Ptychodus (from Greek: πτυχήptyche 'fold' and Greek: ὀδούςodoús 'tooth')[1] is a genus of extinct durophagous (shell-crushing) sharks from the Late Cretaceous.[2][3] Fossils of Ptychodus teeth are found in many Late Cretaceous marine sediments.[3] There are many species among the Ptychodus that have been uncovered on all the continents around the globe.[3] Such species are Ptychodus mortoni, P. decurrens, P. marginalis, P. mammillaris, P. rugosus and P. latissimus to name a few. They died out approximately 85 million years ago. A large number of remains have been found in the former Western Interior Seaway.[2] A 2016 publication found that Ptychodus are likely true sharks belonging to Selachimorpha, rather than hybodonts or batoids as previously thought.[4][5] Their life history coincides with the typical life of many other large sharks: they lived relatively long lives and were slow growing and produced large offspring and small litters.[6]
Due to a global distribution Ptychodus 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.[7] The very first remains of Ptychodus were found in England and Germany in the first half of the 18th century. [8][9]Ptychodus 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 Ptychodus teeth with those of elasmobranchs (rays and sharks). The first discovery of Ptychodus teeth in Kansas came in 1868 when Leidy reported and described a damaged tooth near Fort Hays, Kansas.[10][4] After, many more teeth were uncovered in almost perfect conditions and other species within the genus were identified.[4] 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.[3] The fact that so many fossils of Ptychodus have been found in different regions of the world provides evidence of a distribution of species during the Albian-Turonian time.[7]
The generic name Ptychodus comes from the Greek words ptychos (fold/layer) and odon (tooth), so "fold teeth" describing the shape of their crushing and grinding teeth that were recovered in deposits around the Niobrara Formation.[11][clarification needed]
Descriptionedit
Vertebra
Ptychodus was a large shark, previously estimated at 10 meters (33 feet) long based on extrapolation from tooth.[12][13] 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.[6] Unlike the colossal nektonic planktivores Rhincodon (whale sharks) and Cetorhinus (basking sharks) which relied upon gill rakers to acquire their food, the Ptychodus had a massive arrangement of crushing plate teeth. A Ptychodus 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.[14] 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. Ptychodus marginalis teeth differ from Ptychodus polygyrus. P marginalis was in the Middle Cenomanian to Middle Turonian deposits in the English Chalk, while P. polygyrus was in the Late Santonian-Early Campanian deposits.[15]
Potential size estimates
Paleobiologyedit
While there is no solid evidence of members of the Ptychodus species living among other durophagous sharks like members of Heterodontidae (bullhead sharks), it is believed that this Cretaceous macropredator was the precursor to crushing plate teeth seen in many similar sharks and rays.[16]Ptychodus would have predated benthic shelled invertebrates, however Ptychodus itself was probably not benthic but more likely to be pelagic.[17] It is believed that Ptychodus species not only preferred this area because of the subtropical environment but due to the higher concentration of their prey source Cremnoceramus, Volviceramus and other members of the inoceramids.[17]
Dietedit
Diets of Ptychodus, for example P. decurrens (found in southern India) were probably animals with hard shells.[7]Bivalves and ammonites are example of shelled invertebrates that are probably main food source of Ptychodus.[18]Platyceramus, genus that includes one of the largest bivalves at the time, is able to be a part of the diet of Ptychodus.[19] The Ptychodus diet in each species slightly differed based on the region they came from. The Paraptychodus washitaensis species (found in north-central Texas, USA.) has a dental structure similar to that of its ancestors (Ptychodus), however, its posterior teeth have a sharply raised and pointed tooth crown- a feature not predominantly present in its ancestors.[20] The presence of the sharply raised and pointed tooth crown compared to the flat, wide crowns designed to crush prey also indicates a shift from eating mostly hard-shelled organisms to other types of organisms that have tough skeletons or exoskeletons.
Galleryedit
Ptychodus mammillaris teeth
Teeth of Ptychodus decurrens from Cretaceous of United States
Teeth of Ptychodus sp. from Cretaceous of United States
Teeth attributed to Ptychodus decurrens
Referencesedit
^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.
^ abEverhart, Mike. "Ptychodus mortoni". Ocean of Kansas.
^ abcdThe paleobioloy Database Ptychodus entry accessed on 8/23/09
^ abcEverhart, Michael; Caggiano, Tom. "An associated dentition and calcified vertebral centra of the Late Cretaceous elasmobranch, Ptychodus anonymus Williston 1900". 4 (4): 125–136. {{cite journal}}: Cite journal requires |journal= (help)
^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.
^ abJambura, 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. PMC7176087. PMID 32320430.
^ abcVerma, 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.
^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
^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)
^Everhard, Mike. "Ptychodontid Sharks: Late Cretaceous Shell Crushers". Ocean of Kansas.
^David, Michelle A historical and mechanical description of Ptychodus (Chondrichthyes) dententions with notes on the distribution and systematics of the genus
^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
^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
^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.
^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.
^Shawn A. Hamm The Late Cretaceous shark, Ptychodus rugosus, (Ptychodontidae) in the Western Interior Sea Transactions of the Kansas Academy of Science (1903) - Vol. 113, No. 1/2 (Spring 2010), pp. 44-55
^ abShawn Hamm Ptychodus and species 2011 - SYSTEMATIC, STRATIGRAPHIC, GEOGRAPHIC AND PALEOECOLOGICAL DISTRIBUTION OF THE LATE CRETACEOUS SHARK GENUS PTYCHODUS WITHIN THE WESTERN INTERIOR SEAWAY
^HAMM, SHAWN A. (2020-01-01). STRATIGRAPHIC, GEOGRAPHIC AND PALEOECOLOGICAL DISTRIBUTION OF THE LATE CRETACEOUS SHARK GENUS PTYCHODUS WITHIN THE WESTERN INTERIOR SEAWAY, NORTH AMERICA. New Mexico Museum of Natural History and Science.
^Hamm, Shawn A. (2015). "Paraptychodus washitaensis n. gen. Et n. Sp., of Ptychodontid shark from the Albian of Texas, USA". Cretaceous Research. 54: 60–67. Bibcode:2015CrRes..54...60H. doi:10.1016/j.cretres.2014.10.015.
Williston, Samuel (1900) University Geological Survey of Kansas, Volume VI: Paleontology part II, (Carboniferous invertebrates and Cretaceous fish)
BBC page on Ptychodus mortoni: "Giant predatory shark fossil unearthed in Kansas"
October 28, 2023
ptychodus, from, greek, πτυχή, ptyche, fold, greek, ὀδούς, odoús, tooth, genus, extinct, durophagous, shell, crushing, sharks, from, late, cretaceous, fossils, teeth, found, many, late, cretaceous, marine, sediments, there, many, species, among, that, have, be. Ptychodus from Greek ptyxh ptyche fold and Greek ὀdoys odous tooth 1 is a genus of extinct durophagous shell crushing sharks from the Late Cretaceous 2 3 Fossils of Ptychodus teeth are found in many Late Cretaceous marine sediments 3 There are many species among the Ptychodus that have been uncovered on all the continents around the globe 3 Such species are Ptychodus mortoni P decurrens P marginalis P mammillaris P rugosus and P latissimus to name a few They died out approximately 85 million years ago A large number of remains have been found in the former Western Interior Seaway 2 A 2016 publication found that Ptychodus are likely true sharks belonging to Selachimorpha rather than hybodonts or batoids as previously thought 4 5 Their life history coincides with the typical life of many other large sharks they lived relatively long lives and were slow growing and produced large offspring and small litters 6 PtychodusTemporal range Early Late Cretaceous 112 85 Ma PreꞒ Ꞓ O S D C P T J K Pg NLower jaw of Ptychodus sp Scientific classificationDomain EukaryotaKingdom AnimaliaPhylum ChordataClass ChondrichthyesFamily PtychodontidaeGenus PtychodusAgassiz 1837Type speciesPtychodus latissimusAgassiz 1835Other speciesPtychodus altior Agassiz 1839 Ptychodus anonymus Williston 1900 Ptychodus arcuatus Agassiz 1837 Ptychodus articulatus Agassiz 1837 Ptychodus atcoensis Carrillo Briceno 2013 Ptychodus belluccii Bonarelli 1899 Ptychodus concentricus Agassiz 1839 Ptychodus decurrens Agassiz 1839 Ptychodus elevatus Leriche 1929 Ptychodus gibberulus Agassiz 1837 Ptychodus janewayii Cope 1874 Ptychodus mahakalensis Chiplonkar and Ghare 1977 Ptychodus mammillaris Agassiz 1839 Ptychodus marginalis Agassiz 1839 Ptychodus mortoniAgassiz 1843 Ptychodus multistriatus Woodward 1889 Ptychodus oweni Dixon 1850 Ptychodus paucisulcatus Dixon 1850 Ptychodus polygyrus Agassiz 1839 Ptychodus rugosus Dixon 1850 Ptychodus spectabili Agassiz 1837 Ptychodus whipplei Marcou 1858 Contents 1 Discovery 2 Description 3 Paleobiology 3 1 Diet 4 Gallery 5 References 6 External linksDiscovery edit nbsp 1822 illustration of the first Ptychodus teeth Due to a global distribution Ptychodus 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 7 The very first remains of Ptychodus were found in England and Germany in the first half of the 18th century 8 9 Ptychodus 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 Ptychodus teeth with those of elasmobranchs rays and sharks The first discovery of Ptychodus teeth in Kansas came in 1868 when Leidy reported and described a damaged tooth near Fort Hays Kansas 10 4 After many more teeth were uncovered in almost perfect conditions and other species within the genus were identified 4 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 3 The fact that so many fossils of Ptychodus have been found in different regions of the world provides evidence of a distribution of species during the Albian Turonian time 7 The generic name Ptychodus comes from the Greek words ptychos fold layer and odon tooth so fold teeth describing the shape of their crushing and grinding teeth that were recovered in deposits around the Niobrara Formation 11 clarification needed Description edit nbsp VertebraPtychodus was a large shark previously estimated at 10 meters 33 feet long based on extrapolation from tooth 12 13 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 6 Unlike the colossal nektonic planktivores Rhincodon whale sharks and Cetorhinus basking sharks which relied upon gill rakers to acquire their food the Ptychodus had a massive arrangement of crushing plate teeth A Ptychodus 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 14 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 Ptychodus marginalis teeth differ from Ptychodus polygyrus P marginalis was in the Middle Cenomanian to Middle Turonian deposits in the English Chalk while P polygyrus was in the Late Santonian Early Campanian deposits 15 nbsp Potential size estimatesPaleobiology editWhile there is no solid evidence of members of the Ptychodus species living among other durophagous sharks like members of Heterodontidae bullhead sharks it is believed that this Cretaceous macropredator was the precursor to crushing plate teeth seen in many similar sharks and rays 16 Ptychodus would have predated benthic shelled invertebrates however Ptychodus itself was probably not benthic but more likely to be pelagic 17 It is believed that Ptychodus species not only preferred this area because of the subtropical environment but due to the higher concentration of their prey source Cremnoceramus Volviceramus and other members of the inoceramids 17 Diet edit Diets of Ptychodus for example P decurrens found in southern India were probably animals with hard shells 7 Bivalves and ammonites are example of shelled invertebrates that are probably main food source of Ptychodus 18 Platyceramus genus that includes one of the largest bivalves at the time is able to be a part of the diet of Ptychodus 19 The Ptychodus diet in each species slightly differed based on the region they came from The Paraptychodus washitaensis species found in north central Texas USA has a dental structure similar to that of its ancestors Ptychodus however its posterior teeth have a sharply raised and pointed tooth crown a feature not predominantly present in its ancestors 20 The presence of the sharply raised and pointed tooth crown compared to the flat wide crowns designed to crush prey also indicates a shift from eating mostly hard shelled organisms to other types of organisms that have tough skeletons or exoskeletons Gallery edit nbsp Ptychodus mammillaris teeth nbsp Teeth of Ptychodus decurrens from Cretaceous of United States nbsp Teeth of Ptychodus sp from Cretaceous of United States nbsp Teeth attributed to Ptychodus decurrensReferences edit Roberts George 1839 An etymological and explanatory dictionary of the terms and language of geology London Longman Orme Brown Green amp Longmans p 144 Retrieved 31 December 2021 a b Everhart Mike Ptychodus mortoni Ocean of Kansas a b c d The paleobioloy Database Ptychodus entry accessed on 8 23 09 a b c Everhart Michael Caggiano Tom An associated dentition and calcified vertebral centra of the Late Cretaceous elasmobranch Ptychodus anonymus Williston 1900 4 4 125 136 a href Template Cite journal html title Template Cite journal cite journal a Cite journal requires journal help 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 b Jambura Patrick L Kriwet Jurgen 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 b c 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 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 Brignon A 2019 Le diodon devenu requin l histoire des premieres decouvertes 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 Everhard Mike Ptychodontid Sharks Late Cretaceous Shell Crushers Ocean of Kansas David Michelle A historical and mechanical description of Ptychodus Chondrichthyes dententions with notes on the distribution and systematics of the genus Shimada K Rigsby C K amp 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 Shimada K Everhart M J Decker R amp 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 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 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 Shawn A Hamm The Late Cretaceous shark Ptychodus rugosus Ptychodontidae in the Western Interior Sea Transactions of the Kansas Academy of Science 1903 Vol 113 No 1 2 Spring 2010 pp 44 55 a b Shawn Hamm Ptychodus and species 2011 SYSTEMATIC STRATIGRAPHIC GEOGRAPHIC AND PALEOECOLOGICAL DISTRIBUTION OF THE LATE CRETACEOUS SHARK GENUS PTYCHODUS WITHIN THE WESTERN INTERIOR SEAWAY HAMM SHAWN A 2020 01 01 STRATIGRAPHIC GEOGRAPHIC AND PALEOECOLOGICAL DISTRIBUTION OF THE LATE CRETACEOUS SHARK GENUS PTYCHODUS WITHIN THE WESTERN INTERIOR SEAWAY NORTH AMERICA New Mexico Museum of Natural History and Science A Field Guide to Fossils of the Smoky Hill Chalk Hamm Shawn A 2015 Paraptychodus washitaensis n gen Et n Sp of Ptychodontid shark from the Albian of Texas USA Cretaceous Research 54 60 67 Bibcode 2015CrRes 54 60H doi 10 1016 j cretres 2014 10 015 Williston Samuel 1900 University Geological Survey of Kansas Volume VI Paleontology part II Carboniferous invertebrates and Cretaceous fish External links edit nbsp Sharks portal nbsp Palaeontology portal nbsp Media related to Ptychodus at Wikimedia Commons BBC page on Ptychodus mortoni Giant predatory shark fossil unearthed in Kansas Retrieved from https en wikipedia org w index php title Ptychodus amp oldid 1175077428, wikipedia, wiki, book, books, library,
