Silurian jawless fish

Thelodus (from , 'nipple' and , 'tooth') is an extinct genus of thelodont agnathan that lived during the Silurian period. Fossils have been found in Europe, Asia and North America.

Jamoytius kerwoodi is an extinct species of primitive, eel-like jawless fish known from the Patrick Burn Formation in Scotland, dating to the Llandovery epoch of the Early Silurian period.

Pteraspidiformes is an extinct order of heterostracan agnathan vertebrates known from extensive fossil remains primarily from Early Devonian strata of Europe and North America, and from Upper Silurian Canada.

Lasanius is a genus of basal anaspid from the Early Silurian, around 443.8 million years ago, known from fossils found near Lesmahagow, Scotland. Specimens range from 13.3 to 74.5 mm in length.

Lanarkia is a genus of extinct thelodont agnathan which existed in what is now Scotland and Canada during the upper Silurian period.

Dunyu (meaning "shield fish" in Hanyu Pinyin) is an extinct genus of eugaleaspidiform galeaspid known from the Silurian of Yunnan, southwestern China. Two species are known: D longiforus, the type species and D. xiushanensis, which was initially named as a species of Eugaleaspis. The type specimen of D. longiforus is IVPP V 17681, a complete cephalic shield prepared by C. H. Xiong, and the holotype of D. xiushanensis is IVPP V 6793.1, another complete cephalic shield.

Thelodontiformes is an extinct order of jawless fish of the Silurian.