Proteroctopus

{{Short description|Genus of octopuses}}

{{Speciesbox

| fossil_range = Lower {{fossil range|Callovian}}

| image = Proteroctopus ribeti.jpg

| image_caption = Proteroctopus ribeti holotype.

| display_parents = 2

| taxon = Proteroctopus ribeti

| authority = Fischer & Riou, 1982

| synonyms =

}}

Proteroctopus, from Ancient Greek πρότερος (próteros), meaning "anterior", ὀκτώ (októ), meaning "eight", and πούς (poús), meaning "foot", is an extinct genus of cephalopod that lived in the Middle Jurassic, approximately 164 million years ago. It is only known from a single species P. ribeti. The single fossil specimen assigned to this species originates from the Lower Callovian of Voulte-sur-Rhône in France. It is currently on display at the Musée de Paléontologie de La Voulte-sur-Rhône.{{Cite journal | author=Fischer, J.C.|author2= B. Riou|year= 1982|title= Le plus ancien octopode connu (Cephalopoda, Dibranchiata): Proteroctopus ribeti nov. gen., nov. sp., du Callovien de l'Ardèche (France)|journal=Comptes Rendus de l'Académie des Sciences, Série II|volume=295|pages= 277–280}} While originally interpreted as an early octopus, a 2016 restudy of the specimen considered it to be a basal member of the Vampyropoda, less closely related to octopus or vampire squid than either of the two groups are to each other.{{Cite journal |last1=Kruta |first1=Isabelle |last2=Rouget |first2=Isabelle |last3=Charbonnier |first3=Sylvain |last4=Bardin |first4=Jérémie |last5=Fernandez |first5=Vincent |last6=Germain |first6=Damien |last7=Brayard |first7=Arnaud |last8=Landman |first8=Neil |date=November 2016 |editor-last=Korn |editor-first=Dieter |title=Proteroctopus ribeti in coleoid evolution |journal=Palaeontology |language=en |volume=59 |issue=6 |pages=767–773 |doi=10.1111/pala.12265|bibcode=2016Palgy..59..767K |s2cid=132420410 |doi-access=free }} A phylogenetic analysis by Kruta et. al indicates that Proteroctopus may be more closely related to the Vampyromorpha based on its unique morphology: two fins, head fused to the body, eight arms, two rows of oblique sucker, a gladius and absence of an ink sac. A 2022 phylogenetic analysis also found it to be more closely related to vampire squid than to octopuses.{{Cite journal |last1=Whalen |first1=Christopher D. |last2=Landman |first2=Neil H. |date=2022-03-08 |title=Fossil coleoid cephalopod fr-28333-5/ |journal=Nature Communications |language=en |volume=13 |issue=1 |pages=1107 |doi=10.1038/s41467-022-28333-5 |pmid=35260548 |pmc=8904582 |issn=2041-1723}}

The morphology of P. ribeti suggests a necto-epipelagic mode of life.