Annakacygna paleoart by Nix Illustration
Annakacygna is a genus of swan from the Miocene Japan, which holds the proposed vernacular (common) name of the "Annaka short-winged swan". There are two known species known, A. hajimei and A. yoshiiensis, which were both named in 2022. Annakacygna has many adaptations for its unique lifestyle, including flightlessness, filter-feeding, wings that can be used to cradle offspring, and highly mobile tail, in which the latter two may have been used for display.
Discovery[]
The type specimen of Annakacygna (GMNH-PV-678) was found in 2000 in the sediments of the Haraichi Formation near Usui river, Annaka, Gunma. The specimen consisted of a nearly complete and articulate skeleton embedded in siltstone, and was originally thought to be a relative of Megalodytes which was later disproven after preparation. A. yoshiiensis, the second species, is known from a distal tibiotarsus (GMNH-PV-1685) found 11.5 km southeast from the type specimen. The fossil was dug up in 1995 near the Kabura River and donated to the Gunma Museum of Natural History in 2005.
Both species, A. hajimei and A. yoshiiensis, were then formally described in 2022 by Hiroshige Matsuoka and Yoshikazu Hasegawa. The generic name, Annakacygna, comes from its namesake, the town of Annaka from near which it was found, and the feminine form of "cygnus" (swan in Latin). The specific name of A. hajimei is named after its discoverer, Hajime Nakajima, while A. yoshiiensis is named after the town of Yoshii-machi.