Cheirothrix

{{Short description|Extinct genus of ray-finned fishes}} {{Automatic taxobox | fossil_range = {{Geological range|84|70.6|Late Santonian to Campanian}} | image = Dans l'ombre des dinosaures - Cheirothrix - 010.jpg | image_caption = Specimen of ''C. lewisii'' | taxon = Cheirothrix | authority = Pictet & Humbert, 1866 | subdivision_ranks = Species | subdivision_ref = <ref name="Dietze2009" /> | subdivision = * {{Extinct}}''C. guestphalicus'' {{Small|von der March & Schlüter, 1868}} * {{Extinct}}''C. lewisii'' {{Small|Davis, 1887}} * {{Extinct}}''C. libanicus'' {{Small|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.<ref>{{Cite web |title=PBDB Taxon |url=https://paleobiodb.org/classic/basicTaxonInfo?taxon_no=txn:35558 |access-date=2024-05-12 |website=Paleobiology Database}}</ref> It is named for its enlarged pectoral fins, which show close convergence with modern flying fish.

== Taxonomy == thumb|Specimen of ''C. libanicus'' The following species are known:

* †'''''C. guestphalicus''''' (von der Marck & Schlüter, 1868) - Late Campanian of Germany (=''Telepholis biantennatus'' von der Marck, 1873, ''Megapus guestphalicus'' von der Marck & Schlüter, 1868) * †'''''C. lewisii''''' Davis, 1887 - Late Santonian of Lebanon (Sahel Alma) * †'''''C. libanicus''''' Pictet & Humbert, 1866 - Late Santonian of Lebanon (Sahel Alma)

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.<ref name="NHM">{{cite web |author=Martha Richter |date=2010 |title=''Cheirothrix lewisii'' |url=http://www.nhm.ac.uk/nature-online/species-of-the-day/evolution/cheirothrix-lewisii/ |accessdate=2013-01-13 |publisher=National History Museum}}</ref> 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.<ref name="naturalist">{{cite book |author=American Society of Naturalists |url=https://books.google.com/books?id=9mTyAAAAMAAJ&q=Sahel+Alma++fossils&pg=PA687 |title=The American naturalist, Volume 37 |publisher=Essex Institute |year=1903 |isbn= |page=687}}</ref>

== Description == ''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.<ref name="NHM" />

== Distribution == 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.<ref>{{cite web |author=Chris Walley |title=Geology of Lebanon: A Summary |url=http://ddc.aub.edu.lb/projects/geology/geology-of-lebanon/ |url-status=dead |archive-url=https://web.archive.org/web/20120702121009/http://ddc.aub.edu.lb/projects/geology/geology-of-lebanon/ |archive-date=2012-07-02 |access-date=2013-01-14 |publisher=American University of Beirut}}</ref> Five specimens of ''Cheirothrix lewisii'' were found, each preserved in such detail that the fifty or so vertebrae can be counted<ref>{{cite journal |author=James W. Davis |year=1887 |title=The fossil fishes of the chalk of Mount Lebanon in Syria |url=http://journals.cambridge.org/download.php?file=%2FGEO%2FGEO3_4_09%2FS0016756800194129a.pdf&code=3d8ad19d49e3c90e01f7ea49a2a202a6 |journal=Royal Dublin Society |volume=2 |issue=3}}</ref> 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.<ref name="NHM2">{{cite web |author=Martha Richter |date=2010 |title=''Cheirothrix lewisii'' |url=http://www.nhm.ac.uk/nature-online/species-of-the-day/evolution/cheirothrix-lewisii/ |accessdate=2013-01-13 |publisher=National History Museum}}</ref>

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.<ref name="NHM2" />

==References== {{Reflist|refs= <ref name="Dietze2009">{{cite journal |last1=Dietze |first1=K. |title=Morphology and phylogenetic relationships of certain neoteleostean fishes from the Upper Cretaceous of Sendenhorst, Germany |journal=Cretaceous Research |date=2009 |volume=30 |issue=3 |pages=559–574 |doi=10.1016/j.cretres.2008.11.001|bibcode=2009CrRes..30..559D }}</ref> }}

==External links== *[https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=35558 Cheirothrix - Gnathostomata - Alepisauriformes] - The Paleobiology Database

† Category:Prehistoric ray-finned fish genera Category:Late Cretaceous fish of Asia Category:Cretaceous fish of Europe Category:Late Cretaceous bony fish Category:Santonian genus first appearances Category:Campanian genus extinctions Category:Fossils of Germany Category:Fossils of Lebanon Category:Taxa named by François Jules Pictet de la Rive Category:Fossil taxa described in 1866