Paraustrostrongylus paramelomysi, Smales & Heinrich, 2010

Smales, L. R. & Heinrich, B., 2010, Gastrointestinal nematodes of Paramelomys rubex (Rodentia: Muridae) from Papua Indonesia and Papua New Guinea with the descriptions of three new genera and four new species of Helligmonellidae and Herpetostrongylidae (Nematoda: Trichostrongylida), Zootaxa 2672 (1), pp. 1-28 : 23

Paraustrostrongylus paramelomysi sp. nov.

( Figs 133–147 )

Type host. Paramelomys rubex (Thomas)

Site in host. Small intestine.

Material examined. Holotype male, allotype female from Paramelomys rubex from hill south of Tifalmin (5° 7´S; 141° 25´E), West Sepik District, Sanduan Province, Papua New Guinea, coll. T. Flannery 15. iv. 1986, AM W.36815, W.36816; paratypes 12 males, 12 females, same data AM W.36817.

Etymology. The specific name refers to the host genus name as has been customary for other species in the genus.

Description. General: Small worms, prominent cephalic vesicle present with about 20 fine transverse annulations. Mouth opening triangular with 6 small rounded lips; buccal capsule sub globular with dorsal tooth; labial and cephalic papillae not observed. Oesophagus slender, claviform. Nerve ring, deirids and excretory pore not visible. Body with 2 lateral fluid filled cavities, floats, extending from posterior margin of cephalic vesicle to immediately anterior to bursa in male and to anus in female. Synlophe with up to 6 pointed longitudinal cuticular ridges in both sexes; 2–3 ridges ventrally, oriented from right to left; 2–3 ridges on right float, 2 dorsal, 0–1 ventral; 0–1 ridges on ventral left float.

Male: (Measurements of 6 specimens) Length 1750–2900 (2295), maximum width (without floats) 73–95 (86). Cephalic vesicle 69–88 (79) long. Oesophagus 330–460 (357) long. Bursa symmetrical, lobes indistinct, dorsal lobe not separated from lateral lobes; pattern of rays 2–3; rays 2, 3, diverge distally, recurved ventrally; rays 4, 5, 6 with common origin, rays 4 more robust than rays 5, 6; rays 8 arise near base of dorsal trunk, rays 9 short, slender, asymmetrical, arise close to origin of rays 10, 11. Genital cone, sclerotised, complex; ventral lip with unpaired papilla 0, dorsal lip with paired papillae 7. Spicules simple, twisted together proximally joined at the tips distally, tips sclerotised, 310–330 (318) long. Gubernaculum 37–44 (40) long.

Female: (Measurements of 7 specimens) Length 2900–3400 (3250), maximum width (without floats) 86– 109 (95). Cephalic vesicle 69–89 (79) long. Oesophagus 300–430 (364) long. Ovejector monodelphic, vulva near posterior end, 270–360 (306) from tail tip; vagina, 50, sphincter, 40, shortest elements, vestibule, 100, infundibulum usually looped, 110, longest element. Tail reflected ventrally, 90–130 (105) long; tail tip relatively long, conical. Eggs thin shelled, ellipsoidal, about 13 in utero 63–79 (67.4) by 34–40 (36.8).

Remarks. Paraustrostrongylus paramelomysi n. sp. having a synlophe with longitudinal ridges and paired lateral floats, a dorsal oesophageal tooth and a highly sclerotised genital cone falls within the genus Paraustrostrongylus but differs from all congeners in the extent of the lateral floats, posterior to the vulva in the female. It is similar to P. gymnobelideus Humphery-Smith, 1981 , P. potoroo Mawson, 1973 and P. ratti Obendorf, 1979 in having up to 7 ridges in the synlophe. Of these P. paramelomysi is closest to P. ratti , both having the spicules, twisted together proximally, but differs from it in the length of the spicules 310–330 compared with 640–700, and the origin and proportions of rays 9, closer to the branching of rays 10 and 11 and more stout in P. paramelomysi (see Obendorf 1979)˛ It further differs from P. gymnobelideus in having the spicules twisted together proximally and in the position of the vulva 270–306 compared with 134–217 from the tail tip ( Humphery-Smith 1981) and from P. potoroo in the length of spicules, 310–330 compared with 250–260 and in not having enlarged cuticle anterior to the vulva ( Mawson 1973). Paraustrostrongylus paramelomysi can be distinguished from all other members of the genus in the number of ridges of the synlophe; P. bettongia Mawson, 1973 having 8, P. hypsiprymnodontis Mawson, 1973 , 5 and P. trichosuri Mawson, 1973 , 9 ( Mawson 1973; Durette-Desset 1979).

Figures

FIGURES 133–147. Paraustrostrongylus paramelomysi n. sp. 133. male, transverse section, anterior body; 134. spicules, proximal ends; 135. male, cervical vesicle, lateral view; 136. male, anterior end, lateral view; 137. male, transverse section, mid body; 138. spicules, distal tips; 139. female, transverse section, anterior body; 140. genital cone, lateral view; 141. male, transverse section, posterior body; 142. female, transverse section, mid body; 143. genital cone, ventral view; 144. dorsal ray; 145. female, posterior end, lateral view; 146. bursa, flattened out; 147. ovejector, lateral view. Scales are in m.