unknown possible coprolite from marine late cretaceous

[val horn]

went hunting in the late cretaceous marine severn formation an found something weird.  Its not ironstone, shell or bone and seems large for shrimp burrow.  Could it be a coprolite?

[fifbrindacier]

On 7/17/2018 at 3:01 AM, GeschWhat said:

Rather than writing information about coprolite identification on multiple threads, I thought I would post information about coprolite identification here so it can be referenced in ID threads (I'm getting lazy, I know). I was also thinking it might be fun for others to post coprolites in their own collections so others can use them for comparison. So here we go:

 

IDENTIFYING COPROLITES:  Not all rocks that look like poop have a fecal origin. Here are a few things to consider when trying to make this determination:

 

1. Location, Location, Location – If you haven’t guessed, the first and most important thing to consider is the location your rock was found. Don’t expect to find a coprolite unless you find it in geologic area/layer where other fossils are found. If you find things like bones, teeth and fish scales, or prehistoric tracks, you may just be in in luck.

 

2. Shape – While fecal matter can be rather freeform when exposed to the elements or when digestion issues arise, most coprolites are shaped like poo. As with modern extrusions, fossilized feces can be shaped like pellets, spirals, scrolls, logs, piles, etc.  Their shape is dependent on shape of their producers intestinal and anal structure. Look for things like compaction folds and pinch marks.

 

3. Texture - Most coprolites are fine grained. If your specimen appears granular under magnification, it is most likely not a coprolite.  There are some exceptions, such as marine creatures that feed on bottom sediments or coral. That is why knowing the location and geology of the area where it was discovered is so important.

 

4. Inclusions – Many times, coprolites will have visible inclusions. Things like fish scales, bone fragments, and teeth may not get fully digested, and can be visible on the surface. Some animals ingest stones for ballast or digestive purposes. These are known as gastroliths, and if present, are generally smooth.

 

5. Composition –  Because herbivore scat tends to break a part and decompose rapidly, it rarely survives the fossilization process. So most fossil poo that is found is from carnivores. The reason for this is that their poo is usually high in calcium phosphate, the same mineral found in our bones.  This mineral can appear in many forms. It can be hard and dense or soft and porous. If the potential coprolite appears soft and porous, there is a quick test that is often used in the field. If you touch to stone to the tip of your tongue and it sticks, chances are, it is high in calcium phosphate and could be a coprolite.  If you are not that brave, you can also touch it with wet fingers to see if it feels sticky, but this is not nearly as fun. If the calcium phosphate takes a harder, denser form the “lick test” won’t work. In some instances, chemical analysis is required to definitively identify the mineral composition.

 

@Carl do you have anything you want to add?

 

 

@Carl and @GeschWhat are the ones needed to help you.

[Mark Kmiecik]

I've never seen a hollow coprolite -- of course that doesn't mean they don't exist. It would be very unusual. Have you checked it with a loupe for bits and pieces of things not digested?

[Rockwood]

Could it be a trace burrow constructed from small bits and pieces. It seems like the name should start with xeno.

[abyssunder]

4 hours ago, Rockwood said:

Could it be a trace burrow constructed from small bits and pieces. It seems like the name should start with xeno.

Are you reffering to xenophyophores?

[Rockwood]

2 hours ago, abyssunder said:

Are you reffering to xenophyophores?

It is all I could come up with right off. Not sure if that works here though. ' think ?

[val horn]

didnt see anything interesting with  a microscope.

[Carl]

On 7/27/2022 at 11:32 AM, fifbrindacier said:

@Carl and @GeschWhat are the ones needed to help you.

I'm not seeing convincing coprolite details. I agree that burrow is the best bet.