Mawsonema mokwanensis, 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 : 8

Mawsonema mokwanensis sp. nov.

( Figs 20–37 )

Type host. Paramelomys rubex (Thomas)

Site in host. Small intestine.

Material examined. Holotype male, allotype female from Paramelomys rubex Mokwan area, Arfak Mts (1° 6´S; 135° 35´E), Papua, Indonesia, coll. T. Flannery, 15. iv. 1986, AM W.36780, W.36781; paratypes 5 males, 3 females, same data AM W.36779.

Other material examined. From Paramelomys rubex Papua New Guinea, Sanduan Province; 1 female Ofektaman, Telefomin Valley (5° 5´S; 141° 35´E) , Western Province; 1 male, 1 female near Ok Tedi Mine site (5° 17´S; 141° 14´E) : Indonesia, Papua; 9 males, pieces of males, 28 females, pieces of females Mokwan area, Arfak Mts (1° 6´S; 133° 56´E), AM W36770 , W.36771, W.36772, W.36773, W.36774, W.36775, W.36776, W.36777, W.36778 .

Etymology. The species name is taken from the type locality.

Description. General: Relatively robust worms, body usually with 1 or 2 loose coils anteriorly; prominent cephalic vesicle present with about 6 annulations; buccal capsule vestigial. Mouth opening triangular with rudimentary lips; labial and cephalic papillae not observed. Oesophagus claviform. Nerve ring anterior to deirids and excretory pore in mid oesophageal region. Synlophe (based on sections from 10 worms) of continuous pointed longitudinal cuticular ridges in both sexes extends from posterior margin of cephalic vesicle to immediately anterior to bursa or vulva; 13–14 ridges in anterior, 15 in midbody, 15 in posterior. Ridge 1 more developed than ridge 1´forming a Type A carene. Axis of orientation of ridges sub frontal in anterior; 6–8 ridges dorsal side, 5–7 ridges ventral side. In male anterior ridge 4 largest, ridges 1–3 and ridge 5 about same size, ridges 1´–8´decreasing in size; in female ridge 1– 3 decreasing, ridges 4–6 increasing, 7–8 decreasing in size; ridge 1´largest, ridges 5´– 7´decreasing in size. In mid and posterior body ridges become smaller, about same size, losing orientation.

Male: (measurements of 13 specimens) Length 4500–6400 (5700), maximum width 132–198 (187). Cephalic vesicle 40–53 (47) long. Oesophagus 330–440 (389) long; nerve ring 230, deirids, excretory pore 140–230 (184) from anterior end. Bursa (based on 12 worms) asymmetrical, left lobe larger than right; pattern of rays 2–3 for both lobes; rays 2, 3 diverge distally, recurved ventrally; rays 4, 5, 6 recurved dorsally; rays 4 more stout than rays 5, 6, rays 2, 3 more slender. Dorsal lobe with median notch, shorter than laterals; dorsal trunk bifurcates at about 1/3 length, each branch dividing again at distal tip; terminal divisions, rays 9 slightly longer than rays 10, rays 8 arising at same level from dorsal trunk proximally to division of dorsal ray. Genital cone prominent, broadened distally; ventral lip with unpaired papilla 0, dorsal lip with paired papillae 7. Spicules filiform tips simple 500–830 (703) long. Gubernaculum 42.9–72.6 (58.8) long.

Female: (measurements of 13 specimens) Length 5800–7300 (6500), maximum width 168–315 (186). Cephalic vesicle 59.5–85.8 (73) long. Oesophagus 360–470 (405) long; nerve ring 195, deirids, excretory pore 190–342 (225) from anterior end. Monodelphic ovejector, vulva near posterior end, 130, 190 from tail tip; vagina with small dorsal diverticulum; vestibule, 90, longer than sphincter, 30, infundibulum longest, 130. Tail reflected ventrally, with praepuce, 43, 46 long. Tail tip blunt, conical. Eggs thin shelled, ellipsoidal, numerous, in utero 55–75 (70.5) by 34–59.5 (45).

Remarks. A helligmonellid parasite of a hydromyin rodent from the Island of New Guinea Mawsonema n. g. has all the characteristics of the subfamily Nippostrongylinae except that the orientation of the synlophe ridges exceeds the range given by Durette-Desset (1983). The features of the synlophe; ridge 1 larger than ridge 1´forming a type A carene, the pattern of gradation of sizes, seen only anteriorly, of the 15 ridges, sub frontal orientation anteriorly, losing orientation posteriorly, combined with those of the bursa; left lobe larger, ray pattern 2–3, dorsal ray divided distal to rays 8 distinguish the genus from all others in the sub family. In particular Mawsonema can be distinguished from all the genera presently known from the Oriental, Sunda and Sahul Regions by the characters of the synlophe. Mawsonema is nearest to Odilia , Nippostrongylus and Paraheligmonelloides in having a type A carene but differs from Odilia and Paraheligmonelloides in having ridge 1 larger than ridge 1´and from Nippostrongylus in having the carene supported by two ridges instead of a single hypertrophied left lateral ridge (Durette-Desset 1969, 1970b; Hasegawa et al. 1999; Ow Yang et al. 1983). Mawsonema further differs from all three genera in having the axis of orientation of the ridges sub frontal anteriorly and without orientation in the mid and posterior body rather than an oblique axis oriented at 60–70°. The genera Heligmonelloides and Maxomystrongylus with type B carenes, Bunomystrongylus with both pointed, internally supported and rounded unsupported ridges, Hassanuddinia with an oblique 55–70° axis of orientation of the ridges and Melomystrongylus with an hypertrophied ventral ridge anteriorly, do not have a carene ( Smales, 2009; Hasegawa & Mangali 1996; Hasegawa & Syafruddin 1994b). Of the genera known only from the Oriental and Sunda regions Orientostrongylus has a primitive arrangement of the synlophe with either no or a type B carene, Malaistrongylus has left and right dilatations of a synlophe with more then 30 ridges, Rattustrongylus has no carene, 18-19 ridges with the left dorsal ridges smallest and in Sabanema , also with no carene and more than 30 ridges, the left dorsal and right ventral ridges the smallest (Durette-Desset 1970b; Ow Yang et al. 1983).

Figures

FIGURES 20– 37. Mawsonema mokwanensis n. gen., n. sp. 20. female, anterior end showing synlophe ridges; 21. male, transverse section, anterior body; 22. male anterior end, lateral view; 23. female, transverse section anterior body; 24. male, transverse section, mid body; 26. spicules, proximal ends; 26. genital cone, dorsal view; 27. female, transverse section, mid body; 28. male, transverse section, posterior body; 29. spicules, distal tips; 30. gubernaculum, lateral view; 31. genital cone, ventral view; 32. bursa, partially unfolded; 33. female, transverse section, posterior body; 34. dorsal ray; 35. female posterior end, showing ovejector and ridges of synlophe on praepuce. 36. female tail tip, lateral view. 37. bursa, ventral rays. Scales are in m.