Tuesday, March 28, 2017

Formidable carpal weaponry of Anas chathamica, Chatham Island’s extinct flightless duck

TitleFormidable carpal weaponry of Anas chathamica, Chatham Island’s extinct flightless duck
Publication TypeJournal Article
Year of Publication2015
AuthorsWilliams, M
JournalNotornis
Volume62
Issue3
Pagination113-120
Type of ArticleFull Article
KeywordsAnas chathamica, carpal knobs, Chatham Island duck, intraspecific combat
Abstract

The Chatham Island duck (Anseriformes: Anatidae: Anas chathamica) had a pronounced and rugose enlargement to the tip of the processus extensorius at the proximal end of its carpometacarpus. This “carpal knob” was the equal in size of those found in some much larger waterfowl (e.g., steamer ducks, Tachyeres sp.), and was disproportionately larger than those of all other New Zealand waterfowl. The knobs on 20 carpometacarpi examined all showed evidence of continuous bone deposition at their tips and their use as weapons is implied. Comparisons with other duck species having similarly prominent and rugose carpal knobs suggests the Chatham Island duck maintained long-term pair bonds and occupied combined feeding and breeding territories year-round which both sexes defended belligerently.

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