A field guide to mesozoic birds and other winged dinosaurs

19.07.2019 Views

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. 88

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