| Lycoptera | |
|---|---|
 | |
| L. davidi, from Yixian, Liaoning, China, Lower Cretaceous (Aptian) | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | †Lycopteriformes |
| Family: | †Lycopteridae |
| Genus: | †Lycoptera Müller,1847 |
| Type species | |
| †Lycoptera middendorffi Müller, 1847 | |
| Species | |
| Synonyms | |
| |
Lycoptera is anextinctgenus of fish that lived fromLower Cretaceous,Barremian toAptian[1] in present-dayChina,North Korea,[2]Mongolia andSiberia. Although there is record fromJurassic Formation in Siberia, its age remains questionable.[3] It is known from abundant fossils representing sixteen species, which serve as importantindex fossil used to dategeologic formations in China. Along with the genusPeipiaosteus,Lycoptera has been considered a defining member of theJehol Biota, a prehistoric ecosystem famous for itsfeathered dinosaurs, which flourished for 20 million years during theEarly Cretaceous, where it occurs abundantly in often monospecific beds, where they are thought to have died in seasonalmass death events.[4][5]Lycoptera is acrown groupteleost belonging to an early diverging lineage of theOsteoglossomorpha, which contains livingmooneyes,arapaima,arowana,elephantfish andknifefish/featherbacks.[6]
Lycoptera species were small freshwater fish. Most species fed onplankton, and had numerous tiny teeth. A few species likeL. gansuensis,L. muroii, andL. sinensis had larger teeth and probably fed on smallinsects and their larvae.[7]
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 thecommon minnow.[8]
Lycoptera fossils are commonly found in large groups, buried together quickly in fine lake sediments likely due tomass death events from seasonalupwelling ofanoxic waters during late autumn and winter.[5] This had led to suggestions that they were gregarious in life, congregating inshoals.[7]
Sixteen species ofLycoptera 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 bookThe Jehol Fossils.[7]
| Name | Author | Year | Status | Notes |
|---|---|---|---|---|
| Lycoptera middendorffi | Müller | 1847 | Valid,type species | |
| Lycoptera macrorhyncha | (Eichwald) | (1868) | ||
| Lycoptera davidi | (Sauvage) | (1880) | Valid | |
| Lycoptera sinensis | Woodward | 1901 | Valid | |
| Lycoptera ferox | Grabau | 1923 | ||
| Lycoptera chosenensis | Makiyama | 1927 | ||
| Lycoptera kansuensis | Grabau | 1928 | ||
| Lycoptera woodwardi | Grabau | 1928 | ||
| Lycoptera jaholensis | Grabau | 1928 | ||
| Lycoptera fragilis | Hussakof | 1932 | Valid | |
| Lycoptera takunagai | Seito | 1936 | Valid | |
| Lycoptera muroii | (Takai) | (1943) | Valid | |
| Lycoptera longicephalus | Liuet al. | 1962 | Valid | |
| Lycoptera lunteensis | Liuet al. | 1962 | ||
| Lycoptera polyspondylus | Liuet al. | 1962 | ||
| Lycoptera tungi | Liuet al. | 1962 | ||
| Lycoptera wangi | ||||
| Lycoptera sankeyushuensis | (Ma & Sun) | (1988) | Valid | |
| Lycoptera fuxinensis | Zhang | 2002 | Valid |
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