Megateuthis

{{Automatic taxobox

| fossil_range = {{fossilrange/linked|Toarcian|Bajocian}}

| image = Megateuthis 1.JPG

| image_caption = Fossilised guards of Megateuthis

| taxon = Megateuthis

| authority = Bayle, 1878

| type_species = {{extinct}}Belemnites giganteus

| type_species_authority = (von Schlotheim, 1820) by subsequent designation (Douvillé, 1879, p. 91)

| subdivision_ranks = Species

| subdivision_ref = {{cite journal|url=https://www.researchgate.net/publication/232702259|first1=R.|last1=Weis|first2=N.|last2=Mariotti|year=2007|title=A belemnite fauna from the Aalenian-Bajocian boundary beds of the Grand Duchy of Luxembourg (NE Paris Basin)|journal=Bollettino della Società Paleontologica Italiana|volume=46|issue=2–3|page=166}}

| subdivision =

• {{extinct}}M. suevica Klein, 1773
• {{extinct}}M. elliptica Miller, 1826

}}

Megateuthis is the largest known belemnite genus which lived during the Early to Middle Jurassic, between the Toarcian and Bajocian age. The type species M. suevica, whose junior synonym is M. gigantea, measured around {{convert|2.17|m|ft}} long, and the largest species M. elliptica possibly reached up to {{convert|3.11|m|ft}} long.{{Cite journal |last1=Klug |first1=C. |last2=Schweigert |first2=G. |last3=Hoffmann |first3=R. |last4=Fuchs |first4=D. |last5=Pohle |first5=A. |last6=Weis |first6=R. |last7=De Baets |first7=K. |year=2024 |title=Anatomy and size of Megateuthis, the largest belemnite |journal=Swiss Journal of Palaeontology |volume=143 |issue=1 |at=23 |doi=10.1186/s13358-024-00320-x |doi-access=free |pmc=11139743 }}