Campylaimus arcuatus, Villares & Martelli & Russo & Pastor, 2013

Villares, Gabriela, Martelli, Antonela, Russo, Virginia Lo & Pastor, Catalina, 2013, Three new species and one new record of Campylaimus (Diplopeltidae, Nematoda) from Argentine coasts (Buenos Aires and Santa Cruz, Argentina), Zootaxa 3613 (1), pp. 83-96 : 88-90

Campylaimus arcuatus sp. nov.

( Fig. 3 (A–J), Fig. 5 (C–D); Table 2)

Measurements: see Table 2.

Type material. Male holotype, registration number MACN-In 38919, female allotype, registration number

MACN-In 38920; three males paratypes, registration number CNP NEM 646, 647, 648.

Type locality. Arroyo Pareja , Buenos Aires province, Argentina. Coordinates: 38°54’S, 62°04’W; water depth: low littoral. Collected by Antonela Martelli, 20 March 2011 .

Etymology. From Latin word arcuatis (adj.) = arcuate, referring to the shape of the spicule.

Description. Male (holotype): Body length medium-sized. Cuticle striated, approximately 3 µm thick. Narrow head, tapering towards the anterior end of the body, with a clearly visible cuticular cap. Mouth opening is located subterminally, on dorsal side of body. Lips are absent. Four cephalic setae (3µm in length) located level with the oral opening. Somatic setae absent. Amphidial fovea consisting of two parallel arms, originating anterior to the cephalic setae, the long arm continuous with broad lateral alae extending the length of the body to the tail tip and the shorter amphidial branch measured 32 µm long, both branches measured 6 µm wide or 2.5 times the cephalic diameter. The pharynx measured 130 µm long.

Reproductive system diorchic, testes opposed. Spicules equal in length, 24 µm long measured along the arch, curved with well-developed cephalization at the proximal end. Gubernaculum with dorso-caudally directed apophysis, 16 µm long. Five precloacal papillae of different sizes are present. Tail is cylindrical 150 µm long (c' = 5), gradually tapering toward the distal end with swollen tip. The tip of the tail has two setae, 4 µm long.

Female (allotype): similar to male in general body shape. Gonads paired, opposed; ovaries outstretched, not reflexed. Anterior and posterior ovaries located on the left and right side of intestine, respectively. Vulval orifice ventral, located in the middle of the body. Vagina short not thickened. There are two glands surrounding the vulva. Tail 150 µm long (c'= 4).

Discussion. Campylaimus arcuatus sp. nov. is characterized by the shape of the spicule and gubernaculum and by the presence of five precloacal papillae.

C. arcuatus sp. nov. resembles: C. abnormis Thanh & Gagarin, 2011 in the value of b, the dorsal opening mouth, the length of the spicule and the shape of the gubernaculum but differs in the length of the body, the shape of the spicule, the value of a and c and the presence of precloacal papillae; C. tkatchevi Tchesunov, 1974 in the value of a, b and c, the dorsal opening mouth, the length of the spicule, the shape of gubernaculum but differs in the length of the body and the presence of precloacal papillae; C. bonariensis sp.nov. in the shape of the body, the value of a, b and c, the shape of the tail and the length of the gubernaculum but differs in the length and shape of the spicule, the shape of the gubernaculum and the number of precloacal papillae and C. patagonicus sp.nov. in the shape of the body, the value of c and the shape of the gubernaculum but differs in the shape of the head and the tail, the length and shape of the spicule, the length of the gubernaculum, the value of a and b the number of precloacal papillae (Table 5).

C. arcuatus sp. nov. differs from all known species by the presence of precloacal papillae, from C. rimatus Vitiello, 1974 , C. striatus Boucher & Helléouët, 1977 and C. ponticus Sergeeva, 1981 by the presence of gubernaculum; from C. lefeveri Gerlach, 1956 and C. mirus Gerlach, 1950 by the body shorter than 1000 µm and from C. inaequalis Cobb, 1920 and C. gerlachi Timm, 1961 by the dorsal mouth.

Figures

FIGURE 3. C. arcuatus sp. nov. A. Amphidial fovea of male holotype; B. Head and buccal cavity of male holotype; C. Head and buccal cavity of female allotype; D. Amphidial fovea of female allotype; E. Spicule and gubernaculum of male holotype; F. Spicule and gubernaculum of male holotype; G. Posterior end of male holotype; H. Copulatory apparatus, spicule, gubernaculum and precloacal papillae of male holotype; I. Vulva of female allotype; J. Posterior end of female allotype. Scale bar: 20 µm.

FIGURE 5. A) Entire female allotype of C. patagonicus; B) Entire male of holotype of C. patagonicus; C) Entire male holotype of C. arcuatus; D) Entire female allotype of C. arcuatus; E) Entire female allotype of C. bonariensis; F) Entire male holotype of C. bonariensis. Scale bar: 50 µm.