Hughjonestrongylus alisoni, Smales, 2020

Smales, Lesley, 2020, Gastrointestinal nematodes of Paramelomys levipes and P. mollis (Rodentia Muridae) from Papua, Indonesia and Papua New Guinea with the descriptions of three new genera and nine new species (Nematoda), Zootaxa 4861 (4), pp. 544-572 : 555-556

Hughjonestrongylus alisoni n. sp.

( Figs 4 A–J)

Type host. Paramelomys mollis (Thomas)

Site in host. Small intestine.

Type specimens. Holotype male AM W. 53160, allotype female AM W. 53161, paratypes 2 males, 1 female AM W. 53153, from Paramelomys mollis from Bichate , Arfak Mountains, Papua, Indonesia (1° 06´S 133° 56´E); coll. T. Flannery, A. Szalay 10. x. 1992.

Etymology. The species is named in recognition of the biodiversity survey work carried out by Dr Allan Alison in New Guinea.

Description. General: Small coiled nematodes. Cephalic vesicle prominent, with about 4 transverse annula-

tions. Buccal capsule vestigial, mouth opening triangular with rudimentary lips; cephalic and labial papillae not seen, 2 lateral amphids. Oesophagus claviform, nerve ring, excretory pore and deirids not seen.

Synlophe: (based on sections from 2 male worms) Longitudinal pointed ridges extend from posterior margin of cephalic vesicle to anterior to bursa or vulva; 28 ridges in male mid body. Ridges markedly different in size. Axis of orientation of ridges oblique from right ventral to left dorsal; 11 ridges dorsal side, 17 ventral side. Left ridge distinct from ridge 1´; lateral left and lateral right ridges largest, ridge 2´smaller than ridge 1´ventral ridges 3´–17´about same size, more robust than dorsal ridges; dorsal ridges 1–3 decreasing in size, ridges 9–11 increasing in size. Ridges losing size gradient, reducing in size posteriorly.

Male: (measurements of 5 specimens) Length 2.3–3.7 (2.8) mm, maximum width 69 –107 (85). Cephalic vesicle 24–33 (30) long. Oesophagus 300–400 (354) long; nerve ring, deirids and excretory pore not seen. Bursa slightly dissymmetrical, left lobe larger; pattern of rays 2–3. Dorsal lobe shorter than laterals; dorsal trunk symmetrical divided at about half its length, terminal divisions rays 9, 10 symmetrical, rays 8 symmetrical, arising from dorsal trunk at about same level, reaching margins of bursa; lateral rays 6, 5, 4 all about same size, reaching margin of bursa, rays 3, 2 arise together from common trunk, reaching margin of bursa. Genital cone simple. Spicules sub equal, filiform, tips curved, complex, 490–560 (523) long; spicule to body length ratio 18.5 %. Gubernaculum 26 long.

Female: (measurements of 3 specimens) Length 2.9–3.7 (2.3) mm, maximum width 74–83 (80). Cephalic vesicle 33–49 (38) long. Oesophagus 310–350 (323) long; nerve ring, deirids and excretory pore not seen. Vulva opens 115–130 (126) from tail tip; tail reflected ventrally. Ovejector monodelphic, infundibulum 35 long, sphincter shortest element 20 long, vestibule 60 long, vagina 30 long (one measurement). Tail conical with blunt tip, 36, 51 long. Eggs thin shelled, ellipsoidal, up to 10 in utero, 61.2 long, 34.0 wide.

Remarks. Although only a small number of specimens were available for study, precluding a complete descrip- tion of the synlophe, sufficient information was available to characterise these specimens as a new species of Hughjonestrongylus . The synlophe demonstrated the same arrangement of pointed ridges as described in the diagnosis of Durette-Desset & Digiani (2015) and the bursa was dissymmetrical with a type 2–3 pattern of bursal rays ( Digiani & Durette-Desset, 2014). In the key to the species of Hughjonestrongylus of Smales (2019) Hughjonestrongylus alisoni n. sp. with a synlophe of 28 ridges and complex spicule tips places close to H. pervulgatus Smales, 2019 which has a synlophe of 27–30 ridges in the mid body, spicules 310–350 long and a spicule to body length ratio of 13% and H. woolleyae Smales, 2017 which has a synlophe of 25–27 ridges in the mid body, spicules 290–390 long and a spicule to body length ratio of 8.3%. Hughjonestrongylus alisoni differs from both these species, however, in having spicules 490–560 long and a spicule to body length ratio of 18.5%. Hughjonestrongylus woolleyae occurs in Paramelomys lorentzii , H. pervulgatus in P. platyops and H. alisoni in P. mollis (see Smales 2017, 2019).

Figures

FIGURE 4. Hughjonestrongylus alisoni sp. n. 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, as are the lateral rays of the bursa (right rays with superscripts). A. Female, anterior end lateral view; B. Male, mid body transverse section; C. Male, cervical end lateral view; D. Male, bursa dorsal lobe, not completely rolled flat; E. Female, posterior end lateral view; F. Male, bursa left lobe; G. Male, gubernaculum and spicule tip lateral view; H. Male, spicules, anterior end; I. Male, spicule tips; J. Male, bursa right lobe. Scale bars in µm: A, 100; B, C, F, G, H, I, J, 25; D, E, 50.