Dithyrocaris rolfei rare Positive-Negative Mississippian Montana MT COA 7151

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Dithyrocaris rolfei rare Positive-Negative Mississippian Montana MT COA 7151:
$995.00

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Here is a superb fossil of a Dithyrocaris rolfei, in beautiful condition. From the Mississippian, about 358 to 323 million year ago, long before the first dinosaur.. From the Heath Formation, Bear Gulch Member, Fergus County, Montana. The Bear Gulch Limestone is an important Lagerstaette (area of superb and important fossils), with over 110 species found there, many are not yet found elsewhere. It gives a wonderful story of Mississippian life in the area.
This is one of those rare instances where both the positive and negative halves, when split out, were usable. Not only do you get both the positive and negative sides, both are superb. Not too many of these in positive-negative condition around.
The specimen in nearly 4 inches long. It would measure longer but the animal is slightly curled. A part of the animal, in the back third, did not come up with the rest of the specimen, but the vast majority looks to be intact. (photos).
Dithyrocaris rolfei was aphyllocarid shrimp, a large crustacean from the Carboniferous period.
The "positive" half is in a shale matrix that is about 5" by 1.5" (varies greatly). The negative shale is about 4.4" by 3.3" (varies), The two halves together weigh 885 grams (1 lb. 15.2 oz).
An important and superb clean, exceptionally detailed example of this ancient species.