About Idiosepius pygmaeus Steenstrup, 1881
Idiosepius pygmaeus Steenstrup, 1881, commonly called the two-toned pygmy squid or tropical pygmy squid, is a species of bobtail squid native to the Indo-Pacific region. Its confirmed range includes the South China Sea, Japan, the Philippines, Palau, Indonesia, the Northern Mariana Islands, and northern and northeastern Australia. This squid is traditionally found in shallow, inshore waters, and is heavily concentrated in seagrass meadows. It uses a specialized adhesive organ to attach itself to seagrass. Human activity has disturbed these seagrass meadows, threatening this shelter habitat used by Idiosepius pygmaeus.
Newly hatched I. pygmaeus weigh 0.00033 g, and reach full maturity at 50 days, or 1260 degree days, with a mature weight of 0.175 g. This species prefers waters with a temperature of 25.2 °C. Its calculated growth rate is 12.55, while its calculated physiological growth rate is 0.498. Mature individuals grow to a mantle length of 20 mm. In laboratory settings, this squid feeds on glass shrimp, Acetes sibogae australis. The species' type specimen was collected in the South China Sea at coordinates 04°20′N 107°20′E, and is currently held at the Zoologisk Museum of Kobenhavns Universitet in Copenhagen.
