Erbenochile
aff erbeni
Trilobites
Order Phacopida, Suborder Phacopina, Superfamily Acastoidea, Family Acastidae
Geological
Time: Lower Devonian, Upper Emsian
Size: Trilobite
is 57 mm long by 41 mm wide on a 125 by 100 mm matrix
Fossil Site:
Jebel Oudriss , Morocco
Code: 18090
Price: Sold
Description:
Elegant example of a member of the Order Phacopida, Superfamily
Acastoidea with many fine details present. Once known in the trade
as “Big Eye”, this one is actually Erbenochile, and
has recently become commercially available in limited quantities.
The most diagnostic features of this taxon are the high “eye-towers”.
Fortey and Chatterton described Erbenochile erbeni in September
2003 from a single commercially- prepared specimen, and it created
a stampede among collectors. The “wrap around” eyes
gave a good panoramic view of the trilobite’s environment,
allowing it to keep alert for predator and prey alike. Since fish
had recently evolved true jaws, any advantage a prey species could
derive would place it at an advantage. This one has been prepared
with the genal and axial spines all freestanding, quite an achievement
from such hard matrix. Note the exceptional eye facets seen here,
a feature that is difficult to prepare well due to the matrix..
About 10 years ago a second species Erbenochile issomourensis was
described from Jebel Issoumour with the main differences being a
lower eye tower and lack of a sunshade. Early this year a third
site at Jebel Oudriss turned up a very few examples that while they
looked like E erbeni they had much more dramatic spinose tubercles
to the genals and thoracic segments. There is a progression in the
robust nature of these elements, being smallest in E issoumourensis
and greatest in the Jebel Oudriss material. This one has taken it
to the extreme, with the most pronounced examples I have seen. This
specimen was painstakingly prepared with the spines in situ over
the course of three weeks, resulting in the spectacular specimen
seen here. I have included some in preparation photos that demonstrate
the spines are authentic to the specimen, At this point it is not
certain whether this material constitutes a new species or not.
I will play it safe and simply refer to it as Erbenochile affinis
erbeni for the time being.
A
specimen of the very rare Erbenochile
issomourensis may be seen here, and here is another Erbenochile
erbeni specimen.
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