Field Trip Results and Photographs of Specimens

By Jerry Suchan
GESUCHAN@EARTHLINK.NET
303-648-3410
Revision 5, 11 May 2004

Revision 3 and later of this web page includes some credits for specimen ownership and additional trilobite identification information. Come on everyone, I need more information on who owns these specimens. This may be useful for future studies.

In revision 5 the pictures of the possible Kainella thorax specimens, Tom Nolan's trilobite (IM000624), and Bill Tilly's trilobite have been reproduced at approximately the same scale for comparison.

Also in revision 5, It is speculated that the mystery fossil DSCN9342 might be a hyolithid.

This is the preliminary report on the results of the field trip to the Manitou formation on 2 May 2004. To all accounts the field trip was quite successful. The weather could not have been better, as it was warm, sunny and there was no wind. Around 20 Western Interior Paleontological Society (WIPS) participants and maybe 10 Colorado Springs Mineralogical Society (CSMS) participants attended. It seemed to all that I talked to that everyone found some very acceptable specimens and had a great time.

We were at the location for over five hours, with some people staying much longer. With 30 people looking for five hours, this amounts to about 150 "person" hours spent looking for fossils. This is equivalent to over 18 eight hour days spent by one person at these locations. The result was a huge bonanza of fine paleontological specimens, some of which are better than any I have ever seen before and at least one of which I don't think I have ever seen before.

One area we probably neglected, or at least I did, was paying sufficient attention to the brachiopods. It did appear that no new brachiopods were found, but I confess to not being very at tentative to them, as there were so many great trilobite and cistoid specimens found.

In the following, I am providing a number of pictures of specimens which were found during the field trip. I know who found the specimen in some cases and do not know in others. So, if you are the owner of the specimen illustrated please e-mail me at GESUCHAN@EARTHLINK.NET so I can give appropriate credit of ownership. I will accordingly add this information to this web page as appropriate. The number associated with the specimen pictures is keyed to the photograph I took, so use it to refer to the specimen.

*** We went to two locations. The first location is an old quarry.

Plenty of fine specimens were found. Here are some of the ones found at the first location.

Above (DSCN9338), whose specimen? More or less complete trilobite, probable genera Leiostegium. See my notes on identifying these trilobites at the bottom of this page. Head (cephalon) is at left and tail (pygidium) at right, thorax in between, as is shown in the illustration below.

Above: Illustration of trilobite parts. Whole trilobite at left, Cephalon at right. These illustrations are linked to pictures at http://www.aloha.net/~smgon/trilomajor.htm

Above (DSCN9342), Tom Nolan specimen. Possible hyolithid? Scale is 1 cm for each division, so the specimen is about 5 cm long, or about 2 inches. 5 CM is actually 1.9685 inches.

Left is hylithoid picture linked from http://www.geosurv.gov.nf.ca/images/edgifs/fossils/hyolithi.gif Right is picture of Haplophrentis carinatus linked from http://www.nmnh.si.edu/paleo/images/dhaplo.gif

For now we have the following speculation on the identity of this specimen: Tom Nolan has communicated to me in a reply from Dr. Niles Eldredge from AMNH, that Dr. Eldredge thinks it might be a hyolithid. Additional investigations are under way.

The text with the Haplophrentis carinatus, available at the National Museum of Natural History's Paleobiology website, provides a useful description of the animal.

"This interesting looking, shelled creature was composed of three parts: A long, flat-bottomed, conical shell housing the body, a small lid (operculum) closing the front end, and two curved appendages sticking out sideways, like props, at the front. (Dr. Walcott named these side arms as 'helens' after his daughter!) Presumably the helens acted as struts or stabilizers to keep the body from rolling around sideways in the currents. They may have also worked like oars, sculling the creature slowly along the bottom as it fed on organic stuff in the mud. In turn, these hyoliths served as food for other animals. Specimens have been found lined up, head-to-tail, in the gut of the sand-dweller; Ottoia.

"These creatures were small - from about a 1/10th of an inch up to 1 1/4 inches in length. That, plus a slow method of locomotion must have made them ready "game" for the more active predators. (See the Burgess Shale site reconstruction.) Their unusual morphology makes it difficult to trace their affinities to other animals, although some scientists regard them as mollusks. "

Anothe hylithoid picture is available at http://www.museum.vic.gov.au/prehistoric/image_html/mr007714.html . I am not linking it because the good Museum recommended I contact an attorney to make sure I wasn't infringing on a copyright, But you can use the link yourself to look at their picture directly.

As defined in thefreedictionary.com : Hyolitha are enigmatic animals with small conical shells. They are known only from the Cambrian era. The conical shells have a cover (operculum) and two curved supports known as Helens. The shells are calcerous and are usually triangular or elliptical in cross section. Some species have rings or striations. Most are one to four centimeters in length. Some authors treat them as molluscs, but it is generally agreed that there is no very strong argument to do so. Despite the fact that Hyolithid shells are quite common as fossils , next to nothing is known about their ancestry and internal structures. They were obviously bottom dwellers. There is some evidence that they were carnivores.

In comparing these pictures and descriptions to the specimen DSCN9342 one can make the following observations:

Hyolithid are depicted and described as having a long, flat-bottomed, conical shell housing the body. Specimen DSCN9342 is flexible in appearance, ribbon-like and flat in appearance. This is not conical but flat. Could it be the bottom of the conical shell? It doesn't look very conical. All the pictures of a hyolithid that I have seen are small cones, usually flattened, and have the appearance of being quite a bit shorter in relation to their diameter than specimen DSCN9342. This is not a strong indication this specimen is a hyolithid.
Only "some" species of hyolithid are described as having rings or striations. So the fact that specimen DSCN9342 does not have these is not diagnostic.
Most hyolithid are one to four centimeters in length. Specimen DSCN9342 is about 5 cm long, (or about 2 inches). This is at the large side of the size range of a hyolithid. For example, a search of Fossil Specimens -- Invertebrates reveals no hyolithid larger than 1.9 inches. Of course that proves nothing.
The opening of specimen DSCN9342 is not visible as it is covered by matrix. So an operculum and the helens are not visible, if they exist. While this is not diagnostic, there remains the possibility that a preparation of the anterior part of the fossil will reveal the existence on nonexistence of these features.
The comment that hyolithid are known only from the Cambrian era is not accurate as other references clearly indicate. See for example, ORDOVICIAN AND SILURIAN HYOLITHS AND GASTROPODS REASSIGNED FROM THE HYOLITHA FROM THE GIRVAN DISTRICT, SCOTLAND. So, hyolithid did exist in the Ordovician.

What does all of this tell us? Well, from the available information so far, the hypothesis that specimen DSCN9342 is a hyolithid is not ruled out. On the other hand, no specific diagnostic features are evident on the unprepared specimen. Certain features of specimen DSCN9342, such as it's large size and long ribbon like rather than short conical appearance argue that it may not be a hyolithid. If not then what is it? As I said, additional investigations are under way. We will see if the professionals come up with a conclusion.

Above left (DSCN9355), Tom Nolan specimen. Cystoid stalk with detached head. Genera TBD. A very nice specimen.

Center, for comparison, a drawing of Lepocrinetes quadrifasciatus, a Silurian blastoid from the UK.

Right (DSCN9361), whose specimen? a specimen similar to (DSCN9355) appears to have it's head attached. It is an excellent specimen. This specimen warrants a better and more detailed photograph, so I would like to contact whoever has this specimen about this.

Above left (DSCN9356), Trick Runions specimen, Trilobite, Kainella sp. Head (cephalon) parts with lateral border and glabella. See illustration of trilobites above. While the lateral border of the Kainella was commonly found on this field trip, the addition of the cephalon makes this a very nice specimen. It compares very nicely with the illustration on the right (DSCN9267) of the Kainella sp. of Plate 22 Fig 6 in "Trilobites from the Perless and Manitou Formations of Colorado, Robert R. Berg and Reuben Ross Jr., Journal of Paleontology, v.33, No.1, p. 106-119, January 1959.")

Above (DSCN9364), Phil Bradley specimen. Two detached tails (pygidium), two other detached trilobite parts and a brachiopod. Probable genera Leiostegium. See my notes on identifying these trilobites at the bottom of this page. This collection of several fragments illustrates the following story.

Why are a lot of specimens missing their cephalon or pygidium or are just pieces? Trilobites are arthropods (meaning joint legged) and as such have chitinous exoskeletons, just like insects and crabs. When the animal outgrows its exoskeleton it splits the exoskeleton open and climbs out. Then it solidifies a new exoskeleton over it's now somewhat larger body. This leaves the parts of the exoskeleton lying about and so provides lots of fossils for amateur and professional paleontologists to study. The down side is the specimens are incomplete pieces. Sometimes the animal dies and then there is the opportunity for a whole exoskeleton to be preserved.

*** Location 2 is a larger quarry than location 1.

There were a lot of specimens found at location 2 also. Even more than at location 1, although most of the fossils are of the same species in both places. This shows us that both are really the same deposition despite their slight separation geographically. In a way, that is not as exciting as it would have been if the two deposits had been different in some way.

The following are some specimens that were found at location 2. I am only posting those that show something different than the ones I posted for Location 1.

Above left (DSCN9384) cast and right (DSCN9376) (whose specimen?) mold of an unidentified trilobite. This is the same species as the one I referred to in the Field Guide as "species 1". The genera for this specimen remains TBD. We did not find one of these at Location 1 this field trip, but the one in the field guide was found there.

Above (DSCN9385), Trick Runions specimen. Very large lateral border of the Giant Trilobite, Kainella sp. The lateral border can be seen running from outside the frame of the picture at the left, all the way across to the right and out of the frame again. Scale is 1 cm for each division, so the specimen is over 13 cm long, or about 5 inches from left to right, and that is only the lateral border. This trilobite must have been well over a foot (perhaps 15 inches) long!

Above (DSCN9389), Peter J Modreski specimen. The unidentified cystoids were found at this location also. This one has the head right at the top of it's stalk, and so probably represents an attached head even though the head is represented only as a mold. The counter fossil for this specimen should have the cast of the head on top of the stalk. The black scale at the bottom is 1 CM, so the relatively small size of these cystoids is evident, especially when compared to the huge Kainella (Again I would like to contact the owner of this specimen to better photograph it, especially the counter side of the fossil.)

Above (DSCN9407), whose specimen? Mold (left) and cast (right) of the head of a cystoid. These are fossil and counter fossil of the same specimen.

Above (DSCN9393), Phil Bradley specimen. Part of a curled trilobite (unidentified) protruding from the matrix. Probable genera Leiostegium. See my notes on identifying these trilobites at the bottom of this page. This probably represents the whole preserved animal rather than just a part. Specimen is about 2 cm (about 3/4 inch) across. (This photograph is not a very good one and I would like to remake it if the owner is interested.)

Above (DSCN9398), Stephen Reinhold specimen. Two near complete trilobites on matrix. Probable genera Leiostegium. See my notes on identifying these trilobites at the bottom of this page.

***

The above pictures are reproduced here at about the same scale for comparison. Left, (IM000624, photo by Tom Nolan), Tom Nolan specimen, found by Norma Neyman. Each division of the scale is 1 cm, so the specimen is about 4 cm across, or about 1.5 inches. Right, Bill Tilly's trilobite (photo by John Harrington), found in the 2nd quarry in 1994. Scale provided by the hand holding the specimen indicates it is about 5 inches across. While IM000624 is quite a bit smaller than the other specimen, they appear to be the same genera. They are not a Leiostegium, and not the trilobite I have referred to as "species 1". So what is it? A possability is that these trilobite molts are the body parts of a Kainella. Since I have only seen the lateral border and glabella of a Kainella, I can't be sure. In fact, to date I have not found a better picture of a Kainella than the ones in the web page, so if anyone has a lead to a better picture of a Kainella, please let me know.

That is all that I have for now. I will update this page with identifications and other information as I receive it. If anyone has interestingly different specimens that were not photographed and not included in this web page, I would be interested in getting together with you and adding your specimen here. Gathering this information together and publishing it in a permanent and informative form is an important aspect of accomplishing a "professional" papeontological field trip. You can e-mail me at GESUCHAN@EARTHLINK.NET or call at 303-648-3410. Likewise, if anyone has any corrections, or identifications, or relevant references ot even guesses at identifications, I would be more than happy to correspond with you.

Respectfully Submitted to
the Western Interior Paleontological Society and
the Colorado Springs Mineralogical Society.

Jerry Suchan

*** Notes on trilobite identifications.

Reference "Trilobites from the Perless and Manitou Formations of Colorado", Robert R. Berg and Reuben Ross Jr., Journal of Paleontology, v.33, No.1, p. 106-119, January 1959, provides the following information about the trilobites from the Manitou formation. This formation is where we found all of the fossils on this field trip. There are five genera of trilobites listed from the Maitou, as follows. These pictures are not to the same scale.

Above: Leiostegium (Leoistegium) manituensis Walcott; Left (9) cranidium, right (17) pygidium.

Above: Kainell sp.; Left (13) cranidium, right (6) fragmentary pygidium.

Above: Hystricurus? aff. H.? genacurus (Hintze); Left (23) cranidium, no specimen of pygidium available.

Above; Bellefontia cf. B. chamberlaini Clark; Left (22) cranidium, right (18) pygidium.

Above: Symphysurina cf. S. globocapitella Hintze; Left (3) cranidium, right (25) pygidium.

Considering these five genera, only the Kainell and the Leiostegium are well enough illustrated by reasonably well preserved specimens to be of much help in identifying the fossils we have found. On this basis I tentatively offer tht the specimens that were found are probably one of these two genera. Thus, since the Kainella so far have been obvious and easy to identify, the rest of the specimens are candidates to be Leiostegium.