A NEW SPECIES OF THE GENUS TRICHOSTRONGYLUS LOOSS, 1905 FROM THE SMALL INTESTINE OF SHEEP (RHABDITIDA, STRONGYLATA: TRICHOSTRONGYLIDAE)

In tbe present paper, a new species of Nematode (Trichostrogylidae) isolated from the small intestine of sheep has been described by the authors and there by a brief description of its cha-racteristics is given as in the following:Trichoatrongylus qinghaiensis sp. nov. (figs 1-6)Body filiform, slightly pale yellowish in living. Cuticle with very fine transverse striac. Small mouth with three lips been observed under the oil microscope. Buccal cavity indistinct, cervical papillae devoid. Nerve ring about 0.133 mm (0.117-0.146 mm) to the anterior end. Excretory pore siwated at a depression in cuticle which is 0.166 mm (0.143 to 0.184 mm) from the anterior end. Simple esophagus 0.757 mm (0.670-0.864 mm) long.Male: Body 3.3-5.5mm long with a width of 0.104 to 0.130 mm at the base of caudal bursa. The features of the bursa and the arrangement of its rays coincide with the characteristics of the genus Trichostrongylus. The spicules are similar in shape, and their anterior portions are broader with a wjdth of 0.022 mm than the posterior (0.008 mm wide). Two spicules are either equal or somewhat unequal in length. The left one (0.140-0.156 mm) being slightly longer than the right (0.133-0.148 mm) and each with two sm醠i barbs near to the distal extremity. The upper barb is situated at a distance of 0.018 mm from the distal end of the spicule and the lower one, only a bit nearer, being 0.009 mm.Female: Body 6.7 mm (5.8-7.5 mm) long by 0.112 mm wide at the vulval position. Ovije-ctor 0.473 mm (0.378-0.562 mm) long. Vulva small and slit-like, located at anterior of poste-rior about one-fourth of the body. Anus 0.101 mm. (0.081-0.122 mm) apart from the tip of tail.Discussion: The genus Trichostrongylus has long been examined and identified by Skrja-bin et al (1954). They listed 31 species with the exception of Trichostrongylus (sensu lato) in animals and man. Hereafter, 6 species including l variety were found, namely, T. chiapanensis Caballero, 1958; T. drepanofomis Sommerville, 1959; T. askivali Dunn, 1964; T. colubriformis var. longispicularis Deli et al, 1966; T. dosteri Maples, 1971 and T. anseris Wang, 1979. Up to the present, there are altogether 37 species under this genus so far reported from all over the world.Although the said new species, slightly resembling T. colubriforis (Giles, 1892) Skrjabin, 1954, in the shape of its spicules, but differs clearly from the latter in havtng two barbs which are situated at the end of spicules with the distance of 0.009 and 0.018 mm respecdvely; and qu-ite dif韊rently, instead of being st the end of spicules in T. colubriformis,there is a well defined process in triangular shape, measuring 0,033-0.044 mm. in length (Skrjabin, 1954); further-more, the species novo possesses a gubernaculum similar to the tremade Fasciola hepatica with a long and cone-shaped anterior projection and a slit-like vulva when viewed in dorso-veatral position, but without any lip-shaped structure in the same organ.Locality: Datong (36°55'N, 101° 40'E), Gonghe (36°16'N, 100°36'E) and Maduo (34°55' N, 98°10'E) Counties, Qinghai Province, China.Holotype ♂, allotype ♀, paratypes 30♂♂, 45♀♀ are preserved in the Lanzhou Institute of Veterinary Medicine, Chinese Academy of Agricultural,Sciences.