Plectus gisleni Allgén, 1951b

Holovachov, Oleksandr & Boström, Sven, 2015, Swedish Plectida (Nematoda). Part 10. The genus Deontolaimus de Man, 1880, Zootaxa 4034 (1), pp. 1-44 : 38-39

Plectus gisleni Allgén, 1951b

( Fig. 22 )

Female. Body slender, cylindrical over most of its length, tapering anteriorly in anterior half of pharyngeal region and posteriorly on tail; strongly ventrally curved upon fixation. Cuticle annulated. Lateral field, body pores, epidermal glands and subcephalic, cervical and somatic sensilla cannot be observed. Labial region rounded, continuous with body contour. Inner and outer labial, and cephalic sensilla indistinct. Amphid indistinct. Ocelli absent. Nerve ring, hemizonid and secretory-excretory system cannot be observed. Oral opening terminal. Onchiostyle present but strongly deteriorated. Pharynx cylindrical anteriorly, expanding posteriorly. Reproductive system didelphic, amphidelphic; ovary branches reflexed antidromously. Vagina straight. Epiptygmata and pars refringens vaginae absent. Rectum short. Tail conoid, ventrally curved. Spinneret acute, straight.

Discussion. The description and illustrations of this species superficially match the diagnosis of the family Camacolaimidae , particularly the genera Deontolaimus and Procamacolaimus , in having a single dorsal onchiostyle and a paired female reproductive system ( Allgén, 1951b: 181–182, Fig. 3 a–c). Absence of males prevents more precise identification of this species. It is considered species inquirenda et incerta sedis within the family Camacolaimidae .

Figures

FIGURE 3. Deontolaimus tardus (de Man, 1889) comb. n., male from Oosterschelde. A: Anterior end, median section; B: Anterior end, surface view; C: Male posterior region; D: Pharyngeal region, median section. Scale bar: A – D = 20 µm.

FIGURE 22. Plectus gisleni Allgén, 1951 b, lectotype female. Scale bar: 50 µm.