Echinocaris Clarkii?

[MarleysGh0st]

As I mentioned in my introductory post, I've been volunteering for PRI and collecting fossils at Portland Point (Middle Devonian, Hamilton Formation) for their Fossil Lab to hand out to visitors. While filling up a bucket of brachiopods and trilobites for them, I'll occasionally set aside a particularly nice specimen or one I'm unfamiliar with, for myself.

So, on Monday, I find this:

Seeing those "teeth" got my attention. What the heck is that???

(The scale in the photo is metric. The oval of the carapace is about 18 mm x 12 mm. The rock on the right is a counterpart that flips over and fits to the middle of the one on the left.)

My spare time this week has been an exercise in researching fossils and learning what is and isn't available on the web.

First, I looked through one of PRI's publications: David Linsley's Devonian Paleontology of New York. In Plate 316, among the Phyllocarida, I found one illustration that seemed to match what I had, for Echinocaris clarki.

Through Google Books, I found the original paper describing this species (Beecher, 1902) which included the original illustration for the fossil reprinted by Linsley. Here it is:

What I have appears to be just one of the carapaces; Linsley says it's common for Phyllocarid fossils to be found this way. According to Beecher:

The denticulate border of the valves at once distinguishes this form from any other that belongs to the genus Echinocaris.

So, I think my identification of the fossil is correct (other opinions are welcome!) but how rare or significant is it? Beecher's illustration is from a holotype (meaning it was the one and only specimen he had to work with), coming from the Lower Carboniferous, near Warren, PA. That holotype is apparently now at the Yale Peabody Museum, but they don't have an image of the specimen available online. I can't find any other images for this species and I've only found brief references to the species being found in Ohio and Pennsylvania.

Have I found something significant enough to include in a museum collection? How can I gather data about something like that?

Edited November 11, 2011 by MarleysGh0st

[Fossildude19]

Hello Marley's Ghost,

There was a discussion on the forum about Phyllocarids found HERE.

Perhaps Mikeymig or fossilcrazy, or Piranha will be able to help out here.

At first glance, I thought it might be a Greenops trilobite!

Regards,

[mikeymig]

Your right Tim its a Greenops. The trilobite is upside down or the ventral side up. It might be a complete trilobite if its prepped from the other side. Sorry, not a Phyllocarid.

[piranha]

Tim is correct with the ID of asteropyginid. Greenops boothi appears to be a good fit and the classic array of pygidial spines indicated in a ventral aspect evidenced by the presence of the pygidial doublure.

[pleecan]

Greenops it is.... Tim, Mike and Scott good id.... I am in agreement also : )

[MarleysGh0st]

Greenops? Awwwwwww!

Okay, I can see that now (Linsley, Plate 297). The spine at the center of the pygidium is distinctly shaped, with those on either side curving in towards it. As for prepping the specimen to see if the dorsal side is buried in the matrix, I won't think about that, for now. PRI recently renovated their Prep Lab and I'm waiting for them to schedule a training session for those who'd like to work there. As for my current skill level--well, I can use a rock hammer and chisel without injuring my fingers too badly!

Thanks for all the second opinions. Even though you've burst the bubble of an over-enthusiastic newbie, it's better than if I had run to the museum director with my "great discovery".

[pleecan]

Keep hammering rock.... matter of time ... before that great discovery with your name surfaces ..... we all were newbies at one time.... come to think about it... I am still a newbie :Bananasaur: .... also don't be intimidated by the museum curator.... ask your questions... lots to gain just by asking....

[Fossildude19]

I dunno.

There are those of us who would be thrilled with finding a possibly complete Greenops boothi !!!

Although a Phyllocarid would be cool, I'd settle for the Greenops!

Regards,