A field guide to mesozoic birds and other winged dinosaurs

Sampson’s Talos Talos sampsoni
Time: 76 Ma ago Location: Utah, USA Habitat: Kaiparowits Formation. Floodplain dominated
by large, seasonally flooding rivers. Occupied wide muddy and sandy riverbanks.
Size: WS unknown; BL ~1.6m (5.2ft); TL unknown Features: Mid-sized to large troodontines.
Wings very short w/ slender forearms. Legs slender but shorter than contemporary
Asian species. Sickle claw relatively small. Biology: Like other troodontids, these birds
may have used their large recurved talons to pin prey, likely using a single foot. An injury
to the second toe in the first known fossil specimen supports the idea that the toe was used
routinely to pin down small, struggling animals.
Handsome Wounding Tooth Troodon formosus
Time: 75 Ma ago Location: Montana, USA & Alberta, Canada Habitat: Judith River, Dinosaur
Park and Horseshoe Canyon Formations. Seasonally arid lowland plains dominated
by braided river systems and small forests. Size: WS unknown; BL ~2.3m (7.5ft);
TL unknown Features: Large troodontines. Head long w/ long but broad snout. Wings
very small. Legs moderately long but stouter than contemporary Asian species. Sickle claw
large & flattened similar to eudromaeosaurians, probably for use in predation. Biology:
Carnivorous, but possibly supplementing with fruit or seeds. Small teeth classified in the
species Paronychodon lacustris possibly represent juvenile T. formosus. While fossils attributed
T. formosus have been found in a huge range of formations (including very large
specimens from Alaska) and spanning many millions of years (up to 66 million years ago),
most of these are based on extremely fragmentary remains, and almost certainly petrain
to different species.
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