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Giant Squid and Colossal Squid Fact SheetBy Dr. Steve O'Shea
Last updated: 5/6/03
Note: Steve welcomes discussion in the Physiology & Biology forum of the TONMO.com Message Board.
INTRODUCTION TO FACT SHEETS
To ensure accuracy in reporting of these squid 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 we believe that we are reporting on: Colossal Squid (Mesonychoteuthis hamiltoni), Giant Warty Squid (Kondakovia longimana), with a comparison made to the Giant Squid (Architeuthis dux).
Frequently cited acronyms in text are: Mantle length (ML), and Total length (TL)
1. Introduction to squid anatomy
A standard squid has:
A standard 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 (nine species in New Zealand waters) possess two well-developed fins. These nine species also have a well-developed pen (like a cuttlebone) in their mantle (primitive condition).
The major distinction between squid and 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).
Foreword: On the basis of photographs advanced by the National Museum of New Zealand, Te Papa Tongarewa, we have identified the specimens to be reported on Wednesday as Mesonychoteuthis hamiltoni and Kondakovia longimana. However, identification based solely on photographs must be treated as provisional at best. Close examination of the specimens could reveal initial identifications to be incorrect, and possibly that they represent new species.
2. Size Popular press concentrates on the issue of size. There are several ways in which the size of a squid is reported (and misreported or exaggerated). Measured total length relaxed (post mortem), total length when the animal is alive (and outsretched), both including tentacles; estimated length (the one that got away); and weight.
Architeuthis is frequently reported to attain a lotal length of 60 feet. 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" (Kirk 1887); it measured 55 feet 2 inches in total length, exaggerated by great lengthening (stretching like rubber bands) of the very slight tentacular arms; its mantle length was 71 inches (1.8 m). A comparable-sized female (ML 1.8 m) measured post mortem and relaxed (by modern standards) would have a total length of ~ 32 feet.
Mantle length (as opposed to total length) is the standard measure in cephalopods. Architeuthis is not known to attain a mantle length in excess of 2.25 m. Standard Length (SL) is the length of a squid excluding the tentacles; in Architeuthis this measure very rarely exceeds 5 m. The rest of the animal's length, to a total length of 13 m, is made up of the two long tentacles. Of 105 specimens that we have examined, none has exceeded these figures (Fig. 7).
Architeuthis beaks recovered from the stomachs of sperm whales are smaller or equivalent to Architeuthis beaks recovered from specimens trawled in New Zealand waters. That is to say that no evidence exists for recognising larger specimens than those known from New Zealand. Moreover, it is most likely that a single species, Architeuthis dux, exists worldwide, so 'larger species' of Architeuthis do not occur. To perpetuate myths of more than one species of Architeuthis (up to 20 species have been reported), lengths of 60 feet and weights of up to a ton is a disservice to science.
No mature Mesonychoteuthis is known. Based on the size of beaks recovered from sperm whale stomach contents it is estimated that it attains a mantle length of 2—4 m, which would render it considerably larger than Architeuthis (Fig. 8). The specimen that we will examine in Wellington will first be sexed (female squid often attain a larger size than male squid), then its state of reproductive maturity will be appraised. Both sex, an indication of whether a specimen has mated or not, and the stage of maturity provide insights into the realistic maximum size of a species.
The beaks will be extracted, measured and compared with the largest beaks of this species we have available in New Zealand, recovered from sperm whale stomach contents (Fig. 9). Should the beaks from sperm whale stomach contents be appreciably larger than those from the present carcass, then we can say that the animal does attain a considerably larger size. If not then it would appear that the reputed size that this animal attains has again been exaggerated, as it has for over a century with Architeuthis.
3. Fact sheet
Mesonychoteuthis hamiltoni is reputed to attain a greater size than the giant squid (Architeuthis dux). Oddly enough, few people are aware of its existence. Living at depths in excess of 1000 m, and temperatures near freezing in Antarctic waters, adults of this species are exceedingly rare (in collections). Because the environment in which it lives has been so poorly sampled, its life history, diet and behaviour are unknown.
This species was first described on the basis of two arm (brachial) crowns recovered from sperm whale stomach contents (Robson 1925). Subsequently few specimens have been collected. A sub-mature female of mantle length (ML) 1.25 m is described by Voss (1980), and reference made to two other partial specimens (brachial crowns) in the collections of the United States National Museum, Smithsonian Institution. A further specimen, ML 1.05 m, was trawled in an opening-closing net (RMT8) at a depth of 2000—2200 m (Rodhouse & Clarke 1985). None, to our knowledge, have been reported subsequently.
Six specimens reported; no comprehensive description of the mature adult, male or female, is known.
Recognised distribution: Cosmopolitan throughout Sub-Antarctic to Antarctic waters. Probably extending into southern New Zealand waters.
Publication: In a New Zealand journal by mid-2003 (submission date)—probably New Zealand Journal of Zoology.
Estimated mantle length: 2—4m; total length to 30 feet. Based on a combination of beak dimension, and both factory ship and photographic observations, Clarke (1986: 202) suggests Mesonychoteuthis attains a mantle length in excess of 2 m, possibly exceeding 4 m. Nesis (1987) reports mantle lengths of 2.0—2.25 m, but it is uncertain whether these measures are based on actual specimens, or estimates of size based on beak remains from stomach contents of sperm whales. This is a mantle length equivalent to that of the largest of 105 Architeuthis specimens examined by the authors.
The lower beak standard measurement of rostrum length (LRL) 22.0 mm reported for 1.05 m specimen (Rodhouse & Clarke 1985) is considerably shorter than the greatest LRL described for this species, 48.0 mm (a measure taken from the largest beak known from the stomach of sperm whales). Therefore Mesonychoteuthis obviously attains a size considerably exceeding 1.05 m ML.
New Zealand specimens (trawled): none.
New Zealand reports based on analysis of stomach contents of long-distance foraging marine predators (whales, albatross): 5. 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 Mahia (herein). 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 the sixth Macquarie record, none of them confirms that the species occurs here, as wandering albatross, Diomedia exulans, 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). Mesonychoteuthis beaks have been reported from sperm whale stomachs captured off California (Fiscus et al. 1989), so the whales obviously retain some beaks in the stomach for considerable periods of time.
The occurrence of Mesonychoteuthis beaks in stomachs of female and small male sperm whales is intriguing, as these predators normally occur north of 40癝, while the squid are primarily reported from south of 40癝. Therefore Mesonychoteuthis, presently known from Antarctic waters, could extend as far north as 40癝, with the Subtropical Convergence delimiting the species' northern distribution (Clarke 1980). If true this would place this species in New Zealand waters, extending from ~ Christchurch 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癝, 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 (~ 40 feet) in length, and its stomach contained 7 lower Mesonychoteuthis beaks. It had probably only recently migrated back from the Antarctic, and had likely made few migrations to the region in its life.
Closest record (unreported): between Macquarie Island and Stewart Island, ~ 140 n. miles south of New Zealand waters, an unreported female of mantle length 0.9 m (coordinates 53�.30'S, 159�.44'E) at a depth of 1143 m.
Abundance: Rodhouse & Clarke (1985) consider M. hamiltoni to be a major prey item of sperm whales in the Southern Ocean. Beaks comprise 14 % of the numbers found in sperm whale stomachs from the Antarctic and, because of the large size of the species, this represents an estimated 77 % of the biomass consumed.
Reproduction: Unknown; mature male unknown.
One method of reproduction has been proposed for a related species, Teuthowenia pellucida, but is unknown for Mesonychoteuthis hamiltoni. In Teuthowenia the male embeds spermatophores (packets of sperm) externally into the anterior half of the female's mantle. The sperm reservoirs penetrate the inner wall and release sperm into the mantle cavity, where fertilisation of mature eggs leaving the oviducal glands apparently occurs. The large, swollen nidamental glands seen in mature females suggest that the eggs are released in one or more gelatinous egg masses. Mature females possess 6000—8000 eggs of 3.0 mm maximum diameter (Voss 1985).
Mesonychoteuthis lacks a hectocotylus – a specially modified arm used to transfer spermatophores to the female. As a rule, species that lack a hectocotylus have a relatively large penis, and presumably they use this organ directly to implant spermatophores hydraulically into the female. As no mature Mesonychoteuthis male or female is known, we cannot begin to guess how the monster does its business.
Kondakovia longimana Filippova, 1971 (Fig. 10)
Vernacular: Giant Warty Squid; Longarm Octopus Squid
Kondakovia longimana is one of three squid known to reach giant size in the Antarctic (the others being Mesonychoteuthis hamiltoni and Galiteuthis phyllura). It is a major prey species for sperm whales (second largest food source by weight, with annual consumption estimated to be 2.10 x 106 tonnes) (Roper et al. 1985). It is also the largest squid preyed upon by albatross and increases in dietary importance with increasing latitude / decreasing temperature (Imber 1982). It has been captured in nets from 0 to 50 m depth, but most specimens have been taken from the stomachs of sperm whales caught over water depths in excess of 2 000 m (Roper et al. 1985).
It is possible that the first reported specimens of this species are different from any specimen subsequently referred to this species (that is to say, several species may be presently confused as one). The group is in need of immediate systematic revision.
The largest whole specimen ever recorded washed ashore in Antarctica in 2000, at British Antarctic Survey's Signy Research Station. Although incomplete the specimen measured over two metres in total length and weighed 29 kg. Partial specimens recovered from whale stomachs are often estimated to reach similar sizes based on beak measurements.
This species was originally described based on three immature females (ML 260 mm, 210 mm, and 133 mm) (Filippova 1972). Although at least 12 relatively intact adult specimens have been recovered from sperm whale stomachs, only partial systematic descriptions of the adult female exist, and the only known male specimen in good condition lacked tentacles (Clarke 1980).
Recognised distribution: Probably circumpolar, although reported as far north as South Georgia and the Tasman Sea (see records based on long-distance foraging marine predator stomach contents overpage). Several beaks similar to K. longimana have also been reported from sperm whales caught off Iceland, so it has been suggested that the species may have a bipolar distribution (Kubodera et al. 1998).
Stomach content analyses reveal euphausiid shrimp (krill) as the main food source. Most in-situ-captured specimens have accordingly been recovered from localities with very high concentrations of krill. Filippova (1972) also suggests that the 'peculiar body proportions, looseness of the tissues and a moderate size of radula [rasping tongue] with very minute teeth... [are] indicative of a form adapted to feed upon macrozooplankton'.
Publication: In an international journal, probably by the end of 2003 (submission date).
Estimated mantle length: 1m, probably to 115 cm (Nesis 1987).
New Zealand specimens (trawled): None. A related new species of comparable size occurs in New Zealand waters.
New Zealand reports based on analysis of stomach contents of long-distance foraging marine predators (whales, albatross): 5. Beaks attributed to this species have similarly been encountered in stomachs of sperm whales caught in or proximal to northernmost eastern and western New Zealand waters (Clarke & MacLeod 1982), and from one stranded specimen on Paekakariki Beach (Clarke & Roper 1998). They are also reported from wandering albatross chick regurgitations from the southern New Zealand Auckland and Antipodes, and Australian Macquarie Islands (Imber 1992). However, despite these five citations from or proximal to local waters, none of them confirms that the species occurs here, for the same reasons as discussed for Mesonychoteuthis hamiltoni.
Kondakovia, like Mesonychoteuthis, could occur in southernmost New Zealand waters.
Closest record (unreported): Unknown.
Kondakovia lacks a hectocotylus (the specialised arm used to transfer spermatophores to the female), and if it is anything like the closely related Moroteuthis ingens, will have a relatively large penis. Moroteuthis ingens uses its penis to directly plunge spermatophores through the female's mantle, inserting them near the base of her gill. The method of reproduction in Kondakovia is unknown.
Clarke, M.R. 1972. New technique for the study of sperm whale migration. Nature 238: 405—406.
Clarke, M.R. 1980. Cephalopoda in the diet of sperm whales of the southern hemisphere and their bearing on sperm whale biology. Discovery Reports 37: 1-324.
Clarke, M.R.; MacLeod, N. 1982. Cephalopod remains from the stomachs of sperm whales caught in the Tasman Sea. Memoirs of the National Museum Victoria, 43: 25—42.
Clarke, M.R. (ed.). 1986: A handbook for the identification of cephalopod beaks. Clarendon Press, Oxford: 1-273.
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. South African Journal of Marine Science, 20: 129—133.
Filippova, J.A. 1972. New data on the squids (Cephalopoda: Oegopsida) from the Scotia Sea (Antarctic). Malacologia 11(2): 391-406.
Fiscus, C.H.; Rice, D.W.; Wolman, A.A. 1989. Cephalopods from the stomachs of sperm whales taken off California. NOAA Technical Report NMFS 83: 1—12.
Imber, M.J. 1978. The squid families Cranchiidae and Gonatidae (Cephalopoda: Teuthoidea) in the New Zealand region. New Zealand Journal of Zoology, 5: 445—484.
Imber, M.J. 1992. Cephalopods eaten by wandering albatrosses (Diomedia exulans L.) breeding at six circumpolar localities. Journal of the Royal Society of New Zealand, 22(4): 243—263.
Jouventin, P.; Weimerskirch, H. 1990. Satellite tracking of wandering albatrosses. Nature 343: 746—747.
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Nesis, K.N. 1987. Cephalopods of the world (English translation). Tropical Fish Hobbyist (T.F.H.) publications, Neptune City. 1-352.
O'Shea, S. 1997. Status of three Octopoda recorded from New Zealand, based on beaks recovered from long-distance foraging marine predators. New Zealand Journal of Zoology 24: 265—266.
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Roper, C.F.E.; Sweeney, M.J.; Clarke, M.R.; 1985. Cephalopoda. FAO Species Identification Sheets for Fishery Purposes 1:117-205.
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