Greater Hooked Squid
Encyclopedia
The Greater Hooked Squid (Onykia ingens) is a species of squid
in the family Onychoteuthidae. It occurs worldwide in subantartic oceans.
Although O. ingens was long attributed to the genus Moroteuthis, several authors have recently agreed that Moroteuthis is a junior synonym of Onykia.
may reach lengths of up to 94 cm (37 in). Research has found that egg sizes of the squid average 2.1 mm inside mature females, while juveniles average 4.6 mm or larger. Juveniles are presumed to live near the surface, until they reach a mantle length of approximately 200 mm, at which time they relocate to deeper water, and larger prey. Greater Hooked Squid exhibit sexual dimorphism
, with females growing linearly twice as fast as males, and reaching a fully mature size of more than five times that of male counterparts.
Penis
elongation has been observed in this species; when erect, the penis may be as long as the mantle, head and arms combined. As such, deep water squid like M. ingens have the greatest known penis length relative to body size of all mobile animals, second in the entire animal kingdom only to certain sessile barnacle
s.
The Greater Hooked Squid, as with many (if not all) large squid, has a number of predators. These include the patagonian toothfish
, king penguin
, wandering albatross
, pilot whale
, bottlenose whale
, dwarf sperm whale
, sperm whale
, and other types of squid.
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...
in the family Onychoteuthidae. It occurs worldwide in subantartic oceans.
Although O. ingens was long attributed to the genus Moroteuthis, several authors have recently agreed that Moroteuthis is a junior synonym of Onykia.
Size and growth
The size of a fully grown Greater Hooked Squid, inclusive of tentacles, is currently unknown. Many estimates, however, predict that the mantleMantle (mollusc)
The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself.In many, but by no means all, species of molluscs, the epidermis of the mantle secretes...
may reach lengths of up to 94 cm (37 in). Research has found that egg sizes of the squid average 2.1 mm inside mature females, while juveniles average 4.6 mm or larger. Juveniles are presumed to live near the surface, until they reach a mantle length of approximately 200 mm, at which time they relocate to deeper water, and larger prey. Greater Hooked Squid exhibit sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
, with females growing linearly twice as fast as males, and reaching a fully mature size of more than five times that of male counterparts.
Penis
Penis
The penis is a biological feature of male animals including both vertebrates and invertebrates...
elongation has been observed in this species; when erect, the penis may be as long as the mantle, head and arms combined. As such, deep water squid like M. ingens have the greatest known penis length relative to body size of all mobile animals, second in the entire animal kingdom only to certain sessile barnacle
Barnacle
A barnacle is a type of arthropod belonging to infraclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in erosive settings. They are sessile suspension feeders, and have...
s.
Ecology
It is generally accepted that there are large dietary variations between large and small Greater Hooked Squid. One of the most common findings is that juvenile squid (>200 mm ML) consume a greater percentage of crustaceans and cephalopods compared to their size than mature squid, which consume a large percentage of fish and virtually no crustaceans. Globally, however, myctophid fish (lantern fish) are seen as common prey. Larger squid are known to practice cannibalism (accounting for up to 6% of diet).The Greater Hooked Squid, as with many (if not all) large squid, has a number of predators. These include the patagonian toothfish
Patagonian toothfish
The Patagonian toothfish, Dissostichus eleginoides , is a fish found in the cold, temperate waters of the southern Atlantic, southern Pacific, Indian, and Southern Oceans on seamounts and continental shelves around most sub-Antarctic islands.A close relative, the Antarctic toothfish , is found...
, king penguin
King Penguin
The King Penguin is the second largest species of penguin at about , second only to the Emperor Penguin. There are two subspecies—A. p. patagonicus and A. p...
, wandering albatross
Wandering Albatross
The Wandering Albatross, Snowy Albatross or White-winged Albatross, Diomedea exulans, is a large seabird from the family Diomedeidae, which has a circumpolar range in the Southern Ocean. It was the first species of albatross to be described, and was long considered the same species as the Tristan...
, pilot whale
Pilot whale
Pilot whales are cetaceans belonging to the genus Globicephala. There are two extant species, the long-finned pilot whale and the short-finned pilot whale . The two are not readily distinguished at sea and analysis of the skulls is the best way to tell the difference between them...
, bottlenose whale
Bottlenose whale
The Northern bottlenose whale is a species of the ziphiid family, one of two members of the Hyperoodon genus. The northern bottlenose was hunted heavily by Norway and Britain in the 19th and early 20th centuries...
, dwarf sperm whale
Dwarf Sperm Whale
The Dwarf Sperm Whale is one of three species in the sperm whale family. They are not often sighted at sea. As such, most information is a result of the study of stranded carcasses.-Taxonomy:...
, sperm whale
Sperm Whale
The sperm whale, Physeter macrocephalus, is a marine mammal species, order Cetacea, a toothed whale having the largest brain of any animal. The name comes from the milky-white waxy substance, spermaceti, found in the animal's head. The sperm whale is the only living member of genus Physeter...
, and other types of squid.