc said:

bird teeth from the late K have a pinched base, as I understand it.  There are not many published reports of Lance (or Hell Creek) mammal canines as most of the speices are known from partial jaws (no canines) and isolated teeth.

Makes sense. Finding micros in the hell creek and lance makes me wish there was a coeval lagerstatten where we could get a complete picture of the smaller vertebrate fauna.