Trilobite Fragments = Possible Whole Trilobite?

[colebiederman]

Hello all,

 

I am still learning and have a few questions.

 

1.) If you're searching an area and are finding trilobite fragments, is it safe to assume there is also a possibility to find an intact trilobite? I know trilobites can be rare depending on a multitude of factors, but I am curious if this is a safe assumption to make overall.

 

2.) I have seen some post of fossil preparation where a trilobite in matrix is found and turns out to be an entire trilobite after preparation. How does one know what will be and won't be a whole fossil? I have pieces that are obviously just fragments and wouldn't yield an intact fossil, so I am trying to figure out what to look for.

 

Again, thank you everyone for the help! I am continuing to learn and absolutely love this hobby. 

[rocket]

There is no 100%-answer possible

Some sites have both, fragmented and complete trilobites. Some site only have fragmented...

About the preparation it is a kind of experience... Most of the fossils you find when you break the stone. Like many of the trilobites from morocco and other places. You see a small line of the shell and dots of spines. Than it is necessary to glue it and prep it from one side...

[Kane]

1) Sort of. It is a game of probabilities pending the depositional environment. If it was very high energy, it is unlikely to find complete articulated specimens, albeit in the realm of possibility. The same might be said if it is a tidal wash (think here of the odds of finding a complete sea shell on a shoreline that gets pounded by waves every day). The best odds would be if there was obrution (quick mud burial) so that the trilobites were covered quickly in life without being ripped apart by wave action or scavengers. 

 

2) Sometimes one doesn't know until the rock is brought home and probed with preparation tools. If the specimen seems to continue into the rock having more than just a pygidium (perhaps a visible thoracic segment), it might be a candidate for bringing home and inspecting under magnification and prep tools. Or, it may be only a convex arch of axis that suggests it could be enrolled. In any case, the longer you spend with particular formations, the easier it becomes to get that sixth sense of whether it will be complete or just another moulted/disarticulated fragment -- and even then one can expect to bring the odd dud home.