Graculavus is the namesake for the form taxon "Graculavidae", a plesiomorphic assembly of unrelated birds that were believed to hold a key position in avian evolution as "transitional shorebirds." Two species are known: Graculavus augustus from the Western Interior Seaway and Graculavus velox from the Atlantic Seaboard.[1]
Several species have been named, but most are considered synonyms of G. velox or have been referred to other genera. Most scientists considered G. velox the only valid Graculavus species until 1999, when G. augustus was described.
An additional name, Graculavus "idahensis", was included erroneously in a table of species by Shufeldt in 1915.[1]
"Graculavus" lentus was for some time placed in Ichthyornis or Pedioecetes after being removed from the present genus. It is not related to either however and is nowadays considered an early galliform or close relative and placed in the genus Austinornis.[2]
References
^ abChiappe, Luis M. and Witmer, Lawrence M. (2002): Mesozoic Birds: Above the Heads of Dinosaurs, University of California Press, 2002. ISBN0-520-20094-2, ISBN978-0-520-20094-4
^Clarke, Julia A. (2004): Morphology, Phylogenetic Taxonomy, and Systematics of Ichthyornis and Apatornis (Avialae: Ornithurae). Bulletin of the American Museum of Natural History286: 1–179 PDF fulltext