TRILOBITA.DE
Register Calendar Members List Team Members Search Frequently Asked Questions Go to the Main Page

TRILOBITA.DE » TRILOBITA.DE-Forum » Morphologie / Morphology » TOM for February 2008 » Hello Guest [Login|Register]
Last Post | First Unread Post Print Page | Recommend to a Friend | Add Thread to Favorites
Go to the bottom of this page TOM for February 2008
Author
Post « Previous Thread | Next Thread »
goniagnostus goniagnostus is a male


images/avatars/avatar-21.gif

Registration Date: 27.08.2007
Posts: 68

TOM for February 2008 Reply to this Post Post Reply with Quote Edit/Delete Posts Report Post to a Moderator       Go to the top of this page

What do you say about a largely featureless trilobite? Dysplanus acutigenia is an
effaced illaenid, and it is distinctive for lacking clear axial
structures such as furrows and lobes. I invite you view this month's
TOM here: http://www.trilobites.info
enjoy!

goniagnostus has attached this image (reduced version):
08_02_Dysplanus_acutigenia.jpg



__________________
Sam [goniagnostus]
A Guide to the Orders of Trilobites
http://www.trilobites.info
01.02.2008 08:11 goniagnostus is offline Send an Email to goniagnostus Homepage of goniagnostus Search for Posts by goniagnostus Add goniagnostus to your Buddy List
Michael Michael is a male
Inner Circle


Registration Date: 16.02.2007
Posts: 892
Herkunft: Oberfranken

Reply to this Post Post Reply with Quote Edit/Delete Posts Report Post to a Moderator       Go to the top of this page

Hi Sam,

really a nice Trilo. And the crack running through the matrix and Trilo is clear visible- a good sign for a russian Trilo. What are the dark spots on the Glabella and Pygidium ? On the Glabella it looks like it would be pairy spots, are these muscle- scars ? (I have the work from frank Rudolph about Trilobite´s muscles- "Kopfmuskulatur bei Trilobiten), but I´m at work at the moment and can´t check it.

Many greetings
Michael
01.02.2008 13:09 Michael is offline Send an Email to Michael Search for Posts by Michael Add Michael to your Buddy List
juniper juniper is a male
Inner Circle


images/avatars/avatar-144.jpg

Registration Date: 26.01.2007
Posts: 1,404
Herkunft: Aschaffenburg

Reply to this Post Post Reply with Quote Edit/Delete Posts Report Post to a Moderator       Go to the top of this page

Hi Michael
diese dunklen Flecken werden in der Tat als Ansatzstellen für Muskulatur interpretiert. Sie sind nicht an jedem Exemplar einer Art erhalten, die Qualität der fossilen Erhaltung hat da eine gewisse Bandbreite, eventuell auch abhängig vom Fundort.
Sehr schön anzusehen ist die Transparenz der Calzitschale - man kann die Struktur des Steins darunter erkennen :)
Etwas rätselhaft sind mir die beiden dunklen Streifen an der Pygidialaxis....


Those dark spots are interpreted as points of muscle insertions. That can differ between specimens - it is not always preserved (it may even differ between the locations where the fossils are found).
What’s beautiful, too, is the transparency of the fossil carapace - you can see the stucture of the stone beneath it :)
Quite interesting are those two dark stripes at the axis of the pygidium...

Klaus

__________________
„Ich suche nicht - ich finde.” Pablo Picasso.

2.Trilobiten-Tagung (19./20.2.2011): Abstracts der Vorträge
01.02.2008 15:09 juniper is offline Search for Posts by juniper Add juniper to your Buddy List
Michael Michael is a male
Inner Circle


Registration Date: 16.02.2007
Posts: 892
Herkunft: Oberfranken

Reply to this Post Post Reply with Quote Edit/Delete Posts Report Post to a Moderator       Go to the top of this page

Genau, Klaus.
Diese Deutung als Muskelansatzstellen kenne ich, war aber ebenfalls verwundert über die Strukturen am Pygidium, die sehen dafür eher ungewöhnlich aus. Ist ein schöner Trilobit.

Viele Grüße,
Micha
01.02.2008 16:24 Michael is offline Send an Email to Michael Search for Posts by Michael Add Michael to your Buddy List
Jens Jens is a male
Moderator


Registration Date: 18.03.2007
Posts: 2,167
Herkunft: HGW, momentan Jura, Schweiz

Reply to this Post Post Reply with Quote Edit/Delete Posts Report Post to a Moderator       Go to the top of this page

Die Strukturen am Pygidium sind die Ansätze der Beinpaare, sowas sollte auch auf den Pleuren sichtbar sein, ist es aber meist nicht. Habe Nileen wo sowas auch schön sichtbar ist. Dysplanus hat ne dünne Schale, daher sind die Ansätze gut zu sehen. In diesem Fall wurde der Effekt natürlich in russischer Manier noch durch die Hochglanzpolierung verstärkt :D. Aber schönes Stück.

dieser Dysplanus hier ist etwas natürlicher.

http://www.trilobit.org/Pictures/view_pic.php?view=21

lg,

Jens

This post has been edited 1 time(s), it was last edited by Jens: 01.02.2008 17:40.

01.02.2008 17:38 Jens is offline Send an Email to Jens Homepage of Jens Search for Posts by Jens Add Jens to your Buddy List
Michael Michael is a male
Inner Circle


Registration Date: 16.02.2007
Posts: 892
Herkunft: Oberfranken

Reply to this Post Post Reply with Quote Edit/Delete Posts Report Post to a Moderator       Go to the top of this page

Hallo Jens,
danke für die Aufklärung ! Auf eurem (trilobiten.de)- Dysplanus sind die Ansätze wirklich besser zu erkennen, spiegelt halt nicht ganz so doll ;).
Dass man die Beinansätze am Pyg. so schön erkennen kann, wußte ich nicht, klingt aber logisch, wenn die Struktur so schön links/ rechts gleich ist.

Grüße,
Micha
01.02.2008 18:18 Michael is offline Send an Email to Michael Search for Posts by Michael Add Michael to your Buddy List
juniper juniper is a male
Inner Circle


images/avatars/avatar-144.jpg

Registration Date: 26.01.2007
Posts: 1,404
Herkunft: Aschaffenburg

Reply to this Post Post Reply with Quote Edit/Delete Posts Report Post to a Moderator       Go to the top of this page

Hi Jens

Danke für die Information.
Ich hätte nicht gedacht, daß es möglich ist die Strukturen zu erkennen wo die winzigen Pygidialbeinchen ansetzen. Der Farbunterschied (dunkle Stellen) beruht ja auf der unterschiedlichen Schalendicke.
An Bundenbach-Trilobiten mit erhaltenen Gliedmaßen sieht man manchmal, wie winzig klein (und zahlreich) die Beinchen unter dem Pygidium sind.

Lichtspiegelung: Ich denke, das liegt jetzt weniger daran, daß der Russentrilo so poliert wäre ;)
Das kommt mehr durch die Art der fotografischen Ausleuchtung. (Zitat: „The white spots are reflections of the foto lamps” aus einem internationalen Fossilien-Onlineshop über die Glanzstellen auf den polierten Madagaskar-Ammoniten =) =) =) )


Thanks for these informations. I didn’t know that it would be possible to see the structures, where the tiny pygidial appendages are set to the carapace (the dark structures result from the thickness of the shell).
I guess, the "shiny" appearance of the Russian trilo is less due to the preperation, but more to the way it is photographed ("The white spots are reflections of the foto lamps." quote taken from an international fossil online-shop =) )

Klaus

__________________
„Ich suche nicht - ich finde.” Pablo Picasso.

2.Trilobiten-Tagung (19./20.2.2011): Abstracts der Vorträge
02.02.2008 02:15 juniper is offline Search for Posts by juniper Add juniper to your Buddy List
goniagnostus goniagnostus is a male


images/avatars/avatar-21.gif

Registration Date: 27.08.2007
Posts: 68

Thread Starter Thread Started by goniagnostus
Reply to this Post Post Reply with Quote Edit/Delete Posts Report Post to a Moderator       Go to the top of this page

I agree about the muscle scars, and now that I look closely at the pygidial "zigzag" markings it seems that for each chevron, there would be a leg insertion there, so several legs in that last part of the pygidium...

__________________
Sam [goniagnostus]
A Guide to the Orders of Trilobites
http://www.trilobites.info
12.02.2008 04:48 goniagnostus is offline Send an Email to goniagnostus Homepage of goniagnostus Search for Posts by goniagnostus Add goniagnostus to your Buddy List
Schachtratte
Member


images/avatars/avatar-9.gif

Registration Date: 27.01.2007
Posts: 1,897

Reply to this Post Post Reply with Quote Edit/Delete Posts Report Post to a Moderator       Go to the top of this page

Why are these structures at the cephalon not bilateral symmetric?

I agree, nice Bug and it seems unfaked but heavy polished.

__________________
Und was sagen Sie als Unbeteiligter zum Thema Intelligenz?

Der Idealismus wächst mit der Entfernung zum Problem!

"Ein Kluger bemerkt alles, ein Dummer macht über alles seine Bemerkungen."
12.02.2008 06:44 Schachtratte is offline Search for Posts by Schachtratte Add Schachtratte to your Buddy List
goniagnostus goniagnostus is a male


images/avatars/avatar-21.gif

Registration Date: 27.08.2007
Posts: 68

Thread Starter Thread Started by goniagnostus
Reply to this Post Post Reply with Quote Edit/Delete Posts Report Post to a Moderator       Go to the top of this page

Yes, it is interesting that they are roughly symmetrical, but not perfectly so, especially the pair of scars that are nearest the occipital ring. Maybe it is merely that the effect of the underlying muscle attachment on the surface is not so strongly expressed, or the prep has obscured (over polished?) some of the marking. Or could it be that, like people, one side of the head is not a perfect mirror match for the other side?

__________________
Sam [goniagnostus]
A Guide to the Orders of Trilobites
http://www.trilobites.info
15.02.2008 19:26 goniagnostus is offline Send an Email to goniagnostus Homepage of goniagnostus Search for Posts by goniagnostus Add goniagnostus to your Buddy List
Schachtratte
Member


images/avatars/avatar-9.gif

Registration Date: 27.01.2007
Posts: 1,897

Reply to this Post Post Reply with Quote Edit/Delete Posts Report Post to a Moderator       Go to the top of this page

quote:
Original von goniagnostus
Yes, it is interesting that they are roughly symmetrical, but not perfectly so, especially the pair of scars that are nearest the occipital ring. Maybe it is merely that the effect of the underlying muscle attachment on the surface is not so strongly expressed, or the prep has obscured (over polished?) some of the marking. Or could it be that, like people, one side of the head is not a perfect mirror match for the other side?


Common is a face with unsymmetric sides. A perfect nirror is absolutely rare.

The muscle Inprimts are on the ventral side. They can´t be overpolishet from dorsal.

__________________
Und was sagen Sie als Unbeteiligter zum Thema Intelligenz?

Der Idealismus wächst mit der Entfernung zum Problem!

"Ein Kluger bemerkt alles, ein Dummer macht über alles seine Bemerkungen."

This post has been edited 1 time(s), it was last edited by Schachtratte: 24.02.2008 16:01.

15.02.2008 23:17 Schachtratte is offline Search for Posts by Schachtratte Add Schachtratte to your Buddy List
goniagnostus goniagnostus is a male


images/avatars/avatar-21.gif

Registration Date: 27.08.2007
Posts: 68

Thread Starter Thread Started by goniagnostus
Reply to this Post Post Reply with Quote Edit/Delete Posts Report Post to a Moderator       Go to the top of this page

Indeed, the muscle attachments are on the ventral side, but the discolorations that overlay them persist through all exoskeletal layers from inside to outer surface, and one might expect that their size, shape and darkness might vary depending how far down the layers you go. Or perhaps not, perhaps they are very consistent all the way down to the ventral attachment points? I've never experimented with sanding away at a nice specimen of Illaenid to find out!

__________________
Sam [goniagnostus]
A Guide to the Orders of Trilobites
http://www.trilobites.info
24.02.2008 06:30 goniagnostus is offline Send an Email to goniagnostus Homepage of goniagnostus Search for Posts by goniagnostus Add goniagnostus to your Buddy List
Tree Structure | Board Structure
Jump to:
TRILOBITA.DE » TRILOBITA.DE-Forum » Morphologie / Morphology » TOM for February 2008

Privacy policy

Forum Software: Burning Board 2.3.6, Developed by WoltLab GmbH