History of Gabriceraurus herrmanni

[GerryK]

I had a discussion elsewhere on the FF about Gabriceraurus herrmanni. The history of this trilobite is interesting.

Walter(1924) described Ceraurus herrmanni from the Platteville limestone near the mouth of Catfish Creek, Dubuque Iowa. At this locality the Decorah is exposed and it is probably the unit the trilobite came from. The illustrated specimen only has a thorax and pygidium. Walter discusses how his species is different from Ceraurus dentatus and states that “The specimen is now in the Museum of the Collector, Mr. Richard Herrmann.” What ever happened to the collection of Mr. Herrmann is unknown and the specimen has not shown up in any museum collection and is assumed to be lost.

Later Demott(1987) describes Gabriceraurus dentatus from the same unit the Decorah. In his synonymy he includes Ceraurus herrmanni (he spells “herrmanni” with only one “r”). Demott remarks that Walter(1927) thought C. herrmanni to be different from C. dentatus.  However, the specimen is presumed to be lost and could not be compared to his material So, Demott concluded the specimens he has are the same as Gabriceraurus dentatus.

Since Demott’s paper, more specimens have been collected and made their way into private and museum collections. Specimens of both G. dentatus and G. herrmanni have been examined and are determined to be different. The differences are subtle but different. Attached are two specimens of G. herrmanni I prepared that were collected by Al Scheer. One specimen is crushed flat and the other is in a limestone preserving it 3 dimensionally. The differences are striking and are a good example of how compaction of a trilobite can distort the features of a specimen. The flatten specimen looks more like a G. dentatus, while the 3 dimensional specimen is what G. herrmanni is supposed to look like.

Edited December 23, 2018 by GerryK

[Tidgy's Dad]

Interesting information and beautiful trilobites.

[piranha]

6 hours ago, GerryK said:

I had a discussion elsewhere on the FF about Gabriceraurus herrmanni. The history of this trilobite is interesting.

Walter(1924) described Ceraurus herrmanni from the Platteville limestone near the mouth of Catfish Creek, Dubuque Iowa. At this locality the Decorah is exposed and it is probably the unit the trilobite came from. The illustrated specimen only has a thorax and pygidium. Walter discusses how his species is different from Ceraurus dentatus and states that “The specimen is now in the Museum of the Collector, Mr. Richard Herrmann.” What ever happened to the collection of Mr. Herrmann is unknown and the specimen has not shown up in any museum collection and is assumed to be lost.

Later Demott(1987) describes Gabriceraurus dentatus from the same unit the Decorah. In his synonymy he includes Ceraurus herrmanni (he spells “herrmanni” with only one “r”). Demott remarks that Walter(1927) thought C. herrmanni to be different from C. dentatus.  However, the specimen is presumed to be lost and could not be compared to his material So, Demott concluded the specimens he has are the same as Gabriceraurus dentatus.

Since Demott’s paper, more specimens have been collected and made their way into private and museum collections. Specimens of both G. dentatus and G. herrmanni have been examined and are determined to be different. The differences are subtle but different. Attached are two specimens of G. herrmanni I prepared that were collected by Al Scheer. One specimen is crushed flat and the other is in a limestone preserving it 3 dimensionally. The differences are striking and are a good example of how compaction of a trilobite can distort the features of a specimen. The flatten specimen looks more like a G. dentatus, while the 3 dimensional specimen is what G. herrmanni is supposed to look like.

 

 

 

 

Gerry, Thanks for the Happy Holiday Trilobites!  

[doushantuo]

I noticed some remarks on Gabriceraurus in the Congreve thesis,BTW

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I'll let it stand

 

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