Pontonema incisum Wieser, 1953

Villares, Gabriela, Russo, Virginia Lo & Pastor, Catalina, 2015, A new species of Pontonema (Oncholaimidae, Nematoda) and a redescription of Pontonema incisum Wieser, 1953 from Santa Cruz and Chubut Provinces, Argentina, Zootaxa 4058 (3), pp. 417-428 : 422

Pontonema incisum Wieser, 1953

( Fig. 4 (A–D); Fig. 5 (A–D) & Fig. 6 (A–D); Table 2 )

Measurements. See Table 2 .

Material. Male. Registration number CNP NEM Nº 1429. Locality: “Punta Cascajo”, Puerto Deseado, Santa Cruz Province, Argentina. Coordinates: 47° 45’ 32.41” S; 65° 53’ 57.31” W; water depth: 4m. Collected by Alicia Boraso, 1st November 2002.

Two females and one juvenile. Registration number CNP NEM Nº 1434, 1435, and 1433. Locality: “Punta Cascajo”, Puerto Deseado, Santa Cruz Province, Argentina. Coordinates: 47° 45’ 32.41” S; 65° 53’ 57.31” W; water depth: 4m. Collected by C. Pastor de Ward, 3 January 1980.

Female. Registration number CNP NEM Nº 1436. Locality: “ Isla de los Pájaros”, Puerto Deseado, Santa Cruz Province, Argentina. Coordinates: 47° 45’ 15.62” S; 65° 58’ 15.32” W; water depth: 4m. Collected by E. Romanello and M. Lamamit, 16 February 1981.

Three males, two females and one juvenile. Registration numbers CNP NEM N° 1430, 1431, 1432, 1438, 1439, and 1441. Locality: “Golfito”, Golfo Nuevo, Chubut Province. Coordinates: 42° 46’ 55.41” S; 64° 59’ 23.12” W; water depth: 5m. Collected by C. Pastor de Ward, 10 December 1986.

Description. Male. Body large, more than 2000 µm in length with maximum diameter at mid-length. Cuticle smooth with scattered somatic setae. Anterior end truncate with rounded margins. Six short labial sensillae and ten short cephalic sensillae present.

Buccal cavity large, about twice as long as wide, walls well-cuticularized with one dorsal and two sub-ventral teeth, with rounded end. Sub-ventral teeth long, slender (35 µm), extending slightly anterior to dorsal tooth and located at 36 % of stoma length. Dorsal tooth short (15 µm), located at 72 % of stoma length. Excretory pore opens two buccal cavity lengths from anterior end, not seen in all specimens examined.

Amphideal fovea transversely oval, located ~ level with sub-ventral teeth (30 µm length of stoma). Pharynx 800 Μm long, no bulbs present.

Reproductive system diorchic, testes opposed. Spicules equal in length, 87 µm long measured along blade, slender, with proximal end having developed cephalization. Gubernaculum tubular, with dorsal apophysis, 45 µm long.

One ventral precloacal sensory field present, lacking visible papillae. A glandular sub-ventral area with twelve to fourteen papilliform sensillae, the first located 50 µm anterior of the cloaca. One post-cloacal papillae present.

Tail short and rounded, 130 µm long (c’ = 1.6). Three pairs of setae on the tail. Spinneret well developed.

Figures

FIGURE 4. Female of Pontonema incisum. A. Amphideal fovea and cephalic setae; B. Posterior end; C. Head, buccal cavity and teeth; D. Vulva. Scale bar: A – C = 20 µm; D = 100 µm.

FIGURE 5. Male of Pontonema incisum. A. Amphideal fovea and cephalic setae; B. Copulatory apparatus, spicules, gubernaculum and precloacal sensory field; C. Head, buccal cavity and teeth; D. Posterior end. Scale bar: A – D = 20 µm.

FIGURE 6. Male of Pontonema incisum. A. Entire; B. Head, buccal cavity and teeth; C. Amphideal fovea; D. Copulatory apparatus, spicules, gubernaculum and precloacal sensory field. Scale bar: A = 50 µm; B – D = 20 µm.