Xenusion auerswaldae (lat.) Is a species of extinct invertebrates from the Xenusia group . Previously, it was attributed to the Cambrian , according to modern data - to the ediacaria . The structure of the body resembles onychophore or primitive arthropod . Known for two samples found in glacial remains in Germany , not very well preserved. The oldest of the samples, 10 cm long, has a long, weakly segmented body. Along the body pass small round processes, similar to the limbs of modern onychophores, but without claws. The head is not preserved.
|† Xenusion auerswaldae|
|International scientific name|
Xenusion auerswaldae Pompeckj , 1927
- 1 Importance for the history of Eumetasoa and position in the evolutionary tree
- 2 Find History
- 3 notes
- 4 Literature
- 5 Links
Significance for the History of Eumetasoa and Position in the Evolutionary Tree
In the Proterozoic layers, fingerprints of two rows of legs of certain creatures, possibly similar to Xenusion auerswaldae, are often found. Cambrian paleontology specialist, Doctor of Biological Sciences Andrei Yuryevich Zhuravlev recently [ when? ] expressed some views on the evolutionary tree, with the mention of Xenusion auerswaldae , as evidence of the possibility of primacy of creatures with limbs at the very beginning of the Bilateria tree (or even Eumetazoa), instead of the hypothetical worm-shaped ancestor hypothesized by the creators of the Ecdysozoa hypothesis. His point of view on the origin of vermiform animals from creatures with limbs, that is, regression, has not been proved, as, however, the opposite "classical" point of view deriving arthropods from vermiforms (roundworms or Scalidophora). Previously, according to the so-called “Whole Hypothesis”, which was still supported by some scientists, it was proposed to remove arthropods from annelids. According to Zhuravlev, Xenusion auerswaldae and Xenusia in general could be close to the ancestral forms of bilaterally symmetrical molting , and round and other worms, from his point of view, already simplified forms  . Biologists V. Alyoshin and N. Petrov have spoken about regression in the evolution of multicellular organisms even before this  .
The first scientifically described specimen was found by Fritz Knut, who was digging a ditch in his garden of Zebeck (now Wittstock) in the town of Prignitz. He handed it to Ann Marie von Auerswald, director of the Museum of National History in Prinica, located in the Cistercian Convent of the Holy Sepulcher   . She handed them over for scientific research to Professor Joseph Felix Pompecki , director of the Geological and Paleontological Institute and the Museum of the University of Friedrich-Wilhelm (now Humboldt University , Berlin)   . The first find is currently in the Berlin Museum of Natural History.
Some of the most recent remains of Xenusion auerswaldae were found on the Hiddensee island in 1978 by Helga and Horst Daihfuss, and now are in the collections of the University. Martin Luther in the city of Galle , at the Institute of Earth Sciences   .
- “Shadows of buried ancestors” A. Yu. Zhuravlev. “Nature” No. 3, 2009 Text
- “Regression in the evolution of multicellular animals” Aleshin V.V., Petrov N. B., “Nature” No. 7, 2001
- Bruno Kernchen und Albert Guthke: Finder und Fundort des Xenusion auerswaldae , Prignitz-Forschungen, Bd. 1, 1966, S. 13-17
- Joseph Felix Pompeckj: Ein neues Zeugnis uralten Lebens., Paläontologische Zeitschrift, Bd. 9, 1927, S. 287-313
- H. Jaeger and A. Martinsson: Remarks on the problematic fossil Xenusion auerswaldae., Geologiska Föreningens i Stockholm Förhandlingar, Bd. 88, 1967, S.: 435-452
- Günter Krumbiegel, Helga Deichfuss, Horst Deichfuss: Ein neuer Fund von Xenusion. - Hallesches Jahrbuch für Geowissenschaften, Bd. 5, 1980, S. 97–99
- Jerzy Dzik and Günter Krumbiegel: The oldest 'onychophoran' Xenusion: a link connecting phyla? , Lethaia 22 (2), 1989, 169–181
- Basic Palæontology, Benton and Harper, 1997