Architarbus rotundatus
Phylum Arthropoda, Subphylum Chelicerata, Class Arachnida, Order Phalangiotarbida, Family Phalangiotarbidae
Geological Time: Carboniferous, Westphalian Stage
Size (25.4 mm = 1 inch): Arachnid fossil 10 mm by 7 mm on a 30 mm by 25 mm nodule pair
Fossil Site: Mazon Creek, Francis Creek Shale, Braidwood, Illinois
Code: HMC03
Price: Sold
 Description:
The Mazon Creek deposits of the region near Braidwood, Illinois rival
the other famous Lagerstatten of the Burgess Shale, Solnhofen, and
Liaoning for the variety of detailed life preserved. Many exquisitely-preserved
specimens are found in the ironstone nodules that make up the deposits.
This fine specimen was found recently in Mazon Creek itself, and is
of a spider-like arachnid known as Architarbus. The Mazon Creek location
has yielded some 250 arachnids as of the publication of Richardson’s
guidebook, more than any other Paleozoic locality. While most are
incomplete, the degree of preservation allows for interpretation of
these ancestral creatures. Note that there are several preserved limbs,
and the finely segmented abdomen is quite evident in this part/counterpart
specimen. I have recently been able to procure specimens from a family
who has been collecting this material in the field for three generations,
and will continue posting material as it becomes available to me. |
