Hughjonestrongylus wanumaensis, Smales, 2019

Smales, Lesley, 2019, Gastrointestinal nematodes of Paramelomys platyops (Rodentia: Muridae) from Papua Indonesia and Papua New Guinea with the descriptions of a new genus and five new species of Heligmonellidae (Nematoda: Trichostrongylina) and a key to the species of Hughjonestrongylus, Zootaxa 4679 (1), pp. 107-125 : 118-119

Hughjonestrongylus wanumaensis n. sp.

( Figs 55–64 )

Type host. Paramelomys platyops (Thomas) .

Site in host. Small intestine.

Material examined. Holotype male, allotype female, paratypes 5 males, 14 females BBM NG104215 from Paramelomys platyops from 14 k north northwest Wanuma, Madang Province, Papua New Guinea; coll A. B. Mirza 14. iii. 1974.

Other material examined. From Paramelomys platyops from Papua New Guinea, Madang Province; 6 males, 2 females 14 k north north west Wanuma, BBM NG103897, NG104374, NG104373, NG104075C.

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

Description. General: Very small worms, slightly or tightly coiled: prominent cephalic vesicle with about 10–12 transverse annulations; buccal capsule vestigial. Mouth opening triangular with rudimentary lips; labial and cephalic papillae not observed. Oesophagus claviform. Nerve ring, deirids and excretory pore not observed.

Synlophe: (based on sections from 2 females) of pointed longitudinal continuous ridges extending from posterior margin of cephalic vesicle to immediately anterior to bursa or vulva. Anterior body with 23 ridges, mid body with 21 ridges. Ridges markedly different in size. Axis of orientation frontal from right ventral to left dorsal in mid body; 10 ridges dorsal side, 11 ventral side. Left ridge distinct from ridge 1´; mid left ridges larger than mid right ridges, left ridges 1´, 2´larger than right ridges 8–10; left ridge 2´smaller than 1´, ventral ridges 3´–7´increasing in size, 8´–11´decreasing in size; dorsal ridges 1–7 about same size, ridges 8–10, larger, increasing in size;

Male: (measurements of 10 specimens) Length 1650–2200 (1900), maximum width 40.0–65.0 (51.3). Cephalic vesicle 24.0–45.0 (35.7) long. Oesophagus 290–390 (304) long; nerve ring, deirids and excretory pore not observed. Bursa dissymmetrical, left lobe larger, pattern of rays of left lobe 2–3, dorsal lobe shorter than laterals, dorsal ray symmetrical, divided at about 2/3 its length, each branch dividing again at tip, terminal divisions rays 9, 10 symmetrical, rays 8 arising from dorsal trunk at about same level; left lateral ray 6 curved dorsally, 4, 5 ventrally, ray 5 largest, rays 2, 3 diverge ventrally, reaching margin of bursa. Genital cone small, simple, ventral lip larger. Spicules equal, filiform, 145–230 (184) long, spicule to body length ratio 13.6%, tips simple. Gubernaculum 17.0–24.0 (20.5) long.

Female: (measurements of 15 specimens) Length 1550–2300 (2100), maximum width 49.5–66.0 (55.0). Cephalic vesicle 25.5–39.5 (34.1) long. Oesophagus 390–520 (348) long; nerve ring, deirids and excretory pore not observed. Vulva opens 85–200 (113) from tail tip. Monodelphic ovejector with vagina 25–30, shortest element, sphincter 30–40, vestibule 40–50, infundibulum, 60–100, longest element. Tail more or less tightly reflected ventrally, conical with pointed tip 15.5–31.0 (21.3) long. Eggs thin-shelled ellipsoidal, 2–4 in utero, 66.0–69.3 (67.1) long by 29.7–33 (31.9) wide.

Remarks. As indicated above, sufficient morphological information could be gathered to assign these specimens to genus and describe them as a new species. The new species belongs to the genus Hughjonestrongylus because it has a synlophe showing the same arrangement of pointed ridges as described in the diagnosis of Durette-Desset and Digiani (2015), with a dissymmetrical bursa, a type 2–3 pattern of bursal rays with the dorsal ray divided within the distal half. In having females with a synlophe of 21–23 ridges Hughjonestrongylus wanumaensis n. sp. is closest to a cluster of 3 species H. amplicauda ( Smales & Heinrich, 2010) with 20–24 ridges, H. mirzai ( Smales, 2009) with 21–24 ridges and H. singauwaensis ( Smales, 2009) with 19–23 ridges in the mid body ( Smales 2009; Smales & Heinrich 2010). Hughjonestrongylus wanumaensis can be differentiated from H. amplicauda in having shorter spicules, 145–230 compared with 280–365), a smaller gubernaculum (17–24 compared with 27–29), straight not markedly curved spicule tips, the infundibulum the longest element of the ovejector, not the vestibule and the number of eggs in the uterus (1–2 compared with 8–9) ( Smales & Heinrich 2010). Hughjonestrongylus wanumaensis is smaller than both H. mirzai and H. singauwaensis (mean length of males 1900 long compared with 2800, and 2500 respectively) and has shorter spicules (145–230 compared with 250–320 and 230–385 respectively). Hughjonestrongylus wanumaensis further differs from H. mirzai in the proportions of the ovejector (the infundibulum the longest element not the sphincter), the position of the female posterior end, reflected ventrally but without a praepuce or torsion and from H. singauwaensis in the proportions of the ovejector and the number of eggs in the uterus (2–4 compared with up to 13) ( Smales 2009).

All three new species of Hughjonestrongylus described from P. platyops share the character—infundibulum the longest element in the ovejector. Hughjonestrongylus vanimoensis is apparently the longest worm, males 3100 compared with 2100–2700 for H. pervulgatus and 1600–2200 for H. wanumaensis . Moreover the species can be readily distinguished by the number of ridges in the synlophe at the mid body; 25–29 for H. pervulgatus , 22–23 for H. wanumaensis and 18–19 for H. vanimoensis .

Figures

FIGURES 55–64. Hughjonestrongylus wanumaensis n. sp. In all illustrations of the synlophe in transverse section the dorsal aspect of the body is oriented towards the top of the page and the left side of the nematode to the left of the page. The dorsal and ventral (numbers with superscripts) ridges are numbered. 55. Female anterior end, lateral view; 56. Female cervical end; 57. Female posterior end lateral view showing ovejector; 58. Female transverse section, anterior end; 59. Spicules, proximal ends; 60. Spicule, tips; 61. Female transverse section, mid body; 62. Bursa dorsal view, showing bursal shape and dorsal ray; 63. Bursa left lateral lobe, rays numbered; 64. Gubernaculum, lateral view. Scale bars in µm: 55, 100; 56–63 25; 64, 125.