Archaeichnium

Archaeichnium is a member of the Ediacaran biota (635-542 Ma) first described by Martin Glaessner in 1963.[1][2] It is characterized as a tubular fossil found in the Nama group (570-543 Ma) of South West Africa.

The lobe projecting from the lower part of the bedding plane
On a slab of quartzite

Archaeichnium
Temporal range: Ediacaran
Scientific classification
Kingdom: Animalia
Phylum: Porifera (?)
(unranked): †Archaeocyatha
Genus: †Archaeichnium
Species:
†A. haughtoni
Binomial name
†Archaeichnium haughtoni
Glaessner, 1963

Description

Archaeichnium is a tube-shaped fossil that may be preserved as hollow or infilled tubes. The overall shape of the tube is slightly tapered at one end so that it is vaguely conical. The structure is typically between 3-5 cm long with a 0.5 cm diameter, and the walls of the tube are 0.1 cm thick. Typically, the tubes exhibit longitudinal ribbing on the exterior, which creates 10-12 distinct "ribs". Archaeichnium also has latitudinal restrictions that organize it into approximately three sections cranio-caudally. When cross-sectioned, the tube lacks septae. The fossil is typically found in cross-bedded sandstone that is interpreted as a shallow marine depositional environment. Walls of the tube are typically agglutinated with small quartz grains.

Diversity

Archaeichnium haughtoni is the only described species of Archaeichnium.

Discovery

The rock containing the fossil that would eventually be named Archaeichnium haughtoni was first discovered in 1927 by Dr. H. F. Frommurze and S. H. Haughton while the two were doing geological mapping in Southwest Africa.[3] The rock was found in the Nama group of Cambrian age in Central/ Southern Namibia. In 1959, Haughton published the paper that described the fossils as early archaeocyathids, a taxon of sedentary reef-building organisms that doesn't usually appear in the fossil record until the late Cambrian.[3] However, in 1963 Martin Glaessner revisited the rocks and determined that the fossilized animals did not actually distinctly possess the features that would classify it as an archaeocyathid, nor did he find it to share features with any known species. Glaessner dubbed the fossil anew as Archaeichnium haughtoni [4]

Distribution

Archaeichnium fossils are found in the Nasep quartzite stratigraphic unit within the Nama group[5] at the following sites:

  • Nevada, United States of America[6]
  • Namibia, Africa[4][7]
  • Nilpena, Australia[8]

See also

References
  1. "Fossilworks: Archaeichnium". fossilworks.org. Fossilworks. Retrieved 2020-01-04.
  2. Glaessner, M F; Glaessner, M. F. (1978). "Re-examination of Archaeichnium, a fossil from the Nama Group". Annals of the South African Museum. Annale van die Suid-Afrikaanse Museum. Biodiversity Heritage Library. 74: 335–342. Retrieved 2020-01-04.
  3. Haughton, S. H. (1960-01-01). "An Archaeocyathid from the Nama System". Transactions of the Royal Society of South Africa. 36 (1): 57–59. doi:10.1080/00359196009519032. ISSN 0035-919X.
  4. Glaessner, Martin F. (1962). "Zur Kenntnis der Nama-Fossilien Südwest-Afrikas". Annalen des Naturhistorischen Museums in Wien. 66: 113–120. ISSN 0083-6133. JSTOR 41769170.
  5. Germs, Gerard J. B. (1974-05-01). "The Nama Group in South West Africa and Its Relationship to the Pan-African Geosyncline". The Journal of Geology. 82 (3): 301–317. Bibcode:1974JG.....82..301G. doi:10.1086/627966. ISSN 0022-1376.
  6. Smith, E. F.; Nelson, L. L.; Tweedt, S. M.; Zeng, H.; Workman, J. B. (2017-07-12). "A cosmopolitan late Ediacaran biotic assemblage: new fossils from Nevada and Namibia support a global biostratigraphic link". Proceedings of the Royal Society B: Biological Sciences. 284 (1858): 20170934. doi:10.1098/rspb.2017.0934. PMC 5524506. PMID 28701565.
  7. Crimes, T. Peter; Germs, Gerard J. B. (1982). "Trace Fossils from the Nama Group (Precambrian-Cambrian) of Southwest Africa (Namibia)". Journal of Paleontology. 56 (4): 890–907. ISSN 0022-3360. JSTOR 1304708.
  8. Gehling, James G.; Droser, Mary L. (2013-04-01). "How well do fossil assemblages of the Ediacara Biota tell time?". Geology. 41 (4): 447–450. Bibcode:2013Geo....41..447G. doi:10.1130/G33881.1. ISSN 0091-7613.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.