cormoGen1=Geophilomorpha

6 families.

18 genera.

Note

Many taxa are keyed only as far as genus. This is partly because of the inadequate, provisional nature of the classification of the geophilomorphs. These centipedes are small and often require dissection, clearing, mounting and microscopic examination of the mouthparts in order to identify them. Geophilomorph centipedes range from 9 - 200 mm in length, have 27 - 191 pairs of legs, a slender body of 33 or more segments, filiform antennae with 14 segments (two sensory pits are located on the last segment) and no ocelli (i.e. they are blind) (Hoffman 1982: 684). Members of this order lack T%C3%B6m%C3%B6sv%C3%A1ry organs (Lewis 1981: 14; Edgecombe 2001: 45). The number of pairs of legs varies within most species, and females may have more pairs than males. However, in the Mecistocephalidae, the number is constant for each species (Lewis, 1981: 14). Geophilomorph centipedes are commonly known as 'earthlovers' due to their burrowing activity and habitat preferences. The anterior part of the body narrows posteriorly and bears stout legs on which are used for widening the burrow. The narrow oesophagus occupies the anterior third of the body, thus limiting the mid gut (which contains the bulkier masses of food material) to the posterior region, thus allowing the animal to burrow without undigested food causing it to get stuck. A further adaptation that facilitates locomotion is the central positioning of the head, oesophagus and nerve cord (Lewis 1981: 42). Earthlovers are the only centipedes in which all tergites are the same length (Manton 1965: 276; Edgecombe 2001: 45). Presternites and pretergites are well developed in many geophilid genera; pleurites are also present, and their arrangement differs among families (Lewis 1981: 17; Hoffman 1982: 684). The final pair of legs, which have been modified into 'posterior antennae', have an enlarged coxopleural segment which contains many different pores, and usually lacks a tarsal claw (Lewis 1981: 43; Hoffman 1982: 684). The cephalic plate, covering the square to rectangular head, is small, allowing much of the maxillipedes to be seen from above (Hoffman 1982: 684). Geophilids, like the Craterostigmorpha, digest their food externally by 'chewing' the food with the mandibles, secreting digestive juices onto the prey through ducts in the mandibles, and moving the liquid into the mouth with the maxillae (Manton 1965: 341; Edgecombe 2001: 46). The mandibles are extremely variable in form and are characteristic for each family (Lewis 1981: 15). This variation suggests that they may be specialist feeders (Hoffman 1982: 684). As the name suggests, earthlovers are found in the soil or in forest litter, although some species of Tuoba are adapted to foraging in the seaweed along beaches (Edgecombe 2001: 57). Geophilomorpha can be found from the tropics to the Arctic (Hoffman 1982: 684). Other diagnostic features include: Genital region exposed, consisting of one tergum and two sternites. The posterior sternite bears the gonopods. The sclerotised penis of the male is enclosed in a median conical projection. Coxae of the 1st maxillae are usually fused (a median suture is present in some mecistocephalids and himantariids). The sternum is reduced. Synocoxal lobes usually present medially; smaller lobes may also be present on outer anterior edges. The telopodite usually consists of two segments (although no such segmentation is found in some himantariids). The coxae of the 2nd maxillae are fused medially; the outer edge of the synocoxae is attached to the head along the ventral edge. The telopodite consists of three segments and includes a terminal claw. The coxae are divided into upper and lower halves, not forming a complete ring. The shape of the prosternum is variable, but in many species the cuticle is thickened, underlying the trochanteroprefemoral condyle (Hoffman 1982: 684). References Edgecombe, G. (2001). Centipedes: the great Australian bite. Nature Australia, Autumn 2001: 42 - 51. Hoffmann, R.L. (1982). Chilopoda. pp. 681 - 688 in Parker, S. (ed.) Synopsis and Classification of Living Organisms. New York: McGraw-Hill Vol. 2 Lewis, J.G.E. (1981). The Biology of Centipedes. Cambridge: Cambridge University Press vii 476 pp. Manton, S.M. (1965). The evolution of arthropod locomotory mechanisms. Part 8. Functional requirement and body design in Chilopoda, together with a comparative account of their skeletomuscular systems and an appendix on the comparison between burrowing forces of annelids and chilopods and its bearing upon the evolution of the anthropodan haemocoel. J. Linn. Soc. London Zool. 46: 251 - 483