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Mesozoic Bird Sizes

Due to my recent post on the size of Mesozoic birds, I thought I'd estimate the length of every species I could.  I present them here for future reference.  As before, non-ornithothoracines are based on Chiappe et al.'s (1999) Confuciusornis, enantiornithies on Paul's Cathayornis yandica and euornithines on Hou et al's (1996) Chaoyangia.  All are pretty certainly within 10% of their actual lengths, judging by comparisons I made using different elements or different reconstructions.  Unnamed specimens were not included, except the Spanish hatchling (Sanz et al., 1997).  Femoral length was used to estimate, or else the only element known, unless otherwise stated.
82 mm Liaoxiornis
The only specimen complete enough to have an exact length, though juvenile.
85 mm Iberomesornis
100 mm Longchengornis
105 mm Alexornis
Based on humeral proportions of Enantiornis.
110 mm Kizylkumavis
Based on humeral proportions of Enantiornis.
115 mm Jibeinia
120 mm Cathayornis? caudatus
130 mm Concornis
130 mm Protopteryx
This was based on dorsal length, modified to include one more vertebra than enantiornithines.  The referred specimen is subequal in length.
135 mm Eoenantiornis
135 mm Incolornis silvae
135 mm Nanantius eos
This was based on scaling N? valifanovi's length down 30%, as suggested by the differences in tibiotarsal proportions between the species.
140 mm Cuspirostrisornis
140 mm Sinornis
140 mm Spanish hatchling
Based on humeral length, which would probably make this specimen even larger as wings would be comparatively smaller in a nestling.  Note it is bigger than either Iberomesornis or Concornis.  Are they also young specimens?  Is this one really a nestling?  Was the adult really big?  S many questions....
145 mm Largirostornis
145 mm Longipteryx
150 mm Eoalulavis
Based on coracoid length, roughly estimated from a bad photocopy.
150 mm Liaoningornis
150 mm Otogornis
Based on humeral length.
150 mm Platanornis
165 mm Explorornis nessovi
170 mm Changchengornis
170 mm Wyleyia
175 mm Nanantius? valifanovi

180 mm Abavornis sp.
180 mm Boluochia
Based on femoral diameter, as the taxon has comparatively longer tibiotarsi and shorter tarsometatarsi than Cathayornis.  That's why I don't use lower limb lengths to estimate.
180 mm Confuciusornis dui
185 mm Sazavis
Tibiotarsal diameter was used to avoid differences in lower limb proportions.
190 mm Gobipteryx
The referred specimen is subequal in length.
190 mm Songlingornis
Based on coracoid length.
200 mm Zhyraornis logunovi
205 mm "Ichthyornis" minusculus
215 mm Yixianornis
220 mm Catenoleimus
220 mm Incolornis martini
225 mm Zhyraornis kashkarovi
235 mm Chaoyangia
250 mm Gansus
Based on metatarsal length, as it seems to have similar length/width proportions to Cathayornis.
260 mm Explorornis walkeri
270 mm Ambiortus
Based on humeral length, estimated by comparison to the ambiortid Otogornis.
275 mm Yanornis
190-280 mm Confuciusornis sanctus
280 mm Abavornis bonaparti
285 mm Horezmavis
Metatarsal depth was used to avoid differences in lower limb proportions.
290 mm Neuquenornis
Coracoid length was used, as humeri and femora are damaged.
330 mm Lenesornis
340 mm Yungavolucris
Metatarsal depth was used to avoid differences in lower limb proportions.
345 mm Soroavisaurus
510 mm Gurilynia
Coracoid length was estimated compared to other enantiornithines and used.
530 mm Kuszholia
540 mm Vorona
Tibiotarsal diameter was used.  The referred specimen is about 510 mm long.
545 mm Patagopteryx
I used the skeletal reconstruction in the description, as this taxon has a more elongate neck than Cathayornis.
550 mm Avisaurus
575 mm Lectavis
Metatarsal depth was used to avoid differences in lower limb proportions.
1.0 m Enantiornis
Coracoid length was used.
Note several trends.  Lecho enantiornithines are large, while Yixian ones are small.  Confuciusornis is the largest Yixian bird, with smaller specimens matched only by some euornithines.
I could not estimate the length of several species-
Avisaurus gloriae

Cathayornis yandica


Mickey Mortimer