A reappraisal of the Silurian galeaspids (stem-Gnathostomata) from Tarim Basin, Xinjiang

doi:10.19615/j.cnki.1000-3118.190524

Abstract

Abstract:

Some new galeaspid specimens have been recently found from the Silurian of Tarim Basin, Xinjiang. The description of these specimens and the new examination of the galeaspid collections render us the following understanding on the morphology and taxonomy of the Silurian galeaspids from Xinjiang. 1) Nanjiangaspis zhangi is removed from the Hanyangaspidae, and referred to a new genus of the Xiushuiaspidae, Xiyuaspis gen. nov.; 2) Platycaraspis tianshanensis is the junior synonym of Microphymaspis pani. According to the principle of priority, Microphymaspis pani is retained, but it is removed from the Xiushuiaspidae, and referred to the Dayongaspidae; 3) the specimen that was referred to the Arthrodira indet. from the Kezirtag Formation of Kalpin, is identified as a new genus and species of galeaspids, Jiaoyu imperfectus gen. et sp. nov.; 4) the fragments and the anterior ventral plate with snowflake-like ornaments previously referred to Hanyangaspis from the Tataertag and Yimugantawu formations probably belong to Nanjiangaspis; 5) the age of the upper member of the Kezirtag Formation is probably Early Devonian as indicated by Jiaoyu imperfectus and the invertebrate fossils from the lower member.

Key words: Tarim Basin,Xinjiang, Silurian, Galeaspida, taxonomy, morphology

摘要：

通过对新疆塔里木盆地志留系新一轮野外考察和对原来塔里木志留纪盔甲鱼类再观察,取得了以下认识：1) 依据新增加的材料, 张氏南疆鱼(Nanjiangaspis zhangi)被厘定为一新属西域鱼(Xiyuaspis), 并确定其系统位置隶属修水鱼科(Xiushuiaspidae); 2) 潘氏小瘤鱼(Microphymaspis pani)曾被归于Xiushuiaspidae, 系缘于观察上的失误,通过再观察得出M. pani当属大庸鱼科(Dayongaspidae), 同时与其产于同一产地和层位的天山宽头鱼(Platycaraspis tianshanensis)系前者的同物异名;3) 经重新研究,产于柯坪克兹尔塔格组曾被视为节甲鱼类的标本实属盔甲鱼类,并被鉴定为一新的属种：残缺角鱼(Jiaoyu imperfectus); 4) 产于柯坪塔塔埃尔塔格组的汉阳鱼未定种(Hanyangaspis sp.)的前腹片和产于柯坪塔塔埃尔塔格组及巴楚依木干他乌组的锅顶山汉阳鱼(H. guodingshanensis)具雪花状纹饰的骨片,可能均属柯坪南疆鱼(Nanjiangaspis kelpinensis); 5) 根据所产盔甲鱼残缺角鱼(J. imperfectus), 将克兹尔塔格组的时代修订为早泥盆世。

关键词: 新疆塔里木盆地, 志留系, 盔甲鱼, 分类学, 形态学

CLC Number:

Q915.861

LIU Yu-Hai, ZHU Min, LIN Xiang-Hong, LU Li-Wu, GAI Zhi-Kun. A reappraisal of the Silurian galeaspids (stem-Gnathostomata) from Tarim Basin, Xinjiang. Vertebrata Palasiatica, 2019, 57(4): 253-273.

刘玉海, 朱敏, 林翔鸿, 卢立伍, 盖志琨. 2019, 57(4): 253-273, 新疆塔里木盆地志留纪盔甲鱼类新知. 古脊椎动物学报.

Figures/Tables 8

Fig. 1 Photographs of Xiyuaspis zhangi IVPP V 25445.1-3 and their interpretative drawingA. an incomplete head-shield (V 25445.1): A1, A2. internal mould and its interpretative drawing (V 25445.1a), A3. close-up of granulous ornamental tubercles (box region of A1), A4, A5. external mould and its interpretative drawing (V 25445.1b); B. a nearly complete ventral rim (V 25445.2);C. a nearly complete corner (C1) and its interpretative drawing (C2) (V 25445.3)Abbreviations: c. corner 角;ltca-c. the first to third lateral transverse canals issuing from the infraorbital canal 从眶下管发出的第一至三对侧横管;ltc1-3. the first to third lateral transverse canals issuing from the lateral dorsal canal 从侧背管发出的第一至三对侧横管;md.o. median dorsal opening 中背孔;orb. orbital opening 眶孔;vr. ventral rim 腹环

Fig. 2 Photograph of Xiyuaspis zhangi GMC V 2416.1, 2 (A) and its interpretative drawing (B)

Fig. 3 Restorations of Xiyuaspis zhangi (A) and Microphymaspis pani (B)

Table 1 Measurements of Xiyuaspis zhangi (mm)

	Holotype	GMC V 2416.1	GMC V 2416.2	IVPP V 25445.1
Maximum length of preserved head-shield	76.0	111.0	90.5	92.0
Maximum width of preserved head-shield	72.0	115.0	115.0	101.6
Length of short axis of orbital opening	7.0	6.4	7.2	6.0
Length of long axis of orbital opening	10.0	7.1	7.8	7.6
Distance between orbital openings	24.0	—	21.0	22.5
Length of short axis of median dorsal opening	11.0	—	11.0	10.6
Length of long axis of median dorsal opening	20.0	—	22.5	21.0
Length of short axis of pineal fossa	1.3	—	—	—
Length of long axis of pineal fossa	2.0	—	—	—

Fig. 4 Photographs of Microphymaspis pani and their interpretative drawings A. photograph of an incomplete head-shield (A1) and its interpretive drawing (A2), IVPP V 13332, holotpye;B. photograph of an incomplete head-shield (B1) and its interpretive drawing (B2), IVPP V 13333, paratypeAbbreviations: ldc. lateral dorsal canal 侧背管;ltc. lateral transverse canal 侧横管;md.o. median dorsal opening 中背孔;mtc. medial transverse canal 中横联络管;orb. orbital opening 眶孔

Fig. 5 Photographs of Jiaoyu imperfectus gen. et sp. nov., holotype, GMC V 2195 (A) and Zhaotongaspis janvieri, IVPP V 25965 (B) Abbreviations: c. corner 角;ltc. lateral transverse canals 侧横管;vr. ventral rim 腹环

Fig. 6 The anterior ventrolateral plate (avl) plus spinal plate (sp) in placoderms, ventral view A. arthrodire Dicksonosteus arcticus from Early Devonian of Spitsbergen (modified from Goujet, 1984);B. arthrodire Kujdanowiaspis sp. (modified from Denison, 1958);C. petalichthyid Quasipetalichthys haikouensis (modified from Liu, 1991). av. anterior ventral plate 前腹片

Fig. 7 Jiaoyu imperfectus gen. et sp. nov. and possible restorations A. interpretative drawing of holotype, GMC V 2195; B. restoration of the head-shield based on zhaotongaspid Zhaotongaspis, in dorsal view; C. restoration of the head-shield based on eugaleaspid Pterogonaspis, in dorsal view; D. restoration of the head-shield based on sanchaspid Sanchaspis, in dorsal view

References 53

[1]	Denison R H, 1958. Early Devonian fishes from Utah: Part III. Arthrodira. Fieldiana Geol, 11(9):461-551
[2]	Fu L P, Song L S, 1986. Stratigraphy and paleontology of Silurian in Ziyang region (transitional belt). Bull Xi’an Inst Geol Min Res, Chinese Acad Geol Sci, 14:1-198
[3]	Gai Z K, Zhu M, 2005. A new genus of eugaleaspids (Galeaspida, Agnatha) from the Silurian of Anji, Zhejiang, China. Vert PalAsiat, 43(3):165-174
[4]	Gai Z K, Zhu M, Zhao W J et al., 2005. New material of eugaleaspids from the Silurian of Changxing, Zhejiang, China, with a discussion on the eugaleaspid phylogeny. Vert PalAsiat, 43(1):61-75
[5]	Gai Z K, Donoghue P C J, Zhu M et al., 2011. Fossil jawless fish from China foreshadows early jawed vertebrate anatomy. Nature, 476:324-327 DOI URL
[6]	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(9):e0202217 DOI URL
[7]	Geng L Y, 1993. Discussions on some problems concerning Early Palaeozoic history of northern margin of Tarim Plate. Palaeoworld, 2:211-233
[8]	Goujet D, 1984. Les poissons placodermes du Spitsberg. Arthrodires Dolichothoraci de la Formation de Wood Bay (Dévonien inférieur). Paris: Editions Centre National Recherche Scientifique, Cahiers de Paléontologie. ontologie. 1-284
[9]	Janvier P, Thanh T D, Phuong T H, 1993. A new Early Devonian galeaspid from Bac Thai Province, Vietnam. Palaeontology, 36(2):297-309
[10]	Liu S F, 1986. Fossil eugaleaspid from Guangxi. Vert PalAsiat, 24(1):1-9
[11]	Liu S F, 1993. Paleogeographic significance of Sinacanthus. Chinese Sci Bull, 38:1977-1978 DOI URL
[12]	Liu S F, 1995. The geological significance of Sinacanthus from Tarim, China. Vert PalAsiat, 33(2):85-98
[13]	Liu Y H, 1965. New Devonian agnathans of Yunnan. Vert PalAsiat, 9(2):125-134
[14]	Liu Y H, 1975. Lower Devonian agnathans of Yunnan and Sichuan. Vert PalAsiat, 13(4):202-216
[15]	Liu Y H, 1985. A galeaspid (Agnatha), Antiquasagittaspis cornuta gen. et sp. nov., from Lower Devonian of Guangxi, China. Vert PalAsiat, 23(4):247-254
[16]	Liu Y H, 1991. On a new petalichthyid, Eurycaraspis incilis gen. et sp. nov., from the Middle Devonian of Zhanyi, Yunnan. In: Chang M M, Liu Y H, Zhang G R eds. Early Vertebrates and Related Problems of Evolutionary Biology. Beijing: Science Press. 139-177
[17]	Liu Y H, Gai Z K, Zhu M et al., 2014. The discussion on some problems in galeaspids (Agnatha). Vert PalAsiat, 52(4):349-363
[18]	Liu Y H, Zhu M, Gai Z K et al., 2015. Subclass Galeaspida. In: Zhu M ed. Palaeovertebrata Sinica, Vol I, Fishes, Fascile 1, Agnathans. Beijing: Science Press. 141-272
[19]	Liu Y H, Gai Z K, Zhu M et al., 2018. New findings of galeaspids (Agnatha) from the Lower Devonian of Qujing, Yunnan, China. Vert PalAsiat, 56(1):1-15
[20]	Lu L W, Pan J, Zhao L J et al., 2007. New findings of Middle Paleozoic Agnatha and fishes from Kalpin, Xinjiang. Acta Geosci Sin, 28:143-147
[21]	Pan J, 1986a. New discovery of Silurian vertebrates in China. In: Selected Papers to Memory of Prof. S. H. Yoh. Beijing: Geological Publishing House. 67-75
[22]	Pan J, 1986b. Notes on Silurian vertebrates of China. Bull Chinese Acad Geol Sci, 15:161-190
[23]	Pan J, 1992. New Galeaspids (Agnatha) from the Silurian and Devonian of China. Beijing: Geological Publishing House. 1-77
[24]	Pan J, Chen L Z, 1993. Geraspididae, a new family of Polybranchiaspidida (Agnatha) from Silurian of northern Anhui. Vert PalAsiat, 31(3):225-230
[25]	Pan J, Ji S A, 1993. First discovery of Middle Devonian galeaspids in China. Vert PalAsiat, 31(4):304-307
[26]	Pan J, Wang S T, 1980. New finding of Galeaspiformes in South China. Acta Palaeont Sin, 19(1):1-7
[27]	Pan J, Wang S T, 1981. New discoveries of polybranchiaspids from Yunnan Province. Vert PalAsiat, 19(2):113-121
[28]	Pan J, Zeng X Y, 1985. Dayongaspidae, a new family of Polybranchiaspiformes (Agnatha) from Early Silurian of Hunan, China. Vert PalAsiat, 23(3):207-213
[29]	Pan J, Huo F C, Chao J X et al., 1987. Continental Devonian System of Ningxia and its Biotas. Beijing: Geological Publishing House. 1-237
[30]	P’an K, 1957. The new material of Devonian fish fossils in China. Chinese Sci Bull, 8:341-342
[31]	P’an K, 1959. Devonian fish fossils of China and their stratigraphic and geographic distributions. Monogr Summary Basic Data Chinese Geol, 1:1-13
[32]	P’an K, Wang S T, 1983. Xiushuiaspidae, a new family of Polybranchiaspiformes from Xiushui of Jiangxi Province. Acta Palaeont Sin, 22(5):505-509
[33]	P’an K, Wang S T, Liu Y P et al., 1975. The Lower Devonian Agnatha and Pisces from South China. Prof Pap Stratigr Paleont, 1:135-169
[34]	Rong J Y, Wang Y, Zhan R B et al., 2019. Silurian integrative stratigraphy and timescale of China. Sci China Earth Sci, 62(1):89-111 DOI URL
[35]	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(2):1-13
[36]	Tarlo L B, 1967. Agnatha. In: Harland W B ed. The Fossil Record. London: Geological Society of London. 629-636
[37]	Wang J Q, Wang N Z, 1992. Early Devonian galeaspid Agnatha from Southeast of Yunnan, China. Vert PalAsiat, 30(3):185-194
[38]	Wang J Q, Wang N Z, Zhu M, 1996. Middle Paleozoic vertebrate fossils from the north-western margin of the Tarim Basin, and the related stratigraphy. In: Tong X G, Liang D G, Jia C Z eds. New Advances of the Petroleum Geology of Tarim. Beijing: Science Press. 8-16
[39]	Wang J Q, Wang N Z, Zhang G R et al., 2002. Agnathans from Llandovery (Silurian) of Kalpin, Xinjiang, China. Vert PalAsiat, 40(4):245-256
[40]	Wang N Z, 1986. Notes on two genera of Middle Silurian Agnatha (Hanyangaspis and Latirostraspis) of China. In: Selected Papers from the 13^th and 14^th Annual Conventions of Palaeontological Society of China. Hefei: Anhui Science and Technology Publishing House. 49-57
[41]	Wang N Z, 1991. Two new Silurian galeaspids (jawless craniates) from Zhejiang Province, China, with discussion of galeaspid-gnathostome relationships. In: Chang M M, Liu Y H, Zhang G R eds. Early Vertebrates and Related Problems of Evolutionary Biology. Beijing: Science Press. 41-65
[42]	Wang N Z, Zhang S B, Wang J Q et al., 1998. Early Silurian chondrichthyan microfossils from Bachu County, Xinjiang, China. Vert PalAsiat, 36(4):257-267
[43]	Wang P, Hu J Z, Song S L et al., 1988. The discovery of Sinacanthus in Kalpin region, Xinjiang, and its stratigraphic significance. Geol Xinjiang, 6:47-50
[44]	Wang S T, Xia S F, Chen L Z et al., 1980. On the discovery of Silurian agnathans and Pisces from Chaoxian County, Anhui Province and its stratigraphical significance. Bull Inst Geol Chinese Acad Geol Sci, 1(2):101-112
[45]	Zhang S B, Gao Q Q, Chen Q B et al., 1996. New progress in the studies of Silurian-Devonian stratigraphy on the northwest margin of Tarim Basin. In: Tong X G, Liang D G, Jia C Z eds. New Advances of the Petroleum Geology of Tarim. Beijing: Science Press. 54-66
[46]	Zhang S B, Gao Q Q, Geng L Y, 2001. Silurian. In: Zhou Z Y ed. Stratigraphy of the Tarim. Beijing: Science Press. 81-100
[47]	Zhao W J, 2005. Galeaspids of the Middle Paleozoic in China and its palaeogeographic significance. J Palaeogeogr, 7:305-320
[48]	Zhao W J, Zhu M, 2014. A review of the Silurian fishes from China, with comments on the correlation of fish-bearing strata. Earth Sci Front, 21(2):185-202
[49]	Zhao W J, Wang S T, Wang J Q et al., 2009. The subdivision and correlation of the Silurian fish-bearing strata and Caledonian movement in Kalpin and Bachu regions, the Tarim Basin, Xinjiang. J Stratigr, 33(3):225-240
[50]	Zhu M, 1992. Two new eugaleaspids, with a discussion on eugaleaspid phylogeny. Vert PalAsiat, 30(3):169-184
[51]	Zhu M, 1998. Early Silurian sinacanths (Chondrichthyes) from China. Palaeontology, 41(1):157-171
[52]	Zhu M, Gai Z K, 2006. Phylogenetic relationships of galeaspids (Agnatha). Vert PalAsiat, 44(1):1-27
[53]	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):1-7