Taxonomy of Some New and Known Species of the Genus Tylencholaimellus With a Proposal for Margollus Gen. N. (Nematoda: Dorylaimida)

Abstract

In this paper two new species of the genus Tylencholaimellus (T. loofi and T. cylindricus) are described and new information is provided on T. projectus Siddiqi, 1964 from Malawi and T. hispanicus Pena Santiago & Coomans, 1990 which is transferred to a new genus, Margollus, with M. bellus as type species. Tylencholaimellus loofi sp. n. is characterized by body length 0.6-0.9 mm, lip region offset by a less marked constriction, stylet 19-20.5 μm, pharyngeal bulb 22-30 μm, V = 26.6-33.5, prevulval sac 14-30 μm (0.5-1.0 times the corresponding body width), tail convex conoid to hemispherical (14-30 μm long, c = 37-55 and c' = 0.65-1.1), and males absent. T. cylindricus sp. n. can be distinguished by body 0.7-1.0 mm long, lip region continuous, stylet 25-28 μm, pharyngeal bulb 26-36 μm long, V = 28.7-36, anterior uterine sac 40-90 μm long (0.7-2.2 times body diameter), female tail hemispherical (16-20 μm long, c = 41.8-68.7, c' = 0.5-0.6) and characteristically slender spicules 44-50 μm long. Margollus gen. n. is very close to Tylencholaimellus but differs from it in having a very well developed cephalic framework with labial and postlabial sclerotization. M. bellus sp. n. is recognized by the medium sized body (0.84-0.96 mm long), lip region attenuated with its most anterior part set off by a constriction and the posterior part continuous with the body, labial sclerotization with a hook-like anterior part, stylet 30-22 μm long, pharyngeal bulb length 27-31 μm, female tail convex conoid (its length 21 μm, c = 41.3, c' =1.0), spicules 33-36 μm long and only one ventromedian supplement present.