QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online November 2, 2007
Journal of Experimental Biology 210, 3955-3961 (2007)
Published by The Company of Biologists 2007
doi: 10.1242/jeb.008953

This Article Summary Full Text Full Text (PDF) Supplementary Material Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Tickle, P. G. Articles by Codd, J. R. Search for Related Content PubMed PubMed Citation Articles by Tickle, P. G. Articles by Codd, J. R.

Functional significance of the uncinate processes in birds

Peter G. Tickle¹, A. Roland Ennos¹, Laura E. Lennox¹, Steven F. Perry² and Jonathan R. Codd^1,*

¹ Faculty of Life Sciences, University of Manchester, Jackson's Mill, PO Box 88, Sackville Street, Manchester M60 1QD, UK
² Institute for Zoology, Bonn University, Germany

View larger version (26K): [in this window] [in a new window]   Fig. 1. Representative skeletons showing the morphological differences in the rib cage associated with different forms of locomotion in (A) a walking species, cassowary (Casuaris casuaris); (B) a non-specialist, eagle owl (Bubo bubo); and (C) a diving species, razorbill (Alca torda). Uncinate processes are short in walking species, of intermediate length in non-specialists and long in diving species. In all photographs cranial is to the left; scale bar, 5 cm.

View larger version (10K): [in this window] [in a new window]   Fig. 2. Geometric model of uncinate function. (A) The situation in birds without an uncinate process. The length of the Mm. appendicocostales, L, changes with the rib angle, , depending on the distance down the rib, P, of the posterior attachment. (B) The situation with an uncinate process of perpendicular length Q behind the anterior rib. Cranial is to the left.

View larger version (23K): [in this window] [in a new window]   Fig. 3. (A) Changes in length of the Mm. appendicocostales muscle with rib angle, , for various relative values of uncinate length, Q, and distance of posterior attachment, P. (B) Changes in mechanical advantage of the Mm. appendicocostales muscle with rib angle, , for various relative values of uncinate length, Q, and distance of posterior attachment, P. It can be seen that mechanical advantage increases with , and with higher values of Q.

View larger version (15K): [in this window] [in a new window]   Fig. 4. Mechanical advantage (corrected for muscle length L) for representative species calculated with (solid line) and without (broken line) the uncinate processes. (A) A diving bird, the razorbill Alca torda; (B,C) non-specialist birds, (B) barnacle goose Branta leucopsis and (C) kestrel Falco tinnunculus; and a walking bird (D) the red-legged partridge Alectoris rufa.

View larger version (8K): [in this window] [in a new window]   Fig. 5. Canonical variate analysis (CVA) of skeletal morphology in birds. Function 1 against function 2 for walking species (squares, N=10); non-specialists (circles, N=66); diving birds (triangles, N=24). Functions 1 and 2 were primarily functions of relative uncinate length and width and rib length, respectively. Solid black squares represent significantly different group centroids. Letters highlight borderline species of respective groups: the fulmar (), the green woodpecker (ß) and the swallow (µ).