Treptichnus

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Treptichnus
Temporal range: 542–99.7  Ma
Treptichnus pedum.png
Burrows viewed from the side
Treptichnus pedum 3d.png
Burrows viewed obliquely
Trace fossil classification OOjs UI icon edit-ltr.svg
Ichnogenus: Treptichnus
Miller, 1889
Ichnospecies
  • T. apsorumRindsberg & Kopasa-Merkel, 2005 [1]
  • T. bifurcusMiller, 1889
  • T. pedumSeilacher, 1955
Synonyms [2] [3]
  • Phycodes
  • Manykodes
  • Trichophycus
  • Affinovendia

Treptichnus (formerly named Phycodes, Manykodes by J. Dzik, [2] and also known as Trichophycus [3] ) is the preserved burrow of an animal. As such, it is regarded as the earliest widespread complex trace fossil. Its earliest appearance, around 542 mya, [4] which was contemporaneous with the last of the Ediacaran biota, is used to help define the dividing line, considered geologically at 541 mya, between the Ediacaran and Cambrian periods. [5] [6] It is last seen in the fossil record during the Cenomanian (99.7 Ma). [1]

Contents

Description

Treptichnus pedum fossil marking the Cambrian-Ediacaran GSSP T pedum at base of Cambrian.jpg
Treptichnus pedum fossil marking the Cambrian-Ediacaran GSSP

Treptichnus pedum has a fairly complicated and distinctive burrow pattern: along a central, sometimes sinuous or looping burrow it made successive probes upward through the sediment in search of nutrients, generating a trace pattern reminiscent of a fan or twisted rope. [7] The organism that left such traces is considered more complex than earlier Ediacaran biota; and these trace fossils, which occur worldwide, are usually found in strata above those. [8]

Since only its burrows have been found, it is presumed that the Treptichnus animal lacked any hard anatomical features, such as shells or bones. Its morphology and relationship to modern animals is therefore unknown, and some dispute even its inclusion within the animal kingdom. [9] Despite this lack of fossil evidence, surface trails produced by modern priapulid worms exhibit the same probing morphology as Treptichnus, suggesting a close anatomical relationship between the trace-maker and modern priapulids. [10]

Etymology

The name Treptichnus pedum means "turned-trail (Greek) of feet (Latin)".

Related Research Articles

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The Ediacaran is a geological period of the Neoproterozoic era that spans 96 million years from the end of the Cryogenian period at 635 Mya to the beginning of the Cambrian period at 538.8 Mya. It is the last period of the Proterozoic eon as well as the last of the so-called "Precambrian supereon", before the beginning of the subsequent Cambrian period marks the start of the Phanerozoic eon, where recognizable fossil evidence of life becomes common.

<span class="mw-page-title-main">Neoproterozoic</span> Third and last era of the Proterozoic Eon

The Neoproterozoic Era is the unit of geologic time from 1 billion to 538.8 million years ago.

<span class="mw-page-title-main">Trace fossil</span> Geological record of biological activity

A trace fossil, also known as an ichnofossil, is a fossil record of biological activity by lifeforms but not the preserved remains of the organism itself. Trace fossils contrast with body fossils, which are the fossilized remains of parts of organisms' bodies, usually altered by later chemical activity or mineralization. The study of such trace fossils is ichnology and is the work of ichnologists.

<span class="mw-page-title-main">Vendobionta</span> Group of extinct creatures that were part of the Ediacaran biota

Vendobionts or Vendozoans (Vendobionta) are a proposed very high-level, extinct clade of benthic organisms that made up of the majority of the organisms that were part of the Ediacaran biota. It is a hypothetical group and at the same time, it would be the oldest of the animals that populated the Earth about 580 million years ago, in the Ediacaran period. They became extinct shortly after the so-called Cambrian explosion, with the introduction of fauna formed by more recognizable groups and more related to modern animals. It is very likely that the whole Ediacaran biota is not a monophyletic clade and not every genus placed in its subtaxa is an animal.

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Yorgia waggoneri is a discoid Ediacaran organism. It has a low, segmented body consisting of a short wide "head", no appendages, and a long body region, reaching a maximum length of 25 cm (9.8 in). It is classified within the extinct animal phylum Proarticulata.

<span class="mw-page-title-main">Ediacaran biota</span> Life of the Ediacaran period

The Ediacaranbiota is a taxonomic period classification that consists of all life forms that were present on Earth during the Ediacaran Period. These were enigmatic tubular and frond-shaped, mostly sessile, organisms. Trace fossils of these organisms have been found worldwide, and represent the earliest known complex multicellular organisms. The term "Ediacara biota" has received criticism from some scientists due to its alleged inconsistency, arbitrary exclusion of certain fossils, and inability to be precisely defined.

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<span class="mw-page-title-main">Stratigraphy of the Cambrian</span>

The Stratigraphy of the Cambrian period currently has several schemes used for ordering geologic formations from the period. The International Commission on Stratigraphy−ICS scheme has set a stratotype section for the base of the Cambrian, dated quite accurately to 538.8 ± 0.2 million years ago. Russian and Chinese scientists have developed a different scheme.

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<span class="mw-page-title-main">Terreneuvian</span> First epoch of the Cambrian Period

The Terreneuvian is the lowermost and oldest series of the Cambrian geological system. Its base is defined by the first appearance datum of the trace fossil Treptichnus pedum around 538.8 million years ago. Its top is defined as the first appearance of trilobites in the stratigraphic record around 521 million years ago. This series' name was formally accepted by the International Commission on Stratigraphy in 2007.

<span class="mw-page-title-main">Fortunian</span>

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<span class="mw-page-title-main">Chapel Island Formation</span> Sedimentary formation in the Burin Peninsula, Newfoundland, Canada

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<i>Hallidaya</i> Extinct species of simple animal

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<span class="mw-page-title-main">Matground</span>

Matgrounds are strong surface layers of seabed-hardening bacterial fauna preserved in the Proterozoic and lower Cambrian. Wrinkled matgrounds are informally named "elephant skin" because of its wrinkled surface in the fossil record. Matgrounds supported themselves until early burrowing worms were ubiquitous enough to unharden them. Burrowing animals broke down the hardy mats to further penetrate the underlying sediment for protection and feeding. Once matgrounds disappeared, exceptional preservation of lagerstätten such as the Burgess Shale or Ediacara Hills also did so too. Trace fossils such as Treptichnus are evidence for soft-bodied burrowers more anatomically complex than the Ediacaran biota that also caused the matgrounds disappearance.

References

  1. 1 2 AK Rindsberg and DC Kopaska-Merkel. 2005. Treptichnus and Arenicolites from the Steven C. Minkin Paleozoic Footprint Site (Langsettian, Alabama, USA). Alabama Paleontological Society Monograph 1 : 121-141
  2. 1 2 DZIK, Jerzy (2005). "Behavioral and anatomical unity of the earliest burrowing animals and the cause of the "Cambrian explosion"" (PDF). Paleobiology. 31 (3): 503–521. doi:10.1666/0094-8373(2005)031[0503:BAAUOT]2.0.CO;2. S2CID   55910646.
  3. 1 2 See e.g. fossiilid.info: paleodiversity in Baltoscandia: Trichophycus pedum
  4. Srivastava, Purnima (June 2012). "Treptichnus pedum: An Ichnofossil Representing Ediacaran - Cambrian Boundary in the Nagaur Group, the Marwar Supergroup, Rajasthan, India" (PDF). Proc. Indian Natl. Sci. Acad. 78 (2): 161–169. Retrieved April 8, 2016.
  5. Subcommission on Neoproterozoic Stratigraphy - URL retrieved June 22, 2009
  6. International Commission on Stratigraphy, International Chronostratigraphic Chart, 2012, http://www.stratigraphy.org/column.php?id=Chart/Time%20Scale
  7. McMenamin, Mark A.; Dianna L. McMenamin (1990) [1990-01-15]. The Emergence of Animals . Columbia University Press. ISBN   0-231-06647-3.
  8. "Life in the Cambrian". Archived from the original on 2006-02-20. Retrieved 2006-03-09.
  9. Altermann, Wladyslaw (2002) [2002-07-01]. Precambrian Sedimentary Environments. Blackwell Publishing. ISBN   0-632-06415-3.
  10. Vannier, J.; Calandra, I.; Gaillard, C.; Zylinska, A. (2010). "Priapulid worms: Pioneer horizontal burrowers at the Precambrian-Cambrian boundary". Geology. 38 (8): 711–714. Bibcode:2010Geo....38..711V. doi:10.1130/G30829.1.