Tarrasius problematicus (Traquair 1881; Sallan 2012; Viséan, Early Carboniferous, 340mya; 10cm) was considered similar to the bichir, Polypterus, but phylogenetically close to Eusthenopteron and Phanerosteon. Here it nests with the eels, basal to Gymnothorax, the moray eel. The DGS tracing and reconstruction are different than the Sallan 2012 reconstructions. Distinct from other fish, the vertebral column of this tadpole-like fish is divided into cervical, dorsal, lumbar, sacral and caudal regions, despite lacking pelvic fins. The postorbital is fused to the postfrontal. The squamosal is at its genesis. The teeth are blunt.

Superficiallly similar Paratarrasius is also considered a member of the tarrasiids, but is more closely related to the spiny shark, Brachyacanthus, in the LRT.

Below: The skeleton of the moray eel,Gymnothorax, is compared to the skeleton of Tarrasius.