Ommastrephidae Family of Squid

One Squid from the Ommastrephidae Family can be found in this website:

Humboldt Squid, Dosidicus gigas. A representative of the Ommastrephidae Family of Squid.

Phylogeny: Ommastrephid Squid of the Ommastrepihidae Family are mollusks in the phylum Mollusca and the class Cephalopoda. This class includes octopuses, cuttlefish, and nautiloids. Cephalopods are characterized by having a mantle (body), a head, and a foot that is modified into a series of, at least, eight arms. The arms attach to the head and surround the mouth. The arms may be equipped with suckers, hooks, or cirri. Some will have tentacles in addition to their arms. All cephalopods have three hearts. Two hearts pump blood to the gills, and one heart pumps blood to the rest of the body. Cephalopods have blue blood, because they bind oxygen with hemocyanin. Cephalopods have relatively large brains and complex eyes. Squid are in the subclass Coleoidea, the superorder Decapodiformes. Decapodiformes are characterized as having an elongate body, 8 arms, 2 tentacles, large eyes, and an internal shell, known as a gladius or pen. The pen is made of chitin and may be rod or feather shaped. The pen provides rigidity to the body, as well as an attachment point for muscles. Ommastrephid Squid are in the order Oegopsida and the superfamily Cranchoidea. The Ommastrepihidae Family is one of three families in this superfamily. The Ommastrepihidae Family contains five subfamilies, eleven genera, and around twenty-two species. The name Ommastrepihidae comes from the Greek words meaning “to turn the eye” or “to twist the eye”. This refers to the large eyes and rapid movements of these squid.

Morphology: Ommastrephid Squid have an elongate body with 8 arms and 2 tentacles. The tentacles are modified arms that are usually longer than the arms, are retractile, and terminate in wide, flat lobes (tentacular clubs). The only suckers on the tentacles are located on the tentacular clubs. They have 2 rows of suckers on their arms and either four or eight rows on their tentacular clubs. They have either hooks, or suckers that lack circularis muscles, on their arms and tentacular clubs. Their tentacular clubs have a carpal locking mechanism. Their fins usually join posteriorly to the mantle, and lack a posterior lobe. They do not have a tentacle pocket on their head. Ommastrephid Squid are muscular strong swimmers. Unfortunately, the key defining characteristics of this family are not possible to observe in the field. The most accurate characteristic is that their funnel/mantle locking cartilage has an inverted “T” shape. Their gladius is feather-shaped and has a hollow cone structure. Many species in this family are known as “flying squid, “arrow squid”, or volplaning squid, because of their ability to launch themselves from the water and glide some distance in order to avoid predators. These squid can change the color of their skin at will, and very quickly. They do this by nerve controlled chromatophores (pigment sacks in the skin), iridophores (reflect light to appear iridescent), and leucophores (scatter ambient light). Some species have light producing photophores on their skin. The majority of Ommastrephids are large in stature having mantle lengths up to 1.5 m (5 feet). Their overall lengths may reach 4 m (13 feet).

Habitat and Distribution:  Ommastrephids are found in open water. They range in depth from the surface to depths exceeding 2.000 m (6,560 feet). These squid are generally found in deeper, more open, water than the nearshore Myopsid Squid. Ommastrephids are the most abundant and widely distributed cephalopod species.  They are found worldwide, from polar to tropical seas. At least two species from this family are found in Mexican waters.

Reproduction:  Ommastrephid Squid are gonochoric (male or female for life). Reproduction is sexual, with internal fertilization. During mating, the male grasps the female and inserts the hectocotylus (modified arm for delivering sperm packets) into the female’s mantle cavity where fertilization occurs. They lay their eggs in pelagic masses or strings. The embryos hatch into a planktonic stage and live for some time before they grow larger and develop into swimming juveniles.

Ecosystem Roles: Ommastrephids are predators that consume fish, shrimp, and squid. Cannibalism is common in this family. These squid capture prey by swimming toward it with the arms close together, in a cone shape. They quickly shoot out their tentacles to grab their prey with tooth lined suckers. The tentacles and arms quickly drag the prey to their sharp, parrot-like beak. The suckers and beak quickly shred the prey’s flesh. They often hunt in large groups and some species seem to engage in cooperative, pack-style hunting. In turn they are preyed upon by fish, sea birds, toothed whales, pinnipeds, and each other.