
Belongs within: Conodonti.
The Acanthodontidae are a group of conodonts known from the Ordovician, bearing an apparatus of nongeniculate coniform elements (Sweet 1988).
Characters (from Sweet 1988): Skeletal apparatus basically bimembrate, with nongeniculate, weakly albid or hyaline, coniform elements. One element compressed, bilaterally symmetrical, commonly with sharp anterior and posterior margins; other similar, cusp twisted laterally with respect to base which thus opens to one side.
<==Acanthodontidae |--Eucharodus Kennedy 1980AS93 | `--E. parallellusPBJ03 |--Parapaltodus Stouge 1984S88 | |--P. flexuosus (Barnes & Poplawski 1973)AS93 | `--P. simplicissimusAB04 |--Acanthodus Furnish 1938S88 | |--*A. uncinatus Furnish 1938DJ71 | |--A. costatus Druce & Jones 1971DJ71 | `--A. lineatus (Furnish 1938) [=Drepanodus lineatus]DJ71 `--Drepanodus Pander 1856S88 |--*D. arcuatus Pander 1856DJ71 |--D. acutus Pander 1856DJ71 |--D. sculponeaDJ71 |--D. simplex Branson & Mehl 1933DJ71 |--D. subarcuatus Furnish 1938 [incl. Oistodus larapintinensis Crespin 1943, D. parallelus]DJ71 `--D. tenuis Moskalenko 1967DJ71
*Type species of generic name indicated
References
[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.
[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.
[S88] Sweet, W. C. 1988. The Conodonta: Morphology, taxonomy, paleoecology, and evolutionary history of a long extinct animal phylum. Clarendon Press: Oxford.