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''Lycoptera'' is an
''Lycoptera'' species were small freshwater fish. Most species fed on plankton, and had numerous tiny teeth. A few species like ''L. gansuensis'', ''L. muroii'', and ''L. sinensis'' had larger teeth and probably fed on small insects and their larvae.
Many specimens preserve minute details and impressions of soft tissues. ''Lycoptera'' was covered in tiny oval scales about 1.2 millimeters across, and, in life, would have had a superficial resemblance to the Common minnow.
''Lycoptera'' fossils are commonly found in large groups, buried together quickly in fine lake sediments likely due to mass death events from seasonal upwelling of anoxic waters during late autumn and winter. This had led to suggestions that they were gregarious in life, congregating in
Sixteen species of ''Lycoptera'' have been described, nine from the Jehol Group. The table below is based primarily on the valid species listed by Zhang and Jin in the 2008 book ''The Jehol Fossils''.
extinct
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
genus of fish that lived from the late Jurassic to Cretaceous periods in present-day China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
, North Korea, Mongolia and Siberia. It is known from abundant fossils representing sixteen species, which serve as important index fossil used to date geologic formations in China. Along with the genus '' Peipiaosteus'', ''Lycoptera'' has been considered a defining member of the Jehol Biota, a prehistoric ecosystem famous for its feathered dinosaurs, which flourished for 20 million years during the Early Cretaceous
The Early Cretaceous ( geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma.
Geology
Pro ...
, where it occurs abundantly in often monospecific beds, where they are thought to have died in seasonal mass death events.Jin, F., Zhang, F.C., Li, Z.H., Zhang, J.Y., Li, C. and Zhou, Z.H. (2008). "On the horizon of ''Protopteryx'' and the early vertebrate fossil assemblages of the Jehol Biota." ''Chinese Science Bulletin'', 53(18): 2820-2827. ''Lycoptera'' is a crown group
In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. ...
teleost belonging to an early diverging lineage of the Osteoglossomorpha, which contains living mooneyes, arapaima, arowana, elephantfish and knifefish/featherbacks.
Description
''Lycoptera'' species were small freshwater fish. Most species fed on plankton, and had numerous tiny teeth. A few species like ''L. gansuensis'', ''L. muroii'', and ''L. sinensis'' had larger teeth and probably fed on small insects and their larvae.
Many specimens preserve minute details and impressions of soft tissues. ''Lycoptera'' was covered in tiny oval scales about 1.2 millimeters across, and, in life, would have had a superficial resemblance to the Common minnow.
''Lycoptera'' fossils are commonly found in large groups, buried together quickly in fine lake sediments likely due to mass death events from seasonal upwelling of anoxic waters during late autumn and winter. This had led to suggestions that they were gregarious in life, congregating in shoals
In oceanography, geomorphology, and geoscience, a shoal is a natural submerged ridge, bank, or bar that consists of, or is covered by, sand or other unconsolidated material and rises from the bed of a body of water to near the surface. It o ...
.
Classification and species
Sixteen species of ''Lycoptera'' have been described, nine from the Jehol Group. The table below is based primarily on the valid species listed by Zhang and Jin in the 2008 book ''The Jehol Fossils''.
References
{{Taxonbar, from=Q142019 Early Cretaceous fish of Asia Jurassic bony fish Cretaceous bony fish Late Jurassic first appearances Early Cretaceous extinctions Fossil taxa described in 1847 Osteoglossomorpha Prehistoric ray-finned fish genera