Name: Knightia
Phonetic: Nye-tee-ah.
Named By: Jordan - 1907.
Classification: Chordata, Actinopterygii,
Clupeiformes, Clupeidae, Pellonulinae.
Species: K. alta, K. branneri, K.
eocaena, K. humulus.
Diet: Zooplankton, small invertebrates and
possibly very small fish and fry.
Size: Depending upon species up to 25
centimetres long, the
largest specimens slightly bigger.
Known locations: USA, Wyoming - Green River
Formation.
Time period: Eocene.
Fossil representation: So numerous no one knows
exactly how many specimens have been recovered.
Knightia
were small freshwater fish often described as ‘herring-like’ that
lived in North America during the Eocene period. Also because
Knightia were schooling fish they are often
preserved still in their
shoals with some specimens even being preserved on top of each other.
This is why so many fossils of this fish are known, and why Knightia
specimens are one of the most commonly traded fossils on the market.
The
majority of Knightia specimens are quite small,
but some large
specimens around twenty-five centimetres long are known. Knightia
are often so well
preserved that the
scutes than run from the head to the median (middle) fins across
the back and belly are often visible. Although
Knightia may seem a small and unimportant fish,
their sheer numbers
strongly suggest that they would have formed an important part of their
ecosystems biomass, being an abundant food supply for predators.
Other
fish from the Green River Formation include Heliobatis
and Diplomystus.
Further reading
- The fossil fishes of California, with supplementary notes on other
species of extinct fishes. - University of California Publications,
Bulletin of the Department of Geology 5(7):95-144. - D. S. Jordan -
1907.
- The paleontology of the Green River Formation, with a review of the
fish fauna. - Wyoming Geol. Surv., Bull. 63, pp. 85. - L. Grande - 1980.
- A Revision of the Fossil Genus Knightia, With a
Description of a New
Genus From the Green River Formation (Teleostei, Clupeidae). - American
Museum Novitates. - Lance Grande - 1982.