Spriggina
| Spriggina | ||||||||
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Spriggina floundersi |
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| Temporal occurrence | ||||||||
| Ediacarium | ||||||||
| 560 to 550 million years | ||||||||
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| Systematics | ||||||||
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| Scientific name | ||||||||
| Spriggina | ||||||||
| Glaessner , 1958 | ||||||||
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Spriggina is a genus of extinct creatures . Its representatives lived in the Ediacarium over 550 million years ago. The systematic classification of the genus is controversial. Due to the characteristics of their fossils , they are mostly thought of as early arthropods and possible ancestors of the trilobites . Alternatively, an assignment to the vendobionts or the annelid worms was discussed. The genus Spriggina was named after the Australian geologist Reginald Sprigg .
features
Spriggina fossils show a segmented body up to 5 cm long. The number of segments is between 20 and 40 and varies between fossil finds. The two front segments are different from the rest of the segments. These two horseshoe-shaped segments are interpreted as a head . The two depressions it contains may represent eyes. Possible clues for a mouth were also found. Unsegmented parapodia -like extremities , the ends of which carry setae , extend from the body segments .
Systematics
The systematic classification of Spriggina is controversial in the literature. Usually the genus is assigned to the realm of the multicellular animals (Metazoa). The first person to describe Martin Glaessner ordered Spriggina the counting of the annelids Vielborstern (Polychaetae) to. Spriggina fossils show a resemblance to some of today's many bristles, such as Tomopteris . The majority of paleontologists assign Spriggina to the trunk group of the arthropod lineage. Morphological similarities suggest a relationship with the trilobites. However, this assignment is controversial. In contrast to trilobites, Spriggina also lacks any trace fossils. Adolf Seilacher assigned Spriggina to the extinct Vendobiotes, which he interpreted as large single-celled organisms.
literature
- McCall: The Vendian (Ediacaran) in the geological record: Enigmas in geology's prelude to the Cambrian explosion . In: Earth Science Reviews . 77, 2006, pp. 1-229. doi : 10.1016 / j.earscirev.2005.08.004 .
Web links
Individual evidence
- ↑ a b c d Glaessner, Martin F .: New Fossils from the Base of the Cambrian in South Australia Archived from the original on September 29, 2007. Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. ( PDF ) In: Transactions of the Royal Society of South Australia . 81, 1958, pp. 185-188. Retrieved February 8, 2011.
- ^ Birket-Smith SJR: A reconstruction of the Pre-Cambrian Spriggina. . In: Zoological Yearbooks. Anatomy and ontogeny of animals . 105, 1981, pp. 237-258.
- ↑ Budd GE, Telford MJ: The origin and evolution of arthropods . In: Nature . 457, No. 7231, February 2009, pp. 812-817. doi : 10.1038 / nature07890 .
- ↑ Seilacher A, Grazhdankin D, Legouta A: Ediacaran biota: The dawn of animal life in the shadow of giant protists . In: Paleontological Research . 7, No. 1, 2003, pp. 43-54.
