Ctenurella

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Ctenurella
Fossil of Ctenurella gladbachensis. The species reached a length of about 19 centimeters here. [1]

Fossil of Ctenurella gladbachensis . The species reached a length of about 19 centimeters here.

Temporal occurrence
Upper Devonian
382.7 to 358.9 million years
Locations
  • Germany (Bergisch Gladbach)
Systematics
Vertebrata
Gnathostomata
Placodermi
Ptyctodontida
Ctenurella
Scientific name
Ctenurella
Ørvig , 1960

Ctenurella is an extinct genus of fish from the Placodermi group ("Panzerfische") from the Upper Devonian period . The monotypic genus wasscientifically described for the first time in 1960with the species Ctenurella gladbachensis . The species epithet refers to the Bergisch Gladbach site in the Paffrath Kalkmulde .

description

Ctenurella gladbachensis , live
reconstruction of a male (above) and a female fish.

Ctenurella was about 18 to 20 cm long and had an external appearance, as well as jaws and tooth plates that are strongly reminiscent of the sea ​​cats (Chimaeriformes). However, there is no relationship that was previously often assumed. Because despite the reduced and only weakly developed exosklet, which in Ctenurella mainly surrounded the shoulder area, as well as the upper and lateral head area (with a horseshoe-shaped, open at the front around the orbit ), Ctenurella clearly belongs to the Placodermi group. Ctenurella had two dorsal fins, the first was triangular and lay directly behind the back of the head, the second was behind the pelvic fins, was arched and protected in front by two thick spikes. As with sea cats or grenadier fish , the body ended in a pointed tail thread, on the dorsal side of which there was still a small tail fin. The pectoral fins were relatively large and sat relatively far down behind the lower edge of the gill slit. The pelvic fins were between the first and second dorsal fin. Here a sexual dimorphism was shown , the pelvic fins of the males were provided with hook-shaped clasps . The mouth was below, the protruding "nose" was supported by two rostral cartilages. The upper and lower jaw were each covered with a pair of tooth plates. The head was broad and short; immediately behind the back of the head was the highest point of the fish's body.

Systematics

Ctenurella belongs to the Ptyctodontida , the group of placoderms that was most similar to modern fish, showed a clear sexual dimorphism and in which viviparity has meanwhile been proven. For some Australian forms, which were originally also assigned to Ctenurella , separate genera have now been established.

Individual evidence

  1. ↑ a b c Hans Martin Weber: World-famous fish and crabs from the Devonian of the Strundet valley in Bergisch Gladbach , in: Fundgeschichten - Archeology in North Rhine-Westphalia , writings of the Bodendenkmalpflege in NRW, Volume 9, Ed. Thomas Otten, Römisch-Germanisches Museum der City of Cologne and Verlag von Philipp Zabern, Mainz 2010, p. 24 ff. ISBN 978-3-8053-4204-9
  2. ↑ Tor Ørvig: New finds of acanthodians, arthrodires, crossopterygians, ganoids and dipnoans in the Upper Middle Devonian Calcareous Flags (Oberer Plattenkalk) of the Bergisch Gladbach Paffrath Trough. Part 1. Palaeontological Journal 34, 1960, pp. 295-335.
  3. ^ Karl Albert Frickhinger: Fossil Atlas Fish , Mergus-Verlag, Melle, 1999, ISBN 3-88244-018-X
  4. ↑ Oskar Kuhn: The prehistoric fish and fish , A. Ziemsen Verlag, 1967, Wittenberg
  5. ↑ Long, JA, Trinajstić, KJ, Young, GC & Send, T. 2008. Live birth in the Devonian period. Nature 453, pp. 650-652.
  6. ↑ Long, JA: Ptyctodontid fishes (Vertebrata, Placodermi) from the Late Devonian Gogo Formation, Western Australia, with a revision of the genus Ctenurella Ørvig, 1960 , Geodiversitas 19 (3), 1997, pp. 515-555.

Web links

Commons : Ctenurella  - collection of images, videos and audio files