This should be

a) kept at the singular (costal strut) and

b) is not needed, because costal strut already forwards to rib which has an entry about ribs being called costal struts on Malcor III. --Jörg 18:36, March 11, 2010 (UTC)

...and already done ;-) --Jörg 18:37, March 11, 2010 (UTC)