Hiodon falcatus GRANDE, 1979

Taxonomy

Mooneye

Kingdom: Animalia
Phylum: Chordata
Class: Actinopteri Cope 1871
Order: Hiodontiformes
Family: Hiodontidae
Genus: Hiodon
Species: Hiodon falcatus
Author Citation GRANDE, 1979

Geological Time Scale

Eon: Phanerozoic
Era: Cenozoic
Period: Paleogene
Sub Period: None
Epoch: Eocene
International Age: Ypresian

Stratigraphy

Green River Formation

Provenance

Acquired by: Purchase/Trade

Dimensions

Length: 20 cm

Location

Kemmerer
Wyoming
United States

• eohiodon
• featured
• green river formation
• mooneye

Comments

Today, the family Hiodontidae is represented by two species and a single genus (Hiodon) restricted to North America. They are large-eyed, fork-tailed fish that physically resemble shads.

The “goldeye”, Hiodon alosoides, is widespread across Nord America. It prefers turbid slower-moving waters of lakes and rivers.

The mooneye, Hiodon tergisus, is also widespread across North America, living in the clear waters of lakes, ponds, and rivers.

Hiodontids feed mainly on insects, insect larvae, and a few small fish.

The fossil genus Eohiodon was set up by Cavender in 1966 based on a review of Leuciscus rosei by Hussakof. Since then, three additional species have been included in this genus: Eohiodon rosei is the type species and known from the Tranquille beds near Kamloops, the Horsefly beds near Horsefly, British Columbia, Canada and the Allenby Formation near Princeton.

Eohiodon woodruffi Wilson 1978 is known from the Klondike Mountain Formation near Republic, Washington and the Horsefly beds near Horsefly, British Columbia.

Eohiodon falcatus Grande 1978 has been found from the Fossil Butte Member of the Green River Formation, Lincoln County, Wyoming, USA.

Recent study by Li, Wilson, and Grande, 1997 of new specimen of both Eohiodon falcatus and Eohiodon woodruffi indicates that the two specimens are indistinguishable in the vast majority of characters; Eohiodon falcatus might be treated as a junior synonym of Eohiodon woodruffi.

In their 2008 paper Grande & Hilton reassessed the Hiodontidae and concluded: " After correcting the descriptions of the fossil taxa, we could find no valid synapomorphies to separate the genus †Eohiodon from the genus Hiodon. Therefore, we conclude that †Eohiodon should be regarded as a synonym of Hiodon."

References:

Hilton, E. & Grande, L.: Fossil Mooneyes (Teleostei: Hiodontiformes, Hiodontidae) from the Eocene of western North America, with a reassessment of their taxonomy. In: CAVIN, L., LONGBOTTOM, A. & RICHTER, M. (eds) Fishes and the Break-up of Pangaea. Geological Society, London, Special Publications, 295, 221–251. DOI: 10.1144/SP295.13
 

Grande, L. (1979): Eohiodon falcatus, a new species of hiodontid (Pisces) from the late early Eocene Green River Formation of Wyoming. Journal of Paleontology, 53:103-111.
 

Wilson, M. V. H. (1978): Eohiodon woodruffi n. sp. (Teleostei, Hiodontidae) from the middle Eocene Klondike Mountain Formation near Republic, Washington. Canadian Journal of Earth Sciences, 15:679-686.
 

Cavender, T. (1966): Systematic position of the North American Eocene fish, "Leuciscus" rosei Hussakof. Copeia, 1966:311-320.