Samlinger Lokaliteter TidstavleFaunalister Blin


Leptomylus sp.

 Faktiske data om fund 
Katalognummer:
854
Accessionsnummer:
DK 868
Samling:
Danekræsamlingen
Samler:
Statens Naturhistorisk Museum
Finder:
Mette Hofstedt, Peter Mortensen og Mogens S. Nielsen
Bestemt af:
Gilles Cuny
Lokalitet:
Gundstrup Grusgrav
Stratigrafi:
Periode:
Selandien
Type:
Sediment
Sediment:
Kerteminde Mergel

Billede

Foto ©: Sten Lennart Jakobsen


Billede

Foto ©: Sten Lennart Jakobsen


 Beskrivelse:   af  Gilles Cuny 
DK 868 represents a mandibular toothplate from a chimaera that have been found at Gundstrup gravel pit, in the Kerteminde Mergel (Late Paleocene) by three avocational palaeontologists: Mette Hofstedt, Peter Mortensen and Mogens Nielsen.

Pictures of the specimen were sent to Dr. Evgeny Popov (Department of Palaeontology, Geological Faculty, Saratov State University, 83, Astrakhanskaya Str., Saratov, 410012 Russia), a well-known specialist of fossil chimaeras. Below is Dr. Popov’s comments:

The fossil is a nearly complete left mandibular plate of the rare chimaeroid genus Leptomylus Cope 1869. The genus was described by the famous American paleontologist Edward Drinker Cope (1840-1897) based on specimens collected from the Hornerstowm formation (latest Maastrichthian - earlest Paleocene) of New Jersey, USA.

Besides the type species L. densus Cope 1869 the genus consists of two other species: L. cooki Cope, 1870 and L. forfex Cope 1875 (but they could represent junior synonyms of L. densus). All come from the some deposits. All material (less than one dozen of mandibular and palatine plates) representing this genus and nominal species are deposited in three North American museums: in the collection of the Academy of Natural Sciences, Philadelphia (2 syntypes of L. densus), in the American Museum of Natural History in New York (syntypes of L. cooki and L. forfex) and in Yale Peabody Museum in New Haven (several additional specimens). So, before the recently collected Danish specimen the genus was regarded as a North American early Paleocene endemic chimaeroid with specialized cutting dentition.

The Danish specimen represents therefore the first record of the genus in the Old World and increases its stratigraphical (up to late Paleocene) and paleobiogeographical distribution. A deposition of the specimen in a public museum and a subsequent scientific study will allow to better understanding the evolutionary trends of chimaeroids near the great K/T extinction. Additionally, after a careful examination this specimen could represent a new species or even a new genus of Leptomylus-like chimaeroids which would have a significant systematic impact on fossil Holocephali. The NHM in Copenhagen could be the fourth NHM after the American ones and the single NHM in the Old World to have this rare fossil chimaeroid.

The scientific interest of this specimen is therefore beyond doubt, and its declaration as a Danekrae specimen will make it available for a much needed scientific description that Evgeny Popov will be happy to perform.


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