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). It was originally referred to as the Xitun Member of the Cuifengshan Formation (now the Cuifengshan Group).

Fossil content

Animals

Acanthodians Acanthodians reported from the Xitun Formation Genus Species Presence Material Notes Images Ischnacanthidae Genus indet. Qujing. 4 isolated scales (V7218.1, 3, 6 & 8) & 2 longitudinal sections (V7218.4 & 7). Similar to Ischnacanthus & Acanthodes, may be referrable to Youngacanthus. Nostolepis N. amplifica Xitun, Xishan subdistrict, Qujing.43 trunk scales. N. consueta Xitun, Xishan subdistrict, Qujing. Around 25 trunk scales. N. digitus Xitun, Xishan subdistrict, Qujing. 28 trunk scales. N. qujingensis Xitun, Xishan subdistrict, Qujing. 19 trunk scales. N. striata Xitun, Xishan subdistrict, Qujing. 69 trunk scales. N. sp. indet. Qujing. Body scales. Youngacanthus Y. gracilis Qujing. Jaw elements & teeth. An ischnacanthid.

Actinopterygians Actinopterygians reported from the Xitun Formation Genus Species Presence Material Notes Images Meemannia M. eos Xitun village, Qujing. An early ray-finned fish, formerly thought to be a lobe finned fish.

Arthropods Arthropods reported from the Xitun Formation Genus Species Presence Material Notes Images Qujingopterus Q. spineus A stylonurid eurypterid

Chondrichthyes Chondrichthyes reported from the Xitun Formation Genus Species Presence Material Notes ImagesChangolepisC. tricuspidusQujing.10 scales of various growth stages. Chondrichthyes Genus indet. Qujing. 4 isolated teeth (V7221.1, 2, 3 & 4). May belong to Gualepis or Changolepis. Gualepis G. elegans Xitun, Qilin district, Qujing.Thousands of isolated scales. Ohiolepis? O.? xitunensis Qujing. A complete scale (V7233.1) & an incomplete scale (V7223.2). Peilepis P. solida Qujing. A body scale (V7222).

Jawless fish Jawless fish reported from the Xitun Formation Genus Species Presence Material Notes Images Parathelodus P. asiaticus Qilin district, Qujing.Body scales. A thelodont also known from the Xishancun Formation. P. cornuformis Qilin district, Qujing. Body scales. A thelodont also known from the Xishancun Formation. P. liaokuoensis Qilin district, Qujing. Body scales. A thelodont also known from the Xishancun Formation. P. scitulus Qilin district, Qujing. A complete body scale (IVPP V 12156.1). A thelodont also known from the Xishancun Formation. P. trilobatus Qilin district, Qujing. Body scales. A thelodont also found in the Xishancun Formation. P. wangi Qilin district, Qujing. Body scales. A thelodont also known from the Xishancun Formation. P. xitunensis Qilin district, Qujing. A complete body scale (IVPP V 26113.1). A thelodont. Turinia T. asiatica Qujing. Multiple scales. A thelodont. Xitunaspis X. magnus Qujing. 4 headshields. A galeaspid.

Placoderms Placoderms reported from the Xitun Formation Genus Species Presence Material Notes Images Antiarchi Unnamed antiarch Qujing. MNHN-CHD02 & V10515. Originally referred to ?Xichonelepis. Asterosteidae Gen. et. sp. indet. Qujing. Part of the head shield. Very similar to Gemuendina. Chuchinolepis C. gracilis Qujing. Detached plates. A chuchinolepidid also known from the Xishancun Formation. C. qujingensis Plates. A chuchinolepidid also known from the Xishancun Formation. C. robusta Qujing. A detached AVL plate (V10512). A chuchinolepidid. C. sulcata Qujing. Trunkshield, plates & incomplete pectoral fin. A chuchinolepidid. Cuanyu C. liui Qujing. A actinolepid. Gavinaspis G. convergens Qujing. Skull remains. A phyllolepid. Parayunnanolepis P. xitunensis Almost-complete specimen. A yunnanolepidid. Phymolepis P. cuifengshanensis Cuifengshan and Liaokuoshan, Qujing.Plates. A yunnanolepidid also known from the Xishancun Formation. P. guoruii Qujing. Trunk-shields & plates. A yunnanolepidid. Szeaspis S. yunnanensis Qujing. Neurocranium & associated skull roof (IVPP V 5810a-b). Preoccupied genus name, renamed Szelepis. Szelepis S. yunnanensis Qujing. Neurocranium & associated skull roof (IVPP V 5810a-b). An actinolepid originally named Szeaspis. Yunnanolepis Y. porifera Qujing. A yunnanolepidid also known from the Xishancun Formation. Y. sp. Qujing. A trunk-shield associated with part of skull roof (V10514). A yunnanolepidid, specimen formerly assigned to Vanchienolepis. Zhanjilepis Z. aspratilis Qujing. Plates. A yunnanolepidid also known from the Xishancun Formation.

Sarcopterygians Sarcopterygians reported from the Xitun Formation Genus Species Presence Material Notes Images AchoaniaA. jarvikii Qujing. Anterior cranial portion. A basal lobe finned fish. Diabolepis D. speratus Xichong, Qujing.Multiple specimens. A dipteriform originally named Diabolichthys. Psarolepis P. romeri Xichong, Qujing.4 anterior cranial portions, a posterior cranial portion, 2 complete lower jaws & an incomplete lower jaw. A basal lobe finned fish. Styloichthys S. changae Qujing. Multiple specimens. A basal coelacanth. Youngolepis Y. praecursor Numerous specimens. A basal lobe finned fish also known from the Bac Bun Formation.

Plants Plants reported from the Xitun Formation Genus Species Presence Material Notes ImagesGen. nov. AHuaguo Hill, Shengfeng district of Qujing city.Numerous specimens. aff. Huia aff. H. sp. Huaguo Hill, Shengfeng district of Qujing city. PKU-XH214. A lycophyte. Unnamed spike Huaguo Hill, Shengfeng district of Qujing city. A poorly preserved terminal spike (PKU-XH215a, 215b). Probably from a zosterophyll. Xitunia X. spinitheca Qujing. A zosterophyll. Zosterophyllum Z. minorstachyum Qujing. A zosterophyll. Z. shengfengense A building site at Huaguo Hill, Shengfeng District, Qujing City. A nearly entire individual plant preserved as a compression (PUH-QXI01-1), and its counterpart (PUH-QXI01-1'). A zosterophyll.

See also List of fossil sites— (with link directory)

References