A field guide to mesozoic birds and other winged dinosaurs

Doelling’s Coyote Yurgovuchia doellingi
Time: 126 Ma ago Location: Utah, USA Habitat: Lower Yellow Cat Member, Cedar
Mountain Formation. Open, marshy fern prairies dominated by iguanodonts, sauropods,
pseudosuchians and polocanthids. Size: WS unknown; BL 2.4m (7.9ft); TL unkown Features:
Large eudromaeosaurs known from partial skeletons. Neck held relatively straight
in resting posture (due to relatively smooth surface of the vertebrae). Tail more flexible
than most other eudromaeosaurians. Biology: One of several eudromaeosaurians in this
ecosystem, these were apparently the largest, nearly twice the size of an unnamed species
of itemirine from the same formation. Possibly a precursor to slightly younger giant
dromaeosaurines of the genus Utahraptor, the relatively stout neck may have helped these
to tackle relatively large prey.
Counter-balanced Terrible Claw Deinonychus antirrhopus
Time: 110 Ma ago Location: Montana, Oklahoma & Wyoming, USA Habitat: Cloverly &
Antlers Formations. Tropical delta swamps & bayous dominated by conifers, ginkgos and
tree ferns. Arid savannas dominated by ferns and low scrub with severe dry seasons. Size:
WS >1.2m (4ft); BL 2.6m (8.5ft); TL unknown Features: Head high w/ tall, narrow snout.
Wings highly reduced, but retaining large claws. Wings incapable of folding tightly, held
forward or swept back against the sides. Legs short & powerfully built, tarsus very short.
Large talons with large sickle claw. Stiffened tail probably used to maintain balance. Biology:
Relatively slow-moving due to short tarsus, involved in the musculature for sickle
claw. Preyed on contemporary ornithopods Tenontosaurus tilletti, mainly juveniles. May
have mobbed prey in large flocks. Juveniles had longer wings & were possibly partially arboreal.
Sickle-claw of juveniles more strongly curved than adults, & may have functioned
in climbing.
Flat Bird-lizard Robber Saurornitholestes explanatus
Time: 75 Ma ago Location: Alberta, Canada Habitat: Lower Dinosaur Park/Upper Oldman
Formations. Seasonally arid lowland plains w/ braided river systems and small forests.
Size: WS >75cm (2.5ft); BL 1.5m (5ft); TL unknown Features: Wings reduced but
capable of grasping small objects w/ long, opposable digits in juveniles. Snout short. Juveniles
stouter-skulled w/ longer limbs. Biology: Juvenile based on likely synonymous species
Bambiraptor feinbergorum. Species S. langstoni (Sues 1978) likely synonymous with
“Laelaps” explanatus (Cope 1876), which has priority (Mortimer 2010).
Stocky Dragon Balaur bondoc
Time: 70 Ma Location: Transylvania, Romania Habitat: Sebes Formation, part of Hateg
Island in the Tethys Sea. Warm, monsoonal with mountainous, dry forests and lakes in the
uplands and swampy river deltas in the lowlands. Size: WS >80cm (2.6ft); BL ~1.5m (5ft);
TL unknown Features: Wings large. Third finger lost, rest of wing relatively fused. Legs
short & powerful, w/ sickle-claws on both second & third toes. Biology: The hallux, which
was enlarged & raised parallel to the typical sickle claw, & the unusually short & stocky
hind limbs, indicate a slow-moving ambush predator adapted to pin prey to the ground
using the talons.
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