Dorylaimopsis pellucida ( Cobb, 1920 ) Jensen, 1979

Abolafia, Joaquín, Ruiz-Cuenca, Alba N., Fernandes, Berenice M. M., Cohen, Simone C. & Cárdenas, Melissa Q., 2015, Description of free-living marine nematodes found in the intestine of fishes from the Brazilian coast, Zootaxa 3948 (3), pp. 549-572 : 566

Dorylaimopsis pellucida ( Cobb, 1920) Jensen, 1979

( Figs 11 A–H & 12)

Material examined. One female from Diapterus rhombeus and one male from Eucinostomus argenteus were examined.

Measurements. See Table 2 .

Description. Adults: Body 1.43–1.56 mm long. Cuticle smooth, lacking transverse striations. Lip region with six fused lips having well-developed cephalic setae. Amphids spiral, located posteriorly to lip region. Stoma tubular, with three anterior protusible odontia. Pharynx short, scarcely more than five times body diameter at its base, and posteriorly swollen in a pyriform bulb. Nerve ring surrounding the pharynx at its mid-length. Excretory pore not observed. Cardia well developed, hemispheric. Intestine not differentiated.

Female: Body with C-shaped habitus. Reproductive system didelphic-amphidelphic; ovaries short, straight, with oocytes in several rows at its germinative part and in one row for rest; oviducts very short; uteri short, swollen, about twice the corresponding body diameter, with spermatozoa inside; vagina thin and long, occupying less than half body diameter. Rectum slightly longer than anal body diameter. Tail conoid elongate, with its distal part slightly clavate and ending in a spinneret.

Male: General morphology similar to female, with habitus almost straight and slightly ventrad curved at its posterior region. Spicules sickle-shaped, with rounded and dorsad bent manubrium, short calamus and ventrad curved lamina with hook-like tip. Gubernaculum one third of spicule length, with dorsal apophysis well-developed and directed to the tail. Tail conoid/elongate, with distal part clavate and ending in a spinneret.

Distribution. Dorylaimopsis pellucida was reported from Jamaica by Cobb (1920) in mud in littoral shallows, from Florida ( USA) by Wieser & Hopper (1967) and from French Polynesia by Boucher (1973). This is its first report from Brazil (see Venekey et al. 2010).

Remarks. The material examined is similar to other previously populations studied, especially in having sickle-shaped spicules. However, compared to the type material described by Cobb (1920). it has a shorter body (1.56 mm in female and 1.43 mm in male vs 2.30 mm in female and 2.00 in male), vulva slightly posterior (V= 52 vs 47) and a shorter tail (138 µm in female and 148 in male vs 184 µm in female and 180 in male). It differs from the material examined by Wieser & Hopper (1967) in the shorter body length (vs 1.77–2.00 mm), smaller male pharynx (189 µm vs 250 µm), longer stoma (27–32 µm vs 23µm), shorter spicule (91 µm vs 110 µm) and shorter tail (148 µm vs 200 µm). Compared to the material examined by Boucher (1973), it is smaller (vs 1.95–2.33 mm in females and 2.19–2.35 mm in males), and has a shorter pharynx (189–238 vs 250–283 µm), tails (138 µm in female and 148 µm in male vs 195–223 µm in females and 175 µm in males) and spicules (91 vs 119–124 µm), and a more posterior vulva (V= 52 vs 46–48).

Figures

FIGURE 11. Dorylaimopsis pellucida (Cobb, 1920) Jensen, 1979. A: Female stoma. B: Male stoma. C: Neck. D: Anterior branch of the female genital system. E: Entire male. F: Entire female. G: Female posterior end. H: Male posterior end. Parodontophora breviamphida (Timm, 1952) Timm, 1963 (female). I: Stoma. J: Tail.