Teuthoidea

Teuthoidea [tü′thȯid·ē·ə]

(invertebrate zoology)

An order of the molluscan subclass Coleoidea in which the rostrum is not developed, the proostracum is represented by the elongated pen or gladus, and ten arms are present.

---

Teuthoidea 

(squids), a suborder of cephalopods of the order Decapoda.

The dimensions of Teuthoidea are usually between 0.25 and 0.5 m, but certain species comprise the largest known invertebrates (squids of the genus Architeuthis attain a length of 18 m, including tentacles). The body is elongated and tapered toward the rear (torpedo-shaped), allowing great speed in both water and air (squids can jump out of the water to a height of 7 m). There are two large fins at the posterior end of the body. The head is clearly delineated. The eyes are large. There are ten “arms,” two of them used for catching and capable both of extending greatly when capturing prey and of contracting when swimming; they are usually equipped with suckers and hooks. The shell is rudimentary; it has the appearance of a thin, narrow, horny plate and is completely hidden under the mantle. The coloration of Teuthoidea varies; some deepwater forms are as transparent as glass and are equipped with luminescent organs. There are approximately 300 species, inhabiting the oceans and seas from the surface to the greatest depths. They are especially numerous in tropical waters. There are about 30 species in the USSR. They are fairly common in the northern arctic and common in the Okhotsk, Bering, and Japan seas.

Members of the suborder generally live in the middle depths of the water. They prey on fish and invertebrates. In turn, they serve as food for larger fish, birds, and sea animals; giant sperm whales feed mainly on the largest squids (Moroteuthis, Architeuthis). Squids deposit their eggs on floating objects. Squid meat, canned, as well as fresh, has excellent taste and high nutritional value, so that it is a valuable food product. The commercial squid of the Sea of Japan (Ommastrephes sloanei pacificus) migrates to spawn, swimming for five or six months from its pasturing sites in the north to the subequatorial waters where it reproduces (a distance of 2, 000-3, 000 km). In the USSR, squid is caught commercially in the Far East.

REFERENCES

Rukovodstvo po zoologii, vol. 2. Moscow, 1940.
Ivanov, A. V. Promyslovye vodnye bespozvonochnye. Moscow, 1955.
Akimushkin, I. I. Golovonogie molliuski morei SSSR. Moscow, 1963.
Zhizn’ zhivotnykh, vol 2. Moscow, 1968.

I. M. LIKHAREV