Dinosaurs A to Z
Alvarezsauridae

Jaculinykus yaruui

"Jaculus claw"

Generic theropod body-plan outline
You 1.8 m (5.9 ft) tall
Jaculinykus 5 m (16.4 ft) long
as long as 3 people standing fingertip to fingertip
generic theropod body plan, scaled to length — not a silhouette of Jaculinykus
Length
5 m (16.4 ft)
Period
Late Cretaceous (72–71 Mya)
Place
Mongolia
Food
Carnivore
Clade
Alvarezsauridae
Jaculinykus reconstruction by Ddinodan
Reconstruction · Ddinodan (CC-BY)

Jaculinykus (meaning “Jaculus claw”) is an extinct genus of alvarezsaurid theropod dinosaur from the Late Cretaceous Baruungoyot Formation of Mongolia. The genus contains a single species, J. yaruui, known from a nearly complete articulated skeleton including bones of the skull. Jaculinykus is notable for its unique hand, which has a hypertrophied first digit and greatly reduced second digit, which is intermediate between the tridactyl hand of Shuvuuia and monodactyl hand of Linhenykus.

What we know

  • Named by Kubo et al., 2023.
  • Fossils found in Mongolia.

What we guess

The reconstruction notes for Jaculinykus — soft tissue, color, behavior — haven't been written up yet. Only the recorded basics above are filled in so far.