Montistrongylus ingati, 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 : 12-14

publication ID	https://doi.org/ 10.11646/zootaxa.2672.1.1
DOI	https://doi.org/10.5281/zenodo.5308622
persistent identifier	https://treatment.plazi.org/id/FF7CEC67-FD67-FF86-FF3A-FB2BFE2A75E4
treatment provided by	Felipe
scientific name	Montistrongylus ingati
status	sp. nov.

Treatment

Montistrongylus ingati sp. nov.

( Figs 51 –65 View FIGURES 51–65 )

Type host. Paramelomys rubex (Thomas)

Site in host. Small intestine.

Material examined. Holotype male, allotype female from Paramelomys rubex Dokfuma Star Mts (5° 1´S, 141° 7´E), West Sepik, Sanduan Province , Papua New Guinea, coll. T. Flannery 6. iv. 1987, AM W.36782, W.36783; paratypes 7 males, 6 females, same data AM W.36784. GoogleMaps

Etymology. The species name is taken from one of the local names for the type host.

Description. General: Relatively robust coiled worms, prominent cephalic vesicle present with 15–18 fine annulations; buccal capsule vestigial. Mouth opening triangular with rudimentary lips; labial and cephalic papillae not observed. Oesophagus claviform. Nerve ring not visible, deirids and excretory pore at same level in posterior region of oesophagus. Synlophe (based on sections from 6 worms) of small pointed longitudinal cuticular ridges in both sexes extends from posterior margin of cephalic vesicle to immediately anterior to bursa or vulva; 11–15 ridges in anterior, 12–15 in mid body, 8–11 in posterior. Axis of orientation of ridges passing from ventral right to dorsal left, inclined 55–60° from saggital axis in mid body; 3–8 ridges dorsal side, 4–9 ridges ventral side. In anterior body ridges 4´–6´(male) 5´(female) slightly larger; in mid body ridges 3´–5´(male) 4´–5´(female) slightly larger. Axis of orientation maintained along body.

Male: (Measurements of 9 specimens) Length 3300–4100 (3700), maximum width 92.5–123 (101). Cephalic vesicle 53.75–66 (62) long. Oesophagus 350–400 (380) long; deirids, excretory pore 270, 280 from anterior end. Bursa (based on 7 worms) with right lobe slightly larger, pattern of rays 3–2 for both lobes; rays 2, 3 diverge distally, recurved ventrally; rays 4 recurved ventrally; 5, 6 recurved dorsally; rays 4, more stout than rays 5, 6; rays 2, 3 more slender. Dorsal lobe shorter than laterals, with median notch; dorsal trunk bifurcates at about 2/3 its length, each branch dividing again at distal tip; terminal divisions rays 9 longer than rays 10, symmetrical, rays 8 asymmetrical, left ray 8 longer, arising proximally to right ray 8 from dorsal trunk, both rays proximal to division of dorsal ray. Genital cone small, ventral lip with unpaired papilla 0, dorsal lip with paired papillae 7. Spicules filiform, tips simple 380–450 (414) long. Gubernaculum 27–30.5 (29.4) long.

Female: (Measurements of 9 specimens) Length 5100–6750 (5460), maximum width 94–119 (108). Cephalic vesicle 50–66 (58) long. Oesophagus 335–450 (394) long; deirids, excretory pore 332, 388 from anterior end. Monodelphic ovejector, vulva near posterior end, 150–190 (164) from tail tip; vagina, 40, and sphincter, 30, shorter than vestibule, longest element, 190, infundibulum, 100. Tail reflected ventrally, 33–43 (40) long. Tail tip blunt, conical. Eggs thin shelled, ellipsoidal, up to 20 in utero 77–84.5 (81.25) by 38.5–42.3 (41.5).

Remarks. A helligmonellid parasite of a hydromyin rodent from the Island of New Guinea Montistrongylus n. g. has all the characteristics of the subfamily Nippostrongylinae (see Durette-Desset 1983). The features of the synlophe; the sizes of the 15 ridges, the lack of ridges on the right ventro lateral side the axis of orientation, 55–60° from the saggital plane and lacking a carene, combined with those of the bursa; right lobe larger, pattern of rays 3–2, dorsal ray divides distally to rays 8 in posterior third, left ray 8 longer than the right ray 8 distinguish the genus from all others in the sub family. In lacking a carene but with an oblique axis of orientation of the synlophe ridges Montistrongylus is closest to Bunomystrongylus , Hasanuddinia , and Melomystrongylus from the Sahul region and Malaistrongylus , Orientostrongylus , Rattustrongylus and Sabanema from the Oriental and Sunda regions. Each of these genera differs from Montistrongylus as follows. Bunomystrongylus has a synlophe with some pointed and some rounded elements, Hasanuddinia has a synlophe with three ventral ridges, persisting posteriorly, hypertrophied, and bursal rays 8 more or less symmetrical. Melomystrongylus has an hypertrophied ventral ridge anteriorly and no clear axis of orientation of the ridges in the mid and posterior bodies and bursal rays 8 more or less symmetrical. Malaistrongylus has left and right dilatations of a synlophe with more than 30 ridges. Orientostrongylus has a primitive arrangement of synlophe, may have a type B carene, the ridges more evenly distributed on the synlophe, an almost symmetrical bursa and a thick dorsal ray. Rattustrongylus has 18-19 ridges relatively evenly distributed on the synlophe with the left dorsal ridges smallest, the dorsal ray divided at about the branching of rays 8 which are more or less symmetrical and the left lobe of the bursa larger than the right. Sabanema , has more than 30 ridges relatively evenly distributed on the synlophe, the left dorsal and right ventral being the smallest, the dorsal ray divided in the proximal half and the left lobe of the bursa larger than the right (Durette-Desset 1970b; Hasegawa & Mangali 1996; Hasegawa & Syafruddin 1994b; Ow Yang et al. 1983; Smales 2009).