Alternognathus

{{Short description|Extinct genus of jawless fishes}}

{{Italic title}}

{{taxobox

| fossil_range = {{Fossil range|Famennian}}

| regnum = Animalia

| phylum = Chordata

| classis = †Conodonta

| ordo = †Ozarkodinida

| familia = †Elictognathidae

| genus = †Alternognathus

| genus_authority = Ziegler & Sandberg, 1984

| subdivision_ranks = Species

| subdivision =

• †Alternognathus beulensis
• †Alternognathus regularis

| synonyms =

}}

Alternognathus is an extinct conodont genus in the family Elictognathidae. An extensive study on its population dynamics and lifespan has recently been published.Przemysław Świś (2019). "Population dynamics of the Late Devonian conodont Alternognathus calibrated in days". Historical Biology: An International Journal of Paleobiology. in press. doi:10.1080/08912963.2018.1427088.