Pronunciation: SIEN-o-SOR-us
Meaning: Chinese lizard
Author/s: Young (1948)
Synonyms: See below
First Discovery: Yunnan, China
Discovery Chart Position: #186
Sinosaurus triassicus
Sinosaurus was named for a chunk of jaw with long, serrated, sharp-pointed teeth and some referred fossils from an area once thought to be of Triassic age. However, the Lower Lufeng Formation of Yunnan Province turned out to be Early Jurassic, some of the teeth may belong to a basal archosaur, and the fossils that aren't from the skull may represent at least one and possibly two prosauropods—setting the stage for decades of taxonomic uncertainty.
Variously classified as a coelophysoid, an herrerasaurid, and a ceratosaur, Sinosaurus could just as easily have been a primitive saurischian, a true theropod, or a non-dinosaurian carnivore of almost any persuasion—such was the confusion wrought by nearly half a century of haphazardly assigned odds and ends from the Lower Lufeng. But in 2003, Oliver Rauhut revisited the mess and, following Dong Zhiming’s reassignment of IVPP V79 from Dilophosaurus sinensis to Sinosaurus, drew on that specimen’s distinctive paired crest and skull anatomy to conclude that it was a close relative of the averostran Cryolophosaurus.
Many of the referred fossils were discovered during fieldwork in the 1930s, '40s, and '50s, but most have since been questioned or reassigned. Some skeletal elements were later attributed to Jingshanosaurus, a crested skull named Shuangbaisaurus anlongbaoensis in 2017 may yet prove to be another face of Sinosaurus, and the so-called "Hewanzi specimen" (ZLJT01), described in the thesis of Xing Lida, was proposed as a possible distinct species within the genus, based on the structure of its crest and shape of its brainpan.
Fossils continued to be assigned to the genus as recently as 2023, suggesting that despite its tangled history, Sinosaurus remains a magnet for Early Jurassic theropod material from a certain area of China. Of the referred fossils that have actually been prepared, it probably owns the skull elements with clear theropod affinities—especially those bearing the distinctive crest—and the original jaw chunk and teeth, though even those have not escaped scrutiny.
Variously classified as a coelophysoid, an herrerasaurid, and a ceratosaur, Sinosaurus could just as easily have been a primitive saurischian, a true theropod, or a non-dinosaurian carnivore of almost any persuasion—such was the confusion wrought by nearly half a century of haphazardly assigned odds and ends from the Lower Lufeng. But in 2003, Oliver Rauhut revisited the mess and, following Dong Zhiming’s reassignment of IVPP V79 from Dilophosaurus sinensis to Sinosaurus, drew on that specimen’s distinctive paired crest and skull anatomy to conclude that it was a close relative of the averostran Cryolophosaurus.
Many of the referred fossils were discovered during fieldwork in the 1930s, '40s, and '50s, but most have since been questioned or reassigned. Some skeletal elements were later attributed to Jingshanosaurus, a crested skull named Shuangbaisaurus anlongbaoensis in 2017 may yet prove to be another face of Sinosaurus, and the so-called "Hewanzi specimen" (ZLJT01), described in the thesis of Xing Lida, was proposed as a possible distinct species within the genus, based on the structure of its crest and shape of its brainpan.
Fossils continued to be assigned to the genus as recently as 2023, suggesting that despite its tangled history, Sinosaurus remains a magnet for Early Jurassic theropod material from a certain area of China. Of the referred fossils that have actually been prepared, it probably owns the skull elements with clear theropod affinities—especially those bearing the distinctive crest—and the original jaw chunk and teeth, though even those have not escaped scrutiny.
(Chinese Lizard from the Triassic)Etymology
Sinosaurus is derived from the Latin "Sinae" (Chinese) and the Greek "sauros" (lizard).
The species epithet (or specific name), triassicus, refers to the Triassic, the period the fossils were originally thought to date from.
Dilophosaurus sinensis (Hu, 1993)Shuangbaisaurus anlongbaoensis? (Wang, 2017)
Discovery
The first remains of Sinosaurus triassicus were discovered in the Shawan member of the Lower Lufeng Formation at Huang Jia Tian Village, Jing Shan Town, Lufeng City, Yunnan Province, China, by C.C. Young (Yang Zhongjian) in 1940.
The holotype (IVVP AS V34) is a partial upper and lower jaw with teeth.
Specimen KMV 8701, discovered in 1987 in the Shawan Member of the Lower Lufeng Formation, was originally named Dilophosaurus sinensis by Hu Chengzhi in 1993. It was later synonymized with Sinosaurus triassicus following reassessments by Dong Zhiming and others. However, some experts opine that it is a distinct critter, worthy of its own name.
