Paratarrasius hibbardi

Paratarrasius hibbardi is closely related to the slightly older Scottish Tarrasius problematicus. It ranged from very small to about 7 inches in length.

Scales are small and fine, with an increased number of scale rows relative to body segments. This served to increase body flexibility. The pectoral fins are held high on the flank on long basal lobes and are well webbed paddles. Pelvic fins are absent. The continuous dorsal-caudal-anal fin is well webbed between the fin rays. Fish with this fin disposition today are slow weak swimmers that move either forward or backward, by body undulation, median fin undulation or pectoral paddling. Fish such as these are shelter dwellers in geometrically complex shallow water environments, such as weed or sponge beds.

Paratarrasius has a very small mouth with stout peg-like teeth. The skull has an interestingly primitive-looking actinopterygian snout bone pattern.

Reference:

• Lund, R., and W. G. Melton jr., 1982. "A new actinopterygian fish from the Mississippian Bear Gulch Limestone of Montana." Palaeontology 25: 485-498.
• Lund, R., and C. Poplin. 2002. "Cladistic analysis of the relationships of the Tarrasiids (Lower Carboniferous Actinopterygians)." Journal of Vertebrate Paleontology 22: 480-486.

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