A field guide to mesozoic birds and other winged dinosaurs

Lake Cuenca Bird Concornis lacustris
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 22cm (8.6in); BL ~9cm (3.5in); TL ~10cm (4in) Features: Wings
long w/ short skeletal wing, but long primary feathers. Small claws present on alular &
major digits. Legs long & slender w/ large, hooked claws, & an especially large hallux claw.
Breastbone lacked a keel on its front half. Biology: Unlike C. houi, these had proportionally
short forelimbs w/ long primary feathers, possibly indicating greater reliance on flapping
flight, as opposed to soaring, though the wishbone anatomy suggests a highly unique form
of flight unlike any modern birds. Lakeshore habitat & long legs may indicate a specialization
in small aquatic prey, though the skull is not known.
Hou’s Point-snout Bird Cuspirostriornis houi
Time: 120 Ma ago Location: Liaoning, China Habitat: Jiufotang Formation (see above)
Size: WS 24cm (9.5in); BL 10cm (4in); TL ~12cm (4.7in) Features: Snout short w/ a pointed
tip, but lacking a beak. Five pairs of teeth each in upper & lower jaw. Wings short &
rounded w/ relatively short primary feathers (~4cm long). Legs long w/ long toes & very
large talons. Biology: Like other avisauroids, these may have been similar to modern raptors
in appearance & habits. The long legs w/ short metatarsus & large talons suggest they
were employed in prey-grappling behavior. Similarly, the long wing bones w/ proportionally
short primary feathers are consistent w/ a soaring/flapping flight style.
Amber-loving Opposite Phoenix Enantiophoenix electrophyla
Time: 95 Ma ago Location: Mount Lebanon, Lebanon Habitat: Ouadi al Gabour Formation
Size: WS unknown; BL ~20cm (8in); TL unknown Features: Known from a fragmentary
skeleton distinguished by internal features of the shoulder blade. Legs relatively stout,
w/ large, short claws. Biology: Only known specimen contains small pieces of amber near
the stomach region, suggesting these may have been arboreal sap-eaters.
Thompson’s Seabird Halimornis thompsoni
Time: 80 Ma ago Location: Alabama, USA Habitat: Mooreville Chalk Formation. Shallow
marine environment near the southeastern coast of the Western Interior Seaway. Size: WS
~40cm (1.3ft); BL ~17cm (7in); TL unknown Features: Small avisauroids characterized
by unique features of the wing & leg bones (crest of the humerus nearly at the point of
shoulder contact, femur expanded near the far end). Biology: These appear to have been
marine, as the fossils were found nearly 50km from where the nearest shoreline would
have been at the time. Expansion at the knee joint may indicate some unique adaptations
of the leg, possibly for swimming. While the skull is unknown, they likely fed on fish &
possibly other small birds.
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