Canadian trilobite id

[Fossil Claw]

My next prep project. Double trilobite plate from Fort Steel in Canada. One is mostly exposed and one only the head is exposed. The person i got it from tjought it was and the some kind of Ollinellus trilobite.

There kught even be a third one peaking out under the edge in the top right.

Edited February 9, 2016 by Fossil Claw

[Fossildude19]

Brightened and cropped your pic - looks like the yellow thing might be a part of a cephalon, as well - 4 trilo pieces on there.

Regards,

[fossilized6s]

Looks like five or six bits. I would practice on the bits to get a nice comfortable feel for the matrix. Neat slab. Sorry I can't help with IDs.

[Auspex]

That is a very colorful slab

I hope this aspect will endure the prep process.

[piranha]

The Fort Steele locality is part of the Eager Formation. A couple of theses (Best 1952, Bohach 1997) describe the Eager Fm. olenellids, but unfortunately they are currently in need of revision. I would advise against any additional prep on that matrix. Here is an example of a complete Eager Fm. Olenellus sp. from my collection.

 

 

Best, R.V. (1952)

A Lower Cambrian trilobite fauna from near Cranbrook, B.C.

MSc. Thesis, University of British Columbia, 58 pp.

 

Bohach, L.L. (1997)

Systematics and biostratigraphy of Lower Cambrian trilobites of western Laurentia.

PhD. Thesis, University of Victoria, British Columbia 492 pp.

 

 

 

[Fossil Claw]

I would advise against any additional prep on that matrix.

Any specific reason? It was given to me specifically to practice prepping. I planned to expose the larger trilo with is head sticking out.

[JohnJ]

Any specific reason? It was given to me specifically to practice prepping. I planned to expose the larger trilo with is head sticking out.

It sounds like you may have the potential for undescribed species in that matrix and prepping could risk damage....

[Fossil Claw]

It sounds like you may have the potential for undescribed species in that matrix and prepping could risk damage....

Ah. I didn't get that from the posting.

I will leave it alone for now then.

I will have to look for a local expert to find out.

Glad I posted the ID request.

[Fossil Claw]

I found an article with Lisa Bohach's email address. I sent the picture to her to see if she recognizes the species.

I will post her response.

Edited February 9, 2016 by Fossil Claw

[piranha]

It sounds like you may have the potential for undescribed species in that matrix and prepping could risk damage....

The trilobites have already been described. The taxonomy needs to be updated and revised in a peer-reviewed paper.

[Ridgehiker]

I've collected several specimens from this site. The two most common species are Ollenelus ricei and Wagneria dunnae.

It's a plus that you have a complete specimen. At this site I've collected a hundred trilobite cephalons for every complete specimen. The only other macro fossils in the deposits that I've found are worm traces and small inarticulate brachiopods.

I wouldn't think the specimens would clean up that well if prepped as these are moults and, as stated, 99% of specimens are incomplete. But...I've never tried to prep any as we tend to keep the best specimens and discard the rest. If you go through the rubble piles there are lots of specimens that were either tossed or not noticed and later exposed by the rain.

[piranha]

...The two most common species are Ollenelus ricei and Wagneria dunnae...

Unfortunately, these names are in limbo in Lisa Bohach's thesis. Hopefully they will eventually be formally published.

[JohnJ]

The trilobites have already been described. The taxonomy needs to be updated and revised in a peer-reviewed paper.

Unfortunately, these names are in limbo in Lisa Bohach's thesis. Hopefully they will eventually be formally published.

Thanks, Scott. Yes, hopefully they will be formally published.

Descriptions in the absence of peer review are potentially fraught with confusion. The precision of a good author's work can 'survive' review.

[Ridgehiker]

Thanks, Scott. Yes, hopefully they will be formally published.

Descriptions in the absence of peer review are potentially fraught with confusion. The precision of a good author's work can 'survive' review.

This is a whole interesting area. The validity of taxa as described in a peer reviewed thesis that has been accepted. In general each discipline determines what is valid or not. In the case of the area I worked this meant what 3 or 4 individuals decided. If a doctoral thesis was available from the academic institution then we considered it as published and equal in validity to other publications.

There are formal international agreed upon criteria BUT unless some dispute or challenged then things just plug along. More confusion than peer reviewed thesis are early works going back a century or so. Amateur field naturalist publications would describe new species ( including dinosaurs from Alberta) and can need to be cited in papers. One of these, the Ottawa Field Naturalist, was the equivalent quality of a local bird watching newsletter, but I had to use it as a valid reference when editing a short report on Carboniferous shark teeth from the Banff area.

Edited February 10, 2016 by Ridgehiker

[piranha]

Thanks, Scott. Yes, hopefully they will be formally published.

Descriptions in the absence of peer review are potentially fraught with confusion. The precision of a good author's work can 'survive' review.

Rolf Ludvigsen was the chairperson for the thesis committee, there is little doubt that "Olenellus ricei" and "Wanneria dunnae" are new species.

They won't survive if someone else comes along and publishes them with different names. It's been nearly 20 years since the thesis was written...

[Fossil Claw]

As much as I want to see if the larger trilobite is mostly complete under the matrix, I am going to take piranha's and Canadawest's advice and leave it alone.

[Fossil Claw]

Dr. Bohach suggests it's likely Olenellus schofieldi.

[piranha]

On 2/10/2016 at 5:35 PM, Fossil Claw said:

Dr. Bohach suggests it's likely Olenellus schofieldi.

 

 

Olenellus schofieldi n. sp. is another example that needs to be addressed. Fritz 1992 and Lieberman 1999 mention it briefly, but unfortunately, O. schofieldi has been buried in the Best and Bohach theses for 64 and 20 years! It really is a long overdue wait for this important fauna to be properly described and published. Here are the photo plates of Olenellus schofieldi n. sp. from Best 1952:

 

 

Fritz, W.H. (1992)

Walcott's Lower Cambrian olenellid trilobite collection 61K, Mount Robson Area, Canadian Rocky Mountains.

Geological Survey of Canada Bulletin, 432:1-69

 

Lieberman, B.S. (1999)

Systematic revision of the Olenelloidea (Trilobita, Cambrian).

Peabody Museum of Natural History, Yale University, Bulletin 45:1-150

 

 

 

[piranha]

One more point about the ambiguity of a thesis:

 

Bohach 1997 had obvious uncertainty about the validity of Olenellus schofieldi, instead assigning it tentatively as: Mesonacis? schofieldi

 

Lieberman 1999 disagreed with that assessment:

 

"Best (1952) illustrated the species O. schofieldi Best 1952, which bears some similarity to species of Mesonacis. However, it lacks the diagnostic characteristics of that genus that differentiate it from members of the genus Olenellus, and at this time it is excluded from Mesonacis."

 

Lieberman, B.S. (1999)
Systematic revision of the Olenelloidea (Trilobita, Cambrian).
Peabody Museum of Natural History, Yale University, Bulletin 45:1-150  PDF LINK

[Fossil Claw]

One more point about the ambiguity of a thesis:

Bohach 1997 had obvious uncertainty about the validity of Olenellus schofieldi, instead assigning it tentatively as: Mesonacis? schofieldi

Lieberman 1999 disagreed with that assessment:

"Best (1952) illustrated the species O. schofieldi Best 1952, which bears some similarity to species of Mesonacis. However, it lacks the diagnostic characteristics of that genus that differentiate it from members of the genus Olenellus, and at this time it is excluded from Mesonacis."

She mentioned a publication by palmer that assigned it to a different genus. Didn't have the info handy.

[piranha]

She mentioned a publication by palmer that assigned it to a different genus. Didn't have the info handy.

That would be very confusing. I checked all of Palmer's papers and can't find anything. In any event, Best is first to describe Olenellus schofieldi. Bohach assigned it as Mesonacis? schofieldi and subsequently Lieberman excluded it from Mesonacis. Evidently they are now in agreement since Bohach suggests it's likely Olenellus schofieldi.

[FossilDAWG]

Lisa did get some of her thesis published, though I don't have the paper here and so I can't check if the species in question is covered. The reference is:

Mark Webster & Lisa Bohach 2014. Systematic revision of the trilobite genera Laudonia and Lochmanolenellus (Olenelloidea) from the lower Dyeran (Cambrian Series 2) of western Laurentia. Zootaxa 3824(1):001-066.

We had an email exchange a few years ago where Lisa told me that she finished her thesis just as Bill Fritz and Pete Palmer were putting out a flurry of papers as they were wrapping up things prior to retirement. As a result much of her taxonomy was out of date "before the ink was dry". Another problem (one I hadn't considered before) was that her thesis was far too massive to be published "as is" by any available journal. So, preparing things for publication would have basically entailed culling out what was still new after the Fritz/Palmer/Leiberman publications, re-analyzing the higher order taxonomy, and writing whole new papers. It was not just a simple matter of submitting the thesis "as is" for publication. That's a tall order when you've graduated and moved on to a full-time job.

In my own field of research, students are highly encouraged to write up their work as a series of manuscripts, which are published as each section of the work is done. At the end of the process, the student will have a series of published papers, which are bound together as chapters with the general introduction at the beginning and a general conclusion at the end to make the final thesis or dissertation. This avoids the problems generated by writing up the work in thesis format, then having to reformat everything to journal format to get it published.

It's interesting to note that theses and dissertations no longer constitute "publications" for purposes of taxonomic priority; I think they were allowed at one time. At the least, many European universities used to (and still may) publish PhD dissertations in book format, and distribute them to other university libraries, which met the criteria for "publication" (that the work had to be widely available).

Don

[Fossil Claw]

I am glad my ID request has inspired this fun discussion!

[RJB]

Hey Fossilclaw, apon a very close examination and my own expert analisis, my conclusion is that we are going to have to use that slab of rock for a 'lake skipper'. Ha!!! Ok, just kidding. Im glad you like it.

RB

[piranha]

On 2/11/2016 at 3:44 AM, FossilDAWG said:

Lisa did get some of her thesis published, though I don't have the paper here and so I can't check if the species in question is covered. The reference is:

Mark Webster & Lisa Bohach 2014. Systematic revision of the trilobite genera Laudonia and Lochmanolenellus (Olenelloidea) from the lower Dyeran (Cambrian Series 2) of western Laurentia. Zootaxa 3824(1):001-066...

 

Unfortunately, none of the Eager Fm. olenellids were included.

 

 

On 2/10/2016 at 7:41 PM, Fossil Claw said:

She mentioned a publication by palmer that assigned it to a different genus. Didn't have the info handy.

 

 

Olenellus schofieldi is not mentioned and was not assigned to another genus.

After some detective work I figured out which Palmer paper was referenced:

 

Palmer, A. R. (1998).

Terminal early Cambrian extinction of the Olenellina: documentation from the Pioche Formation, Nevada.

Journal of Paleontology, 72(4):650-672

 

quote:

 

"In Canada, specimens assigned to O. gilberti by Best (1952) and Hu (1985) have a relatively narrower cephalic border, posterior tips of the ocular lobes are consistently advanced from the occipital furrow, and, if present, intergenal spines are at the intergenal angle. At least one articulated exoskeleton has weak axial nodes on Tl to T6 and more distinct nodes on T7 to Tl4. These differences are interpreted here to have species-level value, and the Canadian specimens should be reassigned to a new (?) species."