Xujiachong Formation

Xujiachong Formation
Stratigraphic range: Pragian
Type	Geological formation
Underlies	Chuandong Formation
Overlies	Guijiatun Formation
Location
Region	Yunnan
Country	China

The Xujiachong Formation is an early Devonian formation from China. It preserves a wide range of plant and fish fossils, many being only known from this formation.

Paleobiota

Plants

Color key Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon		Notes Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Plants
Genus	Species	Higher taxon	Notes	Images
Adoketophyton	A. subverticillatum	Lycophyta	Synonymous with "Zosterophyllum spathulatum" [1]	Adoketophyton reconstruction
Bracteophyton	B. variatum	Tracheophyta incertae sedis	Resembles lycophytes somewhat, but likely not one itself. [2]
Drepanophycus	D. qujingensis	Drepanophycales	Formerly placed within D. spinaeformis [3]
Guangnania	G. cuneata	Zosterophyllopsida	Unclear whether it truly is a zosterophyll, somewhat similar to Yunia [4]
Hedeia	H. sinica	Progymnospermopsida	Resembles both seed plants and trimerophytes [4]
Hsua	H. robusta, H. deflexa [5]	Rhyniophyta? [4]
Huia	H. gracilis	Zosterophyllales?	More slender than the type species [6]
Zosterophyllum	Z. yunnanicum, Z. australianum [7]	Zosterophyllales	Used to date the Xujiachong Formation [8]	Z. sp reconstruction

Animals

Animals
Genus	Species	Higher taxon	Notes	Images
Eugaleaspis	E. xujiachongensis [9]	Galeaspida	Formerly placed under "Galeaspis", but this genus was preoccupied by the trilobite Galeaspis .
Gantarostrataspis	G. gengi	Galeaspida	Mostly known from the Posongchong Formation [10]
Mizia	M. longhuaensis, M. parvus	Yunnanolepididae	M. parvus formerly placed within Yunnanolepis [11]	M. longhuaensis reconstruction
Neopetalichthys [12]	N. yenmenpaensis	Petalichthyida	Relatively basal member of the clade [13]	N. yenmenpaensis reconstruction
Pampetalichthys	P. longhuaensis	Petalichthyida	Formerly classed as "Holopetalichthys" [14] [15]
Pterogonaspis	P. yuhaii	Galeaspida	Similar to Tridenaspis [16]
Qushiaspis	Q. elaia	Galeaspida	Most basal member of Gantarostrataspididae. [17]
Sanqiaspis	S. rostrata	Galeaspida	Another species known from Vietnam [18]
Sanchaspis	S. magalarostrata	Galeaspida	Bears an unusual mushroom-shaped rostrum [19]
Szelepis	S. yunnanensis	Actinolepididae	Redescribed in 2017 [20]
Xichonolepis	X. qujingensis [21]	Sinolepidae (Antiarchi)
Youngolepis	Y. praecursor	Dipnoi	Known from various other formations in early Devonian China [22]	Y. praecursor fossil

References

1. Huang, Pu; Zhang, Hourui (22 July 2025). "Zosterophyllum spathulatum Li and Cai from the Lower Devonian of Yunnan Province, China, is Adoketophyton subverticillatum (Li and Cai) Li and Edwards, 1992, with a discussion of spatial–temporal distribution of Adoketophyton". Journal of Paleontology: 1–8. doi:10.1017/jpa.2025.10111.
2. Wang, De-Ming; Hao, Shou-Gang (2004). "Bracteophyton variatum gen. et sp. nov., an Early Devonian Plant from the Xujiachong Formation of Yunnan, China" (PDF). International Journal of Plant Sciences. 165 (2): 337–345. Bibcode:2004IJPlS.165..337W. doi:10.1086/381919. ISSN   1058-5893. JSTOR   10.1086/381919.
3. Cheng-Sen, Li; Edwards, D. (July 1995). "A re-investigation of Halle's Drepanophycus spinaeformis Göpp. from the Lower Devonian of Yunnan Province, southern China". Botanical Journal of the Linnean Society. 118 (3): 163–192. doi:10.1111/j.1095-8339.1995.tb00468.x.
4. Hao, Shou gang; Xue, Jin zhuang (2013). The early Devonian Posongchong flora of Yunnan: a contribution to an understanding of the evolution and early diversification of vascular plants. Beijing: Science press. ISBN   978-7-03-036616-0.
5. Wang, De-Ming; Hao, Shou-Gang; Wang, Qi (July 2003). "Hsüa deflexa sp. nov. from the Xujiachong Formation (Lower Devonian) of eastern Yunnan, China". Botanical Journal of the Linnean Society. 142 (3): 255–271. doi:10.1046/j.1095-8339.2003.00187.x.
6. Wang, De-Ming; Hao, Shou-Gang (April 2001). "A new species of vascular plants from the Xujiachong Formation (Lower Devonian) of Yunnan Province, China". Review of Palaeobotany and Palynology. 114 (3–4): 157–174. Bibcode:2001RPaPa.114..157W. doi:10.1016/S0034-6667(01)00041-0. PMID   11389912.
7. Shou-Gang, Hao (June 1992). "Some observations on Zosterophyllum australianum Lang & Cookson from the Lower Devonian of Yunnan, China". Botanical Journal of the Linnean Society. 109 (2): 189–202. doi:10.1111/j.1095-8339.1992.tb00265.x.
8. Deming, Wang (August 2007). "Two Species of Zosterophyllum from South China and Dating of the Xujiachong Formation with a Biostratigraphic Method". Acta Geologica Sinica - English Edition. 81 (4): 525–538. Bibcode:2007AcGlS..81..525W. doi:10.1111/j.1755-6724.2007.tb00976.x.
9. Yuhai, Liu (October 1975). "川滇早泥盆世的无颌类". Vertebrata PalAsiatica (in Chinese). 13 (4): 202–216.
10. Min, Zhu; Wang, Junqing; Fan, Junhang (1994). "Early Devonian fishes from Guijiatun and Xujiachong Formations of Qujing, Yunnan, and Related Biostratigraphic Problems". Vertebrata PalAsiatica. 32 (1): 1–11.
11. Min, Zhu. (1996). "The Phylogeny of Antiarcha (Placodermi, Pisces), with the Description of Early Devonian Antiarchs from Qujing, Yunnan, China" (PDF). Bulletin du Muséum National d'Histoire Naturelle. 18: 233–347. Archived from the original (PDF) on 2012-06-23. Retrieved 2013-12-29.
12. Yuhai, Liu (1973). "川滇泥盆纪的多鳃鱼和大瓣鱼化石" (PDF). Journal of Vertebrate Paleontology (in Chinese). 11 (2): 132–143.
13. Zhu, Min & Wang, Junqing (October 1996). "A NEW MACROPETALICHTHYID FROM CHINA, WITH SPECIAL REFERENCE TO THE ZOOGEOGRAPHY OF THE MACROPETALICHTHYIDAE (PLACODERMI)" (PDF). Vertebrata PalAsiatica. 34 (4): 253–268.
14. Zhu, Min (2000). "Catalogue of Devonian vertebrates in China, with notes on bio-events". Courier-Forschungsinstitut Senckenberg. 2000: 373–390.
15. Zhu, Min (July 1996). "A new Macropetalichthyid from China, with special reference to the historical zoogeography of the Macropetalichthyidae (Placodermi)". Vertebrata PalAsiatica. 34 (4): 253–268.
16. Zhu, Min (1992). "Two new Eugaleaspids, with a Discussion on Eugaleaspid Phylogeny". Vertebrata PalAsiatica. 30 (3): 169–184.
17. Jiang, Wenyu; Zhu, Min; Shi, Xiaodong; Li, Qiang; Gai, Zhikun (2 December 2021). "Qushiaspis , a new genus of gantarostrataspid fish (galeaspida, stem-gnathostomata) from the Lower Devonian of Yunnan, China". Historical Biology. 33 (12): 3714–3722. Bibcode:2021HBio...33.3714J. doi:10.1080/08912963.2021.1888086.
18. Gai, Zhi-Kun; Jiang, Wen-Yu; Zhao, Wen-Jin; Li, Qiang; Shi, Xiao-Dong; Zhu, Min (March 2022). "Redescription of the Sanqiaspidae (Galeaspida) from the Lower Devonian of South China and its biostratigraphic significance". Palaeobiodiversity and Palaeoenvironments. 102 (1): 173–191. Bibcode:2022PdPe..102..173G. doi:10.1007/s12549-021-00486-Z.
19. Jiang, Pan; Shitao, Wang (April 1981). "New Discoveries of Polybranchiaspids from Yunnan Province" (PDF). Vertebrata PalAsiatica. 19 (2).
20. Dupret, Vincent; Zhu, Min; Wang, Jun-Qing (4 March 2017). "Redescription of Szelepis Liu, 1981 (Placodermi, Arthrodira), from the Lower Devonian of China". Journal of Vertebrate Paleontology. 37 (2) e1312422. Bibcode:2017JVPal..37E2422D. doi:10.1080/02724634.2017.1312422.
21. Ritchie, A.; Shitao, W.; Young, Gavin C.; Guorui, Z. (5 December 1992). "The Sinolepidae, a family of antiarchs (placoderm fishes) from the Devonian of South China and eastern Australia". Records of the Australian Museum. 44 (3): 319–370. doi:10.3853/j.0067-1975.44.1992.38.
22. Mee-Mann, Chang; Xiaobo, Yu (January 1981). "A New Crossopterygian, Youngolepis praecursor gen et. sp nov., from Lower Devonian of E. Yunnan, China". Scientia Sinica. 24 (1): 89–97.