Apparatus elements of Plectodina tenuis, from here.

Belongs within: Conodonti.
Contains: Multioistodontidae, Prioniodontidae, Balognathidae, Cyrtoniodontidae, Prioniodinida, Ozarkodinida.

The Prioniodontida are a group of conodonts characterised by the possession of apparatus including pastinate P elements, though they are believed to be paraphyletic with regard to the Ozarkodinida (with carminate P elements) and Prioniodinida (with digyrate P elements) (Sweet & Donoghue 2001). They first appear in the Lower Ordovician (Tremadocian) in the form of the genus Rossodus, which may include the ancestors of the remainder of the clade (Sweet 1988). Rossodus has been placed in the basal family Oistodontidae, the apparatus of which is composed entirely of coniform elements (Sweet 1988).

Prioniodontida [Prioniodontacea]
    |--Oistodontidae [Oistodontinae, Tripodontinae]AS93
    |    |--Oelandodus Van Wamel 1974S88
    |    |    `--O. elongatusPBJ03
    |    |--Diaphorodus Kennedy 1980AS93
    |    |    `--‘Periodon’ primus Stouge & Bagnoli 1988AS93
    |    |--Tripodus Bradshaw 1969S88
    |    |    |--T. deltatusS88
    |    |    `--T. laevisPBJ03
    |    |--Rossodus Repetski & Ethington 1983SD01, S88
    |    |    |--R. barnesiAB04
    |    |    |--R. manitouensis Repetski & Ethington 1983AS93
    |    |    `--R. tenuis (Miller 1980) [=Utahconus tenuis]AS93
    |    |--Histiodella Harris 1962AS93
    |    |    |--H. altifronsPBJ03
    |    |    |--H. donnaeS88
    |    |    |--H. holodentataPBJ03
    |    |    `--H. sinuosa Graves & Ellison 1941AS93
    |    `--Oistodus Pander 1856S88 [incl. Eobelodina Sweet, Turco et al. 1959M62]
    |         |--*O. lanceolatus Pander 1856DJ71
    |         |--O. fornicalis Stauffer 1935 [=*Eobelodina fornicalis]M62
    |         |--O. gracilisDJ71
    |         |--O. inaequalis Pander 1856DJ71
    |         `--O. multicorrugatusPBJ03
          |    |--Microzarkodina Lindström 1971S88
          |    |    |--*M. flabellumS88
          |    |    |--M. ozarkodellaS88
          |    |    `--M. parvaPBJ03
          |    `--Periodon Hadding 1913S88
          |         |--*P. aculeataS88
          |         |--P. flabellumPBJ03
          |         |--P. gladysiAB04
          |         |--P. grandis (Ethington 1959)AS93
          |         `--P. selenopsis (Serpagli 1974)AS93
             |    |  i. s.: Thrincodus Bauer 1987AS93
             |    |         Tasmanognathus Burrett 1979AS93
             |    |--Bergstroemognathus Serpagli 1974S88
             |    |    |--B. extensus (Graves & Ellison 1941)AS93
             |    |    `--B. hubeiensis An 1985AS93
             |    `--+--Rhipidognathus Branson, Mehl & Branson 1951S88
             |       |    `--*R. symmetrica Branson, Mehl & Branson 1951H62
             |       `--Appalachignathus Bergström et al. 1974S88
             |            `--A. delicatulusS88
                              |  i. s.: ‘Aphelognathus’ gigasS88
                              |         ‘Aphelognathus’ kimmswickensisS88
                              |--Tangshanodus An 1983S88
                              |--Scyphiodus Stauffer 1935S88
                              |    `--*S. primus Stauffer 1935H62
                              `--Plectodina Stauffer 1935S88 [incl. Subcordylodus Stauffer 1935H62]
                                   |--*P. dilata Stauffer 1935H62
                                   |--P. aculeataS88
                                   |--P. aculeatoides Sweet 1979AS93
                                   |--P. flexa (Rhodes 1953)AS93
                                   |--P. joachimensisLM05
                                   `--P. tenuisSS05
Prioniodontida incertae sedis:
  Acodus Pander 1856 (n. d.)S88
    |--*A. erectus Pander 1856DJ71
    |--A. acutusH62
    |--A. cambricus Nogami 1967DJ71
    |--A. deltatusPBJ03
    |--A. kechikaensisPBJ03
    |--A. neodeltatusPBJ03
    |--A. oneotensis Furnish 1938DJ71
    `--A. primusAB04
    |--Paracordylodus Lindström 1955AS93
    |    `--*P. gracilis Lindström 1955H62, AS93
    |--Fahraeusodus Stouge & Bagnoli 1988AS93
    |    `--F. marathonensis (Bradshaw 1969)AS93
    `--Protoprioniodus McTavish 1973AS93
         |--P. arandaPBJ03
         |--P. marathonensisS88
         |--P. nyintiPBJ03
         `--P. simplicissimusPBJ03

*Type species of generic name indicated


[AB04] Albanesi, G. L., & S. M. Bergström. 2004. Conodonts: Lower to Middle Ordovician record. In: Webby, B. D., F. Paris, M. L. Droser & I. G. Percival (eds) The Great Ordovician Biodiversification Event pp. 312–326. Columbia University Press.

[AS93] Aldridge, R. J., & M. P. Smith. 1993. Conodonta. In: Benton, M. J. (ed.) The Fossil Record 2 pp. 563–572. Chapman & Hall: London.

[DJ71] Druce, E. C., & P. J. Jones. 1971. Cambro-Ordovician conodonts from the Burke River Structural Belt, Queensland. Commonwealth of Australia, Bureau of National Development, Bureau of Mineral Resources, Geology and Geophysics, Bulletin 110: 1–159.

[H62] Hass, W. H. 1962. Conodonts. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt W. Miscellanea: Conodonts, Conoidal Shells of Uncertain Affinities, Worms, Trace Fossils and Problematica pp. W3–W69. Geological Society of America, and University of Kansas Press.

[LM05] Lehnert, O., J. F. Miller, S. A. Leslie, J. E. Repetski & R. L. Ethington. 2005. Cambro-Ordovician sea-level fluctuations and sequence boundaries: the missing record and the evolution of new taxa. Special Papers in Palaeontology 73: 117–134.

[M62] Müller, K. J. 1962. Supplement to systematics of conodonts. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt W. Miscellanea: Conodonts, Conoidal Shells of Uncertain Affinities, Worms, Trace Fossils and Problematica pp. W246–W249. Geological Society of America, and University of Kansas Press.

[PBJ03] Pyle, L. J., C. R. Barnes & Z. Ji. 2003. Conodont fauna and biostratigraphy of the Outram, Skoki, and Owen Creek Formations (Lower to Middle Ordovician), Wilcox Pass, Alberta, Canada. Journal of Paleontology 77 (5): 958–976.

[SS05] Sansom, I. J., & M. P. Smith. 2005. Late Ordovician vertebrates from the Bighorn Mountains of Wyoming, USA. Palaeontology 48 (1): 31–48.

[S88] Sweet, W. C. 1988. The Conodonta: Morphology, taxonomy, paleoecology, and evolutionary history of a long extinct animal phylum. Clarendon Press: Oxford.

[SD01] Sweet, W. C., & P. C. J. Donoghue. 2001. Conodonts: past, present, future. Journal of Paleontology 75 (6): 1174–1184.

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