Unknown dense arced fossil from Florida

[RescueMJ]

I have an unknown, dense, arced fossil that is solid.  Image 1 shows the smooth, angled surface. I cannot find a reference for this item.  Found in spoil pile today in inland Venice.  Surrounding material from Pleistocene. Thank you in advance.  This should be challenging...

Regards,   Michael

[Al Dente]

It is a whale bulla. Looks like it is very abraded.

[Rockwood]

Anyone feel free to correct me if I botch this.

The density and shape are adaptations to hearing low frequency sound waves under water. They would likely be stone deaf to sea bird cries. 

[digit]

5 hours ago, Al Dente said:

It is a whale bulla. Looks like it is very abraded.

Agreed. This one is very worn down but folks who have seen lots of them can still recognize the distinctive shape even after 99% of the diagnostic features have worn away.

 

Do an internet image search for "fossil whale tympanic bulla" and you will find lots of images from pristine specimens with the thinnest parts still intact to well worn specimens similar to your item.

 

 

Cheers.

 

-Ken

[PrehistoricWonders]

I agree, nice find!

[RescueMJ]

Thank you all. Whale Ear bone it is. That was on my hunch list. Any idea on age of fossil?  I saw a date of 11 mya. 

[digit]

Without being able to assign a particular species ID to the item, it will remain like many quasi-identified fossils having a very vague age of "when the area was a shallow sea".

 

One of the most interesting (and often overlooked) features of fossil hunting in South Florida is that the (very flat) region has been a variety of habitats throughout repeated introgressions and regressions due to sea level changes. Consider that a single sifting screen while fossil hunting in the Peace River might contain: shark teeth and dugong ribs (and whale ear bones ) from a layer set down when shallow seas covered what is now the lower peninsula of Florida, gator teeth and turtle shell fragments from when the area was swampy like the present day Everglades, and horse, camel, tapir, mammoth/mastodon and even sloth teeth and bones from when the area was high and dry as it is at the moment. The vast changes (several hundred feet) of sea level during the time the glaciers were expanding and retreating caused the are you are finding your fossils to cycle through a variety of ecosystems and habitats leading to totally different types of fossils being deposited. Rivers and creeks (or occasionally bulldozers and front-end loaders ) tend to combine the different fossil layers into a very interesting tossed salad of fossil material. If you are locating fossils "in situ" in a particular formation where there are indicator fossils or other means to place a tighter date range on the fossil material then you can pin down a more narrow date range to an item. Occasionally, ancient waterways or violent storms (Floridians understand this term) will "rework" older fossil material material into lag deposits in younger layers mixing older fossils in with younger ones.

 

The book The Fossil Vertebrates of Florida (edited by Richard C. Hulbert, Jr.) is a must have for Florida fossil hunters. It contains a faunal list of species found in the fossil record of Florida. In many cases it gives a date range for species when that has been determined. For example, I believe I recall that the dugong species Metaxatherium floridanum (for which we find so many rib bone fragments) occurred in Florida from approximately 14-7 Ma (million years ago). When you give someone a dugong rib bone as a "paleo paperweight" you can tell them the approximate age range (which is one of their first questions after "What the heck is a dugong?"). You may also get an idea of the age range of the cetacean fossils by reading through this book and can have a better estimate of the age of your tympanic bulla.

 

https://www.amazon.com/Fossil-Vertebrates-Florida-Richard-Hulbert/dp/0813018226/

 

https://www.floridamuseum.ufl.edu/wp-content/uploads/sites/41/2019/09/Pony-Express-Vol10-No01.pdf

 

 

Cheers.

 

-Ken

[RescueMJ]

I ordered Hubert’s book on Monday.  Your quote of “tossed salad of fossil material” is spot on. In my local dig area, I am finding very dark fossils adjacent to caramel colored ones within the same two feet of excavated soil. Would that suggest they were washed out of different matrix of different time periods then deposited together?

 

Thank you for your info. 
- Michael

[digit]

The lighter colored fossils are generally thought to come from more solid clay layers where there seems to be less of a chance that they are saturated with phosphate rich groundwater (which seems to be what turns the fossils the rather monotone grayscale we are familiar with in Florida). Several fossil hunters here on the forum report finding nicely colored fossils still partially stuck in sticky clay matrix when hunting in rivers and creeks. They may represent similar time frames as nearby black/gray fossils but the preservation conditions account for the coloration difference.

 

 

Cheers.

 

-Ken