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Xenacanthida

January 01, 1970

Xenacanthida (or Xenacanthiformes) is an order or superorder of extinct shark-like chondrichthyans (cartilaginous fish) known from the Carboniferous to Triassic. They were native to freshwater, marginal marine and shallow marine habitats.[1] Some xenacanths may have grown to lengths of 5 m (16 ft).[2] Most xenacanths died out at the end of the Permian in the End-Permian Mass Extinction, with only a few forms surviving into the Triassic.

Xenacanthida
Temporal range: Mississippian–Norian
Life restoration of Xenacanthus
Fossil of Lebachacanthus senckenbergianus
Scientific classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Order: †Xenacanthida
Glikman, 1964
Families and genera

See text

Description edit

 
Teeth of Triodus teberdaensis

The foundation of the tooth is prolonged lingually with a circlet button and a basal tubercle on the oral and aboral surfaces individually. The family Xenacanthidae consists of five genera: Xenacanthus, Triodus, Plicatodus, Mooreodontus and Wurdigneria; all of these are distinguished by cross sections of the points, crown center, length of the median edge, type of vertical cristae, and microscopic anatomy.

Xenacanths are divided into two groups based on dental characteristics. Group one has tricuspid crowns containing two stout, slightly diverging lateral cusps pointing in the same direction, a high median cusp, with a crown-base angle almost at 90 degrees, a large, rounded, apical button with several foramina and multiple, 8-9 coarse vertical cristae on all the cusps. Group two has bicuspid crowns with two upright, asymmetric cusps, where the medial cusp is thicker than the distal one, and consistently lacks a median cusp.[3]

The bodies of xenacanths are elongate and eel-like.[4] Xenacanths had long dorsal fins, as well as a large spine projecting from the top of the head, which was a modified dorsal-fin spine.[5] The spine is usually thought to have acted as a defense against attackers.[2] They also bore two anal fins, with the tail (caudal) fin being pseudo-diphycercal.[4] They were probably slow swimmers that swam using side to side undulations of the body (anguilliform locomotion).[6]

Some xenacanths like Barbclabornia, are thought to have reached lengths of 4.5–5 metres (15–16 ft).[2] While others such as Triodus were only around 0.5 metres (1.6 ft) long.[7]

Ecology edit

Many xenacanths are thought to have been euryhaline and to have migrated between freshwater and marine environments. Orthacanthus platypternus from the Early Permian of North America is suggested to have been catadromous, migrating into freshwater environments as a juvenile before returning to the sea as an adult.[2] Based on isotope analysis of teeth, some xenacanths have been suggested to have lived permanently in freshwater environments.[8][9] However, this proposal has been criticised by some authors, as the mineralization window of individual teeth only spans a short interval of time of days to weeks, and may not be reflective of long term behaviour.[2] However isotopic analysis of fin spines of Orthacanthus and Triodus from the Early Permian of France, suggests that at least for these species, growth exclusively occurred in freshwater environments.[10]

Fossil egg cases assigned to the genus Fayolia, which were probably produced by xenacanths, have a helically twisted collarette running around them, similar to the eggs of bullhead sharks, and taper towards both ends, with one end having a tendril. These eggs are typically found in freshwater deposits.[6]

A number of xenacanths are likely to have been fully marine, such as the small primitive genus Bransonella, which is thought to have had a seafloor dwelling (benthic) ecology similar to that of a modern catshark.[11]

Xenacanths are thought to have been ambush predators.[12] The diet of freshwater xenacanths is known to have included temnospondyl amphibians[7] as well as palaeoniscid fish,[13] acanthodians, and other xenacanths.[11] Large xenacanths are suggested to have acted as the apex predators of late Paleozoic freshwater ecosystems, such as the Early Permian freshwater lakes of the Saar–Nahe Basin in southern Germany.[7][11]

Taxonomy edit

Xenacanths are typically placed as stem-group elasmobranchs, more closely related to modern sharks and rays than to Holocephali, which includes chimaeras.[14][15][16]

Subdivisions edit

  • Order: Bransonelliformes Hampe & Ivanov, 2007
      • Genus: Barbclabornia Johnson, 2003 (Early Permian, possibly also Late Carboniferous, North America)
      • Genus: Bransonella Harlton, 1933 (Early Carboniferous-Middle Permian, Worldwide)
  • Order: Xenacanthiformes Berg, 1955
    • Family: Diplodoselachidae Dick, 1981
      • Genus: Dicentrodus Traquair, 1888 (Early Carboniferous, Europe, North America)
      • Genus: Diplodoselache Dick, 1981 (Early Carboniferous, Europe)
      • Genus: Hagenoselache Hampe & Heidkte, 1997 (mid-Carboniferous, Europe)
      • Genus: Hokomata Hodnett & Elliott, 2018 (mid-Carboniferous, North America)
      • Genus: Lebachacanthus Soler-Gijon, 1997 (Late Carboniferous-Early Permian, Europe)
      • Genus: Reginaselache Turner & Burrow, 2011 (Early Carboniferous, Australia)
    • Family: Sphenacanthidae Maisey, 1982
      • Genus: Sphenacanthus Agassiz, 1837 (Early Carboniferous-Late Permian, Worldwide)
      • Genus: Xenosynechodus Agassiz, 1980 (Middle-Late Permian, Europe, later authors have rejected its placement as a xenacanth[17])
      • Genus: Desinia Ivanov, 2022[17] (Middle-Late Permian, Europe)
    • Family: Orthacanthidae Heyler & Poplin 1990[5]
      • Genus: Orthacanthus Agassiz, 1843 (Late Carboniferous-Early Permian, Europe, North America)[5]
    • Family: Xenacanthidae Fritsch, 1889
      • Genus: Mooreodontus Ginter et al., 2010 (Middle-Late Triassic, Worldwide)
      • Genus: Plicatodus Hampe, 1995 (Late Carboniferous-Early Permian, Europe)
      • Genus: Triodus Jordan, 1849 (Late Carboniferous-Middle Permian, Europe, North America, South America)[1]
      • Genus: Xenacanthus Beyrich, 1848 (Carboniferous-Permian, Worldwide)
      • Genus: Wurdigneria Richter, 2005 (Middle-Late Permian, South America)
    • incertae sedis
      • Genus: Tikiodontus Bhat, Ray & Datta, 2018 (Late Triassic, India)

References edit

  1. ^ a b Pauliv, Victor E.; Martinelli, Agustín G.; Francischini, Heitor; Dentzien-Dias, Paula; Soares, Marina B.; Schultz, Cesar L.; Ribeiro, Ana M. (December 2017). "The first Western Gondwanan species of Triodus Jordan 1849: A new Xenacanthiformes (Chondrichthyes) from the late Paleozoic of Southern Brazil". Journal of South American Earth Sciences. 80: 482–493. doi:10.1016/j.jsames.2017.09.007.
  2. ^ a b c d e Beck, Kimberley G.; oler-Gijón, Rodrigo; Carlucci, Jesse R.; Willis, Ray E. (December 2014). "Morphology and Histology of Dorsal Spines of the Xenacanthid Shark Orthacanthus platypternus from the Lower Permian of Texas, USA: Palaeobiological and Palaeoenvironmental Implications". Acta Palaeontologica Polonica. 61 (1): 97–117. doi:10.4202/app.00126.2014.
  3. ^ Bhat, M. S., Ray, S., & Datta, P. (2018). A new assemblage of freshwater sharks (Chondrichthyes: Elasmobranchii) from the Upper Triassic of India. Geobios, 51(4), 269-283. doi:10.1016/j.geobios.2018.06.004
  4. ^ a b Soler-Gijón, Rodrigo; Ruiz, Antonio Díez (2023-06-20). ""Carbonífero de Puertollano" Natural Monument (Puertollano basin, Spain): a window for the knowledge of Early Vertebrates". Spanish Journal of Palaeontology. 38 (1): 81–94. doi:10.7203/sjp.26788. ISSN 2660-9568.
  5. ^ a b c Babcock, L. E. (2024). "Replacement names for two species of Orthacanthus Agassiz, 1843 (Chondrichthyes, Xenacanthiformes), and discussion of Giebelodus Whitley, 1940, replacement name for Chilodus Giebel, 1848 (Chondrichthyes, Xenacanthiformes), preoccupied by Chilodus Müller & Troschel, 1844 (Actinopterygii, Characiformes)". ZooKeys. 1188 (219–226).
  6. ^ a b Schneider, J. (1993). "Environment, biotas and taphonomy of the Lower Permian lacustrine Niederhäslich limestone, Döhlen basin, Germany". Earth and Environmental Science Transactions of the Royal Society of Edinburgh. 84 (3–4): 453–464. doi:10.1017/S0263593300006258. ISSN 1755-6910.
  7. ^ a b c Kriwet, Jürgen; Witzmann, Florian; Klug, Stefanie; Heidtke, Ulrich H.J (2008-01-22). "First direct evidence of a vertebrate three-level trophic chain in the fossil record". Proceedings of the Royal Society B: Biological Sciences. 275 (1631): 181–186. doi:10.1098/rspb.2007.1170. ISSN 0962-8452. PMC 2596183. PMID 17971323.
  8. ^ Fischer, Jan; Schneider, Jörg W.; Hodnett, John-Paul M.; Elliott, David K.; Johnson, Gary D.; Voigt, Silke; Joachimski, Michael M.; Tichomirowa, Marion; Götze, Jens (2014-11-02). "Stable and radiogenic isotope analyses on shark teeth from the Early to the Middle Permian (Sakmarian–Roadian) of the southwestern USA". Historical Biology. 26 (6): 710–727. doi:10.1080/08912963.2013.838953. ISSN 0891-2963. S2CID 128991144.
  9. ^ Fischer, Jan; Schneider, Jörg W.; Voigt, Silke; Joachimski, Michael M.; Tichomirowa, Marion; Tütken, Thomas; Götze, Jens; Berner, Ulrich (2013-03-29). "Oxygen and strontium isotopes from fossil shark teeth: Environmental and ecological implications for Late Palaeozoic European basins". Chemical Geology. 342: 44–62. doi:10.1016/j.chemgeo.2013.01.022. ISSN 0009-2541.
  10. ^ Luccisano, Vincent; Cuny, Gilles; Pradel, Alan; Fourel, François; Lécuyer, Christophe; Pouillon, Jean-Marc; Lachat, Kathleen; Amiot, Romain (2023-10-15). "Palaeoenvironmental and palaeoecological reconstructions based on oxygen, carbon and sulfur isotopes of Early Permian shark spines from the French Massif central". Palaeogeography, Palaeoclimatology, Palaeoecology. 628: 111760. doi:10.1016/j.palaeo.2023.111760.
  11. ^ a b c Elliott, David K.; Hodnett, John-Paul M. (November 2013). "A new species of Bransonella (Chondrichthyes, Xenacanthimorpha, Bransonelliformes) from the Middle Permian Kaibab Formation of northern Arizona". Journal of Paleontology. 87 (6): 1136–1142. doi:10.1666/12-099. ISSN 0022-3360.
  12. ^ Luccisano, Vincent; Pradel, Alan; Amiot, Romain; Gand, Georges; Steyer, J.-Sebastien; Cuny, Gilles (2021-03-04). "A new Triodus shark species (Xenacanthidae, Xenacanthiformes) from the lowermost Permian of France and its paleobiogeographic implications". Journal of Vertebrate Paleontology. 41 (2). doi:10.1080/02724634.2021.1926470. ISSN 0272-4634.
  13. ^ Greb, Stephen F.; Storrs, Glenn W.; Garcia, William J.; Eble, Cortland F. (April 2016). "Late Mississippian vertebrate palaeoecology and taphonomy, Buffalo Wallow Formation, western Kentucky, USA". Lethaia. 49 (2): 199–218. doi:10.1111/let.12138. ISSN 0024-1164.
  14. ^ Coates, Michael I.; Gess, Robert W.; Finarelli, John A.; Criswell, Katharine E.; Tietjen, Kristen (January 2017). "A symmoriiform chondrichthyan braincase and the origin of chimaeroid fishes". Nature. 541 (7636): 208–211. doi:10.1038/nature20806. ISSN 0028-0836.
  15. ^ Luccisano, Vincent; Rambert-Natsuaki, Mizuki; Cuny, Gilles; Amiot, Romain; Pouillon, Jean-Marc; Pradel, Alan (2021-12-02). "Phylogenetic implications of the systematic reassessment of Xenacanthiformes and 'Ctenacanthiformes' (Chondrichthyes) neurocrania from the Carboniferous–Permian Autun Basin (France)". Journal of Systematic Palaeontology. 19 (23): 1623–1642. doi:10.1080/14772019.2022.2073279. ISSN 1477-2019.
  16. ^ Frey, Linda; Coates, Michael; Ginter, Michał; Hairapetian, Vachik; Rücklin, Martin; Jerjen, Iwan; Klug, Christian (2019-10-09). "The early elasmobranch Phoebodus : phylogenetic relationships, ecomorphology and a new time-scale for shark evolution". Proceedings of the Royal Society B: Biological Sciences. 286 (1912): 20191336. doi:10.1098/rspb.2019.1336. ISSN 0962-8452. PMC 6790773. S2CID 203619135.
  17. ^ a b Ivanov, A. O.; Kovalenko, E. S.; Murashev, M. M.; Podurets, K. M. (December 2022). "Euselachian Sharks (Elasmobranchii, Chondrichthyes) from the Middle and Late Permian of European Russia". Paleontological Journal. 56 (11): 1372–1384. doi:10.1134/S0031030122110065. ISSN 0031-0301.

Further reading edit

  • Bhat, Mohd Shafi; Ray, Sanghamitra; Datta, P.M. (September 2018). "A new assemblage of freshwater sharks (Chondrichthyes: Elasmobranchii) from the Upper Triassic of India". Geobios. 51 (4): 269–283. doi:10.1016/j.geobios.2018.06.004. S2CID 134435176.
  • Huttenlocker, Adam K.; Henrici, Amy; John Nelson, W.; Elrick, Scott; Berman, David S; Schlotterbeck, Tyler; Sumida, Stuart S. (June 2018). "A multitaxic bonebed near the Carboniferous–Permian boundary (Halgaito Formation, Cutler Group) in Valley of the Gods, Utah, USA: Vertebrate paleontology and taphonomy". Palaeogeography, Palaeoclimatology, Palaeoecology. 499: 72–92. Bibcode:2018PPP...499...72H. doi:10.1016/j.palaeo.2018.03.017. S2CID 135112608.

January 01, 1970
xenacanthida, xenacanthiformes, order, superorder, extinct, shark, like, chondrichthyans, cartilaginous, fish, known, from, carboniferous, triassic, they, were, native, freshwater, marginal, marine, shallow, marine, habitats, some, xenacanths, have, grown, len. Xenacanthida or Xenacanthiformes is an order or superorder of extinct shark like chondrichthyans cartilaginous fish known from the Carboniferous to Triassic They were native to freshwater marginal marine and shallow marine habitats 1 Some xenacanths may have grown to lengths of 5 m 16 ft 2 Most xenacanths died out at the end of the Permian in the End Permian Mass Extinction with only a few forms surviving into the Triassic XenacanthidaTemporal range Mississippian Norian PreꞒ Ꞓ O S D C P T J K Pg N Life restoration of Xenacanthus Fossil of Lebachacanthus senckenbergianus Scientific classification Domain Eukaryota Kingdom Animalia Phylum Chordata Class Chondrichthyes Subclass Elasmobranchii Order XenacanthidaGlikman 1964 Families and genera See textContents 1 Description 2 Ecology 3 Taxonomy 3 1 Subdivisions 4 References 5 Further readingDescription edit nbsp Teeth of Triodus teberdaensis The foundation of the tooth is prolonged lingually with a circlet button and a basal tubercle on the oral and aboral surfaces individually The family Xenacanthidae consists of five genera Xenacanthus Triodus Plicatodus Mooreodontus and Wurdigneria all of these are distinguished by cross sections of the points crown center length of the median edge type of vertical cristae and microscopic anatomy Xenacanths are divided into two groups based on dental characteristics Group one has tricuspid crowns containing two stout slightly diverging lateral cusps pointing in the same direction a high median cusp with a crown base angle almost at 90 degrees a large rounded apical button with several foramina and multiple 8 9 coarse vertical cristae on all the cusps Group two has bicuspid crowns with two upright asymmetric cusps where the medial cusp is thicker than the distal one and consistently lacks a median cusp 3 The bodies of xenacanths are elongate and eel like 4 Xenacanths had long dorsal fins as well as a large spine projecting from the top of the head which was a modified dorsal fin spine 5 The spine is usually thought to have acted as a defense against attackers 2 They also bore two anal fins with the tail caudal fin being pseudo diphycercal 4 They were probably slow swimmers that swam using side to side undulations of the body anguilliform locomotion 6 Some xenacanths like Barbclabornia are thought to have reached lengths of 4 5 5 metres 15 16 ft 2 While others such as Triodus were only around 0 5 metres 1 6 ft long 7 Ecology editMany xenacanths are thought to have been euryhaline and to have migrated between freshwater and marine environments Orthacanthus platypternus from the Early Permian of North America is suggested to have been catadromous migrating into freshwater environments as a juvenile before returning to the sea as an adult 2 Based on isotope analysis of teeth some xenacanths have been suggested to have lived permanently in freshwater environments 8 9 However this proposal has been criticised by some authors as the mineralization window of individual teeth only spans a short interval of time of days to weeks and may not be reflective of long term behaviour 2 However isotopic analysis of fin spines of Orthacanthus and Triodus from the Early Permian of France suggests that at least for these species growth exclusively occurred in freshwater environments 10 Fossil egg cases assigned to the genus Fayolia which were probably produced by xenacanths have a helically twisted collarette running around them similar to the eggs of bullhead sharks and taper towards both ends with one end having a tendril These eggs are typically found in freshwater deposits 6 A number of xenacanths are likely to have been fully marine such as the small primitive genus Bransonella which is thought to have had a seafloor dwelling benthic ecology similar to that of a modern catshark 11 Xenacanths are thought to have been ambush predators 12 The diet of freshwater xenacanths is known to have included temnospondyl amphibians 7 as well as palaeoniscid fish 13 acanthodians and other xenacanths 11 Large xenacanths are suggested to have acted as the apex predators of late Paleozoic freshwater ecosystems such as the Early Permian freshwater lakes of the Saar Nahe Basin in southern Germany 7 11 Taxonomy editXenacanths are typically placed as stem group elasmobranchs more closely related to modern sharks and rays than to Holocephali which includes chimaeras 14 15 16 Subdivisions edit Order Bransonelliformes Hampe amp Ivanov 2007 Genus Barbclabornia Johnson 2003 Early Permian possibly also Late Carboniferous North America Genus Bransonella Harlton 1933 Early Carboniferous Middle Permian Worldwide Order Xenacanthiformes Berg 1955 Family Diplodoselachidae Dick 1981 Genus Dicentrodus Traquair 1888 Early Carboniferous Europe North America Genus Diplodoselache Dick 1981 Early Carboniferous Europe Genus Hagenoselache Hampe amp Heidkte 1997 mid Carboniferous Europe Genus Hokomata Hodnett amp Elliott 2018 mid Carboniferous North America Genus Lebachacanthus Soler Gijon 1997 Late Carboniferous Early Permian Europe Genus Reginaselache Turner amp Burrow 2011 Early Carboniferous Australia Family Sphenacanthidae Maisey 1982 Genus Sphenacanthus Agassiz 1837 Early Carboniferous Late Permian Worldwide Genus Xenosynechodus Agassiz 1980 Middle Late Permian Europe later authors have rejected its placement as a xenacanth 17 Genus Desinia Ivanov 2022 17 Middle Late Permian Europe Family Orthacanthidae Heyler amp Poplin 1990 5 Genus Orthacanthus Agassiz 1843 Late Carboniferous Early Permian Europe North America 5 Family Xenacanthidae Fritsch 1889 Genus Mooreodontus Ginter et al 2010 Middle Late Triassic Worldwide Genus Plicatodus Hampe 1995 Late Carboniferous Early Permian Europe Genus Triodus Jordan 1849 Late Carboniferous Middle Permian Europe North America South America 1 Genus Xenacanthus Beyrich 1848 Carboniferous Permian Worldwide Genus Wurdigneria Richter 2005 Middle Late Permian South America incertae sedis Genus Tikiodontus Bhat Ray amp Datta 2018 Late Triassic India References edit a b Pauliv Victor E Martinelli Agustin G Francischini Heitor Dentzien Dias Paula Soares Marina B Schultz Cesar L Ribeiro Ana M December 2017 The first Western Gondwanan species of Triodus Jordan 1849 A new Xenacanthiformes Chondrichthyes from the late Paleozoic of Southern Brazil Journal of South American Earth Sciences 80 482 493 doi 10 1016 j jsames 2017 09 007 a b c d e Beck Kimberley G oler Gijon Rodrigo Carlucci Jesse R Willis Ray E December 2014 Morphology and Histology of Dorsal Spines of the Xenacanthid Shark Orthacanthus platypternus from the Lower Permian of Texas USA Palaeobiological and Palaeoenvironmental Implications Acta Palaeontologica Polonica 61 1 97 117 doi 10 4202 app 00126 2014 Bhat M S Ray S amp Datta P 2018 A new assemblage of freshwater sharks Chondrichthyes Elasmobranchii from the Upper Triassic of India Geobios 51 4 269 283 doi 10 1016 j geobios 2018 06 004 a b Soler Gijon Rodrigo Ruiz Antonio Diez 2023 06 20 Carbonifero de Puertollano Natural Monument Puertollano basin Spain a window for the knowledge of Early Vertebrates Spanish Journal of Palaeontology 38 1 81 94 doi 10 7203 sjp 26788 ISSN 2660 9568 a b c Babcock L E 2024 Replacement names for two species of Orthacanthus Agassiz 1843 Chondrichthyes Xenacanthiformes and discussion of Giebelodus Whitley 1940 replacement name for Chilodus Giebel 1848 Chondrichthyes Xenacanthiformes preoccupied by Chilodus Muller amp Troschel 1844 Actinopterygii Characiformes ZooKeys 1188 219 226 a b Schneider J 1993 Environment biotas and taphonomy of the Lower Permian lacustrine Niederhaslich limestone Dohlen basin Germany Earth and Environmental Science Transactions of the Royal Society of Edinburgh 84 3 4 453 464 doi 10 1017 S0263593300006258 ISSN 1755 6910 a b c Kriwet Jurgen Witzmann Florian Klug Stefanie Heidtke Ulrich H J 2008 01 22 First direct evidence of a vertebrate three level trophic chain in the fossil record Proceedings of the Royal Society B Biological Sciences 275 1631 181 186 doi 10 1098 rspb 2007 1170 ISSN 0962 8452 PMC 2596183 PMID 17971323 Fischer Jan Schneider Jorg W Hodnett John Paul M Elliott David K Johnson Gary D Voigt Silke Joachimski Michael M Tichomirowa Marion Gotze Jens 2014 11 02 Stable and radiogenic isotope analyses on shark teeth from the Early to the Middle Permian Sakmarian Roadian of the southwestern USA Historical Biology 26 6 710 727 doi 10 1080 08912963 2013 838953 ISSN 0891 2963 S2CID 128991144 Fischer Jan Schneider Jorg W Voigt Silke Joachimski Michael M Tichomirowa Marion Tutken Thomas Gotze Jens Berner Ulrich 2013 03 29 Oxygen and strontium isotopes from fossil shark teeth Environmental and ecological implications for Late Palaeozoic European basins Chemical Geology 342 44 62 doi 10 1016 j chemgeo 2013 01 022 ISSN 0009 2541 Luccisano Vincent Cuny Gilles Pradel Alan Fourel Francois Lecuyer Christophe Pouillon Jean Marc Lachat Kathleen Amiot Romain 2023 10 15 Palaeoenvironmental and palaeoecological reconstructions based on oxygen carbon and sulfur isotopes of Early Permian shark spines from the French Massif central Palaeogeography Palaeoclimatology Palaeoecology 628 111760 doi 10 1016 j palaeo 2023 111760 a b c Elliott David K Hodnett John Paul M November 2013 A new species of Bransonella Chondrichthyes Xenacanthimorpha Bransonelliformes from the Middle Permian Kaibab Formation of northern Arizona Journal of Paleontology 87 6 1136 1142 doi 10 1666 12 099 ISSN 0022 3360 Luccisano Vincent Pradel Alan Amiot Romain Gand Georges Steyer J Sebastien Cuny Gilles 2021 03 04 A new Triodus shark species Xenacanthidae Xenacanthiformes from the lowermost Permian of France and its paleobiogeographic implications Journal of Vertebrate Paleontology 41 2 doi 10 1080 02724634 2021 1926470 ISSN 0272 4634 Greb Stephen F Storrs Glenn W Garcia William J Eble Cortland F April 2016 Late Mississippian vertebrate palaeoecology and taphonomy Buffalo Wallow Formation western Kentucky USA Lethaia 49 2 199 218 doi 10 1111 let 12138 ISSN 0024 1164 Coates Michael I Gess Robert W Finarelli John A Criswell Katharine E Tietjen Kristen January 2017 A symmoriiform chondrichthyan braincase and the origin of chimaeroid fishes Nature 541 7636 208 211 doi 10 1038 nature20806 ISSN 0028 0836 Luccisano Vincent Rambert Natsuaki Mizuki Cuny Gilles Amiot Romain Pouillon Jean Marc Pradel Alan 2021 12 02 Phylogenetic implications of the systematic reassessment of Xenacanthiformes and Ctenacanthiformes Chondrichthyes neurocrania from the Carboniferous Permian Autun Basin France Journal of Systematic Palaeontology 19 23 1623 1642 doi 10 1080 14772019 2022 2073279 ISSN 1477 2019 Frey Linda Coates Michael Ginter Michal Hairapetian Vachik Rucklin Martin Jerjen Iwan Klug Christian 2019 10 09 The early elasmobranch Phoebodus phylogenetic relationships ecomorphology and a new time scale for shark evolution Proceedings of the Royal Society B Biological Sciences 286 1912 20191336 doi 10 1098 rspb 2019 1336 ISSN 0962 8452 PMC 6790773 S2CID 203619135 a b Ivanov A O Kovalenko E S Murashev M M Podurets K M December 2022 Euselachian Sharks Elasmobranchii Chondrichthyes from the Middle and Late Permian of European Russia Paleontological Journal 56 11 1372 1384 doi 10 1134 S0031030122110065 ISSN 0031 0301 Further reading editBhat Mohd Shafi Ray Sanghamitra Datta P M September 2018 A new assemblage of freshwater sharks Chondrichthyes Elasmobranchii from the Upper Triassic of India Geobios 51 4 269 283 doi 10 1016 j geobios 2018 06 004 S2CID 134435176 Huttenlocker Adam K Henrici Amy John Nelson W Elrick Scott Berman David S Schlotterbeck Tyler Sumida Stuart S June 2018 A multitaxic bonebed near the Carboniferous Permian boundary Halgaito Formation Cutler Group in Valley of the Gods Utah USA Vertebrate paleontology and taphonomy Palaeogeography Palaeoclimatology Palaeoecology 499 72 92 Bibcode 2018PPP 499 72H doi 10 1016 j palaeo 2018 03 017 S2CID 135112608 Retrieved from https en wikipedia org w index php title Xenacanthida amp oldid 1220244643, wikipedia, wiki, book, books, library,

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