Watton Cliff Microfossil ID?

[BentonlWalters]

In October 2020 I went to Watton Cliff for my first foray into microfossil hunting. I have since dissolved some of the matrix I collected in 20% acetic acid and one of the things I found, amongst all of the crinoid pieces is this. I'm not sure what it is but I'm guessing it's part of a fish. Are the rings visible on the reverse side annual growth rings?

The sample I collected from Watton Cliff is from a loose sandy layer within the Forest Marble and is Bathonian in age.

 

Thanks for giving it a look, as I sort and take more pictures I may post more of what I've found. There is so much crinoid material its difficult to separate it all from the sand.

 

Benton

[rand95]

It might be a scale. It reminds me of some kind of fish scale similar to garfish scale.

[Thomas.Dodson]

5 minutes ago, BentonlWalters said:

 I'm not sure what it is but I'm guessing it's part of a fish.

Correct. It's a ganoid type scale from a fish. Non-teleost bony fish such as gar have these scales.

 

8 minutes ago, BentonlWalters said:

 Are the rings visible on the reverse side annual growth rings?

More or less. The more concentrated bands (annuli) usually form and correspond during periods of slowed growth (usually cold weather in some climates) and thus CAN be used for aging purposes. In reality it's rarely so straightforward as this because some annuli don't distinctly develop, especially in more stable environments, and you often end up underestimating age. This is just one reason it isn't straightforward. Traditionally fisheries scientists used scales to age fish but this was and is a crapshoot compared to more modern methods like sectioning otoliths (ear bones) and counting the annuli of those, which are far more accurate.