Entries in nervous system (1)

Tuesday
Aug182015

The earliest central nervous system identified in a 520-million-year-old fossil

The earliest known complete central nervous system was discovered in a well preserved Cambrian great appendage arthropod fossil. This creature belongs to a now extinct group of animals that had a pair of long, claw-like extensions attached to their heads. The fossil was found in Chengjiang, Yunnan Province, China, which is known for its exceptionally preserved early Cambrian (ca. 510~550 mya) marine fossils.


The team utilized different imaging techniques, including energy-dispersive X-ray fluorescence and X-ray computed tomography, to trace the iron deposits that had selectively accumulated in the nervous system during fossilization. The creature has one optic neuropil separate from a protocerebrum contiguous with four head ganglia, succeeded by eight contiguous ganglia in an eleven-segment trunk. This is similar to today’s Chelicerata, a group of arthropods that include spiders, scorpions and horseshoe crabs.

 

 

References:

(1) Tanaka, G.; Hou, X.; Ma, X.;Edgecombe, G.D.; Strausfeld, N.J. Nature, 2013, 502, 364-367.

(2) Chen, J.; Waloszek, D.; Maas, A. Lethaia, 2004, 37, 3-20.