Mazon Creek Best Of The Best Didontogaster Cordylina Thompson 1979

[RCFossils]

Didontogaster is a polychaete worm (sometimes referred to as bristleworms).

The first formal descriptions of Mazon Creek polychaetes did not occur until 1979. At the time they were described, they were the earliest known polychaetes in the fossil record.

Since this time, polychaete fossils have been found reaching back as early as possibly the Ediacaran.

It is the most common worm found in the Essex portion of the Mazon Creek deposit.

It has been classified as belonging to the family Nephtyidae. Members of this family still exist today and are sometimes referred to as cat worms.

Didontogaster has a fairly basic body plan.

It’s most defining characteristic is a pair of conical shaped jaws that are usually well preserved. 

Due to the position of the jaws within the body, early collectors nicknamed Didontogaster as a Tummy Tooth Worm.

Didontogaster was able to extend it’s jaws outward to feed (see below).

It was likely a burrower as they are occasionally found on multiple bedding planes within the concretion.

Preserved gut contents show they fed on ostracodes along with plant material.

If outstretched, this first specimen would measure around 8 centimeters which is about as big as they get.

Most specimens range between 4-5 centimeters.

 

[RCFossils]

[RCFossils]

This Rare specimen shows the jaws extending outside of the body.

[RCFossils]

This specimen preserves a “death trail”

[caldigger]

Wow, those are some rather nice specimens!  

[grandpa]

Confessions of a parochial Texan:

 

I've never hunted Mazon Creek. 

I know nothing of the fossils found there.

I have long admired what I have seen coming out of that formation.

I really thank you for your posts which I find very informative.

I truly hope that this series of posts gets gathered together and pined for reference.

 

Thanks for the education and great eye-candy.

Grandpa

[JohnJ]

44 minutes ago, grandpa said:

I truly hope that this series of posts gets gathered together and pined for reference.

 

Deservedly so. 

[Bobby Rico]

Stunning specimens . 

[Tidgy's Dad]

Fascinating. 

I love the preservation of internal organs, the external jaw and especially the death trail which i also find slightly sad. 

How silly I am. 

Another clue that this is probably a burrowing form is that most non-burrowing polychates have gills and there is no evidence of those in this species, typical of a burrowing form where damage would be caused to the gills if burrowing so they have adapted to breath through their outer 'skin'. 

[grandpa]

14 minutes ago, Tidgy's Dad said:

especially the death trail which i also find slightly sad. 

How silly I am. 

Count me as silly as well then for I have a collection of insects in amber, some of which have "death trails" or other signs of final struggle that I also find a little (or more) sad.

[FossilNerd]

9 hours ago, RCFossils said:

... polychaete worm (sometimes referred to as bristleworms).

These are a joy for me to see! 
 

One of the many hobbies that I have tried over the years was salt water fish/coral tanks. In the salt water tank community there is a massive debate over bristleworms. I won’t get into it here as that is a topic for another forum , but it is fascinating to see examples of their ancestral cousins. 
 

Thanks for sharing! 

[RCFossils]

Thanks for all of the kind words.

I will continue these posts and am happy that others are enjoying them.

 

[RCFossils]

3 hours ago, grandpa said:

Count me as silly as well then for I have a collection of insects in amber, some of which have "death trails" or other signs of final struggle that I also find a little (or more) sad.

The trails make me a bit sad as well.

These creatures were buried quickly and the fossils record their struggle to try and escape.

[Ruger9a]

These fossils are very much "top draw" quality specimens.  Making me drool a little.....;)

[RCFossils]

1 hour ago, Ruger9a said:

These fossils are very much "top draw" quality specimens.  Making me drool a little.....;)

Just wait to see what’s to come...

[deutscheben]

2 hours ago, RCFossils said:

Just wait to see what’s to come...

I'm looking forward to it! These are great.