Paraheligmonelloides singauwaensis Smales, 2009

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 : 18-20

Paraheligmonelloides singauwaensis Smales, 2009

( Figs 100–116 )

Type host. Melomys rufescens (Thomas)

Site in host. Small intestine.

Material examined. Holotype male, allotype female from Melomys rufescens from Singauwa River , Lae (6° 07´S; 146° 59´E), Morobe Province, Papua, New Guinea coll. P. J. Shanahan iv. 1966; paratypes 3 males, same data BBM NG24762.

Other material examined. From Paramelomys rubex Papua New Guinea, Sanduan Province; 2 males, 3 females east slope Somoro, Torricelli Mts (3° 24´S; 142° 8´E): Indonesia, Papua; 7 males 24 females Urong Forest , Mokwan area , Arfak Mts (1° 6´S; 133° 56´E), AM W.36802, W.36803, W.36804, W.36805, W.36806, W.36807.

Re description. General: Nematodes slightly or tightly coiled; prominent cephalic vesicle present with about 5 annulations; buccal capsule vestigial. Mouth opening triangular with rudimentary lips; labial and cephalic papillae not observed. Oesophagus claviform. Nerve ring surrounds oesophagus in middle third of oesophageal region, deirids and excretory pore at about the same level in posterior third. Synlophe (based on sections from 13 worms) of pointed longitudinal cuticular ridges in both sexes extends from posterior margin of cephalic vesicle to immediately anterior to bursa or vulva; 15–17/23 ridges in anterior, 19–23 in midbody, 14–23 in posterior. Axis of orientation of ridges passing from ventral right to dorsal left sides, inclined about 75–80° from sagittal axis in mid body; 8–11 ridges dorsal side, 9–13 ridges ventral side. In anterior and mid body ridges 1´, 2´more developed than ridges 1, 2; ridges 1–7 increasing, 8–11 decreasing in size; ridges 1´– 3´decreasing, ridges 4´–6´about the same size, ridges 7´–13´smaller. In posterior body ridges reduce in size, retaining orientation.

Male: (measurements of 4 type specimens followed by measurements of 8 voucher specimens from P. rubex ). Length 2350–2750 (2600), 2100–2650 (2400), maximum width 99–100 (99), 73– 83 (77). Cephalic vesicle 37.5–42.5 (40), 29.5–40 (36.5) long. Oesophagus 320–350 (345), 265– 310 (295) long; nerve ring 165, —, excretory pore 240, — from anterior end. Bursa (based on 7 worms) asymmetrical, right lobe larger than left; pattern of rays 2–3 for both lobes; rays 2, 3 diverge distally, recurved ventrally; rays 4, 5, 6, recurved dorsally. Dorsal lobe with median notch, shorter than laterals; dorsal trunk bifurcates at about one third its length, each branch dividing again at distal tip; terminal divisions, rays 9, 10, symmetrical, rays 8 arising at slightly different levels from dorsal trunk proximally to division of dorsal ray. Genital cone short, conical, lightly sclerotised, ventral lip with unpaired papilla 0, dorsal lip bifid, each lobe with single papilla 7. Spicules equal, filiform, proximal ends rounded, tips simple, pointed 230–290 (265), 230– 385 (308) long. Gubernaculum 34–35.5 (35), 29, 30.6 long.

Female: (Measurements of allotype followed by measurements of 8 voucher specimens from P. rubex ). Length 2900, 2330–4200 (3400), maximum width 130, 74–134. (103.) Cephalic vesicle 42.5, 33–46 (39) long. Oesophagus 390, 235–420 (345) long. Monodelphic ovejector, vulva near posterior end, 95, 60–110 (75.5) from tail tip; vagina 60, 50, vestibule and infundibulum about same length, 90, 70, sphincter shorter, 60, 30. Tail may be reflected dorsally, with praepuce 20–34 (27.5) long; tail tip conical, ending in spike. Eggs thin shelled, ellipsoidal, up to 13 in utero 45, 64.5–73 (68.5) by 30, 33–43 (38.8).

Remarks. Paraheligmonelloides singauensis was first described from 5 specimens collected from the type host, Melomys rufescens from a locality in Morobe Province, Papua New Guinea ( Smales 2009). The finding of additional specimens in P. rubex from localities in Sanduan Province ( PNG) and Papua ( Indonesia) represent new host and locality records for the species and have facilitated the preparation of the more detailed description given above. In particular the descriptions of the bursa (rays 6 not being more slender than rays 4 and 5), the female synlophe (the left and right ridges larger in the female) and ovejector (the sphincter the shortest element) have been clarified. The morphology and morophometrics of the specimens from P. rubex were congruent with those of specimens from M. rufescens , with the exception of egg size (larger) and spicule length (longer). These differences could be either a result of host influences or a reflection of the relatively small number of parasites measured in the two populations and did not seem to provide a sufficient basis for the erection of a new species.

Figures

FIGURES 100–116. Paraheligmonelloides singauwaensis Smales, 2009. 100. male, anterior end, lateral view; 101. male, anterior end showing synlophe ridges; 102. male, transverse section, anterior body; 103. female, transverse section, anterior body; 104. male, transverse section, mid body; 105. female, transverse section, mid body; 106. male, transverse section, posterior body; 107. female, transverse section, posterior body; 108. spicule tips; 109. gubernaculum, lateral view; 110. female, posterior end, lateral view; 111. genital cone, ventral view; 112. genital cone, lateral view; 113. dorsal ray; 114. ovejector, lateral view; 115. bursa, left lateral lobe; 116. bursa, right lateral lobe. Scales are in m.