Pontonema golfonuevensis, Villares, Gabriela, Russo, Virginia Lo & Pastor, Catalina, 2015

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 : 419-422

Pontonema golfonuevensis sp. nov.

( Fig. 2 (A–D); Fig. 3 (A–D); Table 1 )

Measurements. See Table 1 .

Type material. Male Holotype; three male Paratypes, registration number CNP NEM Nº 1401, 1402, 1403, 1404. Type locality. Golfo Nuevo, Chubut Province, Argentina. Coordinates: 42° 54.2' S, 64° 15.9' W; water depth: 141 m. Collected during the physiographic survey of the vessel “Puerto Deseado”, 13 June 1997.

Etymology. From the Spanish word “Golfo Nuevo”, in reference to the area where it was collected. Description. Holotype: Male. Large body, more than 2000 µm in length with maximum diameter at midlength. 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 75 Μm long, and twice as long as wide, with well-cuticularized walls. Armed with one dorsal and two sub-ventral teeth. Sub-ventral teeth slender, 25 µm long, extending slightly anterior to dorsal tooth and located at 24 % of stoma length. Dorsal tooth short, located at 60 % of stoma. Excretory pore opening at level of base of buccal cavity.

Amphideal fovea transversely oval, located at level of sub-ventral teeth (40 µm from anterior end). Pharynx 770 Μm long, no bulbs present.

Reproductive system diorchic, with testes opposed. Spicules of equal size, 65 µm long measured along blade, curved, with proximal end having developed cephalization. Gubernaculum tubular, with dorsal and anterior apophysis, 40 µm long. One ventral precloacal sensory field present, with four papillae. A glandular sub-ventral area present, furnished with seven papilliform sensillae, the first located 75 µm anterior to the cloaca. One postcloacal papilla present.

Tail short and rounded, 100 µm long (c’ = 2.0). Two pairs of setae on the tail. Spinneret well developed.

Female: Not collected.

Diagnosis and relationships. Pontonema golfonuevensis sp. nov. is characterized by having slender subventral teeth of moderate length at 24 % of stoma length, a short broad dorsal tooth at 60 % of stoma length, the Excretory pore at opening level with the base of the buccal cavity, and by having a ventral precloacal sensory field with four papillae and a glandular sub-ventral area with seven papilliform sensillae.

P. golfonuevensis sp. nov. resembles P. leidy Mawson (1956) by the position of the excretory pore (at level of base of the buccal cavity) and by having a precloacal sensory field; but differs in the number of papilliform sensillae (7 vs 16); resembles P. c o bb i Mawson (1956) by the position of the excretory pore (at level of base of the buccal cavity) and by having a precloacal sensory field but differs in having a gubernaculum; differs from P. ardens Gerlach (1957) , P. hackingi Mawson (1953) , P. serratodentatum Mawson (1965) , P. subtilis and P. yaenae Inglis (1964) by having a precloacal sensory field; differs from P. parvum (Kreis, 1932) , P. vacillatum Leidy (1855) , P. vulgare (Bastian, 1865) , P. balticum (Schulz, 1932) , P. macrolaimus (Southern, 1914) , P. simile (Southern, 1914) , P. zernovi (Filipjev, 1916) , P. alaeospicula , P. mediterranea , P. multisetosum Timm (1959) , P. parpailliferum (Micoletzky, 1924) , P. problematicum Chitwood (1960) , P. ar t i c u m (Kreis, 1928), P. ditlevseni (Stekhoren in Kreis, 1934), P. brevicaudatoides (Menzel, 1920) and P. papilliferum (Filipjev, 1916) by having only one precloacal sensory field; and resembles P. ocellatum (Kreis, 1932) and P. parocellatum Wieser (1954) by having one precloacal sensory field but differs in tail length (c’ = 2 vs c’ = 3 or more).

Figures

FIGURE 2. Holotype male of Pontonema golfonuevensis sp. nov. A. Head, buccal cavity and teeth; B. Amphideal fovea and cephalic setae; C. Copulatory apparatus, spicules, gubernaculum and precloacal sensory field; D. Posterior end. Scale bar: A – D = 20 µm.

FIGURE 3. Holotype male of Pontonema golfonuevensis sp. nov. 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.

Tables

TABLE 1. Measurements (in Μm) of Pontonema golfonuevensis sp. nov. (range, mean value in parentheses).

	HOLOTYPE	PARATYPES
	Male	MalesN=3
a	49	51–61 (57)
b	5.7	6–7 (6)
c	44	42–53 (47)
c'	2	1.8–2.2 (2.0)
Body length (L)	4400	4600–6100 (5517)
Body width	90	90–100 (97)
Buccal cavity length	75	65–75 (72)
Head diameter	60	65–75 (70)
Cephalic setae length	9	9–10 (10)
Cephalic setae length	9	9–10 (10)
Amphid (%)	14	11–14 (13)
Amphid width	13	7–13 (10)
Pharynx length	770	800–900 (850)
Anal body diameter	53	57–60 (59)
Spicules length	65	60–100 (83)
Spicules (%)	1.2	1.1–1.7 (1.4)
Gubernaculum length	40	40–50 (47)
Gubernaculum (%)	0.7	0.7–0.8 (0.8)
Tail length	100	110–130 (117)