Hypnovenator

Hypnovenator (meaning "sleep hunter") is an extinct genus of troodontid theropod dinosaurs from the Early Cretaceous (Albian) Ohyamashimo Formation of Japan. The genus contains a single species, Hypnovenator matsubaraetoheorum, known from a partial skeleton. Hypnovenator is the only troodontid currently known from Japan, and it represents the oldest definitive member of the subgroup Troodontinae.

== Discovery and naming == thumb|left|H. matsubaraetoheorum Type locality (biology)|type locality The Hypnovenator holotype specimen, MNHAH D1033340, was discovered in sediments of the Ohyamashimo Formation (lower Sasayama Group) in Nishikosa, Tamba-Sasayama city, of Hyōgo Prefecture, Japan. Much of the known material was discovered in September 2010 by a group of amateur fossil hunters during the construction of the Hyogo Prefectural Tamba Namikimichi Central Park. Subsequent expeditions in July of the following year by the prefecture's Museum of Nature and Human Activities revealed an additional block containing material belonging to the same individual. The specimen is somewhat fragmentary, comprising bones of both the axial and appendicular skeleton. These include two caudal vertebrae with a chevron, two ribs, several gastralia, most of the left arm—including the humerus, radius, ulna, carpal, metacarpals, and most of the phalanges and manual unguals—and some of the legs, including part of the left femur, tibia, and fibula, right tibia, both astragali, and several partial metatarsals and pedal phalanges (toe bones).