| cliche. |
this leads one to conclude that (The 'flipper' picture shows a central 'rib', suggesting that propulsion would come from a flipper folding on the forward stroke, the mechanism for which is not apparent. Alternatively, the flipper would have to be rotated, or slewed, on the forward stroke, although again there is no obvious stiffening sufficient for this. This leads one to conclude that the flipper is not a prime source of propulsion, since power would be lost on one stroke rather than being gained on both as with a true flipper; this in turn would eliminate the plesiosaur as a candidate. The animal would therefore have to be propelled by its tail, with the flipper possibly functioning for steering -- or even as a brake. (Adrian Shine) ART Vancouver) |
