Opisthoteuthis massyae

{{Short description|Species of mollusc}}

{{Speciesbox

| status = VU

| status_system=IUCN3.1

| status_ref={{cite iucn |author=Lyons, G. |author2=Allcock, L. |date=2014 |title=Opisthoteuthis massyae |volume=2014 |page=e.T163141A976478 |doi=10.2305/IUCN.UK.2014-3.RLTS.T163141A976478.en |access-date=19 November 2021}}

| genus = Opisthoteuthis

| species = massyae

| authority = Grimpe, 1920{{cite web |title=Opisthoteuthis massyae |url=http://marinespecies.org/aphia.php?p=taxdetails&id=153060 |website=World Register of Marine Species |publisher=Flanders Marine Institute}}

| synonyms =

• Cirroteuthis massyae Grimpe, 1920
• Cirroteuthopsis massyae Grimpe, 1920
• Opisthoteuthis vossi Sanchez and Guerra, 1989
• Cirroteuthis massyae Grimpe, 1920

}}

Opisthoteuthis massyae is an octopus living in the eastern Atlantic Ocean.

O. massyae occupies the benthic zone (seafloor and water immediately above) of the open ocean. The octopus lives from {{convert|600|m|ft|abbr=on}} to {{convert|1,500|m|ft|abbr=on}} deep. It's found as far north as Ireland, in the Rockall Basin,{{cite book |author1=M.A. Collins |author2=R. Villanueva |editor1-last=Gordon |editor1-first=J.D.M. |editor2-last=Atkinson |editor2-first=R.J.A. |editor3-last=Gibson |editor3-first=R.N. |title=Oceanography and Marine Biology: An Annual Review, Volume 44 |date=June 13, 2006 |isbn=9781420006391 |page=297 |url=https://books.google.com/books?id=R7-TfdYeLEgC |chapter=Taxonomy, ecology and behaviour of the cirrate octopods.|publisher=CRC Press }} and as far south as Namibia.{{cite book |last1=Jereb |first1=P. |title=Cephalopods of the World: An Annotated and Illustrated Catalogue of Cephalopod Species Known to Date · Volume 3 |date=2005 |publisher=Food and Agriculture Organization of the United Nations |isbn=9789251079898 |page=256 |url=https://books.google.com/books?id=f_F5DwAAQBAJ}} There are more specimens in the southeast Atlantic than in the northeast Atlantic.

The two foremost arms of mature males are thicker than their other six arms. This is unusual for Opisthoteuthis species. Mature males also have some enlarged suckers, which is more typical of the genus. Males have more suckers than females.{{cite web |last1=Young |first1=Richard E. |last2=Vecchione |first2=Michael |last3=Villanueva |first3=Roger |title=Opisthoteuthis massyae |url=http://tolweb.org/Opisthoteuthis_massyae/20161 |website=Tree of Life Web Project |date=2003}} Specimens with longer arms generally have more suckers.{{cite journal |last1=Sánchez |first1=P. |last2=Villanueva |first2=R. |last3=Voss |first3=N.A. |title=Systematics, distribution and biology of the cirrate octopods of the genus Opisthoteuthis (Mollusca, Cephalopoda) in the Atlantic Ocean, with description of two new species |journal=Bulletin of Marine Science |date=2002 |volume=71 |issue=2 |page=933-985 |url=http://www.marinespecies.org/imis.php?module=ref&refid=40633 |issn=0007-4977}} Males weigh more than females; males can reach a weight of {{convert|5,750|g|lbs|abbr=on}}, and females a weight of {{convert|2,959|g|lbs|abbr=on}}. Females may lay eggs throughout their lifetimes.

O. massyae has the ability to invert or "balloon" their webs.{{efn|See the external links section for photographs of this behavior.}} O. massyae is a carnivore; it probably catches prey by enveloping small animals within its web, similar to some other cirrate octopods.{{cite journal |title=Laboratory Observations of the Feeding Behavior of the Cirrate Octopod, Grimpoteuthis sp.: One Use of Cirri |author1=California Malacozoological Society |journal=The Veliger |date=1999 |volume=42 |issue=2 |page=156 |url=https://www.biodiversitylibrary.org/name/Opisthoteuthis_vossi# |issn=0042-3211}} It eats a variety of small prey: gammarid amphipods, polychaetes, decapods, opossum shrimp, copepods, isopods, tanaids, marine snails, marine slugs, and bivalves.{{cite book |author1=M.A. Collins |author2=R. Villanueva |editor1-last=Gordon |editor1-first=J.D.M. |editor2-last=Atkinson |editor2-first=R.J.A. |editor3-last=Gibson |editor3-first=R.N. |title=Oceanography and Marine Biology: An Annual Review, Volume 44 |date=June 13, 2006 |isbn=9781420006391 |page=308 |url=https://books.google.com/books?id=R7-TfdYeLEgC |chapter=Taxonomy, ecology and behaviour of the cirrate octopods.|publisher=CRC Press }}

Although O. massyae isn't used commercially, it's often taken as bycatch by commercial fishing vessels. This threatens its population.