A field guide to mesozoic birds and other winged dinosaurs

Romeral’s Iberian Middle Bird Iberomesornis romerali
Time: 125 Ma ago Location: Cuenca, Spain Habitat: La Huerguina Formation. Forested
beaches surrounding the large, shallow-water lake Las Hoyas with high concentration of
aquatic life. Size: WS >20cm (8in); BL 9cm (3.5in); TL unknown Features: Wings relatively
short but hand & primary feather lengths unknown. Feet large w/ large, curved claws.
Biology: The smallest known non-avian dinosaur species, weighing around 15-20 grams
(Sanz & Ortega 2002).
Las Hoyas Dawn Bastard-wing Bird Eoalulavis hoyasi
Time: 125 Ma ago Location: Cuenca, Spain Habitat: La Huerguina Formation (see above)
Size: WS >20cm (8in); BL ~9cm (3.5in); TL unknown Features: Wings long, w/ ulna over
twice the length of carpus and significantly longer than humerus. Long, well developed
primary feathers & alula. Sternum fish- or hourglass-shaped but narrow, possibly indicating
a juvenile specimen. Biology: Stomach contents of the only known fossil specimen
include fragments of crustacean exoskeletons, providing direct evidence of diet in this
species. These birds probably foraged in or near the water at least some of the time, as
shoreline generalists. The wishbone shape is consistent with a flap-gliding mode of flight.
Long-toed Liaoning Bird Liaoningornis longidigitris
Time: 124.6 Ma ago Location: Liaoning, China Habitat: Lower Yixian Formation. Temperate
conifer and ginkgo forest set among a series of lakes fed by streams and runoff from
a nearby range of active volcanic mountains. Size: WS unknown; BL ~18cm (7in); TL unknown
Features: Breastbone broad, keeled, & well-developed, with an hourglass- or fishlike
shape. Wings strong and robust but incompletely known. Tarsus short & stout with
long toes. Biology: The breastbone, which is similar in general shape to, but much broader
than, that of Eoalulavis, indicates a stronger flier. The unusual hourglass-like breastbone
shape among enantiornitheans may be a juvenile characteristic (O’Connor 2010).
Graffin’s Heaven Bird Qiliania graffini
Time: 120 Ma ago Location: Gansu, China Habitat: Xiagou Formation. Wide basin dominated
by a system of large, tranquil freshwater lakes. Size: WS unknown; BL ~20cm (8in);
TL unknown Features: Legs long & slender. First toe relatively large, fourth toe relatively
slender, w/ an unusually small claw. Claws long & needle-like w/ very weak curvature. Internally,
the hip bones are fused & the pubic bone tapers to a deflected point rather than an
expanded boot. Biology: Based on the curvature of the toe claws, it is likely that these were
equally likely to forage on the ground as in trees, inhabiting an ecological niche similar to
doves or cuckoos.
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