Description of Chitwoodiellus Gracilis Gen. N., Sp. N. From Spain, With a Study On Its Morphometric Differentiation From Chitwoodius Furstenberg & Heyns, 1966 (Nematoda: Tylencholaimidae)

Abstract

Chitwoodiellus gen. n. is described from a new and three previously known species. It is close to the genera Chitwoodius Furstenberg & Heyns, 1966, Tylencholaimus de Man, 1880 and Xenonchium Siddiqi & Khan, 1964 (subfamily Tylencholaiminae). It differs from Chitwoodius in head shape, presence of perioral pieces, shorter odontostyle, existence of a sclerotized thickened area where the odontophore joins the pharyngeal lumen, guiding ring nearer the anterior end, vagina not fringed and the morphology of the vulva. The new genus can be distinguished from Tylencholaimus by the longer and thinner odontostyle, different morphology of the odontophore and the existence of a sclerotized thickened area surrounding the junction between the odontophore and the pharyngeal lumen. From Xenonchium it differs by the longer and thinner odontostyle, existence of a sclerotized thickened area where the odontophore joins the pharyngeal lumen, different morphology of the vulva and the female genital system being didelphic-amphidelphic. Chitwoodiellus gracilis gen. n., sp. n. is described and illustrated from an undisturbed area in central Spain. Three previously known Chitwoodius species are transferred to the new genus: C. fuscus (Sauer, 1969) n. comb., C. heynsi (Pena Santiago. 1991) n. comb. and C. parafuscus (Pena Santiago, 1991) n. comb. Univariate and multivariate statistical analysis were carried out with species of Chitwoodius and Chitwoodiellus gen. n. in order to confirm their separation into two different groups. The results obtained support the proposal of the new genus.