Big Teeth

Rhizodus is a tooth from certain types of lobe-finned fishes (coelacanths) known as rhizodontiforms. According to Long (p.190), these fish attained lengths of 6-7 metres and individual teeth attained lengths of 22 centimetres. In other words, the specimen illustrated here is a small one :-)

Rhizodus -- about 9cm long From Zittel, 1887, p.182 (fig.189): "Rhizodus Owen (Megalichthys Ag. p.p.). Very large, incompletely known fishes with rough, rugose cycloidal scales. Clavicle with a long upwardly directed process. Teeth smooth, compressed to a sharp edge in front and behind. R. hiberti Ag., and R. ornatus Traq., from Lower Carboniferous [Mississippian], Scotland and Northumberland. Allied species in Coal Measures [coal-bearing Carboniferous-age strata] of North America." Translation from Eastman, 1932. The figure at the bottom is a cross section, showing the lenticular shape and sharp edges. In my experience, many Rhizodus teeth are rounder than this.

The internal structure of fossil teeth is what distinguishes them from coincidentally-shaped rocks. Note the highly folded structure of the bone in the tooth of this cross section of Dendrodus, also produced from a type of lobe-finned fish similar to Rhizodus.

Dendrodus Zittel, 1887, p.178 (fig.183).


Back to the evaluation of Carboniferous bone
Andrew MacRae macrae@geo.ucalgary.ca