Weigeltaspis
Weigeltaspis is a genus of extinct heterostracan agnathan fish known from the Late Silurian and Early Devonian periods. Fossils are known primarily from Early Devonian-aged marine strata of Europe and Canada. Fragments and disarticulated plates of what may be of "Weigeltaspis" are known from Late Silurian-aged marine strata of Arctic Canada. Rare articulated fossils, plus the overall anatomy of its plates suggest the living animals were, at least superficially, similar to psammosteids, some authorities, such as Tarlo, place them within Psammosteida. Because the ornamentation on the plates and scales are very similar to the ornamentation seen on  the plates and scales of "Traquairaspis" to the point of constant confusion, other authorities follow the lead of Obruchev, and place "Weigeltaspis" within Traquairaspidiformes. Still other authorities remain unconvinced of either side, and, instead, follow Denison's lead to simply treat "Weigeltaspis" as "incertae sedis".