Cephalopod size 

The giant squid (Architeuthis sp.) was for a long time thought to be the largest extant cephalopod. It is now known that the Colossal Squid (Mesonychoteuthis hamiltoni) attains an even greater size.

Size has been one of the most interesting aspects of cephalopod science to the general public. This article lists the largest cephalopods from various groups, sorted in order of mantle length, total length, weight, and shell diameter. Extinct taxa are also included.

Contents

Mantle length

Haliphron atlanticus (ML: 0.69 m), the largest known octopus specimen.
The Colossal Squid (Mesonychoteuthis hamiltoni) caught in early 2007 is the largest cephalopod ever recorded.
Octopoda (octopuses)
Species Maximum mantle length References Notes
Haliphron atlanticus 0.69 m O'Shea (2004)
Enteroctopus dofleini 0.6 m Norman (2000:214)
Sepiida (cuttlefish)
Species Maximum mantle length References Notes
Sepia apama 0.5 m Reid et al. (2005:68)
Sepia latimanus 0.5 m Reid et al. (2005:92)
Sepia officinalis 0.49 m Reid et al. (2005:99)
Sepia pharaonis 0.42 m Reid et al. (2005:107)
Sepiolida (bobtail squid)
Species Maximum mantle length References Notes
Euprymna stenodactyla 0.19 m Okutani (1995)
Spirulida (Ram's Horn Squid) (only one extant species)
Species Maximum mantle length References Notes
Spirula spirula rarely exceeds 0.045 m Reid et al. (2005:211)
Teuthida (squid)
Species Maximum mantle length References Notes
Mesonychoteuthis hamiltoni 4 m (estimate) O'Shea (2005a) Estimate based on largest known beak (LRL: 49 mm).
Galiteuthis phyllura 2.65-2.75 m (estimate) Nesis (1985) Estimate based on 0.4 m long arm and 1.15 m tentacle.
Architeuthis sp. 2.25 m O'Shea (2005a)
Moroteuthis robusta 2 m Norman (2000:174) Kubodera et al. (1998) give maximum of at least 1.615 m.
Megalocranchia fisheri 1.8 m Tsuchiya & Okutani (1993)
Taningia danae 1.7 m Nesis (1982)
Dosidicus gigas 1.5 m Norman (2000:165)
Kondakovia longimana probably 1.15+ m (estimate) O'Shea (2005b) Longest confirmed specimen measures 0.85 m (O'Shea, 2005b). Total length to at least 2.3 m (Carrington, 2000).
Thysanoteuthis rhombus 1 m Roper et al. (1984) Commonly grows to a mantle length of 0.6 m (Roper et al., 1984).
Vampyromorphida (Vampire Squid) (only one extant species)
Species Maximum mantle length References Notes
Vampyroteuthis infernalis 0.13 m Nesis (1982)

The taxonomy of the giant squid has not been entirely resolved. Lumpers and splitters may propose as many as eight species or as few as one. No genetic or physical basis for distinguishing between the named species has been proposed.

Total length

A long-arm squid (cf.Magnapinna) filmed in the Gulf of Mexico.
Octopoda (octopuses)
Not to be confused with armspan, which is approximately double the total length.
Species Maximum total length References Notes
Enteroctopus dofleini > 6.1 m Cosgrove (1987)
Haliphron atlanticus 4 m (estimate) O'Shea (2004) Estimate based on incomplete 2.90 m specimen.
Teuthida (squid)
Total length including long feeding tentacles.
Species Maximum total length References Notes
Mesonychoteuthis hamiltoni 14 m (estimate) O'Shea (2005a) Estimate based on largest known beak (LRL: 49 mm).
Architeuthis sp. 13 m (female) O'Shea (2005a) Measured post mortem and relaxed. Older records were exaggerated by stretching of the tentacles (O'Shea, 2005a).
cf.Magnapinna at least 8 m (estimate) Bolstad (2003) Estimate based on video evidence.
Asperoteuthis acanthoderma 5.5 m Tsuchiya & Okutani (1993) Length of immature specimen measuring 0.45 m ML. Largest known specimen (0.78 m ML) would presumably be longer if it were complete (Okutani, 1995).
Moroteuthis robusta over 4 m Verrill (1876)
Galiteuthis phyllura over 4 m (estimate) Nesis (1985) Estimate based on 0.40 m long arm and 1.15 m tentacle.

Weight

North Pacific Giant Octopus, Enteroctopus dofleini.
Octopoda (octopuses)
Species Maximum weight References Notes
Haliphron atlanticus 75 kg (estimate) O'Shea (2004) Estimate based on incomplete 61.0 kg specimen.
Enteroctopus dofleini 71 kg Cosgrove (1987) Weight of live specimen. There exists a highly dubious record of a 272 kg specimen (High, 1976).
Sepiida (cuttlefish)
Species Maximum weight References Notes
Sepia apama in excess of 10.5 kg Reid et al. (2005:68)
Sepia latimanus 10 kg Reid et al. (2005:92)
Sepia pharaonis 5 kg Reid et al. (2005:107)
Sepia officinalis 4 kg Reid et al. (2005:99)
Teuthida (squid)
Species Maximum weight References Notes
Mesonychoteuthis hamiltoni 495 kg [Anonymous] (2007) Weight of mature specimen caught in early 2007. Originally estimated to weigh 450 kg (Anderton, 2007).
Architeuthis sp. 275 kg (female) O'Shea (2005a)

Shell diameter

Nautilus shells: N. macromphalus (left), A. scrobiculatus (centre), N. pompilius (right).
Argonauta hians shell, 121.5 mm in diameter.
Internal shell of Spirula spirula.
Nautilida (nautiluses) (all extant species listed)
Species Maximum shell diameter References Notes
Nautilus pompilius pompilius 268 mm [1] Pisor (2005:93) lists maximum shell diameter of 254.0 mm. Nautilus repertus is treated here in synonymy with N. pompilius pompilius. Pisor (2005:93) lists 230.0 mm record for N. repertus.
Nautilus belauensis 226 mm Jereb (2005:54)
Allonautilus scrobiculatus 215.0 mm Pisor (2005:93)
Nautilus stenomphalus 201.0 mm Pisor (2005:93)
Allonautilus perforatus around 180 mm Jereb (2005:55)
Nautilus macromphalus 180.0 mm Pisor (2005:93)
Nautilus pompilius suluensis 148.0 mm Pisor (2005:93)
Octopoda (octopuses) (all extant Argonauta species listed)
Females of the genus Argonauta produce a calcareous eggcase in which they reside.
Species Maximum shell diameter References Notes
Argonauta argo 300.0 mm Pisor (2005:12)
Argonauta nodosa 292.0 mm Pisor (2005:12)
Argonauta pacifica 220.0 mm Pisor (2005:12)
Argonauta hians 121.5 mm Pisor (2005:12) lists maximum shell diameter of 112.6 mm.
Argonauta cornuta 98.6 mm Pisor (2005:12)
Argonauta nouryi 95.5 mm Pisor (2005:12)
Argonauta bottgeri 67.0 mm Pisor (2005:12)
Spirulida (Ram's Horn Squid) (only one extant species)
The Ram's Horn Squid possesses a chambered internal shell, which it uses for buoyancy control.
Species Maximum shell diameter References Notes
Spirula spirula 28.8 mm [2] Pisor (2005:108) lists maximum shell diameter of 26.9 mm.

Species status questionable.

Extinct taxa

Cast of Parapuzosia seppenradensis
Ammonoidea (ammonites)
Species Maximum shell diameter References Notes
Parapuzosia seppenradensis 2.55 m (estimate) Kennedy & Kaplan (1995) Estimate based on 1.95 m diameter specimen with an incomplete living chamber.
Belemnoidea (belemnites)
Species Maximum rostrum length References Notes
Megateuthis gigantea 0.46 m Eyden (2003) The whole belemnite is estimated to have been 3-5 m long.
Nautiloidea (nautiloids)
Species Maximum shell length References Notes
Cameroceras sp. 11 m (estimate) Teichert & Kummel (1960)
Vampyromorphida (vampire squid)
Species Maximum mantle length References Notes
Tusoteuthis longa over 1.8 m (estimate) Eyden (2004)

References