Menu
Home
People
Places
Arts
History
Plants & Animals
Science
Life & Culture
Technology
Reference.org
Ptychodus
open-in-new
<h2 id="discovery">Discovery</h2> <p>Due to a global distribution <i>Ptychodus</i> is well represented in the fossil record; many fossils have been uncovered such as isolated teeth, fragments of dentition, calcified vertebral centra, denticles, and associated fragments of calcified cartilage.<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a> The very first remains of <i>Ptychodus</i> were found in England and Germany in the first half of the 18th century.<a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a><a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a> <i>Ptychodus</i> teeth have long been identified as palates of diodon, or porcupinefish (Osteichthyes, Diodontidae), well-known for their ability to inflate their bodies in defense. At the beginning of the 19th century, several authors including Swiss paleontologist Louis Agassiz eventually demonstrated the affinities of <i>Ptychodus</i> teeth with those of elasmobranchs (rays and sharks). The first discovery of <i>Ptychodus</i> teeth in Kansas came in 1868 when Leidy reported and described a damaged tooth near Fort Hays, Kansas.<a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a><a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a> After, many more teeth were uncovered in almost perfect conditions and other species within the genus were identified.<a class="footnote-ref" id="fnref:12" href="#fn:12"><sup>12</sup></a> </p><p>Fossils of species within this genus have been found in the marine strata of United States, Brazil, Canada, the Czech Republic, France, Germany, India, Israel, Japan, Jordan, Mexico, Sweden, and the United Kingdom.<a class="footnote-ref" id="fnref:13" href="#fn:13"><sup>13</sup></a> The fact that so many fossils of <i>Ptychodus</i> have been found in different regions of the world provides evidence of a distribution of species during the Albian-Turonian time.<a class="footnote-ref" id="fnref:14" href="#fn:14"><sup>14</sup></a> </p><p>The generic name <i>Ptychodus</i> comes from the Greek words <i>ptychos</i> (fold/layer) and <i>odon</i> (tooth), so "fold teeth" describing the shape of their crushing and grinding teeth.<a class="footnote-ref" id="fnref:15" href="#fn:15"><sup>15</sup></a> </p> <h2 id="taxonomy">Taxonomy</h2> <p>While the affinity of <i>Ptychodus</i> as some kind of <a href="/facts/Cartilaginous_fish/xcW7PJDU">cartilaginous fish</a> has long been accepted, the exact position in the group was long uncertain. A 2016 publication found that <i>Ptychodus</i> are likely true sharks belonging to <a href="/facts/Shark/gnS0bGPW">Selachimorpha</a>, rather than <a href="/facts/Hybodonts/3u2ESMbm">hybodonts</a> or <a href="/facts/Batoidea/4w6wfqlh">batoids</a> as previously thought.<a class="footnote-ref" id="fnref:16" href="#fn:16"><sup>16</sup></a><a class="footnote-ref" id="fnref:17" href="#fn:17"><sup>17</sup></a> A 2024 study of a complete skeleton concluded that they belong to the <a href="/facts/Lamniformes/VFrPGhlJ">Lamniformes</a> (mackerel sharks).<a class="footnote-ref" id="fnref:18" href="#fn:18"><sup>18</sup></a> </p> <h2 id="description">Description</h2> <h3>Size</h3> <p><i>Ptychodus</i> was a large shark, previously estimated at 10 meters (33 feet) long based on extrapolation from teeth.<a class="footnote-ref" id="fnref:19" href="#fn:19"><sup>19</sup></a><a class="footnote-ref" id="fnref:20" href="#fn:20"><sup>20</sup></a> The subadult specimen with the largest vertebra showed that it could reach lengths of 4.3–7.07 m (14.1–23.2 ft), so a 10 m (33 ft) length is possible, but more analysis is required for verification.<a class="footnote-ref" id="fnref:21" href="#fn:21"><sup>21</sup></a> </p> <h3>Dentition</h3> <p>Unlike the colossal nektonic planktivores <i><a href="/facts/Rhincodon/JNKjpvJf">Rhincodon</a></i> (whale sharks) and <i><a href="/facts/Cetorhinus/uz7bSmVR">Cetorhinus</a></i> (basking sharks) which relied upon gill rakers to acquire their food, the <i>Ptychodus</i> had a massive arrangement of crushing plate teeth. A <i>Ptychodus</i> jaw contains many teeth, up to 550 teeth, 220 of which are on the lower jaw and 260 in the upper jaw. These teeth were very large as well—Paleontologists believe that the largest tooth plate measured 55 centimeters in length and 45 centimeters in width. There are two distinct formations of tooth plates between the genus; one being juxtaposed, non-overlapping tooth rows, and another being imbricated tooth rows.<a class="footnote-ref" id="fnref:22" href="#fn:22"><sup>22</sup></a> </p> <p>It is believed that the shape coincides with the diet of the species and their geographic locations, but the time it lived has a big part as well. <i>Ptychodus marginalis</i> teeth differ from <i>Ptychodus polygyrus</i>. <i>P marginalis</i> was in the Middle Cenomanian to Middle Turonian deposits in the English Chalk, while <i>P. polygyrus</i> was in the Late Santonian-Early Campanian deposits.<a class="footnote-ref" id="fnref:23" href="#fn:23"><sup>23</sup></a> </p> <h3>Body</h3> <p>The only known complete body remains are from the <a href="/facts/Agua_Nueva_Formation/0yVd7kYY">Agua Nueva Formation</a> in Mexico, which suggest that <i>Ptychodus</i> had a <a href="/facts/Fusiform/SwpG126w">fusiform</a> body, with a large and elongate head, the primarily dorsal fin was large and placed forward on the body while the second posterior dorsal fin was much smaller, with a small anal fin being present. The overall body form closely resembles that of the <a href="/facts/Great_white_shark/9uLc7Adh">great white shark</a> and <i><a href="/facts/Lamna/MfWLd9tl">Lamna</a></i> (which includes the <a href="/facts/Porbeagle/7pP6po7B">porbeagle</a> and <a href="/facts/Salmon_shark/rus5pcTo">salmon shark</a>).<a class="footnote-ref" id="fnref:24" href="#fn:24"><sup>24</sup></a> </p> <h2 id="paleobiology">Paleobiology</h2> <p>Based on analysis of vertebrae from Spain, it is suggested that species of <i>Ptychodus</i> lived relatively long lives and were slow growing and produced large offspring and small litters.<a class="footnote-ref" id="fnref:25" href="#fn:25"><sup>25</sup></a> </p> <h3>Diet</h3> <p><i>Ptychodus</i> is thought to have been <a href="/facts/Durophagous/hcWxSxJv">durophagous</a>, using its low rounded teeth to crush hard-shelled organisms.<a class="footnote-ref" id="fnref:26" href="#fn:26"><sup>26</sup></a> Many authors have suggested that <i>Ptychodus</i> fed on bottom dwelling (<a href="/facts/Benthic_zone/N3lM6P7I">benthic</a>) prey like <a href="/facts/Bivalvia/IQDxHVc8">bivalves</a> (particularly <a href="/facts/Inoceramidae/1AykFBt2">inoceramids</a>) and <a href="/facts/Crustacean/PBobIVJP">crustaceans</a>, while also consuming some hard bodied organisms that lived in open water (<a href="/facts/Pelagic_zone/D6heJr5f">pelagic</a>). A 2024 study suggested that based on its body morphology, the species likely primarily consumed pelagic hard prey, like <a href="/facts/Ammonites/cRCH9GVd">ammonites</a> and <a href="/facts/Marine_turtles/74lTgK3I">marine turtles</a>, rather than benthic prey.<a class="footnote-ref" id="fnref:27" href="#fn:27"><sup>27</sup></a> </p> <ul><li>Williston, Samuel (1900) <i>University Geological Survey of Kansas, Volume VI: Paleontology part II, (Carboniferous invertebrates and Cretaceous fish)</i></li></ul> <h2 id="external-links">External links</h2> <ul> <li>Sharks portal</li><li>Palaeontology portal</li></ul> <ul><li> Media related to Ptychodus at Wikimedia Commons</li> <li><a href="http://news.bbc.co.uk/earth/hi/earth_news/newsid_8530000/8530995.stm">BBC page on <i>Ptychodus mortoni</i>: "Giant predatory shark fossil unearthed in Kansas"</a></li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>Roberts, George (1839). An etymological and explanatory dictionary of the terms and language of geology. London: Longman, Orme, Brown, Green, & Longmans. p. 144. Retrieved 31 December 2021. <a href="https://archive.org/details/anetymologicala00robegoog" target="_blank">https://archive.org/details/anetymologicala00robegoog</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>Vullo, Romain; Villalobos-Segura, Eduardo; Amadori, Manuel; Kriwet, Jürgen; Frey, Eberhard; González González, Margarito A.; Padilla Gutiérrez, José M.; Ifrim, Christina; Stinnesbeck, Eva S.; Stinnesbeck, Wolfgang (2024-04-30). "Exceptionally preserved shark fossils from Mexico elucidate the long-standing enigma of the Cretaceous elasmobranch Ptychodus". Proceedings of the Royal Society B: Biological Sciences. 291 (2021). doi:10.1098/rspb.2024.0262. ISSN 0962-8452. PMC 11040243. <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2024.0262" target="_blank">https://royalsocietypublishing.org/doi/10.1098/rspb.2024.0262</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>The paleobioloy Database Ptychodus entry accessed on 8/23/09 <a href="https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=34513" target="_blank">https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=34513</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>Vullo, Romain; Villalobos-Segura, Eduardo; Amadori, Manuel; Kriwet, Jürgen; Frey, Eberhard; González González, Margarito A.; Padilla Gutiérrez, José M.; Ifrim, Christina; Stinnesbeck, Eva S.; Stinnesbeck, Wolfgang (2024-04-30). "Exceptionally preserved shark fossils from Mexico elucidate the long-standing enigma of the Cretaceous elasmobranch Ptychodus". Proceedings of the Royal Society B: Biological Sciences. 291 (2021). doi:10.1098/rspb.2024.0262. ISSN 0962-8452. PMC 11040243. <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2024.0262" target="_blank">https://royalsocietypublishing.org/doi/10.1098/rspb.2024.0262</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>Everhart, Mike. "Ptychodus mortoni". Ocean of Kansas. <a href="http://oceansofkansas.com/ptychodus.html" target="_blank">http://oceansofkansas.com/ptychodus.html</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> <li id="fn:6"><p>"THE VERTEBRATE FAUNA OF THE SELMA FORMATION OF ALABAMA" (PDF). 3 (7). 1970. {{cite journal}}: Cite journal requires |journal= (help) <a href="https://libsysdigi.library.uiuc.edu/OCA/Books2008-08/vertebratefaunao38appl/vertebratefaunao38appl.pdf" target="_blank">https://libsysdigi.library.uiuc.edu/OCA/Books2008-08/vertebratefaunao38appl/vertebratefaunao38appl.pdf</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li> <li id="fn:7"><p>Verma, Omkar; et al. (February 1, 2012). "Ptychodus decurrens Agassiz (Elasmobranchii: Ptychodontidae) from the Upper Cretaceous of India". Cretaceous Research. 33 (1): 183–188. Bibcode:2012CrRes..33..183V. doi:10.1016/j.cretres.2011.09.014. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li> <li id="fn:8"><p>Brignon, A., 2015, Senior synonyms of Ptychodus latissimus Agassiz, 1835 and Ptychodus mammillaris Agassiz, 1835 (Elasmobranchii) based on teeth from the Bohemian Cretaceous Basin (the Czech Republic). Acta Musei Nationalis Pragae, Series B – Historia Naturalis, 71(1–2): 5–14 <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li> <li id="fn:9"><p>Brignon, A., 2019, Le diodon devenu requin : l'histoire des premières découvertes du genre Ptychodus (Chondrichthyes) [The porcupinefish that became a shark: History of the early discoveries of the genus Ptychodus (Chondrichthyes)]. Published by the author, Bourg-la-Reine, France, 100 pp., ISBN : 978-2-9565479-2-1 (printed), 978-2-9565479-3-8 (ebook) <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li> <li id="fn:10"><p>Everhard, Mike. "Ptychodontid Sharks: Late Cretaceous Shell Crushers". Ocean of Kansas. <a href="http://oceansofkansas.com/ptychodus2.html" target="_blank">http://oceansofkansas.com/ptychodus2.html</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li> <li id="fn:11"><p>Everhart, Michael; Caggiano, Tom (2004). "An associated dentition and calcified vertebral centra of the Late Cretaceous elasmobranch, Ptychodus anonymus Williston 1900". Paludicola. 4 (4): 125–136. <a href="#fnref:11" class="footnote-back-ref">↩</a></p></li> <li id="fn:12"><p>Everhart, Michael; Caggiano, Tom (2004). "An associated dentition and calcified vertebral centra of the Late Cretaceous elasmobranch, Ptychodus anonymus Williston 1900". Paludicola. 4 (4): 125–136. <a href="#fnref:12" class="footnote-back-ref">↩</a></p></li> <li id="fn:13"><p>The paleobioloy Database Ptychodus entry accessed on 8/23/09 <a href="https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=34513" target="_blank">https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=34513</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></p></li> <li id="fn:14"><p>Verma, Omkar; et al. (February 1, 2012). "Ptychodus decurrens Agassiz (Elasmobranchii: Ptychodontidae) from the Upper Cretaceous of India". Cretaceous Research. 33 (1): 183–188. Bibcode:2012CrRes..33..183V. doi:10.1016/j.cretres.2011.09.014. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:14" class="footnote-back-ref">↩</a></p></li> <li id="fn:15"><p>David, Michelle A historical and mechanical description of Ptychodus (Chondrichthyes) dententions with notes on the distribution and systematics of the genus <a href="http://contentcat.fhsu.edu/cdm/ref/collection/thesis/id/756" target="_blank">http://contentcat.fhsu.edu/cdm/ref/collection/thesis/id/756</a> <a href="#fnref:15" class="footnote-back-ref">↩</a></p></li> <li id="fn:16"><p>Everhart, Michael; Caggiano, Tom (2004). "An associated dentition and calcified vertebral centra of the Late Cretaceous elasmobranch, Ptychodus anonymus Williston 1900". Paludicola. 4 (4): 125–136. <a href="#fnref:16" class="footnote-back-ref">↩</a></p></li> <li id="fn:17"><p>Hoffman, Brian L.; Hageman, Scott A.; Claycomb, Gregory D. (July 2016). "Scanning electron microscope examination of the dental enameloid of the Cretaceous durophagous shark Ptychodus supports neoselachian classification". Journal of Paleontology. 90 (4): 741–762. Bibcode:2016JPal...90..741H. doi:10.1017/jpa.2016.64. S2CID 132252846. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:17" class="footnote-back-ref">↩</a></p></li> <li id="fn:18"><p>Vullo, Romain; Villalobos-Segura, Eduardo; Amadori, Manuel; Kriwet, Jürgen; Frey, Eberhard; González González, Margarito A.; Padilla Gutiérrez, José M.; Ifrim, Christina; Stinnesbeck, Eva S.; Stinnesbeck, Wolfgang (2024-04-30). "Exceptionally preserved shark fossils from Mexico elucidate the long-standing enigma of the Cretaceous elasmobranch Ptychodus". Proceedings of the Royal Society B: Biological Sciences. 291 (2021). doi:10.1098/rspb.2024.0262. ISSN 0962-8452. PMC 11040243. <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2024.0262" target="_blank">https://royalsocietypublishing.org/doi/10.1098/rspb.2024.0262</a> <a href="#fnref:18" class="footnote-back-ref">↩</a></p></li> <li id="fn:19"><p>Shimada, K., Rigsby, C. K., & Kim, S. H. (2009). Partial skull of Late Cretaceous durophagous shark, Ptychodus occidentalis (Elasmobranchii: Ptychodontidae), from Nebraska, U.S.A.. Journal of Vertebrate Paleontology, 29(2), 336–349. https://doi.org/10.1671/039.029.0226 <a href="https://doi.org/10.1671/039.029.0226" target="_blank">https://doi.org/10.1671/039.029.0226</a> <a href="#fnref:19" class="footnote-back-ref">↩</a></p></li> <li id="fn:20"><p>Shimada, K., Everhart, M. J., Decker, R., & Decker, P. D. (2010). A new skeletal remain of the durophagous shark, Ptychodus mortoni, from the Upper Cretaceous of North America: an indication of gigantic body size. Cretaceous Research, 31(2), 249–254. https://doi.org/10.1016/j.cretres.2009.11.005 <a href="https://doi.org/10.1016/j.cretres.2009.11.005" target="_blank">https://doi.org/10.1016/j.cretres.2009.11.005</a> <a href="#fnref:20" class="footnote-back-ref">↩</a></p></li> <li id="fn:21"><p>Jambura, Patrick L.; Kriwet, Jürgen (2020-04-22). "Articulated remains of the extinct shark Ptychodus (Elasmobranchii, Ptychodontidae) from the Upper Cretaceous of Spain provide insights into gigantism, growth rate and life history of ptychodontid sharks". PLOS ONE. 15 (4): e0231544. Bibcode:2020PLoSO..1531544J. doi:10.1371/journal.pone.0231544. ISSN 1932-6203. PMC 7176087. PMID 32320430. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7176087" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7176087</a> <a href="#fnref:21" class="footnote-back-ref">↩</a></p></li> <li id="fn:22"><p>Shimada, Kenshu (October 31, 2012). "Dentition of Late Cretaceous shark, Ptychodus mortoni (Elasmobranchii, Ptychodontidae)". Journal of Vertebrate Paleontology. 32 (6): 1271–1284. Bibcode:2012JVPal..32.1271S. doi:10.1080/02724634.2012.707997. S2CID 85133916. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:22" class="footnote-back-ref">↩</a></p></li> <li id="fn:23"><p>Hamm, Shawn (May 2010). "The Late Cretaceous shark Ptychodus marginalis in the Western Interior Seaway, USA". Journal of Paleontology. 84 (3): 538–548. Bibcode:2010JPal...84..538H. doi:10.1666/09-154.1. S2CID 130948112. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:23" class="footnote-back-ref">↩</a></p></li> <li id="fn:24"><p>Vullo, Romain; Villalobos-Segura, Eduardo; Amadori, Manuel; Kriwet, Jürgen; Frey, Eberhard; González González, Margarito A.; Padilla Gutiérrez, José M.; Ifrim, Christina; Stinnesbeck, Eva S.; Stinnesbeck, Wolfgang (2024-04-30). "Exceptionally preserved shark fossils from Mexico elucidate the long-standing enigma of the Cretaceous elasmobranch Ptychodus". Proceedings of the Royal Society B: Biological Sciences. 291 (2021). doi:10.1098/rspb.2024.0262. ISSN 0962-8452. PMC 11040243. <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2024.0262" target="_blank">https://royalsocietypublishing.org/doi/10.1098/rspb.2024.0262</a> <a href="#fnref:24" class="footnote-back-ref">↩</a></p></li> <li id="fn:25"><p>Jambura, Patrick L.; Kriwet, Jürgen (2020-04-22). "Articulated remains of the extinct shark Ptychodus (Elasmobranchii, Ptychodontidae) from the Upper Cretaceous of Spain provide insights into gigantism, growth rate and life history of ptychodontid sharks". PLOS ONE. 15 (4): e0231544. Bibcode:2020PLoSO..1531544J. doi:10.1371/journal.pone.0231544. ISSN 1932-6203. PMC 7176087. PMID 32320430. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7176087" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7176087</a> <a href="#fnref:25" class="footnote-back-ref">↩</a></p></li> <li id="fn:26"><p>Verma, Omkar; et al. (February 1, 2012). "Ptychodus decurrens Agassiz (Elasmobranchii: Ptychodontidae) from the Upper Cretaceous of India". Cretaceous Research. 33 (1): 183–188. Bibcode:2012CrRes..33..183V. doi:10.1016/j.cretres.2011.09.014. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:26" class="footnote-back-ref">↩</a></p></li> <li id="fn:27"><p>Vullo, Romain; Villalobos-Segura, Eduardo; Amadori, Manuel; Kriwet, Jürgen; Frey, Eberhard; González González, Margarito A.; Padilla Gutiérrez, José M.; Ifrim, Christina; Stinnesbeck, Eva S.; Stinnesbeck, Wolfgang (2024-04-30). "Exceptionally preserved shark fossils from Mexico elucidate the long-standing enigma of the Cretaceous elasmobranch Ptychodus". Proceedings of the Royal Society B: Biological Sciences. 291 (2021). doi:10.1098/rspb.2024.0262. ISSN 0962-8452. PMC 11040243. <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2024.0262" target="_blank">https://royalsocietypublishing.org/doi/10.1098/rspb.2024.0262</a> <a href="#fnref:27" class="footnote-back-ref">↩</a></p></li> </ol>