Cervonema Wieser 1954

Genus Cervonema Wieser 1954

Emended diagnosis. Sabatieriinae with striate cuticle; fine punctations may be also observed. Anterior and posterior cephalic sensilla in distinctly separate crowns and usually equal in length. Buccal cavity short and undifferentiated. Posterior elongate oesophageal bulb. Cervical region elongate and narrowed, amphids usually set back from cephalic setae, about 2 hd from the anterior, and up to 7 turns. Spicules simple, poorly sclerotized and <2 abd in length, usually ≤ 1 abd. Gubernaculum plate-like, or not observed, apophyses absent. Supplements minute tubular pores or absent. Tail conico-cylindrical.

Remarks. To date 13 species of Cervonema have been described: C. allometricum Wieser 1954, C. tenuicauda Schuurmans Stekhoven jr. 1950, C. macramphis Jensen 1979, C. jenseni Gourbault 1980, C brevicauda, Gourbault 1980, C. papillatum Jensen 1988, C. deltensis Hope & Zhang 1995, C. minutus (Muthumbi et al. 1997), C. gourbaulti Muthumbi et al. 1997, C. chilensis Chen & Vincx 2000, C. hermani Chen & Vincx 2000, C. shia Chen & Vincx 2000, C. proximamphidu Tchesunov 2000. Table 5 presents a comprehensive comparison of the morphometric characteristics of these species and Table 6 provides the calculated body proportions, such as de Man's ratios. Where measurements were not presented in the original descriptions they are supplemented by measurements made by the authors from the original published figures where possible.

Here one species, Cervonema pseudodeltensis is described based on male and female specimens, and a further two species are informally described owing to a lack of males. The intention of these informal descriptions is to indicate the presence of additional species and to describe them as best as possible, without males, to allow subsequent researches an ability to compare records. Although for some taxa it is common practise to describe species based on females, it is not so for nematodes. Whilst for the Cervonema the male characters are not very informative to species differentiation, there is a risk of introducing nomenclatural problems, as yet unforeseen, if these species are described based on females only.