Re: bird sizes

["Mickey Mortimer" <Mickey_Mortimer11@msn.com>]

Daniel Bensen wrote-

> Can anyone tell me the body lenghths or skull or femur lengths of these
> birds?

These will of course be gross estimates in many cases, as most of these
species are very fragmentary.  I use Chiappe et al.'s skeletal
reconstruction of Confuciusornis for the non-ornithothoracine birds.  For
the enantiornithines, I'm using Paul's skeletal reconstruction of
Cathayornis yandica (=Sinornis?).  Other enantiornithines like Nanantius?
valifanovi, Neuquenornis or other Liaoning taxa probably had different
proportions.  So if I used those lesser known taxa for reference, I might
get different results, although I don't think they would vary that much.
Interestingly, compared to femoral length, Iberomesornis would have near
identical vertebral proportions as Paul's Cathayornis.  Also, you may be
interested to know that if I were to use the Confuciusornis reconstruction
for estimating enantiornithine length or vice versa, there would be only an
insignificant (~1%) difference in my total length estimates.  I used Hou et
al.'s (1996) reconstruction of Chaoyangia for the euornithine birds, which
has an identical femur/total length ratio to the Confuciusornis and
Cathayornis reconstructions, and only a slightly longer humerus/total length
ratio (.25 vs. .22).

> Catenoleimus anachoretus- ~220 mm
This is the most risky length estimation I've ever done.  If I'm correctly
interpreting the coracoid fragment, it was about this long.
> Changchengornis hengdaoziensis- 170 mm
> Abavornis bonaparti- ~280 mm
> A. sp.- ~180 mm
> Explorornis nessovi- ~165 mm
> E. walkeri- ~260 mm
> E. sp.- ~165 mm
> Incolornis silvae- ~135 mm
> I. martini- ~220 mm
> Zhyraornis kashkarovi- ~225 mm
> Longipteryx chaoyangensis- ~145 mm
> Platanavis nana- ~150 mm
> Vorona berivotrensis- ~540
This was an interesting case, because only distal limb elements are
complete, which are not as useful for estimating total length as vertebrae,
femora or humeri are, as they have varying proportions among Mesozoic
pygostylians.  Using the tibiotarsus to estimate gives a length of 690 mm,
while using the metatarsus gives a length of 460 mm.  I decided to use
tibial diameter, figuring this would remain more constant in different taxa.
This gives the 540 mm estimate above, which seems appropriate.  This is
based off the referred specimen, the holotype was about 6% smaller, or about
510 mm long.
> Kuszholia sp.- ~530 mm
The species is. K. mengi.
> Otogornis genghisi- ~150 mm
> Ambiortus dementjevi- ~270 mm
> Gargantuavis philoinos- ~1.3 m
Estimates of this species are difficult, as the large size might have
resulted in a comparatively smaller skull or other changes.  But assuming a
build like most Mesozoic pygostylians, 1.3 meters is a good guess.
> Songlingornis linghensis- ~190 mm
> Liaoningornis longiditrus- ~150 mm
The species is L. longidigitris.

Mickey Mortimer