Aplectana artigasi n.sp. (Nematoda: Cosmocercidae) from the Frog Eupsophus calcaratus (Anura: Leptodactylidae) in Southern Chile

A new species of nematode found in the intestine of Eupsophus calcaratus (Anura: Leptodactylidae) from Yaldad, Chile (45°5’S;73°43’W) is described. This new nematode is compared with other South American species of the genus. Aplectana artigasi differs from the only known Chilean species, Aplectana chilensis, as the former has a greater number of postanal papillae and a double papilla in the ventral region of the tail.


MATERIALS AND METHODS
Twenty six female and five male nematodes of the genus Aplectana were removed from the intestine of three adults of E. calcaratus from Yaldad (45°5'S; 73°43'W), on the Isla Grande of Chiloé, Chile. The nematodes were fixed in 70% ethanol and cleared in lactophenol for morphological study. Measurements are in µm, unless otherwise indicated. Ranges are followed by averages in parenthesis.
The following type material from the Helminthological collection of the Instituto Oswaldo Cruz, Brazil was studied: A. crucifer Travassos, 1925(coll. No. 5173), A. bonariensis (Gutiérrez, 1945, A. crossodactyli (Baker, 1980) (coll. No. 30466 c,d) and A. delirae (De Fabio, 1971) (coll. No. 30591 m, j). Specimens of A. chilensis (coll. No. 231555) from Museo of Zoología de la Universidad de Concepción, Chile, were also studied. Small slender worms. Cuticle bearing transverse striations from posterior to lips to tail. Triangular oral opening surrounded by one dorsal and two subventral lips. Each lip with a cuticular flap on anterior edge. Cephalic sense organs consisting of inner circle of 6 min papillae and a circle of four outer submedian papillae, one on each subventral lip and two on dorsal lip. Two large amphids present. Lateral alae narrow extending from 70-74 posterior to cephalic extremity to anal region in female and in males, beyond the anus. Anterior part of oesophageal corpus small compared to posterior one; isthmus small and bulb provided with valvular apparatus. Excretory pore a broad transverse slit with fringed border situated between anterior and medial region of the bulb.

REMARKS
A study of one female and one male of A. chilensis (coll. No. 231555), from P. thaul (Benavides et al. 1996) showed the characteristics of the original description of Lent and Freitas (1948), but the male specimen showed one unpaired papilla on the anterior lip of the anus, a characteristic that was not mentioned in the original paper.
Examination of the poorly processed type material of A. crossodactyli (coll. No. 30466 c,d),A. delirae (coll. No. 30591 m,30591 j) and A. crucifer (coll. No. 5173) did not reveal details of the spicules and gubernaculum. Specimens of A. bonariensis (coll. No. 16600 a, b, c), considered by Baker (1987) as a synonym of A. hylambatis, showed a gubernaculum and spicules.
The type material of A. chilensis and A. meridionalis was requested for study from the Museo de Montevideo, Uruguay, but unfortunately it was not received.
Compared with descriptions of the above mentioned species by Miranda (1924), Travassos (1931), Lent and Freitas (1948), da Silva (1954), Pallarés and Maciel (1974) Baker (1980), Baker and Vaucher (1986) and Dyer (1990), the new species can be distinguished from A. membranosa, A. micropenis, A. vellardi, A. hylambatis, A. lopesi, A. elenae, A. paraelenae, A. pudenda, A. travassosi, and A. macintoshii because it does not have a gubernaculum. A. artigasi n.sp. has a smaller number of caudal papillae than A. crucifer and A. meridionalis with 11 and 14 pairs of papillae respectively. The new species differs from A. chilensis because it has a larger number of postanal papillae, and it has an unpaired double papilla on the ventral region of the tail. The described species also differs from A. crucifer because it presents a prominent papilla on the anterior border of the anus and from A. meridionalis because its spicules are two or three times longer.