{{short description|Species of cephalopod known as the Atlantic white-spotted octopus}} {{Speciesbox | name = Atlantic white-spotted octopus | image = Octopus_macropus.jpg | image_caption = ''Callistoctopus macropus'' | status = LC | status_system = IUCN3.1 | status_ref = <ref name=IUCN>{{cite iucn |author=Allcock, L. |author2=Taite, M. |author3=Allen, G. |year=2018 |title=''Callistoctopus macropus'' |volume=2018 |article-number=e.T163354A1001383 |doi=10.2305/IUCN.UK.2018-2.RLTS.T163354A1001383.en |access-date=18 February 2022}}</ref> | genus = Pinnoctopus | species = macropus | authority = (Risso, 1826) | synonyms = {{Specieslist | Octopus macropus | Risso, 1826 | Callistoctopus macropus | (Risso, 1826) | Polypus macropus | (Risso, 1826) | Octopus didynamus | Rafinesque, 1814 | Octopus frayedus | Rafinesque, 1814 | Octopus granosus | Blainville, 1826 | Octopus macropodus | Sangiovanni, 1829 | Octopus alderii | Vérany, 1851 }} | synonyms_ref = <ref name = MolluscaBase>{{cite web |publisher=MolluscaBase eds |year=2025 |website=MolluscaBase |title=Pinnoctopus A. d'Orbigny, 1845 |url=https://www.molluscabase.org/aphia.php?p=taxdetails&id=341453 |access-date=3 March 2026}}</ref> }}
'''''Pinnoctopus macropus''''', also known as the '''Atlantic white-spotted octopus''', '''white-spotted octopus''',<ref name=Norman>Norman, M.D. 2000. ''Cephalopods: A World Guide''. ConchBooks.</ref><ref name="WoRMS">Bouchet, P. (2014). Callistoctopus macropus (Risso, 1826). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=534558 on 2015-02-01</ref> '''grass octopus''' or '''grass scuttle''', is a species of octopus found in shallow areas of the Mediterranean Sea, the warmer parts of the eastern and western Atlantic Ocean, the Caribbean Sea, and the Indo-Pacific region. This octopus feeds on small organisms which lurk among the branches of corals.
==Description== ''Pinnoctopus macropus'' grows to a mantle length of {{convert|20|cm|0|abbr=on}} with a total length of {{convert|150|cm|0|abbr=on}}. The first pair of arms are a metre or so long, and are much longer than the remaining three pairs. The arms are all connected by a shallow web. This octopus is red, with white blotches on its body, and paired white spots on its arms. When it is disturbed, its colour becomes more intense, deimatic behaviour which may make it appear threatening to a potential predator.<ref name=Bermuda>{{cite web |url=http://www.thecephalopodpage.org/MarineInvertebrateZoology/Octopusmacropus1.html |title=Grass octopus (''Octopus macropus'') |author=Wigton, Rachel |editor=Wood, James B. |work=Marine Invertebrates of Bermuda |publisher=The Cephalopod Page |access-date=2014-07-25 |archive-url=https://web.archive.org/web/20160119135721/http://www.thecephalopodpage.org/MarineInvertebrateZoology/Octopusmacropus1.html# |archive-date=2016-01-19 }}</ref>
==Distribution and habitat== Populations of ''Pinnoctopus macropus'' form a species complex found in the Mediterranean Sea, the temperate and tropical Atlantic Ocean and the Caribbean Sea. It is also present in the Pacific and Indian Oceans. It lives near the shore at depths down to about {{convert|17|m|0|abbr=on}}. Its favoured habitat is sand, rubble or seagrass meadows, and it sometimes buries itself under the sand.<ref name=Bermuda/>
==Ecology== left|thumb|upright|''Callistoctopus macropus'' ''Pinnoctopus macropus'' is more fastidious in its diet than is the common octopus (''Octopus vulgaris''), a species with which it shares some of its range and which feeds by day.<ref>{{cite journal |author1=Meisel, Daniela V. |author2=Byrne, Ruth A. |author3=Kuba, Michael |author4=Mather, Jennifer |author5=Ploberger, Werner |author6=Reschenhofer, Erhard |year=2006 |title=Contrasting activity patterns of two related octopus species, ''Octopus macropus'' and ''Octopus vulgaris'' |journal=Journal of Comparative Psychology |volume=120 |issue=3 |pages=191–197 |doi=10.1037/0735-7036.120.3.191 |pmid=16893256 }}</ref> ''Pinnoctopus macropus'', by contrast, feeds by night.<ref name=Bermuda/> Its method of feeding is to move from one clump of branching coral to another, often ''Acropora'' or ''Stylophora'' spp.. The octopus wraps its mantle around a coral head and probes with its arms among the branches, searching for the small fish and invertebrates that seek protection there. It has been found that a number of groupers (family Serranidae) and other predatory fish associate with the octopus when it is feeding, pouncing on small organisms that are flushed from the coral head by the octopus.<ref>{{cite journal |author1=Diamant, Ariel |author2=Shpigel, Mucky |year=1995 |title=Interspecific feeding associations of groupers (Teleostei: Serranidae) with octopuses and moray eels in the Gulf of Eilat (Agaba) |journal=Environmental Biology of Fishes |volume=13 |issue=2 |pages=153–159 |doi=10.1007/BF00002584 |s2cid=45887863 }}</ref>
For many years, the breeding habits of this octopus were not known. Then a female was observed attaching short-stalked eggs, measuring {{convert|4|by|1.2|mm|2|abbr=on}}, to a hard surface forming a sheet of eggs. The female then brooded the eggs, caring for them by aerating them and keeping them clean. The female octopus stopped feeding at the time the eggs were laid and died soon after they had hatched, as is common among octopus species. The planktonic larvae which emerged from the eggs were each about {{convert|5.5|mm|1|abbr=on}} in length with short, seven-suckered arms. They fed on zooplankton such as crustacean larvae.<ref name=Bermuda/><ref>{{cite journal |author1=Boletsky, Sigurd v. |author2=Fuentès, Michael |author3=Offner, Nicolas |year=2001 |title=First record of spawning and embryonic development in ''Octopus macropus'' (Mollusca: Cephalopoda) |journal=Journal of the Marine Biological Association of the UK |volume=81 |issue=4 |pages=703–704 |doi=10.1017/S002531540100443X |s2cid=85695823 }}</ref>
==References== {{Reflist}} * Norman M.D. & Hochberg F.G. (2005) ''The current state of Octopus taxonomy.'' Phuket Marine Biological Center Research Bulletin 66:127–154
==External links== * {{sealifephotos|534558}}
{{Edible molluscs}}
{{Taxonbar|from1=Q13449622|from2=Q2235326}}
Category:Octopodidae Category:Molluscs of the Atlantic Ocean Category:Molluscs of the Indian Ocean Category:Molluscs of the Mediterranean Sea Category:Molluscs of the Pacific Ocean Category:Fauna of the Caribbean Category:Marine molluscs of Africa Category:Marine molluscs of Europe Category:Marine molluscs of North America Category:Cephalopods of Europe Category:Cephalopods described in 1826 Category:Taxa named by Antoine Risso