Seven stars PA Hamilton group

[Nebfossil]

Anyone know if this is the head of a trilobite? I know some big ones are found there. Also what is the third pic. Been there many times and never found these two.

[Nebfossil]

[Nebfossil]

[Kane]

Dipleura dekayi cephalon and, the subsequent piece, thorax. 

[daves64]

And here I was about to summon @Kane and low and behold... he appears before I can. 

[Fossildude19]

I agree, nice pieces of Dipleura dekayi.   

[ScottBlooded]

Very cool find, I’ve been hoping to happen across one of these at one of my usual dig sites (also Hamilton), but no luck yet.

[Jeffrey P]

I agree with the diagnosis: Dipleura dekayi. I've seen individuals that were collected at Seven Stars. They are prevalent in a number of Hamilton formations, especially in Central New York and Central PA. The trick is finding a complete one. Those are fairly rare. I do admire partial specimens like yours. Nice job!

[Top Trilo]

Whoever named this likes coelacanths, or who ever named a coelacanth likes this trilobite. the name diplurus newarki looks a lot like dipleura dekayi. Luckily I have Tim's avatar to help me remember which is which. 

[Petalodus12]

2 hours ago, Top Trilo said:

Whoever named this likes coelacanths, or who ever named a coelacanth likes this trilobite. the name diplurus newarki looks a lot like dipleura dekayi. Luckily I have Tim's avatar to help me remember which is which. 

If you think this is bad consider the difference between Dyrosaurus and Dryosaurus...confusing stuff

[piranha]

3 hours ago, Top Trilo said:

...the name diplurus newarki looks a lot like dipleura dekayi...

 

Here is the Greek etymology: [diploos = twofold] [pleura = ribs] [ouros = tail]

 

Dipleura Green 1832

This genus derives its name from two Greek words, which signify double ribs; many of the trilobites are thus characterized; but in no species, is this organization so remarkable as in those which belong to the genus Dipleura.

 

Green, J.M. 1832
Monograph of the Trilobites of North America: With Coloured Models of the Species.
Philadelphia: Joseph Brano Publishing, 93 pp.

 

Diplurus Newberry 1878
In Holophagus and Undina and in the Jurassic species of Coelacanthus described by T.C. Winkler, the supplemental caudal fin seems to spring directly from the extremity of the caudal. In Diplurus there is a distinct interval between them; a character which suggested the name Diplurus, or double-tail.

 

Newberry J.S. 1888
Fossil Fishes and Fossil Plants of the Triassic Rocks of New Jersey and the Connecticut Valley.

United States Geological Survey, Monograph, 14:1-152

[Nebfossil]

Update with it cleaned up a bit with size references

[Nebfossil]

Body segment 

[Nebfossil]

I don’t know what the pillar structure is to the left however