Genus: Hyphalosaurus GAO, TANG & WANG, 1999
Etymology: Greek, hyphalos, “submerged, underwater” and Greek, sauros, “lizard”;
Underwater lizard.
= Sinohydrosaurus LI, ZHANG & LI, 1999
Etymology:
Species: lingyuanensis GAO, TANG & WANG, 1999
Etymology: In reference to Lingyuan, Liaoning Province,
China.
Holotype: IVPP V11705
Locality: Fanzhangzi, Dawangzhangzi (Daxinfanzi) bed, Lingyuan, Liaoning Province, China.
Horizon: Horizon II, Yixian Formation, Jehol Group.
Biostratigraphy: Psittacosaurus fauna, Liaoxiornis Avifauna.
Age: Lower Hautervian Stage, Uppermost Neocomian Subepoch, Lower Early Cretaceous Epoch, Early Cretaceous.
Material: Complete specimen with 6 Lycoptera on the slab.
Referred material:
Note: Hundereds of specimens have been found in Liaoning ranging from babies to adults.
GAO & KSEPKA, 2008
PKUP V1052: Skull and skeleton.
Note: Has integument along the neck.PKUP V1057, 1058, BMNHC V050: Fragmentary specimens.
GMC, unnumbered: Juvenile specimens.
BUFFETAUT, LI, TONG, & ZHANG, 2007
Locality: Wanfuotang, Yixian, Liaoning Province, China.
Horizon: Yixian Formation.
Biostratigraphy:
Age: Early Cretaceous.
Material:
SPM R10: Embryo.
Note: Mutation with two necks and heads.
SPM R13: Embryo.
= Sinohydrosaurus lingyuanensis LI, ZHANG & LI, 1999
Etymology: In reference to Lingyuan.Holotype: BVC 398
Locality: Fanzhangzi, Dawangzhangzi, Lingyuan, Liaoning Province, China.
Horizon: Yixian Formation.
Biostratigraphy:
Age: Early Cretaceous.
Material: Complete specimen with 6 Lycoptera on the slab.
Note: Part and counterpart of the same specimen, Hyphalosaurus lingyanensis GAO, TANG & WANG, 1999 was published shortly after LI, ZHANG & LI, 1999
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Species: baitaigouensis JI, JI, CHENG, YOU, LÜ & YUAN, 2004
Etymology: In refererence to the
Baitaigou village, northwest of the Yizhou town, Yixian County,
Liaoning Province, China.
Holotype: CAGS-IG-03-7-02
Locality: Baitaigou village, northwest of the Yizhou town, Yixian County, 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: Fragmentary adult with 12 leathery eggs and embryos.
Referred material:
AZUMA, 2005
IG-15, 16: Two skeletons.
HOU, LI, KSEPK, GAO, & NORELL, 2009
LPM-R168: Flex shelled egg and hatchling.
LPM-R169: Flex shelled egg.
JI, JI, LU, YOU & YUAN, 2006
CAGS-IG-03-7-08: 1 adult specimen and 1 juvenile.
GAO & KSEPKA, 2008
PKP V1056, LMPC R00052, R00065, R00066, BMNHC V050, V060, V014: Fragmentary skulls and skeletons.
JI, WU & CHENG, 2010
CAGS-IB-06131: Nearly complete specimen.
Note: Has 18 embryos in the body cavity.