Total Pageviews

Showing posts with label Cambrian. Show all posts
Showing posts with label Cambrian. Show all posts

Tuesday, March 1, 2016

520-Million-Year-Old Fossils in China Have Nerve and Verve

       The fossilized remains of Chengjiangocaris kunmingensis, a crustacean-like animal that lived 520 million years ago in what is now Xiaoshiba, China, were detailed in a paper published yesterday by researchers at the University of Cambridge.




      The species’s hard exoskeleton is well-preserved and its nervous system is outlined with such intricacy that individual nerves are distinguishable.

     


     Note that the animal’s ventral cord, the purplish line running down its center, above, is clearly visible. In addition, the tiny fibers that comprise the animal’s bundled ganglia are also detectable with precision instruments.

     This level of soft tissue preservation is rare, especially from the Cambrian period, when life on Earth first blossomed into the rich biodiversity we know today. But the Xiaoshiba fossil deposit, located in China’s Yunnan Province, is "chucky-jam full" of these Cambrian period fossils.




     Readers of PEOTS may remember our forays into the Kunming Karst topography of the Yunnan Province, including the limestone pillars from Kunming installed in a Denver, CO, USA, park.




      “Under normal circumstances it is extremely difficult to obtain preservation of soft tissues, as these decay rapidly and lose most of the morphological information,” according to study co-author Javier Ortega-Hernández, a research fellow at the University of Cambridge.

     “However, there are cases in which the environmental conditions are more prone to produce exceptional preservation,” he said. “These include when the animals are entombed rapidly by a large amount of fine sediment, and all of this occurs in an oxygen-depleted environment. This process helps to limit the extent of decay on the carcasses and may result in the superb preservation of delicate features such as the ventral nerve cord and other parts of the internal anatomy.”


     Studying this extinct animal’s nervous system demonstrated that some of the species’s modern relatives, like velvet worms, maintain a similar internal structure.




          "Others, like the nearly indestructible tardigrades (or water bears), have done away with the complex rubric of nerve fibers found in their Cambrian forebears, in favor of more minimalistic systems. These insights capture a broader evolutionary picture through the aperture of C. kunmingensis’s fossilized nerves."

How's your nerve and verve today?
Steph

Tuesday, December 16, 2014

Clam to Clam: "Don't Make Me Put My Foot Down!" or "Bivalve, Will Travel"

          Part of today's True North map looked like an open clamshell:


          [Maizie and I have been putting in extra semi-circular walks gearing up for watching a friend's energetic dog over Solstice-Christmas.]


          And then, just like that, the tide and other things nautical, such as puns, came in: "Don't make me put my foot down!" 

           These molluscs were likely quite similar to the clams which first appeared 510 million years ago during the Cambrian period.


            Some clams were opalized (or replaced with hydrated silica), as in these particularly magnificent Australian specimens:
   



                 The gemmy clams and other molluscs are full of fire, 






though, lately, I've been thinking of having a few of these ON the fire:




 
          Hmmmm, an ocean trip with some clammy companions?! That's my idea of steamy ;-). Would enjoy your clam tales of any sort. I am putting my foot down about putting my feet up. . .




Clamming up now (it's almost Wednesday here),

Steph