Physical Description
As both common names imply, these squid have elongate, cylindrical bodies with a length to width ratio of 7:1. The arms are in contrast short and weak; the two tentacles are somewhat less than the mantle length. The rhombus-shaped fins are large, up to about 50 percent of the mantle length. Running the ventral length of the mantle is a noticeable ridge. The squid are a reddish orange colour with a large complement of chromatophores.
The suckers of the arms possess blunt teeth. On the meaty ends (clubs) of the tentacles, there are four rows of suckers; the inner two (mesial) rows are three times as large as the outer two (marginal) rows. The larger suckers have horny rings with up to 45 teeth.
These squid reach a maximum mantle length of 33 centimetres in males and 22 centimetres in females. Sexual dimorphism is apparent, with the left ventral arm in males modified into a hectocotylus; this is used to facilitate fertilization during mating. Males also have a number of purple stripes running lengthwise on the ventral side of the mantle; along with other visual cues produced by chromatophores, these stripes are used in elaborate courtship displays.
Read more about this topic: Doryteuthis Plei
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