pennibrachium

English

Etymology

From Latin penna (“feather”) + brachium (“arm”). Coined by Sullivan et al. in 2010.

Noun

pennibrachium (plural pennibrachia)

1. (zoology, paleontology) A forelimb, found on various species of extinct and extant coelurosaur, that is not used in flight or gliding but still bears long, typically pennaceous feathers which form a winglike surface.
   • 2010 July 7, Corwin Sullivan, “The asymmetry of the carpal joint and the evolution of wing folding in maniraptoran theropod dinosaurs”, in Proceedings of the Royal Society B: Biological Sciences, volume 277, number 1690, page 2027:

     Some dromaeosaurid, troodontid, oviraptorosaur and therizinosaur specimens show the presence of what we term a ‘pennibrachium’, a forelimb bearing long feathers that form a planar, wing-like surface but are not necessarily used in aerial locomotion.

Usage notes

Although the term is usually reserved for the structures found on members of extinct lineages within the Maniraptora such as Oviraptorosauria and Dromaeosauridae, certain extant bird species may be said to have pennibrachia as well, such as the flightless ostrich and the semi-flighted kagu.