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Cheirothrix

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Cheirothrix
Temporal range: Late Santonian to Campanian
Specimen of C. lewisii
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Aulopiformes (?)
Family: Cheirothricidae
Genus: Cheirothrix
Pictet & Humbert, 1866
Species[1]
  • C. guestphalicus von der March & Schlüter, 1868
  • C. lewisii Davis, 1887
  • C. libanicus Pictet & Humbert, 1866
Synonyms
  • Chirothrix, Chirotrix, Cheirotrix (misspellings)

Cheirothrix (meaning "hand hair") is an extinct genus of marine ray-finned fish from the Late Cretaceous.[2] It is named for its enlarged pectoral fins, which show close convergence with modern flying fish.

Taxonomy

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Specimen of C. libanicus

The following species are known:

The fossilised remains of Cheirothrix lewisii were found in limestone strata in Lebanon dating back about 85 million years. This fish was first described by James William Davis in 1887 and was named in honour of Professor E. R. Lewis of the American College in Beirut.[3] Professor Lewis had originally found the fossil at Sahel Alma on Mount Lebanon. In this famous fossil location, about sixty species of fish have been found, none of them known from elsewhere in the world.[4]

Description

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Cheirothrix is characterized by enormous pectoral fins and the ventral lobe of the tail fin is also much enlarged. It seems likely that these fish could launch themselves out of the water and glide hundreds of metres (yards) through the air, probably to evade predators.[3]

Distribution

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During the Cretaceous period, sea levels were much higher than they are now. The fish remains at Sahel Alma are very well preserved. The rock is a fine-grained limestone found in an area much folded and faulted and is laid down in thick beds. The fish may have died because of a localized shortage of oxygen.[5] Five specimens of Cheirothrix lewisii were found, each preserved in such detail that the fifty or so vertebrae can be counted[6] and the branching rays of the pectoral fins can be seen clearly. The holotype is a cleft slab of limestone with remains of the fish on both sides. It is now kept in the Natural History Museum in London.[7]

Another member of the genus, Cheirothrix libanicus, is found in the same fossil bed and other members of the genus are known from 84-to-70-million-year-old deposits in Germany.[7]

References

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  1. ^ Dietze, K. (2009). "Morphology and phylogenetic relationships of certain neoteleostean fishes from the Upper Cretaceous of Sendenhorst, Germany". Cretaceous Research. 30 (3): 559–574. Bibcode:2009CrRes..30..559D. doi:10.1016/j.cretres.2008.11.001.
  2. ^ "PBDB Taxon". paleobiodb.org. Retrieved 2024-05-12.
  3. ^ a b Martha Richter (2010). "Cheirothrix lewisii". National History Museum. Retrieved 2013-01-13.
  4. ^ American Society of Naturalists (1903). The American naturalist, Volume 37. Essex Institute. p. 687.
  5. ^ Chris Walley. "Geology of Lebanon: A Summary". American University of Beirut. Archived from the original on 2012-07-02. Retrieved 2013-01-14.
  6. ^ James W. Davis (1887). "The fossil fishes of the chalk of Mount Lebanon in Syria". Royal Dublin Society. 2 (3).
  7. ^ a b Martha Richter (2010). "Cheirothrix lewisii". National History Museum. Retrieved 2013-01-13.
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