Tealliocaris is an extinct genus of pygocephalomorphans that lived from the Late Devonian to Early Carboniferous periods in Europe and North America.

The generic name combines the surname of Jethro Teall (the Director of the Geological Survey of Scotland at the time and Peach's former Chief) with the Ancient Greek word καρίς (karís, meaning "shrimp"), with the suffix being added to distinguish this genus from Tealia (a genus of sea anemone currently deemed invalid).

[5] In addition, Peach erects three new species which he named T. loudonensis, T. tarrasiana and T. robusta respectively, and two new subspecies designated as T. woodwardi var.

In addition, the remains placed within T. tarrasiana were found to be poorly preserved specimens that also show no objective difference when compared to T. woodwardi and T. loudonensis.

Furthermore, Schram found T. etheridgii (referred to as T. etheridgei due to Peach's misspelling), T. formosa and T. robusta to all be synonymous with each other, believing their fossils represent only one species.

[5] Briggs and Clarkson (1985) supported this synonymy, but used the fossil described in 1877 by Etheridge as the holotype rather than the lectotype chosen by Schram.

Clark redescribing Tealliocaris was published in which it was determined that T. robusta is a distinct species from T. etheridgii, and thus was reinstated as a valid name.

The species T. belli was established based on a single fossil (GSC 10138) and named after Canadian geologist Walter A.

Furthermore, he states that this species differs from other known Tealliocaris in having long anterolateral (orbital) spines and large branchiolateral keels on the carapace.

Clark published in 2013 found that the features used by Brooks in 1962 to distinguish the genus from Pseudotealliocaris are actually present on Scottish specimens of Tealliocaris, including the type species T. woodwardi.

The species P. palincsari and P. holthuisi were also moved into Tealliocaris, though Clark does mention that their material should be reanalysed to confirm if such a placement is accurate.