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Related to Pygostyle: Synsacrum


(vertebrate zoology)
A specialized bone in birds which is formed by a number of fused tail vertebrae.



in most birds (except ratites and tinamous), a bone formed from four to six concresced posterior caudal vertebrae. The pygostyle, which is a flattened vertical plate, serves to anchor the rectrices forming the tail of the bird.

References in periodicals archive ?
Because the rectrices and bulb attach only to the pygostyle, the tail fan is isolated on this terminal bone.
2) Isolation of the fan on the pygostyle effectively decouples the fanning mechanism from other tail movements.
The disparity between Archaeopteryx and modern birds is relatively large, yet can be attributed to three processes: shortening of caudal centra, sequestering of proximal caudals into the synsacrum, and fusing of distal caudals to form a pygostyle.
Although the early radiation of birds is still poorly known, forms such as Sinornis (Sereno and Rao 1992) and Iberomesornis (Sanz and Bonaparte 1992) had much shorter tail skeletons with a pygostyle.
In Early Cretaceous birds such as Sinornis and Iberomesornis, wing modifications indicative of advanced flight function are accompanied by a shortened tail skeleton and pygostyle (Sanz and Bonaparte 1992; Sereno and Rao 1992).
Pygostyle (py), part of the tail, is at end of vertebrate column.