Climactichnites

From Wikipedia, the free encyclopedia

Climactichnites, late Cambrian, central Wisconsin.
Climactichnites, late Cambrian, central Wisconsin.
Burrows thought to be produced by the same animal that made Climactichnites trackways, late Cambrian, central Wisconsin.
Burrows thought to be produced by the same animal that made Climactichnites trackways, late Cambrian, central Wisconsin.

Climactichnites is an enigmatic, late Cambrian fossil formed on sandy tidal flats around 510 million years ago. It is usually interpreted as the trace fossil of a slug-like organism, thought to have moved by sliding over a mucus-rich slime trail.

Contents

[edit] Morphology

Climactichnites consists of two parallel ridges separated by chevron-shaped raised cross bars. The fossils range from 2 to 15cm in width,[1][2] and may exceed ten feet in length, making them far larger than most invertebrate trace fossils.[verification needed]

[edit] Interpretation

[edit] Climactichnites as a trace fossil

The traditional interpretation of Climactichnites suggests that it represents the trackway of an animal. This would make it the earliest evidence of organisms moving about on the land.[3] While the identity of the animal is still conjectural, it may have been a large slug-like animal—its trackways produced as it crawled over and processed the wet sand to obtain food. 2 The binding effect of microbial mounds on the sidiment surface is believed to have contributed to the exceptional preservation of Climactichnites tracks. [4]

Burrows believed to have been made by the animal that produced Climactichnites have been discovered recently (Getty and Hagadorn, 2006, and Getty, 2007).

[edit] Climactichites as a body fossil

Pointing to the fact that some Climactichnites tracks disturb the underlying structures, such as ripple marks and other Climactichnites, to a lesser extent than one might expect from an organism plowing its way across the surface, one team of researchers (Damrow et al., 2001) questioned whether Climactichnites may instead be a body fossil of a strap-like organism. This theory has not been supported by subsequent researchers, who argue that modern soft-bodied organisms exhibit folding, twisting, tearing or transport when washed ashore. This is observed in jellyfish fossils from beds close to Climactichnites, so would be expected in at least some of the Climactichnites if they were indeed stranded organisms. Other lines of evidence also refute the Climactichnites as body fossil theory (see Getty, 2007, page 2).[5]

[edit] References

  1. ^ Getty, P.R. (2005). "Small Climactichnites Trackways: Their Abundance And Implications For Trackmaker Physiology". 2005 Salt Lake City Annual Meeting. 
  2. ^ Damrow, D.F.; Lipps, J.H.; Gershwin, L. (2001). "Is Climactichnites Really A Trace Fossil?". GSA Annual Meeting, November 5-8, 2001. 
  3. ^ MacNaughton, R.B.; Cole, J.M.; Dalrymple, R.W.; Braddy, S.J.; Briggs, D.E.G.; Lukie, T.D. (2002). "First steps on land: Arthropod trackways in Cambrian-Ordovician eolian sandstone, southeastern Ontario, Canada". Geology 30 (5): 391-394. doi:10.1130/0091-7613(2002)030<0391:FSOLAT>2.0.CO;2. 
  4. ^ Getty, P.R. (2006). "Producing And Preserving Climactichnites". 2006 Philadelphia Annual Meeting. 
  5. ^ Patrick R. Getty (2007). "Paleobiology of the Climactichnites Trackmaker: An Enigmatic Late Cambrian Animal Known Only from Trace Fossils" (masters thesis). 
 This article or section is missing citations or needs footnotes.
Using inline citations helps guard against copyright violations and factual inaccuracies. (June 2008)

[edit] External links

Includes additional photographs and information on Climactichnites from the exceptional Blackberry Hill localities.
Cambrian jellyfish, Climactichnites and arthropod tracks
Discusses a major source of Climactichnites trackways. With useful photograph slideshow.