Ordovician nautiloid... and trilobite... and fisherites...

[ToeKnee]

 

I only recently got into collecting after being out hiking and literally tripping over a large coral fossil a couple years ago and the hunt has been on since!  SO much to learn!  I wish I'd have started 30 or 40 years ago. I haven't posted any of my finds as I've been trying learn a little first and see if I could identify some of these.  I think I've got some of them and others I haven't found a name for, so I hope you don't mind me dumping several on you.

Are all these Receptaculites Oweni?  They were found in the Galena dolomite in the Dubuque area in what I think is the Fairplay member of the Dunleith.  (30 or 40 feet above river level) The third photo of the slightly smaller one was found in a drainage ravine so I can't be sure the layer it came from, but I don't believe it had been carried very far if at all.  It was 30 or 40 feet higher than the other two.  Is the last one Ischadites Iowensis or another Oweni? Is there a good guide to these somewhere?

 

 

These next are of a nautiloid I haven't found the name for. This was found in the Guttenburg member of the Decorah  also in the Dubuque area near river level.  It was in the outcrop about a foot above the top of what I think is the Spechts Ferry member. I also found quite a few Rafinesquina brachiopods laying around in the talus and the pygidiums of a couple different trilobite.  I think one is Gabricerarus Mifflenensis and the other Isotelus?  It looks a lot like the ones in the last photos of what I'm pretty sure are some Isotelus Iowensis I found near Elgin, IA).

 

 

 

 

Are these Isotelus Iowensis?  These were found near Elgin, IA in what I think is the Elgin member of the Maquoketa. About a foot above the Turkey river that day.  You can actually make out what I assume are compound eyes?  Being kind of new to this I'm amazed at the detail you can still see in some of these for something so old.  

 

 

I haven't found the name of these cephalopods yet either. They were found the same day and not far from the trilobites in Elgin and about 5 or 6 feet higher in the rock layer.

 

 

 

[ynot]

Welcome to TFF!

Can not help with the ID's, just wanted to say nice pieces.

Did You prepare them or find them as is?

[Fossildude19]

Welcome to the Forum.   
Great fossils!

Maybe these folks can help. 

 

@Raggedy Man   @Bev   

 

[FranzBernhard]

Welcome to the forum from Austria! You have found some very, very nice specimens! Congrats!

And you have done a good deal of researching and reading also, thats very good.

And very good photography, too!

But I can not help with id, sorry!

 

3 hours ago, ToeKnee said:

I wish I'd have started 30 or 40 years ago.

Just one point: There was no TFF around that time...

Franz Bernhard

[ToeKnee]

Thank you.  A little research ahead of time on strata and locations is a definite help, but luck has a big hand.  Some are as is out of the rock and some a little cleaned up.  The trilobites from Elgin are amazingly clean and they are as is. Other than cutting them out of a larger piece they were in.   The nautiloid and trilobite parts from the Decorah were cleaned up a little by me.  When found I could just could just barely make out ridges along the top and thought it was maybe flexicalymene at first. There might be more of the Gabricerarus under the front part of that one but it wasn't cleaning up as easily so I quit while I was ahead.  The fisherites were all pretty much as is other than splitting the rock they were in in half and cutting some of the surrounding matrix away. They're somewhat common in the area if you know the right layers to look in, but finding a whole one or getting them out of the rock in less than a 1000 pieces isn't always easy.  I believe there are two types in the area (oweni, and ischadites) but I'm new enough to not know the difference yet, other than ischadites is smaller I believe.

[Kane]

Great finds! And, yes, definitely compound eyes on your Isotelus, and those would be holochroal eyes.

 

Excerpt from Kaesler (1997), Treatise "O" :

 

"Holochroal (CLARKE) or compound (LINDSTRÖM) eyes have a visual surface of many closely packed, small lenses that are in direct contact with one another. The whole ensemble of lenses is covered by a single, thin, pellucid sheet, the cornea, which is calcitic and grades laterally into the outer layer of the cuticle. If the cornea is thin and the individual lens surfaces slightly convex, the lenses can be clearly seen and typically have hexagonal outlines."

[Manticocerasman]

those Receptaculites are spectacular 

[Al Tahan]

I can’t reliably ID these for you but I just wanted to drop a WOW!!!! Nice finds  

[minnbuckeye]

5 hours ago, ToeKnee said:

I believe there are two types in the area (oweni, and ischadites) but I'm new enough to not know the difference yet, other than ischadites is smaller I believe.

 

I am no expert but the samples of ischadites that I have found are small (about the size of the one in the picture) and have looked identical to  the specimen in the middle of the picture  :

 

 

[ToeKnee]

Thank you everyone.  I'm a little blessed to be living in a fairly fossil rich area with tons of riverside bluffs giving fairly easy access to hundreds of feet of strata.  I've found so many neat things in this area.  Blocks of galena the size of my fist, some 100+ lb rocks covered in dog tooth spar calcite crystals, a really neat fist sized phantom dog tooth crystal, pentamarides, corals, brachiopods... the Graf cephalopods, and on...  It was all there, I just had to stop and really look at things.  As I'm sure some of you may be, my wife is close to having me on a 'one rock in, one rock out' policy

 

The photo is somewhat helpful, but to my untrained eye, maybe ischadites, or maybe oweni.  I don't think I have that particular photo saved in my collection of notes though.  The field could use some updated specimen photos.  The old geological survey sketches and black and white photos don't always give me enough detail to figure some of them out.  Not just the receptaculites but in general.  At least for me not having seen actual specimens or learning the subtleties to differentiate between some these yet.  It's been kind of fun trying to learn the local stratigraphty.  A higher res color photo of a particular formation or member of strata really helps though when I'm trying to learn for sure what layer I'm in. That's where this site can be helpful.  There is a mountain of information out there, but nothing beats someone with experience or knowing where to look. 

[Raggedy Man]

1 hour ago, ToeKnee said:

Thank you everyone.  I'm a little blessed to be living in a fairly fossil rich area with tons of riverside bluffs giving fairly easy access to hundreds of feet of strata.  I've found so many neat things in this area.  Blocks of galena the size of my fist, some 100+ lb rocks covered in dog tooth spar calcite crystals, a really neat fist sized phantom dog tooth crystal, pentamarides, corals, brachiopods... the Graf cephalopods, and on...  It was all there, I just had to stop and really look at things.  As I'm sure some of you may be, my wife is close to having me on a 'one rock in, one rock out' policy

 

The photo is somewhat helpful, but to my untrained eye, maybe ischadites, or maybe oweni.  I don't think I have that particular photo saved in my collection of notes though.  The field could use some updated specimen photos.  The old geological survey sketches and black and white photos don't always give me enough detail to figure some of them out.  Not just the receptaculites but in general.  At least for me not having seen actual specimens or learning the subtleties to differentiate between some these yet.  It's been kind of fun trying to learn the local stratigraphty.  A higher res color photo of a particular formation or member of strata really helps though when I'm trying to learn for sure what layer I'm in. That's where this site can be helpful.  There is a mountain of information out there, but nothing beats someone with experience or knowing where to look. 

Beautiful finds! Any chance you can post pictures of the trilobite on the right in this picture? Im pretty sure you have something amazing here. 

Gabriceraurus mifflinensis is no longer valid and was renamed Ceraurus mifflinensis.

 

[ToeKnee]

Raggedy Man, here are some closer pictures of the trilobite from the Decorah.  The under side is kind of neat in it's own right as it's full of brachiopods. 

 

 

[ToeKnee]

Speaking of reclassification I think receptaculites oweni is also incorrect. I think they were reclassified as Fisherites reticulatus.

 

I dug through my pile of receptaculites again and think I may have found a partial ischadites in my pile. It looks slightly physically different than most of the others I have.

 

 

 

And yeah... I kind of have a small pile of these 

 

 

I attached a pdf I came across that may be helpful to someone else.  It did help me a little, but it started getting in a little deep for my level of knowledge at this point. 

 

Morphology and merom gradients in the Ordovician receptaculid Fisherites reticulatus - app38-233.pdf

[abyssunder]

Take a look to this topic:

 

[minnbuckeye]

28 minutes ago, ToeKnee said:

39 minutes ago, ToeKnee said:

here are some closer pictures of the trilobite from the Decorah

 

 

So, so close! Still a very nice partial.

[ToeKnee]

2 hours ago, abyssunder said:

Take a look to this topic:

 

Thank you. I hadn't come across this one. The Kelsing/Graham paper looks interesting. 

[ToeKnee]

2 hours ago, minnbuckeye said:

 

So, so close! Still a very nice partial.

I hoped maybe it was a whole one when I picked it up because it had an oval hemispherical shape the right size for a whole one to be in there.  Until I started cleaning towards the front of it and all the sudden there's a big gap where the cephalon should be.  Maybe it separated from the rest of the body and is still buried under the front part of it.  I'll probably start picking at it again someday.

[GerryK]

20 hours ago, ToeKnee said:

Raggedy Man, here are some closer pictures of the trilobite from the Decorah.  The under side is kind of neat in it's own right as it's full of brachiopods. 

 

 

There are only two types of Ceraurus like trilobites that occur in the Decorah, Ceraurus plattinensis and Gabriceraurus herrmanni. By looking at the pygidium, the trilobite is a Gabriceraurus herrmanni.

[ToeKnee]

22 hours ago, GerryK said:

There are only two types of Ceraurus like trilobites that occur in the Decorah, Ceraurus plattinensis and Gabriceraurus herrmanni. By looking at the pygidium, the trilobite is a Gabriceraurus herrmanni.

Thank you! I looked those up and I see the difference in those two species in the way their pygidiums terminate between the rear spines.  That would make this one hermanni.  Pardon my probably dumb question, but did you know that from experience, or is there a resource you use to know there are only a couple of different species in the Decorah?  Knowing there were only a couple species in that member would have narrowed my search.  Also, Raggedy Man mentioned Gabri had been deprecated on the mifflinesis and it was just Ceraurus.  I just came across both Gabriceraurus hermanni and Ceraurus hermanni.  Is there an official site that lists current taxonomy along with all of the previous names it was classified as? As you can see I'm still learning where to look stuff up! 

[piranha]

According to Congreve 2013 Ceraurus herrmanni is no longer valid:

 

C. hermanni [sic] Walter, 1924 was excluded from the analysis because the type specimen was in a private collection that has since been lost, thereby turning the species into a nomen nudum.

 

Congreve 2013 on G. mifflinensis:

 

Since G. mifflinensis was described from an isolated cranidium and an isolated pygidium, we were unable to ascertain with complete confidence whether or not the original holotype and paratype material are in fact mismatched without first describing a complete specimen from the locality.

 

Discussion.-- Ceraurus mifflinensis is removed from Gabriceraurus and placed into Ceraurus based on the presence of paired exsagittally arranged nodes next to the eye and the triangular shaped furrow anterior of the terminal axial piece of the pygidium, as well as the fact that the characteristics used to place the species in Gabriceraurus (eyes aligned with L2, cephalic outline subrectangular) have been shown to be plesiomorphic.

 

Congreve, C.R. 2013

Evolutionary patterns of trilobites across the end Ordovician mass extinction.

PhD Thesis, University of Kansas, 255 pp.  PDF LINK

[GerryK]

Curt Congreve, Lisa Amati and I are working on the revision of Ceraurus and related genera. My part is collecting specimens from the Ordovician in IA,WI and MN region. There are a lot of undescribed species of Ceraurus from this area. Al Scheer who lives in the area, is very knowledgeable of the Ordovician trilobites in this region and has been very helpful. His web site “Midwest Paleo” lists and illustrates many trilobite from the region.

There are two Ceraurus species described from the Decorah, C. plattinensis and C. herrmanni. I’ve collected both species and so far no other species of Ceraurus in the Decorah have been found. C. herrmanni is a Gabriceraurus but the type is lost and we are working on the validity of this species. Your specimen at this time would be called Gabriceraurus herrmanni but what we will call it is to be determined.

[piranha]

On 12/1/2018 at 1:43 PM, GerryK said:

Curt Congreve, Lisa Amati and I are working on the revision of Ceraurus and related genera...

 

 

Excellent news, I recall you mentioned this ongoing work a few years ago.  That will certainly be a highly anticipated paper!

 

[Bev]

Spectacular finds @Toeknee!!! 

You are doing GREAT! Yes, you are in a truly fossil rich area. You are getting wonderful feedback on your finds and I can't add anymore myself.

 

It is easier to get IDs if you put ONE, or a group of like fossils, in the ID section with something like: Ordovician, Galena Formation, NE Iowa.

 

LOL, on the "one in one out" wifey thing. That is when you buy a storage shed and name it your fossil barn! Also, some of these would be great on an auction for TFF perhaps if you are getting too many of the same thing. I have been attempting to edit only my best down to a large DRY aquarium (they are marine life) that is lighted and keeps the dust off of them. Something for you to consider. They are also saleable. And you can always create fossil gardens, like I did, and that organizes your "not good enough to go in the house but too good to toss" fossils.  :-D

[dalmayshun]

gorgeouis finds, and your are fortunate it is one in, one out....mine has lately become, "one more in, I'm out." LOL

[Innocentx]

@ToeKnee. Lucky for us that you've been bitten by the fossil bug. Great finds and photos for our viewing pleasure!!