# Protoconodont

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Order of jawless fishes

Protoconodont Temporal range: Cambrian PreꞒ Ꞓ O S D C P T J K Pg N Possible Carboniferous occurrence in Eoserratosagitta? Scientific classification Kingdom: Animalia Phylum: Chaetognatha (?) Order: †Protoconodontida Landing, 1995 Synonyms Amphigeisinacea Miller, 1981

**Protoconodonts** are an extinct group of [Cambrian](/source/Cambrian) animals known from fossilized [phosphatic](/source/Calcium_phosphate) tooth-like structures. They were originally described as an informal group of early [conodonts](/source/Conodont),[1][2][3] though more recent studies consider them to be more closely related to [chaetognaths](/source/Chaetognatha) (arrow worms).[4][5][6]

Protoconodont elements are slender and pointed, with a hollow interior which opens towards the base of the structure. They develop entirely by the addition of layers to the inner cavity, extending the rim of the base. There is no additional mineralization on the outer surface, in contrast to [paraconodonts](/source/Paraconodontida) or euconodonts (true conodonts).[1][7] Protoconodont elements are frequently found bundled together into 'superteeth', paired claw-like clusters which may have had a grasping function. These 'superteeth' were previously known by the name *"Prooneotodus" tenuis*,[8] now classified as a species of *[Phakelodus](https://en.wikipedia.org/w/index.php?title=Phakelodus&action=edit&redlink=1)*.*[5]* A few protoconodont genera were previously assigned to the class Conodonta and the order Paraconodontida, and the genus *[Amphigeisina](https://en.wikipedia.org/w/index.php?title=Amphigeisina&action=edit&redlink=1)* was even given its own superfamily, **Amphigeisinacea**.[2] Protoconodonts were assumed to have been forerunners to paraconodonts, and by extension euconodonts.[1][3]

It is now thought that protoconodont elements (e.g., *[Protohertzina](/source/Protohertzina) anabarica* Missarzhevsky, 1973), are probably grasping jaw spines of [stem group](/source/Stem_group) chaetognaths rather than the oropharyngeal (mouth or throat) elements of paraconodonts or true conodonts. The jaw spines of *[Sagitta maxima](/source/Sagitta_(arrowworm))*, a modern chaetognath, are practically identical to the fossils of *Phakelodus tenuis* in nearly every respect:[4][5] shape, position, co-occurrence with smaller jaw spicules, and the presence of a sheath-like covering to protect the spines when not in use. This even extends to their three-layered internal microstructure, with a fibrous middle layer and a compatible array of [trace elements](/source/Trace_element). Although chaetognath jaws are fully [organic](/source/Organic_compound) (rather than phosphatic), this was likely true of protoconodonts as well, with mineralization only occurring after death due to [diagenetic](/source/Diagenesis) alteration.[4][5] In light of their taxonomic distinction from paraconodonts and euconodonts, protoconodonts were given their own formal order in 1995: **Protoconodontida**.[9]

## List of genera

- *[Amphigeisina](https://en.wikipedia.org/w/index.php?title=Amphigeisina&action=edit&redlink=1)* (Bengtson, 1976)[1]

- *[Ganloudina](https://en.wikipedia.org/w/index.php?title=Ganloudina&action=edit&redlink=1)* He, 1983

- *[Gapparodus](/source/Gapparodus)* Abaimova, 1978

- *[Glauderia](https://en.wikipedia.org/w/index.php?title=Glauderia&action=edit&redlink=1)?* Poulsen, 1967

- *[Gumella](https://en.wikipedia.org/w/index.php?title=Gumella&action=edit&redlink=1)* Müller & Hinz, 1991

- *[Hagionella](https://en.wikipedia.org/w/index.php?title=Hagionella&action=edit&redlink=1)* Xie, 1990

- *[Hertzina](/source/Hertzina)* Müller, 1959

- *[Huayuanodontus](https://en.wikipedia.org/w/index.php?title=Huayuanodontus&action=edit&redlink=1)*? (Dong, 1993)

- *[Kijacus](https://en.wikipedia.org/w/index.php?title=Kijacus&action=edit&redlink=1)?* Missarzhevsky and Mambetov, 1981

- *[Mongolodus](/source/Mongolodus)* Missarzhevsky, 1977

- *[Paibiconus](https://en.wikipedia.org/w/index.php?title=Paibiconus&action=edit&redlink=1)*? Dong, 1993

- *[Phakelodus](https://en.wikipedia.org/w/index.php?title=Phakelodus&action=edit&redlink=1)* Miller, 1984[10]

- *[Protohertzina](/source/Protohertzina)* Missarzhevsky, 1973

## References

1. ^ [***a***](#cite_ref-:5_1-0) [***b***](#cite_ref-:5_1-1) [***c***](#cite_ref-:5_1-2) [***d***](#cite_ref-:5_1-3) Bengtson, Stefan (1976). ["The structure of some Middle Cambrian conodonts, and the early evolution of conodont structure and function"](https://www.idunn.no/doi/pdf/10.1111/j.1502-3931.1976.tb00966.x). *Lethaia*. **9** (2): 185–206. [doi](/source/Doi_(identifier)):[10.1111/j.1502-3931.1976.tb00966.x](https://doi.org/10.1111%2Fj.1502-3931.1976.tb00966.x). [ISSN](/source/ISSN_(identifier)) [0024-1164](https://search.worldcat.org/issn/0024-1164).

1. ^ [***a***](#cite_ref-:0_2-0) [***b***](#cite_ref-:0_2-1) Clark, David L. (1981). ["Chapter 3: Systematic Descriptions"](https://journals.ku.edu/InvertebratePaleo/article/view/5663/5137). In Moore, Raymond C.; Robison, R.A. (eds.). [*Part W, Miscellanea, Supplement 2: Conodonta*](https://journals.ku.edu/InvertebratePaleo/issue/view/522). [Treatise on Invertebrate Paleontology](/source/Treatise_on_Invertebrate_Paleontology). Boulder, Colorado; Lawrence, Kansas: Geological Society of America; University of Kansas. pp. 111–180. [ISBN](/source/ISBN_(identifier)) [0-8137-3028-7](https://en.wikipedia.org/wiki/Special:BookSources/0-8137-3028-7).

1. ^ [***a***](#cite_ref-:1_3-0) [***b***](#cite_ref-:1_3-1) Bengtson, Stefan (1983). ["The early history of the Conodont"](https://foreninger.uio.no/ngf/FOS/pdfs/F&S_15_005.pdf) (PDF). *Fossils and Strata*. **15**: 5–19.

1. ^ [***a***](#cite_ref-:2_4-0) [***b***](#cite_ref-:2_4-1) [***c***](#cite_ref-:2_4-2) Szaniawski, Hubert (1982). "Chaetognath Grasping Spines Recognized among Cambrian Protoconodonts". *Journal of Paleontology*. **56** (3): 806–810. [JSTOR](/source/JSTOR_(identifier)) [1304409](https://www.jstor.org/stable/1304409).

1. ^ [***a***](#cite_ref-:3_5-0) [***b***](#cite_ref-:3_5-1) [***c***](#cite_ref-:3_5-2) [***d***](#cite_ref-:3_5-3) Szaniawski, H. (2002). ["New evidence for the protoconodont origin of chaetognaths"](http://www.app.pan.pl/archive/published/app47/app47-405.pdf) (PDF). *[Acta Palaeontologica Polonica](/source/Acta_Palaeontologica_Polonica)*. **47** (3): 405–419.

1. **[^](#cite_ref-6)** Zooproblematica and mollusca from the Lower Cambrian Meishucun section (Yunnan, China) and taxonomy and systematics of the Cambrian small shelly fossils of China. P. Y. Parkhaev and Y. Demidenko, Paleontological Journal, 2010, volume 44, issue 8, pages 883-1161, [doi](/source/Doi_(identifier)):[10.1134/s0031030110080010](https://doi.org/10.1134%2Fs0031030110080010)

1. **[^](#cite_ref-7)** Fåhraeus, Lars E. (1984). ["A critical look at the Treatise family-group classification of Conodonta: an exercise in eclecticism"](https://dx.doi.org/10.1111/j.1502-3931.1984.tb00675.x). *Lethaia*. **17** (4): 293–305. [doi](/source/Doi_(identifier)):[10.1111/j.1502-3931.1984.tb00675.x](https://doi.org/10.1111%2Fj.1502-3931.1984.tb00675.x). [ISSN](/source/ISSN_(identifier)) [0024-1164](https://search.worldcat.org/issn/0024-1164).

1. **[^](#cite_ref-8)** Landing, Ed (1977). "*"Prooneotodus" tenuis* (Müller, 1959) Apparatuses from the Taconic Allochthon, Eastern New York: Construction, Taphonomy and the Protoconodont "Supertooth" Model". *Journal of Paleontology*. **51** (6): 1072–1084. [JSTOR](/source/JSTOR_(identifier)) [1303822](https://www.jstor.org/stable/1303822).

1. **[^](#cite_ref-9)** Landing, Ed (1995). ["Upper Placentian—Branchian series of mainland Nova Scotia (middle-upper Lower Cambrian): Faunas, paleoenvironments, and stratigraphic revision"](https://www.researchgate.net/publication/292626367). *Journal of Paleontology*. **69** (3): 475–495. [doi](/source/Doi_(identifier)):[10.1017/s0022336000034879](https://doi.org/10.1017%2Fs0022336000034879). [ISSN](/source/ISSN_(identifier)) [0022-3360](https://search.worldcat.org/issn/0022-3360). [JSTOR](/source/JSTOR_(identifier)) [1306322](https://www.jstor.org/stable/1306322).

1. **[^](#cite_ref-10)** Miller, James F. (1984), ["Cambrian and earliest Ordovician conodont evolution, biofacies, and provincialism"](https://pubs.geoscienceworld.org/books/book/334/chapter/3796056/), *Geological Society of America Special Papers*, vol. 196, Geological Society of America, pp. 43–68, [doi](/source/Doi_(identifier)):[10.1130/spe196-p43](https://doi.org/10.1130%2Fspe196-p43), [ISBN](/source/ISBN_(identifier)) [978-0-8137-2196-5](https://en.wikipedia.org/wiki/Special:BookSources/978-0-8137-2196-5){{[citation](https://en.wikipedia.org/wiki/Template:Citation)}}: CS1 maint: work parameter with ISBN ([link](https://en.wikipedia.org/wiki/Category:CS1_maint:_work_parameter_with_ISBN))

- Middle and Upper Cambrian Protoconodonts and Paraconodonts from Hunan, South China. Dong Xi-Ping and Stig M. Bergström, Palaeontology, September 2001, Volume 44, Issue 5, pages 949–985, [doi](/source/Doi_(identifier)):[10.1111/1475-4983.00210](https://doi.org/10.1111%2F1475-4983.00210)

- On the evolution and histology of some Cambrian protoconodonts, paraconodonts and primitive euconodonts. Dong Xiping, Science in China Series D: Earth Sciences, July 2004, Volume 47, Issue 7, pages 577–584, [doi](/source/Doi_(identifier)):[10.1360/03yd0535](https://doi.org/10.1360%2F03yd0535)

- Ion microprobe U–Pb dating and Sr isotope measurement of a protoconodont. Yuji Sano, Kosaku Toyoshima, Akizumi Ishida, Kotaro Shirai, Naoto Takahata, Tomohiko Sato and Tsuyoshi Komiya, Journal of Asian Earth Sciences, Volume 92, 1 October 2014, Pages 10–17, [doi](/source/Doi_(identifier)):[10.1016/j.jseaes.2014.05.024](https://doi.org/10.1016%2Fj.jseaes.2014.05.024)

## External links

- ["*Protoconodont*"](http://www.eol.org/pages/13073406). *The [Encyclopedia of Life](/source/Encyclopedia_of_Life)*.

- ["Protoconodonta"](https://paleobiodb.org/classic/basicTaxonInfo?taxon_no=3). *[Paleobiology Database](/source/Paleobiology_Database)*. Retrieved 17 July 2016.

Taxon identifiers Protoconodonta Wikidata: Q28431190 Paleobiology Database: 181614

v t e Conodonts Kingdom: Animalia Clade: Bilateria Phylum: Chordata Subphylum: Vertebrata Conodont-like fossils Protoconodontida? (Probably stem-chaetognaths) Amphigeisina Ganloudina Gapparodus Glauderia? Hagionella Huayuanodontus? Kijacus? Mongolodus Paibiconus? Phakelodus Protohertzina Paraconodontida Diaphanodus? Dolabrodus Bengtsonella Hunanognathus Laiwugnathus Prodistacodus? Serratocambria Shandongodus Trolmenia Yongshunella Furnishinacea Furnishinidae Albiconus Furnishina Muellerodus Nogamiconus Proacodus Problematoconites Prooneotodus Prosagittodontus Proscandodus Westergaardodinidae Westergaardodina Conodonta / Conodontophorida / "true conodonts" (Euconodonta) see below Conodonta Cavidonti Belodellida? Ansellidae? Ansella Hamarodus? Tokognathus? Belodellidae Belodella Caenodontus? Coelocerodontus Drepanodistacodus? Dvorakia Stolodus Walliserodus Dapsilodontidae? Besselodus? Dapsilodus Proconodontida Proconodontus Pseudooneotodus? Cordylodontidae Cambrooistodus Cordylodus Eoconodontus Eodentatus Iapetognathus Fryxellodontidae Dzikodus? Fryxellodontus Kallidontus Polonodus? Pygodontidae? Conodonti Protopanderodontida Besselodus? Dapsilodus? Acanthodontidae Acanthodus Kirkupodus Parapaltodus Scalpellodus? Ulrichodina? Clavohamulidae Clavohamulus Dasytodus Eoserratognathus Granatodontus Hirsutodontus Hispidodontus Laiwunodus Nericodus? Paraserratognathus Drepanoistodontidae? (Distacodontidae)? Distacodus Drepanodus? Drepanoistodus Laurentoscandodus Nordiodus? Paltodus Paroistodus Venoistodus Protopanderodontidae Aloxoconus? Colaptoconus Drepanodus Eucharodus Filodontus? Molloydenticulus Monocostodus Oneotodus Parutahconus Planusodus Polycostatus Protopanderodus Pseudooneotodus? Semiacontiodus Scolopodus Staufferella Striatodontus Stultodontus Teridontus Utahconus Variabiloconus Ventricodus Serratognathidae? Serratognathoides Serratognathus Strachanognathidae? (Cornuodontidae)? Cornuodus Decoriconus Macerodus Scabbardella Strachanognathus Panderodontida Cristodus? Loxodus? Thrincodus? Panderodontidae Belodina Culumbodina Naimanodus Neopanderodus Nudibelodina Panderodus Parabelodina Parapanderodus Plegagnathus Pseudobelodina Taoqupognathus Belodellidae? Prioniodontida see below Prioniodontida incertae sedis Multidentodus? Rossodus Schopfodus Ansellidae? Acodontidae? Acodus Diaphorodus Nealeodus? Pteracontiodus Triangulodus Tripodus Tropodus Balognathidae Aldridgeognathus Amorphognathus Arianagnathus Baltoniodus Barrandegnathus Birksfeldia Complexodus Icriodella Lenodus Notiodella Omanognathus Pranognathus Prioniodus Promissum Pterospathodus Rhodesognathus Sagittodontina Trapezognathus Distomodontidae Anticostiodus Distomodus Moskalenkodus Gamachignathidae? Birksfeldia Galerodus Gamachignathus Icrodellidae Icriodella Icriognathus Pedavis Icriodontidae Caudicriodus Icriodus Pelekysgnathus Jablonnodontidae? Cononcfiodontus Fungulodus Jablonnodus Mitrellataxis Multioistodontidae Dischidognathus Leptochirognathus? Multioistodus Neomultioistodus Wandelia Nurrellidae? Nurrella Oistodontidae Graciliconus Histiodella Juanognathus Jumudontus Loxognathodus Loxodentatus Oistodus Oleandodus Tricostatus Ozarkodinida see below Paracordylodontidae Cooperignathus Oelandodus Paracordylodus Protoprioniodus Periodontidae Fahraeusodus? Hamarodus? Microzarkodina Periodon Pohlerodus Phragmodontidae Acanthocordylodus Acanthodina Nordiora Paraprioniodus Phragmodus Protophragmodus Playfordiidae? Playfordia Plectodinidae Bryantodina Plectodina Scyphiodus Polyplacognathidae Baltoplacognathus Cahabagnathus Polonodus? Polyplacognathus Prioniodinida see below Prioniodontidae Angulodus Astognathus Cardiodella Dichognathus Drucognathus Embsaygnathus Eocarniodus Eoneoprioniodus Guizhouprioniodus Kailidontus Lambdagnathus Prioniodus Reutterodus Stiptognathus Pygodontidae? Nericodus? Pygodus Rhipidognathidae Appalachignathus Bergstroemognathus Rhipidognathus Ozarkodinida Anchignathodontidae Anchignathodus Diplognathodus Hindeodus Pseudohindeodus Synprioniodina ?Archeognathidae Archeognathus Neocoleodus ?Belodontidae Albiconus Belodus Bengtsonella Cambropustula Gumella Hunanganthus Lepognathus Microcoelodus Paibiconus Ptiloconus ?Coleodontidae Coleodontinae Coleodus Hindeodina Pravognathus Hibbardellinae Diplododella Elsonella Hibbardella Hibbardelloides Ptilognathus Roundya Tetraprioniodus Zentagnathus Hindeodellinae Arcugnathus Cervicornoides Hindeodella Kladognathus Metaprioniodus Oncodella Tasmanognathus Ligonodinae Euprioniodella Euprioniodina Hamulosodina Hindeodelloides Ligonodina Lonchodina? Lonchodus Synprioniodina Neoprioniodontinae Leptochirognathus Loxodus Neoprioniodus Pachysomia Subprioniodus Plectospathodontinae Anastrophognathus Aphelognathus Gothodus Keislognathus Plectospathodus Cryptotaxidae Cryptotaxis ?Eognathodontidae Eognathodus Gigantholus Gondwania Pseudogondwania Rhodalepis Schmidtognathus Siphonodella Elictognathidae Alternognathus Elictognathus Pinacognathus ?Francodinidae Francodina Planadina Sweetodina Urbanekodina Vogelgnathus ?Gladigondolellidae Gladigondolella Gondolellidae Acuminatella Ancyrogondolella Borinella Carnepigondolella Clarkina Conudina Epigondolella Gondolella Hayashiella Icriospathodus Jinogondolella Kraussodontus Mazzaella Mesogondolella Metapolygnathus Misikella Mockina Neocavitella Neogondolella Neospathodus Nicoraella Norigondolella Paragondolella Parapetella Parvigondolella Platyvillosus Pridaella Primatella Pseudofurnishius Quadralella Scythogondolella Sephardiella Gnathodontidae FIiognathus Icriodus Peudognathodus Idiognathodontidae Gnathodus Idiognathodus Protognathodus ?Iowagnathidae Iowagnathus Kockelellidae Ctenognathodus Kockelella Mestognathidae Laterignathus Mestognathus ?Novispathodontidae Discretella Gongolelloides Guanxidella Icriospathodus Kashmirella Mosherella Novispathodus Smithodus Sweetospathodus Triassospathodus Polygnathacea Cavusgnathidae Adetognathus Cavusgnathus Clydagnathus Ferganaegnathodus Neolochriea Patrognathus Pseudopolygnathus Rhachistognathus Scaphignathus Taphrognathus Weyerognathus Palmatolepidae Conditolepis Dinodus Kielcelepis Klapperilepis Lagovilepis Manticolepis Mesotaxis Palmatolepis Panderolepis Tripodellus Polygnathidae Avignathus Bispathodus Ctenopolygnathus Mehlina Nicollidina Pandorinellina Parapolygnathus Polygnathus Streptognathodus Synclydagnathus Pterospathodontidae Astropentagnathus Carniodus Complexodus Pranognathus Pterospathodus Xainzadontus Spathognathodontidae Flajsella Lanea Ozarkodina Spathognathodus Tortodus Wurmiella Zieglerodina Sweetognathidae Meiognathus Sweetognathus ?Trucherognathidae Trucherognathus ?Vjalovognathidae Vjalovognathus ?Wapitiodontidae Wapitiodus Prioniodinida Bactrognathidae Bactrognathus Doliognathus Staurognathus Chirognathidae Chirognathus Curtognathus Erraticodon Lumidens? Oistodella Ellisoniidae Ellisonia Foliella Hadrodontina Parapachycladina Parafurnishius Stepanovites ?Oepikodontidae Lissoepikodus Oepikodus Prioniodinidae Bryantodus Camptognathus Chirodella Cornuramia Dyminodina Falodus Guizhoudella Gyrognathus Idioprionodus Kamuellerella Lagovidina Metalonchodina Multidentodus Neoplectospathodus Oulodus Palmatodella Pluckidina Polygnathellus Prioniodella Prioniodina Prionognathodus Pristognathus Scotlandia Subbryantodus Uncadina Veghella ?Xaniognathidae Chirodella Crypridodella Ketinella Xaniognathus List Category Commons

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Adapted from the Wikipedia article [Protoconodont](https://en.wikipedia.org/wiki/Protoconodont) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Protoconodont?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.