Coccolepididae Explained

Coccolepididae is an extinct family of ray-finned fish, known from the Early Jurassic to Early Cretaceous, most of which were originally referred to the type genus Coccolepis. They had a widespread distribution, being found in North and South America, Australia, Asia and Europe. They are mostly known from freshwater environments, though several species have been found in marine environments. They are morphologically conservative, and have poorly ossified endo and exoskeletons, which usually results in poor preservation. This makes it difficult to distinguish species.^[1] They are generally small fish, with the largest known specimens reaching a length of 210 mm. Historically, they have been classified as members of “Palaeonisciformes”, a paraphyletic grouping of non-neopterygian fish, due to their plesiomorphic conservative morphology closely resembling those of many other groups of primitive fish.^[2] Some recent authors have suggested that they may belong to the order Chondrostei as relatives of the Acipenseriformes (which contains sturgeons and paddlefish).

Taxonomy

After^[3]

• Coccolepis Agassiz, 1843 Solnhofen Limestone, Germany, Late Jurassic (Tithonian)
  • Coccolepis bucklandi Agassiz, 1843
  • Coccolepis solnhofensis López-Arbarello, and Ebert, 2021
• "Coccolepis" liassica Woodward, 1890 Blue Lias or Charmouth Mudstone Formation, England, Early Jurassic (Sinemurian)
• "Coccolepis" australis Woodward, 1895 Talbragar Fossil Beds, Australia, Late Jurassic (Tithonian)
• Morrolepis Kirkland, 1998
  • M. schaefferi Kirkland, 1998 Morrison Formation, United States Late Jurassic (Tithonian)
  • M. aniscowitchi (Gorizdro-Kulczycka), 1926 Karabastau Formation, Kazakhstan, Middle-Late Jurassic (Callovian/Oxfordian)
  • M. andrewsi (Woodward, 1891) Purbeck Group, United Kingdom, Early Cretaceous (Berriasian)
• Barbalepis Olive, Taverne, and López-Arbarello, 2019 Sainte-Barbe Clays Formation, Belgium, Early Cretaceous (Barremian/Aptian) formerly Coccolepis macroptera Traquair, 1911
• Condorlepis López-Arbarello, Sferco, and Rauhut, 2013
  • Condorlepis groeberi (Bordas, 1943) Cañadón Calcáreo Formation, Argentina, Upper Jurassic
  • Condorlepis woodwardi (Waldman, 1971) Koonwarra fossil bed, Australia, Early Cretaceous (Aptian)
• Iyalepis Sytchevskaya, 2006 Cheremkhovskaya Formation, Russia, Early Jurassic (Toarcian) formerly Angaraichthys rohoni Sytchevskaya and Yakovlev, 1985
• Plesiococcolepis Wang, 1977 Lingling-Hengyang, Hunan, China, Early Jurassic
  • Plesiococcolepis hunanensis Wang, 1977
• Sunolepis Liu, 1957 Yumen, Gansu Province, China, Upper Jurassic or Lower Cretaceous
  • Sunolepis yumenensis Liu, 1957
• Toarcocephalus Cooper et al., 2024 Posidonia Shale, Germany, Early Jurassic (Toarcian)^[4]
  • Toarcocephalus morlok Cooper et al., 2024

Notes and References

1. López-Arbarello. Adriana. Ebert. Martin. 2021. Diversity of Coccolepis AGASSIZ, 1843 (Coccolepididae, Chondrostei) from the Upper Jurassic Solnhofen-Archipelago, Southern Germany. Acta Palaeontologica Polonica. 66. 10.4202/app.00873.2021. 240243638 . free.
2. Skrzycka. Roksana. 2014-07-03. Revision of two relic actinopterygians from the Middle or Upper Jurassic Karabastau Formation, Karatau Range, Kazakhstan. Alcheringa: An Australasian Journal of Palaeontology. en. 38. 3. 364–390. 10.1080/03115518.2014.880267. 129308632 . 0311-5518.
3. Olive. Sébastien. Taverne. Louis. López-Arbarello. Adriana. March 2019. A new genus of coccolepidid actinopterygian from the Cretaceous Iguanodon-bearing locality of Bernissart, Belgium. Cretaceous Research. en. 95. 318–335. 10.1016/j.cretres.2018.11.020. 134207366 . subscription.
4. Cooper . S. L. A. . López-Arbarello . A. . Maxwell . E. E. . First occurrence of a †coccolepidid fish (?Chondrostei: †Coccolepididae) from the Upper Lias (Toarcian, Early Jurassic) of southern Germany . Palaeontologia Electronica . 2024 . 27 . 1 . 1–25 . 10.26879/1326 . English . 1094-8074. free .