| Longodus Temporal range: | |
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| Family: | Longodidae Märss, 2006 |
| Genus: | Longodus Märss, 2006 |
| Species: | L. acicularis |
| Binomial name | |
| Longodus acicularis Märss, 2006 [1] | |
Longodus (Long meaning long and odus meaning tooth) is an extinct genus of thelodont, placed in its own family[1][2] – Longodidae – which existed in what is now Estonia during the Ludlow epoch of the upper Silurian period.[3] The type and only species is Longodus acicularis.[1][3] They are most noted for their long, needle-like scales, which run vertically along their trunk.
Description
Longodus acicularis possessed narrow but elongated scales, approximately 0.5 mm to 1.0 mm in length, with a width to length ratio of up to 1:11. Their heads were almond shaped, connected to a medium trunk and short, distinctly forked tail. Scales contained ridges along the margins, creating a ripple like visual effect. They also possess lateral spines posterior to the crown.[2] The scales on the crown are dentine based, covered by enameloid, while the scales of the base are acellular aspidin based.
References
- 1 2 3 T. Märss (2006). "Thelodonts (Agnatha) from the basal beds of the Kuressaare Stage, Ludlow, Upper Silurian of Estonia" (PDF). Proceedings of the Estonian Academy of Sciences, Geology. 55 (1): 43–66. doi:10.3176/geol.2006.1.03. S2CID 199522655.
- 1 2 Mark V. H. Wilson & Tiiu Märss (2009). "Thelodont phylogeny revisited, with inclusion of key scale-based taxa" (PDF). Estonian Journal of Earth Sciences. 58 (4): 297–310. doi:10.3176/earth.2009.4.08.
- 1 2 Märss, T., Turner, S. & Karatajūte-Talimaa, V. 2007. "Thelodonti". In H.P. Schultze (ed.). Agnatha II (PDF). Vol. 1B. Verlag Dr. Friedrich Pfeil, München. p. 143.
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