Baisesaurus (meaning "Baise lizard") is an extinct genus of ichthyosauromorph reptiles from the early Triassic (Spathian age) Luolou Formation of Guangxi, China. The genus contains a single species, Baisesaurus robustus, known from a partial postcranial skeleton.
| Baisesaurus Temporal range: Early Triassic,
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| Holotype specimen | |
Scientific classification 
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| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | †Ichthyosauromorpha |
| Genus: | †Baisesaurus Ren et al., 2022 |
| Species: | †B. robustus
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| Binomial name | |
| †Baisesaurus robustus Ren et al., 2022
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Discovery and naming
editThe Baisesaurus holotype specimen, CUGW VH107, was discovered in 2018 in a layer of the Luolou Formation (Triassospathodus symmetricus–T. homeri conodont assemblage zones[1]) in the Nanpanjiang Basin of Zhebao Township in Baise, China. The specimen consists of assorted ribs, gastralia, a limb element (likely a radius), twelve vertebral centra, and seven neural arches.[2]
In 2022, Ren et al. described Baisesaurus robustus, a new genus and species of basal ichthyosauromorphs. The generic name, "Baisesaurus", combines a reference to the type locality in Baise, China, with the Greek "saurus", meaning "lizard". The specific name, "robustus", means "robust".[2]
Description and classification
editBaisesaurus was likely at least 3 m (9.8 ft) long. It was more similar to Utatsusaurus than to any other ichthyosauromorph, with similar size and anatomical traits. It can be inferred from related animals that Baisesaurus was a strong swimmer with long, compact forelimb bones.[2]
Baisesaurus likely represents a basal member of the clade Ichthyosauromorpha, albeit outside of the clades Hupehsuchia or Nasorostra. In their 2022 description, Ren and colleagues explained that it may more precisely represent a member of the Ichthyopterygia, but such a classification is highly tentative.[2]
References
edit- ^ a b Wang, Yi-Nuo; Jiang, Da-Yong; Motani, Ryosuke; Yao, Ming-Tao; Zhou, Min; Sun, Zuo-Yu; Huang, Jian-Dong; Ma, Zhao-Liang (May 2025). "Dating of Early Triassic Chaohu Fauna by precise U-Pb age constraints: Temporal calibration of the emergence and first radiation of Mesozoic marine reptiles". Palaeoworld: 200963. doi:10.1016/j.palwor.2025.200963.
- ^ a b c d Ren, Jicheng; Jiang, Haishui; Xiang, Kunpeng; Sullivan, Corwin; He, Yongzhong; Cheng, Long; Han, Fenglu (2022-04-07). "A new basal ichthyosauromorph from the Lower Triassic (Olenekian) of Zhebao, Guangxi Autonomous Region, South China". PeerJ. 10: e13209. doi:10.7717/peerj.13209. ISSN 2167-8359. PMC 8995025. PMID 35415016.