A SCANNING ELECTRON-MICROSCOPE STUDY OF THE NEMATODE SPIRURA-DENTATA (SPIRUROIDEA) WITH NOTES ON THE MORPHOMETRIC VARIATIONS IN A SPANISH POPULATION OF THIS SPECIES

This work provides a detailed morphological description by optic and s canning electron microscopy of the nematode Spirura dentata (Monnig, 1 938), a parasite of Herpestes ichnenmon in southern and central Spain, together with an analyses of the morphometric variations within this population. Our findings in adult specimens include some important cha racters not recorded in previous descriptions, and contradict these in a few details: a) the four denticles arising from the inner wall of t he oral opening are double, not simple as reported in the original des cription, b) four simple denticles are present, each located between t he corresponding double denticles and the central protuberance of the pseudolabium, c) lateral crests are present running along the first th ird of the body in the adult, starting a short distance behind the dei rids, and d) the pair of small submedian post-cloacal papillae mention ed in the original description has not been observed. The fourth-stage larva is described for the first time. The relative growth rate (i.e. , growth rate with respect to body length) of the reproductive zone wa s higher in females. In adult males, the growth of the left (longer) s picule was positive, whereas that of the right (shorter) spicule was n egative.