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Isopoda is an order of crustaceans.Members of this group are called isopods and include both aquatic species, and terrestrial species such as woodlice.All have rigid, segmented exoskeletons, two pairs of antennae, seven pairs of jointed limbs on the thorax, and five pairs of branching appendages on the abdomen that are used in respiration.
It contains a vast total of named species, second only to the insects in overall number. The fossil history of this class goes back to the Late Cambrian . As of 2017 [update] , 721 families of gastropods are known, of which 245 are extinct and appear only in the fossil record, while 476 are currently extant with or without a fossil record.
The subphylum Hexapoda (from Greek for 'six legs') or hexapods comprises the largest clade of arthropods and includes most of the extant arthropod species. It includes the crown group class Insecta (true insects), as well as the much smaller clade Entognatha, which includes three classes of wingless arthropods that were once considered insects: Collembola (springtails), Protura (coneheads) and ...
The winged insects are nocturnal and provide food for night-flying birds, bats, small mammals, amphibians and arthropods. The larval stage lasts much longer, often for one or more years, and has a bigger impact on the environment. [20] They form an important part of the diet of fish such as the trout. The fish acquire them by two means, either ...
The ant's diet includes sweet secretions that are retrieved from aphids and other insects that it tends. This species is a competitor of the meat ant (Iridomyrmex purpureus), and food robbery and nest-plugging is known to occur between these two ants. Workers prey on insects, killing them with a spray of formic acid. Banded sugar ants are ...
The "traditional" view of the arthropod "family tree" shows chelicerates as less closely related to the other major living groups (crustaceans; hexapods, which includes insects; and myriapods, which includes centipedes and millipedes) than these other groups are to each other.
These two groups have long been considered close relatives because of the common presence of trochophore larvae, but the annelids were considered closer to the arthropods because they are both segmented. [53] Now, this is generally considered convergent evolution, owing to many morphological and genetic differences between the two phyla. [54]
These minute arthropods are apterous, unlike some orders of insects that have lost their wings secondarily (but are derived from winged ancestors). Their mouthparts are enclosed within a pouch in the head capsule, called the gnathal pouch, so only the tips of the mandibles and maxillae are exposed beyond the cavity. [1]