Hasegawanema yuroense, 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 : 113

Hasegawanema yuroense sp. nov.

( Figs 16–28 )

urn:lsid:zoobank.org:act:DF4DB22F-44BD-4ACE-8C4F-A8211BA75E3C

Type host. Paramelomys platyops (Thomas) .

Site in host. Small intestine.

Material examined. Holotype male, AHC 48784, allotype female, AHC 48785 paratypes 9 males, 9 females AHC 23265 from Paramelomys platyops from Yuro , Papua New Guinea.

Etymology. This species name is derived from the collection locality.

Description. General: Small worms, slightly or tightly coiled: prominent cephalic vesicle with about 9 transverse annulations; buccal capsule vestigial. Mouth opening triangular with rudimentary lips; labial and cephalic papillae not observed. Oesophagus claviform. Nerve ring surrounds oesophagus in mid oesophageal region; deirids and excretory pore at about same level, posterior to nerve ring.

Synlophe: (based on sections from 4 worms) of pointed, longitudinal, continuous ridges extending from posterior margin of cephalic vesicle to immediately anterior to bursa or vulva; 21–23 ridges in mid body male and female, fewer ridges anteriorly. Ridges markedly different in size. Axis of orientation oblique. Ridges supporting careen not hypertrophied, left ventral ridges larger than left dorsal ridges; ridge 1´distinct from left ridge; 10–11 ridges dorsal side, 11–12 ventral side. Dorsal ridges 1–6, 7 about same size, ridges 7, 8–9, 10 increasing in size, ridge 10, 11 smaller; ventral left ridge 2´smaller than 1´, ventral ridges 3´–12´about same size.

Male: (measurements of 10 specimens) Length 3300–4800 (4100), maximum width 73–132 (104). Cephalic vesicle 43.0–49.5 (45.5) long. Oesophagus length not observed; 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 not symmetrical, divided at about 1/3 its length, each branch dividing again at tip; terminal divisions rays 9, 10 dissymmetrical, left rays 9, 10 larger, rays 8 dissymmetrical, left ray larger, arising from dorsal trunk at about same level as dorsal ray divides; lateral rays 6 curved dorsally, 4, 5 ventrally, rays 5 largest, rays 2, 3 diverge ventrally, reaching margin of bursa. Genital cone elongated, sclerotized. Spicules equal, filiform, 440–550 (495) long, spicule to body length ratio 12.07 %, tips simple, straight. Gubernaculum 31.0–49.5 (38.6) long.

Female: (measurements of 10 specimens) Length 3000–4600 (4150), maximum width 73–132 (129). Cephalic vesicle 36.0–49.5 (46.2) long. Oesophagus length, nerve ring not observed; deirids, excretory pore 200 (1 measurement) from anterior end. Vulva opens 110.0–200.0 (152.5) from tail tip; posterior end female coiled ventrally, covered with cement plug containing eggs in most specimens observed. Ovejector monodelphic with vagina 25, vestibule with thickened walls 70, sphincter 80, infundibulum shorter 35, (single measurements). Tail conical with pointed tip 25, 40 long. Eggs thin-shelled ellipsoidal, more than 14 in utero, 53.0–73.0 (62.7) long by 33.0–39.6 (36.3) wide.

Remarks. These specimens may previously have been stored in glycerol at some time because the annular nature of the buccal capsule was easy to observe although the annulations around the cephalic vesicle had been lost and the soft tissue features could not be clearly discerned. As discussed above, it was difficult also to prepare sections of the synlophe, although sufficient data was collected to provide a description of the new species. The new species could be placed in the genus Hasegawanema 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 the dorsal ray divided within the distal half. As presently constituted the genus comprises H. mallomyos ( Hasegawa & Syafruddin, 1994) with 16 synlophe ridges in the mid body, H. maxomyos ( Hasegawa, Miyata & Syafruddin, 1999) with23–28 ridges, H. mamasaense ( Hasegawa, Miyata & Syafruddin, 1999) with 19–23 ridges, H. moatense (Hasegawa, Myiata & Syafruddin, 1999) with 15-16 ridges, and H, sulawasiense ( Hasegawa, Miyata & Syafruddin, 1999) with 16–17 ridges. Of these five species Hasegawanema yuroense n. sp. comes closest to H. mamasaense in having 20–22 synlophe ridges while differing in the length of the spicule (440–550 compared with 303–359), in having a cuticularised genital cone, the shape of female posterior end and the proportions of the ovejector (Hasegawa & Syafruddin 1994a; Hasegawa, Miyata & Syafruddin 1999). Hasegawanema yuroense is found in P. platyops from Papua New Guinea, whereas H. mallomyos is found in Mallomys rothschildi weylandi, Thomas from Papua, H. maxomyos and H. mamasaense are found in Maxomys musschenbroekii (Jentnik) from Sulaswesi, and H. moatense and H. sulawesiense are in Rattus xanthurus (Gray) also from Sulawesi, all Indonesian localities (Hasegawa & Syafruddin 1994a; Hasegawa, Miyata & Syafruddin 1999).

Figures

FIGURES 16–28. Hasagawanema yuroensis 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. 16. Female posterior end, lateral view showing ovejector; 17. Female transverse section, anterior end; 18. Male, cervical vesicle lateral view; 19. Female transverse section, mid body; 20. Spicules, proximal ends; 21. Female posterior end showing torsion; 22. Female transverse section, posterior body; 23. Genital cone, lateral view; 24. Gubernaculum, spicules and genital cone, dorsal view; 25. Female tail, lateral view; 26. Bursa not extended, showing shape, left lateral lobe larger; 27. Dorsal ray; 28. Bursa, left lateral lobe partially unrolled, rays numbered. Scale bars in µm: 16, 21, 26, 28, 50; 17–20, 22–25, 27, 25.