Apparatus elements of Chirognathus, from Sweet (1988).

Belongs within: Prioniodontida.
Contains: Prioniodinidae.

The Prioniodinida are a group of conodonts known from the Ordovician to the Triassic, in which the elements of an apparatus tend to be all somewhat similar in appearance (Sweet 1988).

Characters (from Sweet 1988): Mineralized cephalic apparatus typically sexi- or septimembrate. P elements extensiform digyrate; M elements ramiform; but all six or seven types of elements in the apparatus tending to be stout, of the same size, and intergradational morphologically, with little difference in size or basal morphology. Denticles characteristically discrete and peglike; white matter commonly of minor amount and often confined either to axial regions of cusp and denticles or to diffuse, fuzzy-edged clouds irregularly distributed through cusp and denticles.

<==Prioniodinida [Chirognathidae, Chirognathinae, Trucherognathidae, Trucherognathinae]
    |  i. s.: Scutula Sannemann 1955H62
    |           |--*S. venusta Sannemann 1955H62
    |           `--S. bipennataH62
    |--Erraticodon Dzik 1978S88
    |    |--E. balticusAB04
    |    `--E. patu Cooper 1981AS93
    |  `--Erismodus Branson & Mehl 1933S88
    |       |--*E. typus Branson & Mehl 1933H62
    |       |--E. asymmetricusPBJ03
    |       |--E. quadridactylusS88
    |       `--E. radicans (Hinde 1879)AS93
    `--+--Curtognathus Branson & Mehl 1933S88 (see below for synonymy)
       |    |--*C. typa Branson & Mehl 1933H62
       |    |--*Trucherognathus’ distorta Branson & Mehl 1933H62
       |    `--*Polycaulodus’ inclinatus Branson & Mehl 1933H62
       `--Chirognathus Branson & Mehl 1933S88
            |--*C. duodactylus Branson & Mehl 1933 [=C. duodactyla]SS05
            |--C. reversaH62
            |--C. tridensH62
            `--C. variansH62

Curtognathus Branson & Mehl 1933S88 [incl. Polycaulodus Branson & Mehl 1933S88, H62, Trucherognathus Branson & Mehl 1933S88, H62]

*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.

[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.

[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.

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