[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Running Speed & SVPCVA 2000



Thanks to HP Holtz for the reference to SVPCVA 2000.

I'm wondering if this analysis causes any need to change prior calculations
of running speed?  I notice the emphasis on forelimb length, and seem to
remember that dino forelimbs tended to be disproportionately short compared
to hind limbs (?).
Another question:  if graviportal animals are excluded, doesn't this have an
impact on the effect of body mass calculations?


>From the abstract of the paper

Speed and appendicular anatomy in mammals
Per Christiansen

<The present study used a
database of 76 parasagittal, running mammals (no graviportal or saltatorial
species were used), and includes peak running speed, body mass and 14
measurement and ratio variables. In contrast to Garland (1983) no
significant relationship between body mass and speed was found (P>0.05). In
the bivariate analyses forelimb length showed a slight but significant
relationship with running speed ..., but hindlimb length did not, unless
normalized for body mass .... When normalized for body mass ...forelimb
length displayed a substantially greater correlation with speed... The limb
ratios correlated rather well with speed, e.g. radius/humerus ratio...,
metacarpus/humerus ratio..., metatarsus/femur ratio... or calcaneal
tuber/3?body mass... Residual plots revealed no significant departures from
linearity or consistency in decreasing variances, so residual variation was
considered random...>

>From the web:

Graviportal means slow-moving due to massiveness.

Capable of leaping; formed for leaping; saltatory; as, a saltatorious insect
or leg.

The Ornithosuchia have a mesotarsal ankle, which is a simple hinge joint
between the lower leg and astragulus and calcaneum, and the distal ankle
bones. This restricts the posture to a more erect orientation, so the gait
can be called parasagittal -- the limbs move parallel to the vertebral
column, and are held relatively vertically...

 Another proposed advantage of an erect stance and parasagittal gait was
that it was more efficient, but this has not held up to experimental
analysis -- erect animals move about as efficiently as similarly-sized
sprawling ones.

The final 2 paras are from:

http://www.ucmp.berkeley.edu/diapsids/archomm.html

The conclusion in the second para seems counter-intuitive (and the part of
the statement after the dashes is probably missing the word 'only' somewhere
in there).  I thought from 'Dino Heresies' that the more erect posture was a
sign of a more active life.

Thanks!