Reddish Crotalocephalina

[Mahnmut]

Hello together,

I just acquired this nice little trilo from morocco, by the name of Crotalocephalina gibbus. Besides asking myself what the actual name is (I found Crotalocephalina, Cheirurus and Crotalocephalus) I wonder if the reddish parts are natural. Most Trilos of the kind I saw are rather greenish, I wonder if these colours represent different oxidation levels of iron, or maybe artificial alteration.

Thanks in Advance,

J

[aeon.rocks]

It's natural, as you mentioned colors can change due to different levels of limonite/iron deposits etc. Looks like Crotalocephalina. But to be sure compare pygidium spines to other types.

[Malcolmt]

Its real.. prep looks like a very typical medium quality commercial prep. Your coloring is very normal from these from that couche

[Mahnmut]

Thanks,

nice to know that these colours are natural.

Here is a picture of the pygidium, I did not realize the Cheirurus, Crotalocephalina and Crotalocephalsu are different species, I thought they where older synonyms.

 

Best Regards,

J

 

[aeon.rocks]

They are different speices, not sure what genus names are up to date however. The main difference is in less robust and longer pygidial spines. To compare with your Crotalocephalina gibbus:

 

 

 

Quote

typical medium quality commercial prep.

 

Commercial or not (everything we see here is commercial anyway?), it always depends on preservation - these are sticky usually, so "typical medium quality commercial prep" doesn't mean too bad, i hope?   

 

 I'ld say, if it's done fast enough to sell cheap, considering price, it is a good prep expertly done. 

Edited December 10, 2021 by aeon.rocks

[Malcolmt]

That bug is not badly prepped by any stretch of the imagination. but the pleural crevices were never cleaned for a start and there are a fair number of scribe dings and missing buts of skin. Again typical of what I would expect of a 2 to 3 hour Moroccan prep. The bug is not a brutalized quickie 1 hour prep with a CP scribe and a .040 nozzle using Aluminum Oxide

 

  Aeon....The bugs in your pictures were prepped to a very different standard of care and are in a totally different price league

 

I use the terminology Commercial Prep and Museum quality prep. I can prepare that bug in about 3 hours or that same bug in about 12 hours. Obviously it is a lot harder to find a buyer for the 12 hour prep given the established pricing range for a more quickly prepared bug. The museum prep is predominantly done with HW and microjack scribes even on the "sticky" ones  (my experience and I have done quite a few of these is that they are always sticky)with a final finish using fairly low PSI dolomite or Baking soda with a .015 or smaller nozzle

[aeon.rocks]

I agree, but just wanted to point out that it's well prepped because:

 

a) it was prepped by an expert, although fast (still probably in more than 2-3 hours, except if there's good separation)

b) preservation of these is usually not preparator-friendly (as you pointed it out too, Crotalo. is always sticky)

c) preparation quality is not so different to bugs in my pictures (downloaded from commerce web.), it just lacks some more fine detailed work and matrix landscaping. But the position of the bug is different, of course, and different preservation.

 

Why I'm pointing it out? Because these are very cheap considering the work that goes into and it's really expertly well done Moroccan prep job, despite the fact that we "rate" it as commercial prep, especially considering the price/skills/time. 

Edited December 10, 2021 by aeon.rocks

[Mahnmut]

4 hours ago, aeon.rocks said:

They are different speices, not sure what genus names are up to date however. The main difference is in less robust and longer pygidial spines. To compare with your Crotalocephalina gibbus:

 

 

 

 

 

Commercial or not (everything we see here is commercial anyway?), it always depends on preservation - these are sticky usually, so "typical medium quality commercial prep" doesn't mean too bad, i hope?   

 

 I'ld say, if it's done fast enough to sell cheap, considering price, it is a good prep expertly done. 

Thanks for your Answers,

that second image looks like a good fit to my unaccustomed eye (Trilobites are relatively new to me, rather a tetrapod bias on my side until now.)

 

The seller where I got this had a whole range of qualities, from the small and quickly prepped ones like the above up to perfectly freestanding Walliserops and Erbenochile that would cost me a month' rent. This little critter caught my eye only because of the color, which makes it special and beautiful to me even if it is not exactly rare.

Thanks for reassuring me that its also real/natural.

Best Regards,

J

 

[aeon.rocks]

16 hours ago, Mahnmut said:

 

that second image looks like a good fit to my unaccustomed eye

 

 

 

The second is what's refered to Crotalocephalus sp., I think. Different genus to Crotalocephalina. The pygidial spines are distinctly different. 

 

Quote

This little critter caught my eye only because of the color, which makes it special and beautiful to me even if it is not exactly rare.

 

It's a nice bug. 

Edited December 11, 2021 by aeon.rocks