found "juvenile Dipleura dekayi trilobite Cephalon

[grg1109]

Found in Tully Limestone, Cortland Cnty., Central NY, Middle Devonian

I assume this is a juvenile Dipleura dekayi trilobite (approx. 1" across)...Cephalon only.

Greg

[Kane]

That is correct.

[Misha]

Awesome find!

[lipstick]

Out of curiosity what tells you it’s from a juvenile?

[Tidgy's Dad]

1 hour ago, lipstick said:

Out of curiosity what tells you it’s from a juvenile?

Because it is very small. 

[piranha]

Just now, lipstick said:

Out of curiosity what tells you it’s from a juvenile?

 

 

The size---an adult of maximum size would have a cephalon measuring approximately twice the size.

[lipstick]

24 minutes ago, Tidgy's Dad said:

Because it is very small. 

 

23 minutes ago, piranha said:

 

 

The size---an adult of maximum size would have a cephalon measuring approximately twice the size.

Thanks guys. I’m not as familiar with Dipleura specifically, but for instance,  in the case of Eldregeops I could go into the other room and pull out two enrolled specimens that vary widely in size, with a cephalon approaching double the size. Likewise I have a complete Dipleura whose cephalon is about a half inch wider than this one yet it seems to be of adult form. Guess I’m curious if size alone is enough to determine maturity?

Edited December 19, 2020 by lipstick
fixed italics

[Tidgy's Dad]

1 hour ago, lipstick said:

 

Thanks guys. I’m not as familiar with Dipleura specifically, but for instance,  in the case of Eldregeops I could go into the other room and pull out two enrolled specimens that vary widely in size, with a cephalon approaching double the size. Likewise I have a complete Dipleura whose cephalon is about a half inch wider than this one yet it seems to be of adult form. Guess I’m curious if size alone is enough to determine maturity?

Firstly, make sure it's the same species, the genera Dipleura, Eldredgeops and others may have different species of considerably different size.  

You should also be a bit careful with the locality and even the bed it came from as regional differences in living conditions could effect the growth of an organism. 

Check against the size of the average adult from the bed and area. 

[grg1109]

I found both of my  Dipleura dekayi in the same linier plane only a couple of feet apart.  I assumed from this and the size difference ...and knowing that they have the ability to grow much larger...that this was most likely a juvenile but wanted to make sure.  I get your point though...perhaps I should have used the term "young" instead of "juvenile"...since I don't know their life cycle.  I'm new to fossils.

Greg