Gilpichthys greenei
Superclass Agnatha
Geological Time: Pennsylvanian (~300 m.y.a.)
Size (25.4 mm = 1 inch): Fossil is 70 mm long (curve measure) on a 73 mm by 48 mm nodule half
Fossil Site: Pit 11, Francis Creek Shale, Braidwood, Illinois
Code: AW48
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.
The majority of collecting areas are the spoil heaps of abandoned
coal mines, the most famous of which is Peabody Coal Pit 11. Pit
11 now serves as a cooling pond for the Braidwood nuclear power
plant, but with over 100 other localities, specimens still come
to light. This fish is still something of an enigma. It is known
to possess a Buccopharynx bearing teeth, and was first thought
to be a nudibranch. It was then found to be a vertebrate by virtue
of possession of a notochord, gill slits, and a postanal caudal
region. No other fossil or extant forms show the specializations
of Gilpichthys. Some researchers assign it to the Myxinoidea with
the hagfishes, but I think that is just a lumping tactic for trying
to shoehorn an enigmatic taxon into a known category. |
