Oriverutoides, Ahmad and Sturhan, 2002

Peña-Santiago, Reyes, Liébanas, Gracia & Ahmad, Wasim, 2014, Taxonomy of the genus Oriverutus Siddiqi, 1971 (Nematoda: Dorylaimida: Nordiidae), Journal of Natural History 48 (21), pp. 1253-1278 : 1266

Oriverutoides

The only and type species of this genus, Oriverutoides attenuatus from New Zealand, resembles some representatives of Oriverutus in the morphology of lip region with protruding papillae, attenuate odontostyle, opisthodelphic female genital system and tail shape. Ahmad and Sturhan (2002) originally distinguished it from Oriverutus in the more posterior location of DO, DN and amphid aperture (versus more posterior than usual), sclerotized cheilostom and the absence of cardiac cells. Re-examination of type material (three female paratypes) of Oriverutoides attenuatus ( Figure 9 ) confirms the resemblance between this species and some representatives of Oriverutus . Unfortunately, the differences between them cannot be totally confirmed herein. On one hand, the position of the amphid aperture is quite posterior ( Figure 9E, F ), more than usually observed in Oriverutus , as mentioned by Ahmad and Sturhan (2002); besides, the aperture is a comparatively large oval, not a transverse slit as often occurs in Oriverutus species ( Figure 2 ). On the other hand, the location of pharyngeal gland nuclei and their outlets is obscure in the three available specimens; and the existence of sclerotization in the cheilostomatal walls seems questionable since the best preserved female does not show any distinct differentiation in cheilostom ( Figure 9A ) whereas in another female, in a worse state of preservation, it is possible to distinguish two small granular bodies ( Figure 9B ) at both sides of the cheilostom, which might represent the inner core of the respective lips. Of course, the absence of cardiac glands is not a difference between Oriverutoides and Oriverutus (see above). Consequently, and taking also into consideration the geographical distribution of Oriverutoides , which is far from the current known range of Oriverutus , both genera are provisionally considered as valid and separate taxa.

Figures

Figure 2. Lip region of Oriverutus species (scanning electron microscopy). (A, D) Oriverutus asaccatus (Dhanachand and Jairajpuri 1980) Ahmad and Jairajpuri, 1987; (B, E) Oriverutus sundarus (Williams, 1964) Siddiqi, 1971; (C, F) Oriverutus tropicus Ahmad and Shaheen, 2003; (G-I) Oriverutus occidentalis Peña-Santiago and Peralta, 1991. A–C: Sublateral or ventral view; D–E: frontal view. Scale bars 5 µm.

Figure 9. Oriverutoides attenuatus Ahmad and Sturhan, 2002 (female, light microscopy). (A, B) Anterior region in median, lateral view; (C) Pharyngo-intestinal junction; (D) Caudal region; (E, F) Anterior region in surface, lateral view. Scale bars: A, B, E, F = 5 µm; C = 10 µm; D = 20 µm.