Mazon Creek, Worm?

[araucaria1959]

This is a Mazon Creek nodule (with counterpart). It looks worm-like, but it is longer and looks different from other worms I have (e.g., Astreptoscolex). There are no defining features present such as bristles or so. It doesn't seem to be completely preserved over its full original length. Scale = match = 45 mm.

Any help would be appreciated. (The last two pictures are from the other half of the nodule).

Thanks,

araucaria1959

[snolly50]

Based on general appearance alone, you may wish to consider Pieckonia helenae or the rarer Nemavermes mackeei.

Simply guesses based on the look of it.

[glacialerratic]

Not the best preserved, but you can see some segments.

I'd lean towards Pieckonia, but maybe a Didontogaster cordylina, also.

Didontogaster seems like a fairly common worm.

[RCFossils]

Interesting specimen. I cannot make out any defining features to pin down an identification. I cannot make out any jaws although there is a bump near one end which may be the remnants of them.

If i had to guess, I would lean towards Didontogaster.

[snolly50]

I agree. The smart money would go with the odds and call, Didontogaster. I'm just not seeing the expected "pointy end" for that critter. The fossil here appears very rounded at both ends. A close look is warranted with a 10x. In the first picture the end on the right side appears perfectly natural and rounded. However, the last photo of the counterpart gives a view that suggests there may have been more. That is, is the missing "pointy end" (of Didontogaster) lopped off? The first photo suggests "no," it's naturally terminated. The last photo may show otherwise. With the fossil in hand I feel that inquiry would be most enlightening.

[Wrangellian]

Has the worm been coated with something glossy (just along the length of the worm, not the whole rock surface)? or is that just an artifact of the preservation I'm seeing?

[glacialerratic]

Eric, I wonder if it's due to the lighting? The white stuff is kaolinite, which looks like it is obscuring any detail.

I've never tried, but is that removable? With tools or an acid? Or would that ruin the fossil?

I do see what you mean snolly50, about the lack of a tapering tail if it's a Didontogaster... looks much smaller, about half the size, than the few I have in my collection. I do have one tiny worm I think is a little Didontogaster; it does have a sharply tapering tail.

[araucaria1959]

Thanks for the extensive discussion of the specimen. Since the discussion seems to focus on the end of the specimen, I post two new pictures from the end (from both sides). (the other end is missing).

araucaria1959

[RCFossils]

The new pictures helped.

The little bump near the front of the worm is what is left of the jaw.

Definitely didontogaster.

[araucaria1959]

Thanks altogether for your help!

araucaria1959

[Wrangellian]

Eric, I wonder if it's due to the lighting? The white stuff is kaolinite, which looks like it is obscuring any detail.

I'm not sure if they're the same areas along the edge of the worm, but in your earlier pics it appears dark (just as a shiny/glossy coating would, at different angles). It must be the preservation as it looks like it would have been a lot of trouble to apply a coating that accurately when most people would just coat the whole surface.

[araucaria1959]

I didn't find the specimen myself, so I cannot exclude that there was some coating, but it looks natural. I've never got the idea of the possibility of coating until it was suggested here.

araucaria1959

[Wrangellian]

Whatever it is it seemed to be making it difficult to make out details in the worm. I've seen any number of fossils that have been coated with something glossy because people seem to think it's the thing to do, not realizing it makes it difficult to take good photos.

But the point is moot if you've already got a confident ID!

[JimB88]

good ole' tummy tooth worm....

[Missourian]

Very interesting specimen. I wish Essex-style Pennsylvanian faunas were more widespread than Mazon Creek.