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Entognathous
The Entognatha, from Ancient Greek ἐντός (''entós''), meaning "inside", and γνάθος (''gnáthos''), meaning "jaw", are a class (biology), class of wingless and Ametabolism, ametabolous arthropods, which, together with the insects, makes up the subphylum Hexapoda. Their Arthropod mouthparts, mouthparts are entognathous, meaning that they are retracted within the head, unlike the insects. Entognatha are apterous, meaning that they lack insect wing, wings. The class contains three Order (biology), orders: Collembola (springtails, 9000 species), Diplura ("two-tail", 1000 species) and Protura ("first-tail", 800 species). These three groups were historically united with the now-obsolete order Thysanura to form the class Apterygota, but it has since been recognized that the hexapodous condition of these animals has evolved independently from that of insects, and independently ''within'' each order. The orders might not be closely related, and Entognatha is now considered to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protura
The Protura, or proturans, and sometimes nicknamed coneheads, are very small (0.6–1.5mm long), soil-dwelling animals, so inconspicuous they were not noticed until the 20th century. The Protura constitute an order of hexapods that were previously regarded as insects, and sometimes treated as a class in their own right. Some evidence indicates the Protura are basal to all other hexapods, although not all researchers consider them Hexapoda, rendering the monophyly of Hexapoda unsettled. Uniquely among hexapods, proturans show anamorphic development, whereby body segments are added during moults. There are close to 800 species, described in seven families. Nearly 300 species are contained in a single genus, ''Eosentomon''. Morphology Proturans have no eyes, wings, or antennae, and, lacking pigmentation, are usually whitish or pale brown. The sensory function of the absent antennae is fulfilled by the first pair of the three pairs of five-segmented legs, which are held up, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |