Ophthalmology

Your eyes are half a billion years old

Look after your eyes – they are at least half a billion years old, and a good deal older than your brain. The eyes are one of our most remarkable and precious organs, yet their origins have been shrouded in mystery until ...

Medical research

New bio-adhesive polymer demonstrated in JoVE

A new video-article in JoVE, Journal of Visualized Experiments, details the use of a new laser-activated bio-adhesive polymer. The chitosan-based polymer, SurgiLux, was developed by scientists at the University of New South ...

Crustacean

Thylacocephala? Branchiopoda

Remipedia Cephalocarida Maxillopoda

Ostracoda

Malacostraca

Crustaceans (Crustacea) form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at 0.1 mm (0.004 in), to the Japanese spider crab with a leg span of up to 12.5 ft (3.8 m) and a mass of 44 lb (20 kg). Like other arthropods, crustaceans have an exoskeleton, which they moult to grow. They are distinguished from other groups of arthropods, such as insects, myriapods and chelicerates, by the possession of biramous (two-parted) limbs, and by the nauplius form of the larvae.

Most crustaceans are free-living aquatic animals, but some are terrestrial (e.g. woodlice), some are parasitic (e.g. fish lice, tongue worms) and some are sessile (e.g. barnacles). The group has an extensive fossil record, reaching back to the Cambrian, and includes living fossils such as Triops cancriformis, which has existed apparently unchanged since the Triassic period. More than 10 million tons of crustaceans are produced by fishery or farming for human consumption, the majority of it being shrimps and prawns. Krill and copepods are not as widely fished, but may be the animals with the greatest biomass on the planet, and form a vital part of the food chain. The scientific study of crustaceans is known as carcinology (alternatively, malacostracology, crustaceology or crustalogy), and a scientist who works in carcinology is a carcinologist.

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