Xitun Formation | |
---|---|
Stratigraphic range: | |
Type | Geological formation |
Unit of | Cuifengshan Group[1] |
Underlies | Guijiatun Formation[2] |
Overlies | Xiaxishancun Formation[2] |
Lithology | |
Primary | Calciferous mudstones[2] |
Location | |
Coordinates | 25°29.853'N and 103°46.309'E[2] |
Region | Yunnan Province |
Country | China |
Extent | Qujing |
Type section | |
Named for | Xitun village |
The Xitun Formation is a palaeontological formation which is named after Xitun village in Qujing, a location in South China. This formation includes many remains of fossilized fish and plants of the Early Devonian period (Late Lochkovian).[1][2] It was originally referred to as the Xitun Member of the Cuifengshan Formation (now the Cuifengshan Group).[3]
Color key
|
Notes Uncertain or tentative taxa are in small text; |
Acanthodians reported from the Xitun Formation | |||||
---|---|---|---|---|---|
Genus | Species | Presence | Material | Notes | Images |
Ischnacanthidae | Genus indet. | Qujing.[3] | 4 isolated scales (V7218.1, 3, 6 & 8) & 2 longitudinal sections (V7218.4 & 7).[3] | Similar to Ischnacanthus & Acanthodes, may be referrable to Youngacanthus. | |
Nostolepis | N. amplifica | Xitun, Xishan subdistrict, Qujing.[4] | 43 trunk scales.[4] | ||
N. consueta | Xitun, Xishan subdistrict, Qujing.[4] | Around 25 trunk scales.[4] | |||
N. digitus | Xitun , Xishan subdistrict, Qujing.[4] | 28 trunk scales.[4] | |||
N. qujingensis | Xitun, Xishan subdistrict, Qujing.[4] | 19 trunk scales.[4] | |||
N. striata | Xitun, Xishan subdistrict, Qujing.[4] | 69 trunk scales.[4] | |||
N. sp. indet. | Qujing.[3] | Body scales.[3] | |||
Youngacanthus | Y. gracilis | Qujing.[3] | Jaw elements & teeth.[3] | An ischnacanthid. |
Actinopterygians reported from the Xitun Formation | |||||
---|---|---|---|---|---|
Genus | Species | Presence | Material | Notes | Images |
Meemannia | M. eos | Xitun village, Qujing.[5] | An early ray-finned fish, formerly thought to be a lobe finned fish.[6] |
Chondrichthyes reported from the Xitun Formation | |||||
---|---|---|---|---|---|
Genus | Species | Presence | Material | Notes | Images |
Changolepis | C. tricuspidus | Qujing.[3] | 10 scales of various growth stages.[3] | ||
Chondrichthyes | Genus indet. | Qujing.[3] | 4 isolated teeth (V7221.1, 2, 3 & 4). | May belong to Gualepis or Changolepis. | |
Gualepis | G. elegans | Xitun, Qilin district, Qujing.[7] | Thousands of isolated scales.[3][7] | ||
Ohiolepis? | O.? xitunensis | Qujing.[3] | A complete scale (V7233.1) & an incomplete scale (V7223.2).[3] | ||
Peilepis | P. solida | Qujing.[3] | A body scale (V7222).[3] |
Jawless fish reported from the Xitun Formation | |||||
---|---|---|---|---|---|
Genus | Species | Presence | Material | Notes | Images |
Parathelodus | P. asiaticus | Qilin district, Qujing.[8] | Body scales.[8] | A thelodont also known from the Xishancun Formation. | |
P. cornuformis | Qilin district, Qujing.[8] | Body scales.[8] | A thelodont also known from the Xishancun Formation. | ||
P. liaokuoensis | Qilin district, Qujing.[8] | Body scales.[8] | A thelodont also known from the Xishancun Formation. | ||
P. scitulus | Qilin district, Qujing.[8] | A complete body scale (IVPP V 12156.1).[8] | A thelodont also known from the Xishancun Formation. | ||
P. trilobatus | Qilin district, Qujing.[8] | Body scales.[8] | A thelodont also found in the Xishancun Formation. | ||
P. wangi | Qilin district, Qujing.[8] | Body scales.[8] | A thelodont also known from the Xishancun Formation. | ||
P. xitunensis | Qilin district, Qujing.[8] | A complete body scale (IVPP V 26113.1).[8] | A thelodont. | ||
Turinia | T. asiatica | Qujing.[3] | Multiple scales.[3] | A thelodont. | |
Xitunaspis | X. magnus | Qujing.[9] | 4 headshields.[9] | A galeaspid. |
Placoderms reported from the Xitun Formation | |||||
---|---|---|---|---|---|
Genus | Species | Presence | Material | Notes | Images |
Antiarchi | Unnamed antiarch | Qujing.[1] | MNHN-CHD02 & V10515.[1] | Originally referred to ?Xichonelepis. | |
Asterosteidae | Gen. et. sp. indet. | Qujing.[10] | Part of the head shield.[10] | Very similar to Gemuendina.[10] | |
Chuchinolepis | C. gracilis | Qujing.[1] | Detached plates.[1] | A chuchinolepidid also known from the Xishancun Formation. | |
C. qujingensis | Plates.[1] | A chuchinolepidid also known from the Xishancun Formation. | |||
C. robusta | Qujing.[1] | A detached AVL plate (V10512).[1] | A chuchinolepidid. | ||
C. sulcata | Qujing.[1] | Trunkshield, plates & incomplete pectoral fin.[1] | A chuchinolepidid. | ||
Gavinaspis | G. convergens | Qujing.[11] | Skull remains.[11] | A phyllolepid. | |
Parayunnanolepis | P. xitunensis | Almost-complete specimen.[12] | A yunnanolepidid. | ||
Phymolepis | P. cuifengshanensis | Cuifengshan and Liaokuoshan, Qujing.[1][13] | Plates.[1][13] | A yunnanolepidid also known from the Xishancun Formation. | |
P. guoruii | Qujing.[1] | Trunk-shields & plates.[1] | A yunnanolepidid. | ||
Szeaspis | S. yunnanensis | Qujing.[14] | Neurocranium & associated skull roof (IVPP V 5810a-b).[14] | Preoccupied genus name, renamed Szelepis. | |
Szelepis | S. yunnanensis | Qujing.[14] | Neurocranium & associated skull roof (IVPP V 5810a-b).[14] | An actinolepid originally named Szeaspis. | |
Yunnanolepis | Y. porifera | Qujing.[1] | A yunnanolepidid also known from the Xishancun Formation. | ||
Y. sp. | Qujing.[1] | A trunk-shield associated with part of skull roof (V10514).[1] | A yunnanolepidid, specimen formerly assigned to Vanchienolepis. | ||
Zhanjilepis | Z. aspratilis | Qujing.[1] | Plates.[1] | A yunnanolepidid also known from the Xishancun Formation. |
Sarcopterygians reported from the Xitun Formation | |||||
---|---|---|---|---|---|
Genus | Species | Presence | Material | Notes | Images |
Achoania | A. jarvikii | Qujing.[15] | Anterior cranial portion.[15] | A basal lobe finned fish. | |
Diabolepis | D. speratus | Xichong, Qujing.[16] | Multiple specimens.[16][17] | A dipteriform originally named Diabolichthys. | |
Psarolepis | P. romeri | Xichong, Qujing.[18] | 4 anterior cranial portions, a posterior cranial portion, 2 complete lower jaws & an incomplete lower jaw.[18] | A basal lobe finned fish. | |
Styloichthys | S. changae | Qujing.[19] | Multiple specimens.[19] | A basal coelacanth.[20] | |
Youngolepis | Y. praecursor | Numerous specimens.[21] | A basal lobe finned fish also known from the Bac Bun Formation. |
Plants reported from the Xitun Formation | |||||
---|---|---|---|---|---|
Genus | Species | Presence | Material | Notes | Images |
Gen. nov. A | Huaguo Hill, Shengfeng district of Qujing city.[2] | Numerous specimens.[2] | |||
aff. Huia | aff. H. sp. | Huaguo Hill, Shengfeng district of Qujing city.[2] | PKU-XH214.[2] | A lycophyte. | |
Unnamed spike | Huaguo Hill, Shengfeng district of Qujing city.[2] | A poorly preserved terminal spike (PKU-XH215a, 215b).[2] | Probably from a zosterophyll. | ||
Xitunia | X. spinitheca | Qujing.[22] | A zosterophyll. | ||
Zosterophyllum | Z. minorstachyum | Qujing.[22] | A zosterophyll. | ||
Z. shengfengense | A building site at Huaguo Hill, Shengfeng District, Qujing City.[23] | A nearly entire individual plant preserved as a compression (PUH-QXI01-1), and its counterpart (PUH-QXI01-1’).[23] | A zosterophyll. |