Zalonema ditlevseni ( Micoletzky, 1922 )

Armenteros, Maickel, Ruiz-Abierno, Alexei & Decraemer, Wilfrida, 2014, Revision of Desmodorinae and Spiriniinae (Nematoda: Desmodoridae) with redescription of eight known species, European Journal of Taxonomy 96, pp. 1-32 : 16-17

Zalonema ditlevseni ( Micoletzky, 1922) Figs 6C–D , 8 , Table 1

Heterodesmodora ditlevseni Micoletzky, 1922: 89 .

Desmodora ocellata Wieser, 1954: 172 .

Desmodora (Zalonema) ditlevseni – Gerlach 1963: 92.

Material examined

10 ♂♂, 10 ♀♀ and 10 juveniles, deposited in the nematode collection at Centro de Investigaciones Marinas, Universidad de La Habana, CUBA.

Description

Cuticle coarsely striated in anterior body region (annuli ~ 0.6–0.8 μm width) but narrower at mid-body (annuli ~ 0.5 µm). Head capsule well-developed. Inner and outer labial sensilla setiform papillae. Four cephalic sensilla (4–6 μm long) and eight subcephalic setae (4–6 μm long) almost at the same level on the head capsule. Amphidial fovea spiral with 2.0–2.5 turns. Eight longitudinal rows of short somatic setae (~ 1–3 μm long), reduced to six rows at mid body and four rows in the posterior region. Buccal cavity with 12 cheilorhabdia, a strong dorsal tooth and two smaller ventrosublateral teeth. Pharynx muscular with posterior bulb and plasmatic interruptions, internal lining conspicuous and well-sclerotized. Cardia relatively small. Secretory-excretory system not observable. Tail conical, showing sexual dimorphism i.e., markedly bent in males and with two short subterminal setae in the tip, while more regularly conical and without subterminal setae in female.

Male monorchic, anterior testis to the right of the intestine. Spicules wide, curved, weakly cephalated. Gubernaculum a narrow rod. One or two small post-cloacal supplements in form of pits.

Female didelphic, ovaries antidromously reflexed, both genital branches to the left of intestine. Vulva a narrow transversal aperture.

Juveniles are similar to adults, except for the development of the reproductive system.

Remarks

There exist only a few detailed descriptions of Z. ditlevseni despite the high number of junior synonymies for this species. The body size of the single male specimen described by Gerlach (1964) lies within the range of the Cuban specimens (males: 1590 µm vs 847–2022 µm); however, the single female specimen described by Schuurmans Stekhoven (1950) is slightly outside the higher range for the Cuban specimens (female: 1420 µm vs 898–1380). The relatively wide range of morphological variation in the body length of the species possibly masks a complex of cryptic species.

Figures

Fig. 6. A–B. Desmodora pontica Filipjev, 1922, ♂. A. Anterior region. B. Tail region, partim in surface view and copulatory apparatus. C–D. Zalonema ditlevseni (Micoletzky, 1922), ♂. C. Anterior region. D. Tail region and copulatory apparatus.

Fig. 8. Zalonema ditlevseni (Micoletzky, 1922), SEM microphotographs of ♂ (C) and ♀ (A, B & D). A. Head in oblique en face view. B. Vulva region. C. Tail tip of ♂, subterminal opening of caudal glands. D. Tail tip of ♀.