Centipedes

• Centipedes (from Latin prefix centi- , “hundred”, and pes, pedis , “foot” ) are arthropods belonging to the class Chilopoda of the subphylum Myriapoda, an arthropod group which also includes Millipedes and other multi-legged creatures.
• Centipedes are elongated metameric creatures with one pair of legs per body segment. Centipedes are known to be highly venomous, and often inject paralyzing venom. Despite the name, centipedes can have a varying number of legs, ranging from 30 to 354. Centipedes always have an odd number of pairs of legs (Lloyd et al., 2006; Arthur 2002; Arthur etal., 2005). Therefore, no centipede has exactly 100 legs. A key trait uniting this group is a pair of venom claws or forcipules formed from a modified first appendage. Centipedes are predominantly carnivorous (Lewis 2007).
• Their size can range from a few millimetres in the smaller lithobiomorphs and geophilomorphs to about 30 cm (12 in) in the largest scolopendromorphs. Centipedes can be found in a wide variety of environments. They normally have a drab coloration combining shades of brown and red. Cavernicolous (cave-dwelling) and subterranean species may lack pigmentation, and many tropical scolopendromorphs have bright aposematic colours.
• Centipedes have a rounded or flattened head, bearing a pair of antennae at the forward margin. They have a pair of elongated mandibles , and two pairs of maxillae . The first pair of maxillae form the lower lip, and bear short palps . The first pair of limbs stretch forward from the body to cover the remainder of the mouth. These limbs, or maxillipeds , end in sharp claws and include venom glands that help the animal to kill or paralyze its prey (Barnes 1982)
• Behind the head, the body consists of 15 or more segments. Most of the segments bear a single pair of legs, with the maxillipeds projecting forward from the first body segment, and the final two segments being small and legless. Each pair of legs is slightly longer than the pair immediately in front of it, ensuring that they do not overlap, so reducing the chance that they will collide with each other while moving swiftly. In extreme cases, the last pair of legs may be twice the length of the first pair. The final segment bears a telson and includes the openings of the reproductive organs (Barnes 1982)

• Worldwide, an estimated 8,000 species of centipedes are thought to exist (Adis et al., 2000) of which 3,000 have been described. Centipedes have a wide geographical range, where they even reach beyond the Arctic Circle (Lewis 2007).
• They are found in an array of terrestrial habitats from tropical rainforests to deserts. Within these habitats, centipedes require a moist microhabitat because they lack the waxy cuticle of insects and arachnids, therefore causing them to rapidly lose water. Accordingly, they are found in soil and leaf litter, under stones and dead wood, and inside logs. Centipedes are among the largest terrestrial invertebrate predators, and often contribute significantly to the invertebrate predatory biomass in terrestrial ecosystems.

References:

Lloyd, John (2006). The Book of General Ignorance . London: Bloomsbury House. p. 119. ISBN 0571273785 . Retrieved June 10, 2014.

Arthur, W. (2002). “The interaction between developmental bias and natural selection from centipede segmentation to a general hypothesis”. Heredity . 89 (4): 239–246. doi : 10.1038/sj.hdy.6800139 . PMID 12242638 .

Arthur, Wallace; Chapman, Ariel D. (2005). “The centipede Strigamia maritima: what it can tell us about development and evolution of segmentation”. BioEssays . 27 (6): 653–660. doi : 10.1002/bies.20234 . PMID 15892117

Lewis, J. G. E. (2007). The Biology of Centipedes . Cambridge University Press . ISBN 978-0-521-03411-1 .

Adis, Joachim; Harvey, Mark S. (2000). “How many Arachnida and Myriapoda are there worldwide and in Amazonia?”. Studies on Neotropical Fauna and Environment. 35 (2): 139–141. doi : 10.1076/0165-0521(200008)35:2;1-9;FT139

Barnes, Robert D. (1982). Invertebrate Zoology. Philadelphia, PA: Holt-Saunders International. pp. 810–816. ISBN 0-03-056747-5 .