Forelimb and hindlimb-type cartilage morphologies are not the result of heterochrony.

A–C; Micromasses were established from forelimbs (A) and hindlimbs (B, C) of embryos 0.5dpc apart (11.5dpc; A–B and 12.0dpc; C). Total chondrogenic area, nodule size and hydraulic radius of 11.5dpc forelimb and hindlimb cultures were significantly different (D–E). Nodules in 12.0dpc hindlimb cultures had significantly larger total area (D), nodule size (E) and hydraulic radius (F) than 11.5dpc forelimb nodules. 11.5dpc HL and 12.0dpc HL cultures displayed similar values for total area (D) and hydraulic radius of nodules (F). Nodule size was significantly larger in 12.0dpc HL cultures than in 11.5dpc FL cultures, although smaller than in 11.5dpc HL cultures. *p<0.05, **p<0.01, Student’s t-test.