Genus: Sinornithosaurus XU, WANG & WU, 1999
Etymology: Sinornithosaurus derived from Sin-Ornitho-Saurus, Latin, sino, "China", Greek, ornitho, "bird" and Greek, sauros, "lizard": meaning a bird-like dinosaur form China.

Species: millenii XU, WANG & WU, 1999
Etymology: Latin, millenii derived from Millennium, "one-thousand years": referring to its discovery near the end of the twentieth century.

Holotype: IVPP V12811

Locality: Sihetun, Shangyuan, Beipaio City, Western Liaoning Province, China.

Horizon: Layer 6, Horizon 1, Lower part of the (Chaomidianzi) Yixian Formation, Jehol Group.

Biostratigraphy: Psittacosaurus Fauna, Confuciusornis Avifauna.

Age: Valanginian Stage, Upper Neocomian Subepoch, Early Early Cretaceous Epoch, Early Cretaceous.

Material: Crushed skull and fragmentary skeleton.
Note: With feather impressions, and skin impressions (McNAMARA, ZHANG, KEARNS, ORR, TOULOUSE, FOLEY, HONE, ROGERS, BENTON, JOHNSON, XU & ZHOU, 2018).

Note: Has furcula.

Note: Possibly venomous (GONG, MARTIN, BURNHAM & FALK, 2009)

Referred material:

AZUMA, 2005

Locality: Western Liaoning Province, China.

Horizon: Yixian Formation, Jehol Group.

Biostratigraphy: Psittacosaurus Fauna, Confuciusornis Avifauna.

Age: Valanginian Stage, Upper Neocomian Subepoch, Early Early Cretaceous Epoch, Early Cretaceous.

Material:

IG-3: Skull and skeleton.

IG-5b: Skull and skeleton with feather impressions.

 

= Dromaeosauridae gen. sp indet Ji, NORELL, GAO, JI, & REN, 2001
= Sinornithosaurus sp JI, JI, YUAN & JI, 2002 (they believed this specimen was an indeterminate species of Sinornithosaurus.
Turner et al., (2012) refer this specimen to Sinornithosaurus millenii.

Locality: Fanzhangzi quarry, 20 km southwest of Lingyuan City, Liaoning Province, China.

Horizon:

Biostratigraphy:

Age: Early Cretaceous.

Material:

NGMC 91 part and counterpart: Nearly complete specimen with ‘feathery’ integument and some claw sheaths (nicknamed “Dave”).
Note: a Lycoptera near the left foot.

Sinornithosaurus millenii (modified from Ji, NORELL, GAO, JI, & REN, 2001), NGMC 91.

 

= Sinornithosaurus haoiana LIU, JI, TANG & GAO, 2004
Etymology: In honor of Professor Hao.

Holotype: D2140

Locality: Near Toutai, Yixian County, Liaoning Province, China.

Horizon: Yixian Fromation.

Biostratigraphy:

Age: Early Cretaceous.

Material: Skull and skeleton.

Note: Possibly venomous (GONG, MARTIN, BURNHAM & FALK, 2009)