Hughjonestrongylus vanimoensis, 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 : 117-118

Hughjonestrongylus vanimoensis n. sp.

( Figs 45–54 )

urn:lsid:zoobank.org:act:2849EF5F-6FBC-48AB-90B0-26875AA89782

Type host. Paramelomys platyops (Thomas) .

Site in host. Small intestine.

Material examined. Holotype male, allotype female, paratype 1 female BBM NG104584 from Paramelomys platyops from 60 k southeast Vanimo Sanduan Proviince Papua New Guinea; coll A. B. Mirza, 9. iv. 1974.

Other material examined. From Paramelomys platyops from Papua New Guinea, Madang Province; 4 males, 4 females 14 k north north west Wanuma , BBM NG103897 .

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

Description. General: Small worms, slightly or tightly coiled: prominent cephalic vesicle with about 8–9 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; 18 ridges in mid body. Ridges markedly different in size. Axis of orientation oblique from right ventral to left dorsal in mid body; 8–9 ridges dorsal side 9–10 ridges ventral side. Left ridge distinct from ridge 1´; mid left ridges larger than mid right ridges; left ridges 1´, 2´, forming comarette, larger than right ridges 7–9, left ridge 2´smaller than 1´, ventral ridges 3´–9, 10´about same size, dorsal ridges 1–6 about same size, ridges 7–9 larger.

Male. (measurements of holotype) Length 3000, maximum width 60. Cephalic vesicle 36.3 long. Oesophagus 330 long; nerve ring, deirids and excretory pore not observed. Bursa dissymmetrical, left lobe larger, pattern of rays 2–3, dorsal lobe shorter than laterals, dorsal trunk symmetrical, divided at about 2/3 its length, each branch dividing again at tip; terminal divisions rays 9, 10 symmetrical, rays 8 symmetrical, arising from dorsal trunk at about same level; lateral rays 6 curved dorsally, 4, 5 ventrally, largest, rays 2, 3 diverge ventrally, reaching margin of bursa. Genital cone small, simple. Spicules slightly unequal, filiform, 390 long, spicule to body length ratio 12.6 %, one tip curved and hooked over other. Gubernaculum 39 long.

Female: (measurements of allotype and paratype) Length 3300, 4100, maximum width 66.0, 80.5. Cephalic vesicle 33.0, 42.9 long. Oesophagus 297, 330 long; nerve ring, deirids, excretory pore not observed. Vulva opens 150, 210 from tail tip; posterior end female coiled ventrally, most specimens covered with cement plug containing eggs. Monodelphic ovejector with sphincter 25, 30, shortest element vagina 30, 40, vestibule 40, 50, infundibulum 160, 180 longest element. Tail more or less tightly reflected ventrally, conical with pointed tip 26.5, 33.0 long. Eggs thin-shelled ellipsoidal, 2–4 in utero, 66.0 long by 29.7 wide.

Remarks. As indicated above sufficient morphological information could be gathered to assign these specimens to a genus and describe them as a new species. The new species could be placed in 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 and with the dorsal ray divided within the distal half. Hughjonestrongylus vanimoensis n. sp. differs from all previously described species in the genus in having 18 synlophe ridges, ridges 1’, 2’ forming a comarete, in the midbody. In this respect the synlophe of H. vanimoensis resembles that of the monospecific genus Krishnasamyos Digiani and Durette-Desset, 2014 but otherwise differs from it in the pattern and sizes of the ridges ( Digiani and Durette-Desset 2014). As a complete description of the synlophes of males and females could not be prepared from the available material it seems prudent to place this new species within the genus Hughjonestrongylus rather than erect a new genus. Within the genus Hughjonestrongylus H. vanimoensis comes closest to H. singauwaensis which has 19–23 ridges ( Smales & Heinrich 2010) but being further distinguished from it in having 18 ridges on the synlophe in the mid body. Hughjonestrongylus vanimoensis is a slightly larger worm (males 3100 compared with 2350–2750 long) with longer spicules (390 compared with 230–385) and a longer gubernaculum (39 compared with 29–35.5) than H. singauwaensis . The females of H. vanimoensis have the infundibulum markedly the longest element of the ovejector, not the same length as the vestibule and 2– 4 eggs in utero 66.0 long compared with 13 eggs 64.5–73 long for H. singauwaensis ( Smales & Heinrich 2010) .

Figures

FIGURES 45–54. Hughjonestrongylus vanimoensis 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. 45. Male anterior end, lateral view; 46. Female posterior end lateral view, showing ovejector; 47. Female transverse section, mid body; 48. Bursa showing shape, left side larger; 49. Spicules, proximal ends; 50. Spicule tips; 51. Gubernaculum, lateral view; 52. Bursa left lateral lobe, rays numbered; 53. Dorsal ray; 54. Bursa right lateral lobe, rays numbered. Scale bars in µm: 45, 75; 46, 100; 47–54, 25.