The dorsal neural arches are not fused to the centra. I don't see why
people ignore Spinosaurus' size, or claim it's uncertain that it was larger
than Tyrannosaurus.
Can we be certain that Stromer's measurements were accurate? The type
material was obliterated (*sob*), so the dimensions of individual elements
are based on Stromer's descriptions alone.
This same issue applies to the type material for _Amphicoelias fragillimus_:
Cope's measurements of the type vertebra suggests a truly enormous sauropod.
Although it may seem unlikely that someone could get something as simple
as linear measurements wrong (how hard is it to use a tape measure?), I seem
to recall that this is what happened with the scapula referred to
_Ultrasaurus_. A second look at this scapula showed that the original
length given for this bone was exaggerated, and that the scapula was no
larger than one previously referred to _Brachiosaurus_.