aftershaft

Thân thiện

A small bird preens its feathers, revealing a tiny aftershaft near the base.

Definition

Noun: A small, supplementary feather that grows from the underside of the base of the main shaft (rachis) of a feather in certain bird species. It is a secondary, often downy, structure.

Usage

The term is used specifically in ornithology and the study of avian anatomy to describe a particular morphological feature of feathers. * The presence of an aftershaft is a characteristic feature in the plumage of birds like emus and cassowaries. * Under the microscope, the biologist observed the aftershaft branching from the calamus of the primary feather.

Advanced Usage

• The size and development of the aftershaft can vary significantly between different bird families and is sometimes used as a taxonomic clue.
• In some species, the aftershaft is nearly as large as the main feather, contributing substantially to insulation.

Variants and Related Words

• Aftershafted (adjective): Describing a feather or a bird that possesses an aftershaft.
  • The specimen had distinctly aftershafted contour feathers.

Synonyms

• Supplementary feather
• Accessory feather
• Hyporachis (a more technical, anatomical term)

Antonyms

• Main shaft (rachis)
• Primary feather (as a complete, standard structure without this supplementary part)

Notes

The aftershaft is not present on all feathers or in all birds. It is most prominent in some flightless birds and certain other groups. Its function is primarily related to providing additional insulation.

Học thuật

Noun

1. a supplementary feather (usually small) on the underside of the base of the shaft of some feathers in some birds