Jump to content

My trilobite of the week.


rew

Recommended Posts

Trilobite #15  Another Devonian bug of the same genus, Cyphaspis eberhardiei from the Timrhanhart Formation of Foum Zguid, Morocco.  This one looks like it's on the runway ready to take off.

dorsal-rotated-cropped-small.jpg

right-side-cropped-small.jpg

  • I found this Informative 6
  • Enjoyed 2
Link to comment
Share on other sites

Here is trilobite #16, the official trilobite of this week, and I'm not exactly sure what it is.  It is a Middle Devonian pustulose scutellid from Jebel El Mrakib, Morocco.  It was sold as an undetermined species within the Goldius genus, which according to Sam Gon's trilobites.info site is a junior synonym of the Scutellum genus.  So maybe it's an undetermined species of Scutellum.    What this isn't is Metascutellum pustulatum; that species has an indentation partway up the center section of the pygidium that this specimen lacks.

 

If there are any scutellid experts out there who can pin this down better please speak up.  It is certainly a very fine example of whatever it is.

 

Like all trilobites in the order Corynexochida this has holochroal eyes (a single cornea over all the lenses).  Nevertheless the lenses are well preserved.  They are a bit too small to be seen with the naked eye but are readily seen with the aid of a naked magnifying macro lens.

 

 

dorsal-small.jpg

left-side-cropped-small.jpg

right-eye-small.jpg

  • I found this Informative 5
  • Enjoyed 2
Link to comment
Share on other sites

You have amassed an amazing collection of trilos. How many more to go? How long did it take you to collect what you've got so far?

Link to comment
Share on other sites

We've hardly begun.  Posting the bugs here gives me an incentive to get my trilobites photographed.  (I have other, non-trilobite fossils too, including a few in the "awesome" category, but they'll have to go in another thread.)   One advantage of posting them here is that any errors in identification or in other statements made about them have a fair chance of being corrected.

 

I've been collecting trilobites for about 7 years.

Link to comment
Share on other sites

19 hours ago, rew said:

Here is trilobite #16, the official trilobite of this week, and I'm not exactly sure what it is.  It is a Middle Devonian pustulose scutellid from Jebel El Mrakib, Morocco.  It was sold as an undetermined species within the Goldius genus, which according to Sam Gon's trilobites.info site is a junior synonym of the Scutellum genus.  So maybe it's an undetermined species of Scutellum.    What this isn't is Metascutellum pustulatum; that species has an indentation partway up the center section of the pygidium that this specimen lacks.

 

If there are any scutellid experts out there who can pin this down better please speak up.  It is certainly a very fine example of whatever it is.

dorsal-small.jpg

 

 

Bronteus pustulatus Barrande 1846 was reclassified as Metascutellum pustulatum Šnajdr 1960 (median pygidial rib distinctly bifurcate)

 

Šnajdr, M. 1960

Studie o celedi Scutelluidae (Trilobitae).

[A study of the family Scutelluidae (Trilobita).] 

Rozpravy Ústředního Ústavu Geologického, 26:1-280

 

 

Here is the response from a colleague that specializes in the Scutelluidae:

 

The specimen belongs to Scutellum. There are some similar specimens from Morocco illustrated on the internet as Scutellum pustulatum, but other specimens illustrated on the internet under this name are not conspecific or even congeneric. Also, there are possible taxonomic problems with that name. It was proposed by a German worker Anne Archinal in 1994, but it may be a junior homonym of a name by Barrande (1846).

 

figures from:

 

Archinal, A. 1994

Zur Morphologie, Systematik, Stratigraphie und Okologie der Gattung Scutellum (Trilobita; Devon).

[On the morphology, systematics, stratigraphy and ecology of the genus Scutellum (Trilobita, Devonian).] 

Senckenbergiana Lethaea, 74:291-324

 

image.thumb.png.8ee7c0a846b8d1ecb35d5f79bd62a93e.png

  • I found this Informative 5

image.png.a84de26dad44fb03836a743755df237c.png

Link to comment
Share on other sites

What's a weekend "Trilobite of the Week" without some midweek bonus trilobites?

 

Here is trilobite #17, Asaphus lepidurus, a relatively common asaphid from the Putilovo quarry in the St. Petersburg region of Russia.

dorsal-small.jpg

right-side-small.jpg

  • I found this Informative 6
  • Enjoyed 2
Link to comment
Share on other sites

Trilobite #18 is Asaphus cornutus, from the Vilpovitsy quarry of the St. Petersburg region of Russia.  The eyes of this trilobite are a bit raised compared to A. lepidurus.   These Russian bugs are sometimes placed in the genus Neoasaphus rather than Asaphus.  I'm interested in any informed opinion as to which is the preferred genus.

dorsal-small.jpg

right-side-hi-exp-small.jpg

  • I found this Informative 5
  • Enjoyed 1
Link to comment
Share on other sites

Here is the official trilobite of the week, trilobite #19.  It is a classic Silurian lichid from the Rochester Shale of upstate New York, Arctinurus boltoni:

 

dorsal-small.jpg

  • I found this Informative 4
  • Enjoyed 1
Link to comment
Share on other sites

  • 2 weeks later...

Well, I had a busy week, so no mid-week bonus trilobites this time.  This trilobite of the week is #20, an undetermined species of Cyclopyge, from the  Ktaoua Formation of El Kaid Errami, Morocco, of early Ordovician age.  This small trilobite is all about its bulbous head with enormous eyes.  And despite the relatively poor quality of shell preservation, most of the lenses are visible.

 

dorsal-small.jpg

left-eye-small.jpg

right-eye-small.jpg

  • I found this Informative 5
Link to comment
Share on other sites

Okay, I make up for last week by having two early middle of the week bonus trilobites.  Both are small trilobites, each about 12 mm long, both are of Middle Cambrian age, both are in the order Ptychopariida, and both are from the Western United States.  Trilobite #21 is Piochaspis sellata from the Chisholm Shale in Pioche, Nevada.  Trilobite #22 is Bolaspidella drumensis from the Pierson Cove Formation in Millard County, Utah.  The Piochaspis is a fairly ordinary bug, the Bolaspidella features a pustulose head, an occipital spine, and several axial spines.

dorsal-small.jpg

dorsal-small.jpg

  • I found this Informative 5
  • Enjoyed 1
Link to comment
Share on other sites

The new trilobite of the week is trilobite #23, Bellacartwrightia whiteleyi.  This Middle Devonian Acastid comes from the Windom Shale of Hamburg, New York.  It has axial nodes.  While it doesn't quite have an occipital spine, at least it has an occipital point.

 

dorsal-small.jpg

dorsolateral-small.jpg

  • I found this Informative 4
  • Enjoyed 2
Link to comment
Share on other sites

19 minutes ago, rew said:

The new trilobite of the week is trilobite #23, Bellacartwrightia whiteleyi.  This Middle Devonian Acastid comes from the Windom Shale of Hamburg, New York.  It has axial nodes.  While it doesn't quite have an occipital spine, at least it has an occipital point.

 

dorsal-small.jpg

dorsolateral-small.jpg

 

If this example is truely from the Windom member, then it should be labeled as Bellacartwrightia sp. This species has not yet been described. The B. whiteleyi is described only from the Wanakah member, below the Tichenor LS. The Bellacartwrightia sp. from the Windom was deemed to have enough differences to be classified as a different species. I'm currently in the process of trying to collect enough examples to have it properly described. Regardless, this is one of the nicer examples I have seen. In fact, if you feel so inclined, would you mind sending me some more photographs of this one along with your info so that I can include it in my collection of info?

  • I found this Informative 3

Jay A. Wollin

Lead Fossil Educator - Penn Dixie Fossil Park and Nature Reserve

Hamburg, New York, USA

Link to comment
Share on other sites

Some truly beautiful trilobites.

Love #20, great eyes! 

Life's Good!

Tortoise Friend.

MOTM.png.61350469b02f439fd4d5d77c2c69da85.png.a47e14d65deb3f8b242019b3a81d8160-1.png.60b8b8c07f6fa194511f8b7cfb7cc190.png

Link to comment
Share on other sites

9 hours ago, DevonianDigger said:

 

If this example is truely from the Windom member, then it should be labeled as Bellacartwrightia sp. This species has not yet been described. The B. whiteleyi is described only from the Wanakah member, below the Tichenor LS. The Bellacartwrightia sp. from the Windom was deemed to have enough differences to be classified as a different species. I'm currently in the process of trying to collect enough examples to have it properly described. Regardless, this is one of the nicer examples I have seen. In fact, if you feel so inclined, would you mind sending me some more photographs of this one along with your info so that I can include it in my collection of info?

Hopefully we will be finding some for ourselves this season. FYI I am planning being there the Friday through Monday of the Dig With The Experts Weekend. 

Link to comment
Share on other sites

Yes I am going in disguise as one, I think he just wanted my saw and big prybars there. Should be fun but sticking around Fri and Monday (Mon depending on Weather) so I can get in a bit of digging time for myself. If anyone else is going I will be the homeless looking guy in the Jurassic park hat and Fossil Forum Tee Shirt on the Friday.. Hope to see a few of you there. Get your tickets NOW!!!! for the Saturday and Sunday Dig.. Space is limited and they are selling out fast.

Link to comment
Share on other sites

8 minutes ago, Malcolmt said:

Yes I am going in disguise as one, I think he just wanted my saw and big prybars there. Should be fun but sticking around Fri and Monday (Mon depending on Weather) so I can get in a bit of digging time for myself. If anyone else is going I will be the homeless looking guy in the Jurassic park hat and Fossil Forum Tee Shirt on the Friday.. Hope to see a few of you there. Get your tickets NOW!!!! for the Saturday and Sunday Dig.. Space is limited and they are selling out fast.

 

In fact, there are only around 30 tickets left for Sat or Sun. But let's not hijack this awesome thread, lol.

Jay A. Wollin

Lead Fossil Educator - Penn Dixie Fossil Park and Nature Reserve

Hamburg, New York, USA

Link to comment
Share on other sites

Perhaps make a Dig with The Experts Thread 2019 and consolidate stuff there. 

Link to comment
Share on other sites

This midweek bonus trilobite (#24) is a more common cousin of Bellacartwrightia, Greenops boothi, from the Moscow Shale of Erie County, New York.  It is middle Devonian in age.  This specimen, 27 mm long, is typical size for the species.  It shares its rock with a piece of horn coral, a reminder that back in the Devonian upstate New York was a shallow tropical sea, south of the equator.

dorsal-small.jpg

whole-plate-small.jpg

  • I found this Informative 2
  • Enjoyed 2
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...