INTRODUCTION TO FACT SHEETS

Two fins

A mantle

A head

8 arms and two tentacles, each endowed with hooks and/or suckers and sucker rings (Figs 1—4)

A mantle

A head

8 arms endowed with one or two rows of suckers (but never hooks or sucker rings); they have no tentacles (Fig. 5)

The relatively short arms are endowed with a combination of hooks and suckers.

The tentacle club, the expanded distal portion of the tentacle, is endowed with two rows of swivelling hooks (Figs 3, 4)

The beaks are the largest known of any squid (Figs 9, 10), exceeding those of Architeuthis in size and robustness

in size and robustness The eyes are probably the largest in the animal kingdom (even larger than those of Architeuthis )

) The 'colossal' cranchiid squid Mesonychoteuthis hamiltoni is thought to be the largest of all Recent cephalopods. However, due to lack of material, and the fragmentary, partially digested or juvenile nature of almost every previously reported specimen, the biology and morphology of this species have remained poorly known.

To ensure accurate reporting of these squid species, the following brief notes have been prepared. First, a simplified account of squid morphology (Fig. 1), where we detail the differences between squid and octopus; second, an introduction to size and how it has been measured (and misreported); and third, an introduction to the two species that you will be hearing a lot about: Colossal Squid () and Giant Squid ().We already have online an introduction to octopus and squid anatomy in our article, Deep-Sea Cephalopods: An Introduction and Overview , so will not unnecessarily duplicate that information. For the sake of this article we will focus on the absolute basics of cephalopod anatomy, and some frequently cited measures, particularly Mantle Length (ML), Standard Length (SL), and Total length (TL).A basic squid has:A basic octopus has:Some squid naturally lose the tentacles in post-larval stages, so that the adult possesses 8 arms only; some squid can have more than 2 fins. Some octopuses (9 species in New Zealand waters) possess two well-developed fins; these 9 species also have a well-developed pen (like a cuttlebone ) in their mantle, and are considered rather primitive, commonly referred to as 'Dumbo Octopuses'.The only universal distinction between a squid and an octopus is that the suckers of squid are armed with hooks or sucker rings (or a combination of the two), while octopus have simple suckers without secondary armature (Fig. 5). It is the squids' hooks and rings that have enthralled the public most. You will find additional information on squid and octopus in our Guide to Frequently Used Characters, Character States and Measures With this basic introduction to octopus and squid anatomy aside, we can move on to the real purpose of this fact sheet.(Figs 6–9):Quite a lot – check out these popular articles:There is also a tremendous body of scientific literature available for this species.The juvenile was caught and filmed live by Dr Steve O'Shea in 2001; unfortunately all died before they could be grown in captivity. The adult was photographed live off Japan in a series of stills by Dr Tsunemi Kubodera in September 2004; the adult was subsequently filmed live at the surface off Japan in December 2006, also by Dr Tsunemi Kubodera.is frequently misreported to attain a total length of 20 metres (~65 feet). However, the largest specimen known washed ashore on a New Zealand beach, Lyall Bay (Wellington) in the winter of 1887. It was a female and "in all ways smaller than any of the hitherto-described New Zealand species", according to Kirk (1887), the gentleman who described this very specimen. Apparently it measured 55 feet 2 inches in total length (16.8m), but this simply cannot be correct, and this length almost certainly is a product of imagination or lengthening (stretching like rubber bands) of the very slight tentacular arms, as it mantle was only 71 inches long (1.8m). We know that it was not measured with a conventional tape, but was paced, as Kirk says so in his publication. A comparable-sized female (ML 1.8m) measured post mortem and relaxed (by modern standards) today would have a total length of ~32 feet (9.8m).Mantle length (as opposed to total length) is the standard measure in cephalopods. Of more than 130specimens that the authors have examined, none has attained a mantle exceeding 2.25m (7.4 feet), or total length of 13m (42 feet).Standard Length (SL) is the length of a squid excluding the tentacles; inthis measure very rarely exceeds 5m. The rest of the animal's length, to a total length of 13m, is made up of the two long tentacles. Of more than 130 specimens that we have examined, none has exceeded these figures (Fig. 7).beaks recovered from the stomachs of sperm whales are smaller than or of comparable size tobeaks recovered from specimens trawled in New Zealand waters. Therefore, since we believe sperm whales capable of catching even the largest giant squid, no evidence exists for recognising larger specimens than those that are currently known. Moreover, it is most likely that a single species,, exists worldwide, so 'larger species' ofdo not occur. Accordingly, to perpetuate myths ofto 20 metre lengths (60 feet) and weights of up to 1000kg (a ton, or 2205lbs) is a disservice to science.On April 1, 2003 the popular press was first alerted to the Colossal Squid, a.k.a., although this species has been known to the scientific community since 1925, after it was described from two arm (brachial) crowns recovered from sperm whale stomachs (Robson 1925). We have located 11 further reports in which adult and subadult specimens have been described, and are aware of at least 7 further, similarly sized specimens that have yet to be reported. Juveniles of this species are not uncommon from surface waters to ~1000m depth.Otherwise this species doesn't really differ from any other cranchiid squid (Family Cranchiidae) in any remarkable manner, with the exception of its size.is actually a quite-well studied species, with 11 specimens above juvenile size (arbitrarily taken as 90mm ML), including the two Syntypes, having been reported since 1925. McSweeny (1970) provides a complete description of the juvenile of this species. Klumov & Yukhov (1975, in Russian) describe several (possibly 5) specimens of ML 390–1550mm, and offer a detailed account of hook, radular, beak, gladius, photophore, arm, tentacular club, and spermatophore morphology. Voss (1980) describes a subadult female of ML 1.25m and refers to ‘several large partial specimens' (brachial crowns) in collections of the United States National Museum, Smithsonian Institution. Rodhouse & Clarke (1985) report a further specimen, ML 1.05m, trawled at a depth of 2000-2200m. Finally, Lu & Williams (1994) briefly report two specimens (one male, 107mm ML, and one female, 118mm ML), from a midwater trawl in Prydz Bay, Antarctica. Several additional authors have touched on various aspects of the species' anatomy in other papers: Clarke (1962, 1980) describes and illustrates the beaks; Engeser & Clarke (1988) illustrate both arm and tentacular hooks; Young (1984) illustrates the statocyst; Herring. (2002) further describe the ocular photophores on the specimen reported by Rodhouse & Clarke (1985); and Xavier. (2003) report a single tentacle fromrecovered from a longline hook off South Georgia. Clarke (1966) refers to 'several complete specimens... collected from sperm whale stomachs in the Antarctic,' the largest of which had a ML of 2–2.25m, but it is not certain whether either of these specimens has been reported on or described further; the location of these specimens also is unknown.Further information has been gleaned from gut-content analysis of its predators, primarily sperm whales, wandering albatross, Patagonian and Antarctic Toothfish, and sleeper sharks. Even the first two described specimens of this species were recovered from the stomach of a sperm whale, although they are undetermined sex and are in poor condition.Based on all sources,appears to be abundant in the Antarctic, and important in the diets of apex predators such as the sperm whale (76–77% of male whale diet (Clarke 1980, Rodhouse & Clarke 1985) and sleeper shark (52% by weight (Cherel & Duhamel 2004).This species attains the greatest weight, but not necessarily greatest length of all squid species, and is known to attain a mantle length of at least 2.5m. Should accounts relayed to us be correct, the largest specimen that we will be defrosting at the end of April 2008 has a ML of 4m.In the absence of numerous specimens taken from a variety of localities (with the exception of paralarvae (relatively tiny juveniles), known to have circumpolar Antarctic distribution (Voss 1980, Nesis 2003)), the life history and zoogeography ofmust be inferred from more indirect sources. Although predators are useful in providing some information on large squid species (perhaps our best source at present), deriving information on the geographic distribution of prey species solely from gut content specimens is risky (O'Shea 2007). Certain predators ofare known to undertake extensive migrations; wandering albatross range in excess of 1200 km from their nest sites on average in search of prey (Jouventin & Weimerskirch 1990) and sperm whales are also known to migrate thousands of kilometres.Popular press has focussed on the size of this squid, and there has been considerable debate at an academic level as to whether the Colossal Squid is actually the largest squid, because the Giant Squid,, attains a greater total length.There are several ways in which squid are measured (and in which their size or length may be exaggerated): Total Length relaxed (post mortem); Total Length when the animal is live (and outstretched); Standard Length, the length of the animal minus its two long tentacles; estimated length (the one that got away); weight; and, most inappropriately, length relative to a London double-decker bus.As this Colossal Squid is likely to make international press, information often is misquoted. For your ease we've provided a few conversions below:1 foot = 0.3048 metres (alternatively, 1 metre = 3.2808 feet)1 kilogram = 2.2 pounds (alternatively, 1 pound = 0.5kg)Therefore, a 2.5m ML Colossal Squid of 300kg is equivalent to an 8.202 foot ML Colossal Squid weighing 660 lbs; the 495kg Colossal Squid to be defrosted at the end of April 2008 weighs in at a colossal 1089 lbs.The specimen reported on April 1, 2003 was a submature female of ML 2.5 m; despite it being extensively damaged it weighed ~300kg, and had a Total Length of 5.4m. At the time it was both the heaviest squid known to science, and squid with the longest mantle (reliable measures). The lower beak of this particular specimen had a rostral length (LRL) of 38mm. Lower beaks ofare known to 49mm LRL, so we know that this species grows considerably larger. In late April we actually will be examining at least four: the 495kg specimen; a second, evidently extensively damaged specimen weighing ~150kg; and several considerably smaller specimens more recently taken in Antarctic waters.Just how big doesget? Well, we don't know; the largest LRL currently known measures 49mm. The first thing that we will do when this specimen is completely defrosted is measure LRL, and should this be less than 49mm we will know thatgets even larger and heavier than the specimen we have.Next we will determine the sex of the specimens (as a rule female squid attain a larger size than males), and their state of reproductive maturity will be appraised. Both sex and an indication of maturity provide insights into the realistic maximum size of a species.Beaks attributed to this species have previously been encountered in stomachs of sperm whales caught in or proximal to northernmost eastern and western New Zealand waters (Clarke & MacLeod 1982), from one stranded specimen on Paekakariki Beach (Clarke & Roper 1998), and otherwise from numerous stranded specimens from beaches around New Zealand (Gomez-Villota 2007). They are also reported from wandering albatross chick regurgitations from Antipodes Islands (Imber 1992) and immediately south of New Zealand (Australian waters), Macquarie Island (Imber 1978, 1992). However, despite these five citations from local waters, and a sixth, as yet unpublished Macquarie Island record (an actual specimen trawled from 1143m), none of them confirms that the species occurs here, as wandering albatross,, average in excess of 1200 km from the nest site in search of prey (Jouventin & Weimerskirch 1990), and sperm whales, especially large males, undertake extensive migrations (O'Shea 1997).beaks have been reported from sperm whale stomachs captured off California (Fiscusl. 1989), so the whales obviously retain some beaks in the stomach for considerable periods of time.The occurrence ofbeaks in stomachs of female and small male sperm whales is intriguing, as these predators normally occur north of 40°S, while the squid are primarily reported from south of 40°S. Therefore, presently known from Antarctic waters, could extend as far north as 40°S, with the Subtropical Convergence delimiting the species' northern distribution (Clarke 1980). If true this would place this species in New Zealand waters, extending from a latitude equivalent to Christchurch through to the Chatham Islands.In the southern hemisphere, female and young male sperm whales (to ~39 feet in length) are not normally found in latitudes higher than 40°S, while large males occur in Antarctic waters; large bulls must migrate from the lower-latitude breeding areas into colder Antarctic waters (the smallest male reported from the Antarctic was 35 feet in length (Clarke 1972). The male stranded on Mahia Peninsula 28/11/2002 was 13 metres (42 feet) in length, and its stomach contained 7 lowerbeaks. It had probably only recently migrated back from the Antarctic, and had likely made few migrations to the region in its life.: between Macquarie Island and Stewart Island, ~140 n. miles south of New Zealand waters, an immature female, ML (when fresh) 0.9m (coordinates 53° 49.30'S, 159° 04.44'E), from 1143m.: Unknown; mature male unknown.: tentacle club of, showing circular-saw-like sucker rings.: tentacle club of, with swiveling hooks.: Profile oftentacle club, showing hooks.: Suckers of, the giant gelatinous octopus (the world's largest species of octopus), lacking secondary armature.: size comparison ofand, based on accounts of maximum mantle length.: size comparison of mature Mesonychoteuthis (left) Architeuthis (right) beaks recovered from sperm whale stomachs.Cherel, Y.; Duhamel, G. 2004. Antarctic jaws: cephalopod prey of sharks in the Kerguelen waters.: 17–31.Clarke, M.R. 1962. The identification of cephalopod "beaks" and the relationship between beak size and total body weight.: 419–480.Clarke, M. 1966. A review of the systematics and ecology of oceanic squids.4: 91–300.Clarke, M.R. 1980. Cephalopoda in the diet of sperm whales of the southern hemisphere and their bearing on sperm whale biology.: 324 pp.Clarke, M.R.; MacLeod, N. 1982. Cephalopod remains from the stomachs of sperm whales caught in the Tasman Sea.: 25–42.Clarke, M.R.; Roper, C.F.E. 1998. Cephalopods represented by beaks in the stomach of a sperm whale stranded at Paekakariki, North Island, New Zealand.: 129–133.Engeser, T.S.; Clarke, M.R. 1988. Cephalopod hooks, both recent and fossil.: 133–150.Fiscus, C.H.; Rice, D.W.; Wolman, A.A. 1989. Cephalopods from the stomachs of sperm whales taken off California.: 1–12.Gomez-Villota F 2007. Sperm whale diet in New Zealand. Unpublished MAppSc thesis. Division of Applied Sciences, Auckland University of Technology, Auckland, New Zealand. 221 p.Herring, P.J.; Dilly, P.N.; Cope, C. 2002. The photophores of the squid family Cranchiidae (Cephalopoda: Oegopsida).: 73–90.Imber, M.J. 1978. The squid families Cranchiidae and Gonatidae (Cephalopoda: Teuthoidea) in the New Zealand region.: 445–484.Imber, M.J. 1992. Cephalopods eaten by wandering albatrosses (L.) breeding at six circumpolar localities.: 243–263.Kirk, T.W. 1887. Brief description of a new species of large decapod () .20: 34–39 + 3 Pls.Klumov, S.K.; Yukhov, V.L. 1975.Robson, 1925 and its importance in the feeding of sperm whales in the Antarctic.14: 159–189. [Russian]Lu, C.C.; Williams, R. 1994. Contribution to the biology of squid in the Prydz Bay region, Antarctica.: 223–229.McSweeny, E. 1970. Description of the juvenile form of the Antarctic squidRobson.: 323–332.Nesis, K.N. 2003. Distribution of Recent Cephalopoda and implications for Plio-Pleistocene events.: 199–224.O'Shea, S. 1997. Status of three Octopoda recorded from New Zealand, based on beaks recovered from long-distance foraging marine predators.: 265–266.Robson, G.C. 1925. On, a new genus of oegopsid Cephalopoda.: 272 –277, 2 figures.Rodhouse, P.G.; Clarke, M.R. 1985. Growth and distribution of youngRobson (Mollusca: Cephalopoda): an Antarctic squid.: 223–230.Voss, N.A. 1980. A generic revision of the Cranchiidae (Cephalopoda: Oegopsida).: 365–412.Xavier, J.C.; Croxall, J.P.; Trathan, P.N.; Rodhouse, P.G. 2003. Inter-annual variation in the cephalopod component of the diet of the wandering albatross,, breeding at Bird Island, South Georgia.: 611–622.Young, J.Z. 1984. The statocysts of cranchiid squids (Cephalopoda).: 1–21.Steve and Kat welcome discussion in the Physiology & Biology forum of the TONMO.com Message Board.-- Last updated: April 6, 2008