Xitunaspis, a new eugaleaspid fish (Eugaleaspiformes, Galeaspida) from the Lower Devonian of Qujing, Yunnan
Received date: 2021-12-24
Online published: 2022-04-13
A new genus and species of the family Eugaleaspidae (Eugaleaspiformes, Galeaspida), Xitunaspis magnus gen. et sp. nov., is described from the Lower Devonian Xitun Formation in Qujing, Yunnan Province, China. The new genus displays the diagnostic characters of the Eugaleaspidae, including a slit-like median dorsal opening, no inner cornual process, developed median dorsal canals, and only three pairs of lateral transverse canals extending from lateral dorsal canals. Different from the other eugaleaspids, X. magnus possesses a large headshield with thick dermal bone and a more plesiomorphic sensory canal system. The phylogenetic analysis of the Galeaspida reveals that Xitunaspis clusters with Dunyu and Eugaleaspis to form a monophyletic clade Eugaleaspidae Liu, 1965, and has a closer relationship with Dunyu than Eugaleaspis by sharing the thick dermal bone of the headshield. The new finding represents the first convincing fossil record of the Eugaleaspiformes in the middle Lochkovian Xitun Formation and adds to our knowledge about the morphology of eugaleaspiforms and the evolutionary pattern of the sensory canal system in the Eugaleaspiformes and even Galeaspida.
SUN Hao-Ran, GAI Zhi-Kun, CAI Jia-Chen, LI Qiang, ZHU Min, ZHAO Wen-Jin . Xitunaspis, a new eugaleaspid fish (Eugaleaspiformes, Galeaspida) from the Lower Devonian of Qujing, Yunnan[J]. Vertebrata Palasiatica, 2022 , 60(3) : 169 -183 . DOI: 10.19615/j.cnki.2096-9899.220412
| [1] | Cai C Y, Fang Z J, Li X X et al., 1994. New advance in the study of biostratigraphy of Lower and Middle Devonian marine-continental transitional strata in east Yunnan. Sci China Ser B, 24: 634-639 |
| [2] | Gai Z K, Zhu M, 2017. Evolutionary History of Agnathans and their Fossil Records in China. Shanghai: Shanghai Scientific & Technical Publishers. 1-314 |
| [3] | Gai Z K, Zhu M, Zhao W J, 2005. New material of eugaleaspids from the Silurian of Changxing, Zhejiang, China, with a discussion on the eugaleaspid phylogeny. Vert PalAsiat, 43: 61-75 |
| [4] | Gai Z K, Lu L W, Zhao W J et al., 2018. New polybranchiaspiform fishes (Agnatha: Galeaspida) from the middle Palaeozoic of China and their ecomorphological implications. PLoS One, 13: e0202217 |
| [5] | Gai Z K, Shan X R, Sun Z X et al., 2020. A redescription of the Silurian Sinogaleaspis shankouensis (Galeaspida, stem-Gnathostomata) from Jiangxi, China. Vert PalAsiat, 58: 85-99 |
| [6] | Goloboff P A, Catalano S A, 2016. TNT version 1.5, including a full implementation of phylogenetic morphometrics. Cladistics, 32: 221-238 |
| [7] | Janvier P, 1996. Early Vertebrates. Oxford: Clarendon Press. 1-393 |
| [8] | Jiang W Y, Zhu M, Shi X D et al., 2021. Qushiaspis, a new genus of gantarostrataspid fish (Galeaspida, stem-Gnathostomata) from the Lower Devonian of Yunnan, China. Hist Biol, doi: 10.1080/08912963.2021.1888086 |
| [9] | Liu S F, 1983. Agnathan from Sichuan, China. Vert PalAsiat, 21: 97-102 |
| [10] | Liu S F, 1986. Fossil eugaleaspid from Guangxi. Vert PalAsiat, 24: 1-9 |
| [11] | Liu Y H, 1965. New Devonian agnathans of Yunnan. Vert PalAsiat, 9: 125-134 |
| [12] | Liu Y H, 1975. Lower Devonian agnathans of Yunnan and Sichuan. Vert PalAsiat, 13: 202-216 |
| [13] | Liu Y H, 1979. On the arctolepid Arthrodira from Lower Devonian of Yunnan. Vert PalAsiat, 17: 23-34 |
| [14] | Liu Y H, 1980. A nomenclatural note on Eugaleaspis for Galeaspis Liu, 1965; Eugaleaspidae for Galeaspidae Liu, 1965; Eugaleaspiformes for Galeaspiformes Liu, 1965. Vert PalAsiat, 18: 256-257 |
| [15] | Liu Y H, 1986. The sensory line system of the Galeaspida (Agnatha). Vert PalAsiat, 24: 245-259 |
| [16] | Liu Y H, 2002. The age and correlation of some Devonian fish-bearing beds of East Yunnan, China. Vert PalAsiat, 40: 52-69 |
| [17] | Liu Y L, Huang L B, Zong R W et al., 2021. The oldest eugaleaspiform (Galeaspida) from the Silurian Fentou Formation (Telychian, Llandovery) of Wuhan, South China. J Syst Palaeont, 19: 253-264 |
| [18] | Maddison W P, Maddison D R, 2019. Mesquite: a modular system for evolutionary analysis. Version 3. 61. http://mesquiteproject.org |
| [19] | Meng X Y, Gai Z K, 2021. Falxcornus, a new genus of Tridensaspidae (Galeaspida, stem-Gnathostomata) from the Lower Devonian in Qujing, Yunnan, China. Hist Biol, doi: 10.1080/08912963.2021.1952198 |
| [20] | Meng X Y, Zhu M, Gai Z K, 2021. Redescription of Nochelaspis maeandrine, the largest eugaleaspiform from the Lower Devonian of Qujing, Yunnan. Vert PalAsiat, 59: 257-272 |
| [21] | Pan J, 1986. Notes on Silurian vertebrates of China. Bull Chinese Acad Geol Sci, 15: 161-190 |
| [22] | Pan J, 1992. New galeaspids (Agnatha) from the Silurian and Devonian of China. Beijing: Geological Publishing House. 1-86 |
| [23] | Pan J, Wang S T, 1981. New discoveries of polybranchiaspids from Yunnan Province. Vert PalAsiat, 19: 113-121 |
| [24] | P’an K, Wang S T, Liu Y P, 1975. The Lower Devonian Agnatha and Pisces from South China. Prof Pap Stratigr Paleont, 1: 135-169 |
| [25] | Qiao T, King B, Long J A et al., 2016. Early gnathostome phylogeny revisited: multiple method consensus. PLoS One, 11: e0163157 |
| [26] | Sansom R S, 2009. Phylogeny, classification and character polarity of the Osteostraci (Vertebrata). J Syst Palaeont, 7: 95-115 |
| [27] | Shan X R, Zhu M, Zhao W J et al., 2020. A new genus of sinogaleaspids (Galeaspida, stem-Gnathostomata) from the Silurian Period in Jiangxi, China. PeerJ, 8: e9008 |
| [28] | Si C D, Gai Z K, Zhao W J, 2015. A new species of Siyingia from the Lower Devonian Xishancun Formation of Qujing, Yunnan. Vert PalAsiat, 53: 1-13 |
| [29] | Tarlo L B, 1967. Agnatha. In: Harland W B ed.ed. The Fossil Record. London: The Geological Society of London. 629-636 |
| [30] | Wang N Z, 1991. Two new Silurian galeaspids (jawless craniates) from Zhejiang Province, China, with a discussion of galeaspid-gnathostome relationships. In: ChangM M, LiuY H, ZhangG R eds. Early Vertebrates and Related Problems of Evolutionary Biology. Beijing: Science Press. 41-66 |
| [31] | Zhao W J, 2005. Galeaspids of the middle Paleozoic in China and its palaeogeographic significance. J Palaeogeogr, 7: 305-320 |
| [32] | Zhao W J, Zhu M, 2010. Siluro-Devonian vertebrate biostratigraphy and biogeography of China. Palaeoworld, 19: 4-26 |
| [33] | Zhu M, 1992. Two new eugaleaspids, with a discussion on eugaleaspid phylogeny. Vert PalAsiat, 30: 169-184 |
| [34] | Zhu M, 2000. Catalogue of Devonian vertebrates in China, with notes on bio-events. Cour Forsch-Inst Senckenberg, 223: 373-390 |
| [35] | Zhu M, Gai Z K, 2006. Phylogenetic relationships of galeaspids (Agnatha). Vert PalAsiat, 44: 1-27 |
| [36] | Zhu M, Wang N Z, Wang J Q, 2000, Devonian macro- and microvetebrate assemblages of China. Cour Forsch-Inst Senckenberg, 223: 361-372 |
| [37] | Zhu M, Liu Y H, Jia L T et al., 2012. A new genus of eugaleaspidiforms (Agnatha: Galeaspida) from the Ludlow, Silurian of Qujing, Yunnan, southwestern China. Vert PalAsiat, 50: 1-7 |
| [38] | Zhu M et al., 2015. Palaeovertebrata Sinica, Vol. I, Fishes, Fascile 1, Agnathans. Beijing: Science Press. 1-294 |
/
| 〈 |
|
〉 |