Prooncholaimus ornatus ( Kreis, 1932 ) Kreis, 1934

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 : 551-552

Prooncholaimus ornatus ( Kreis, 1932) Kreis, 1934

( Figs 1 E–H & 3)

Material examined. Five females and five males were examined from Diapterus rhombeus .

Measurements. See Table 1 .

Description. Adult: Body 1.70–2.28 mm long. Cuticle smooth, lacking annuli. Large bubble-like cells appear between the intestine and the lateral chord. Lip region with labial papillae and short cephalic setae. Amphids well developed, located at mid-stoma length, with ovoid aperture occupying half of lip region diameter. Stoma length about twice width, bearing three teeth, the left ventrosublateral one larger and the dorsal and right ventrosublateral ones with similar morphology. Pharynx subcylindrical, more swollen in posterior half. Nerve ring surrounding pharynx at mid-length. Excretory pore located at level of anterior part of pharynx. Cardia poorly developed. Intestine not differentiated.

Female: Body with sigmoid habitus. Reproductive system monodelphic-prodelphic; ovary, oviduct and uterus in bad condition. Demanian system absent. Rectum slightly longer than anal body diameter. Tail conoid, ending in a small spinneret.

Male: General morphology similar to female, having sigmoid habitus. Spicules short, length 1.5 times anal body diameter, manubrium well developed. Gubernaculum present, short, more or less sigmoid and slightly shorter than half spicule length. Genital setae thirteen, located anteriorly and posteriorly to the cloaca. Tail conoid, dorsad bent, with a conoid proximal part (bearing genital setae) and a subcylindrical distal part ending in a small spinneret.

Distribution. Prooncholaimus ornatus was reported by Kreis (1932, 1934) from the Banda and Java seas and the Sunda Strait ( Indonesia). This is its first report from Brazil (see Venekey et al. 2010).

Remarks. The material examined is similar to the type population from Indonesia described by Kreis (1932, 1934) although it has some differences in body length (1.71–2.14 mm vs 2.17–2.76 mm in females, 2.11–2.28 mm vs 1.99–2.01 mm in males), and a shorter and broader tail (c=20.3–34.0 vs 16.9–20.3 and c'= 2.0–3.0 vs 3.7–4.1 in females and c= 25.5–36.2 vs 17.5–18.0 and c'= 1.6–2.6 vs 4.5–4.7 in males).

Species M. amplus P. ornatus O. labiatus

Predatοr Diapterus rhombeus Diapterus rhombeus Diapterus rhombeus Τhis specimen presents the bοdy slightly cοntracted and the cuticle separate in several parts.

Figures

FIGURE 1. Metoncholaimus amplus Hopper, 1967. A: Stoma. B: Neck. C: Female posterior end. D: Male posterior end. Prooncholaimus ornatus (Kreis, 1932) Kreis, 1934. E: Stoma. F: Neck. G: Female posterior end. H: Male posterior end. Oncholaimellus labiatus (Kreis, 1932) Gerlach & Riemann, 1974. I: Stoma. J: Female posterior end. K: Male posterior end.