Johnson, G.D. (2018)
Orthacanthus platypternus (Cope, 1883) (Chondrichthyes: Xenacanthiformes) teeth and other isolated vertebrate remains from a single horizon in the early Permian (Artinskian) Craddock Bonebed, lower Clear Fork Group, Baylor County, Texas, USA. Acta Geologica Polonica, 68(3), 421–436
DOI: 10.1515/agp-2018-0025
Fischer, J. & Schneider, J.W. & Hodnett, J.-P.M. & Elliott, D.K. & Johnson, G.D. & Voigt, S. & Joachimski, M.M. & Tichomirowa, M. & Götze, J. (2014)
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
Johnson, G.D. (2013)
Xenacanth Sharks and other Vertebrates from the Geraldine Bonebed, Lower Permian of Texas. New Mexico Museum of Natural History and Science, Bulletin, 60, 161–167
Johnson, G.D. (2012)
Sharks from the geraldine bonebed, lower permian of Texas [Abstract]. Journal of Vertebrate Paleontology, 32(Suppl. 1), 118
DOI: 10.1080/02724634.2012.10635175
Johnson, G.D. (2012)
Possible origin of the xenacanth sharks Orthacanthus texensis and Orthacanthus platypternus in the Lower Permian of Texas, USA. Historical Biology, 24(4), 369–379
DOI: 10.1080/08912963.2012.669128
Johnson, G.D. & Thayer, D.W. (2009)
Early Pennsylvanian xenacanth chondrichthyans from the Swisshelm Mountains, Arizona, U.S.A. Acta Palaeontologica Polonica, 54(4), 649–668
DOI: 10.4202/app.2008.0051
Johnson, G.D. (2008)
Ctenacanthiform Cladodont Teeth from the Lower PermianWichita Group, Texas, U.S.A. Acta Geologica Polonica, 58(2), 205–209
Hampe, O. & Johnson, G.D. & Turner, S. (2006)
Dicentrodus (Chondrichthyes: Xenacanthida) from the Early Carboniferous (Visean: upper St Louis Formation) of Iowa, USA. Geological Magazine, 143(4), 545–549
DOI: 10.1017/S0016756806002093
Johnson, G.D. (2006)
Iniopterygian tooth whorls from the Lower Permian of Texas, U.S.A. In Yang, Q., Wang, Y., and Weldon, E. A. (Eds.), Ancient Life and Modern Approaches––Abstracts of the Second International Paleontological Congress. University of Science and Technology of China Press: 143–144
Stiernagle, W. & Johnson, G.D. (2006)
Evidence For Enameloid In Xenacanthid Shark Teeth [Abstract]. Proceedings of the South Dakota Academy of Science, 85, 295
Johnson, G.D. (2005)
Underdeveloped and unusual xenacanth shark teeth from the Lower Permian of Texas. Proceedings of the South Dakota Academy of Science, 84, 215– 223
Johnson, G.D. (2005)
An unusual tricuspid chondrichthyan tooth from the Lower Permian of Texas, USA. Revista Brasileira de Paleontologia, 8(2), 159–164
Johnson, G.D. (2003)
Dentitions of Barbclabornia (new genus, Chondrichthyes: Xenacanthiformes) from the upper Palaeozoic of North America. Mitteilungen aus dem Museum für Naturkunde in Berlin, Geowissenschaftliche Reihe, 6, 125–160
DOI: 10.1002/mmng.20030060106
Zidek, J. & Johnson, G.D. & May, W. & Claborn, A. (2003)
New specimens of xenacanth and hybodont sharks (Elasmobranchii: Xenacanthida and Hybodontoidea) from the Lower Permian of southwestern Oklahoma. Oklahoma Geology Notes, 63(4), 136–147
Johnson, G.D. (1999)
Dentitions of late Palaeozoic Orthacanthus species and new species of ?Xenacanthus (Chondrichthyes: Xenacanthiformes) from North America. Acta Geologica Polonica, 49(3), 215–266
Johnson, G.D. (1996)
Vertebrate Microfossils from the Lueders Formation, Albany Group, and the faunal transition from the Wichita Group into the Clear Fork Group, Lower Permian of Texas. Modern Geology, 20, 371–382
Johnson, G.D. (1992)
Chondrichthyan biostratigraphy of the North American Permian System. In Nairn, A. E. M.,and Koroteev, V. (Eds.), Contributions to Eurasian Geology. Papers Presented at the International Congress on the Permian System of the World, Perm, Russia, 1991––Part 1. Occasional Publications ESRI, New Series, 8B: 41–50.
Johnson, G.D. (1987)
Deformed xenacanthodiid shark teeth from the Permian of Texas. In Martin, J. E., and Ostrander, G. E. (Eds.), Papers in Vertebrate Paleontology Honoring Morton Green. Dakoterra, 3: 22–27
Murry, P.A. & Johnson, G.D. (1987)
Clear Fork vertebrates and environments from the lower Permian of North-Central Texas. The Texas Journal of Science, 39(3): 253–266
Johnson, G.D. (1984)
A new species of Xenacanthodii (Chondrichthyes, Elasmobranchii) from the Late Pennsylvanian of Nebraska. In Mengel, R. M.(ed.), Papers in Vertebrate Paleontology Honoring Robert Warren Wilson. Special Publication of Carnegie Museum of Natural History, 9, p. 178–186. Pittsburgh.
Johnson, G.D. (1981)
Hybodontoidei (Chondrichthyes) from the Wichita-Albany Group (Early Permian) of Texas. Journal of Vertebrate Paleontology, 1(1), 1–41
DOI: 10.1080/02724634.1981.10011876
Johnson, G.D. (1980)
Xenacanthodii (Chondrichthyes) from the Tecovas Formation (Late Triassic) of west Texas. Journal of Paleontology, 54(5), 923–932
Johnson, G.D. (1979)
Early Permian vertebrates from Texas: Actinopterygii (Schaefferichthys), Chondrichthyes (including North American Pennsylvanian and Triassic Xenacanthodii, and Acanthodii). Unpubl. Ph.D. thesis, 653 pp. Southern Methodist Univ., Dallas, Texas.