Odilia dividua Smales, 2014, sp. nov.
Creators: name: Smales, L. R.
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Nematoda
Chromadorea
Rhabditida
Heligmonellidae
Odilia
Odilia dividua

description: Odilia dividua sp. nov.
(Figs 24–35)
Type host. Pogonomys macrourus (Milne-Edwards). Site in host. Small intestine.
Material examined. Holotype male, allotype female, from Pogonomys macrourus Murum River below Wilbeite (3° 25´S, 142° 06´E), Torricelli Mountains, West Sepik, Sanduan Province, Papua New Guinea, coll. T. Flannery 10. vi. 1988 AM W. 46854, W. 46555; paratypes 5 males, 4 females, same data AM W.46856.
Other material examined. From Pogonomys macrourus Papua, Indonesia: 1 female, Armbere Forest above Jeute Village (1° 06´S, 133° 58´E), Arfak Mountains, AM W. 46853.
Etymology. The species name refers to the interrupted, divided ventral ridges of the synlophe.
Description. General: Small coiled nematodes, cephalic vesicle prominent, buccal capsule vestigial. Mouth opening triangular, with rudimentary lips; cephalic and labial papillae not seen, 2 lateral amphids. Oesophagus claviform, nerve ring not seen, deirids dome shaped, at about same level as excretory pore.
Synlophe: Longitudinal cuticular ridges extend from posterior margin of cephalic vesicle to anterior to bursa or vulva, ventral ridges interrupted; 12–15 ridges in anterior, 16 in mid body, 13 in posterior; axis of orientation of ridges from right ventral to left dorsal about 65° to sagittal plane; 4–8 ridges dorsal side, 7–9 ventral side; midbody ridges 1–6 increasing in size, ridge 7 smaller, 1’–9’ deccreasing in size, anterior and posterior ridges more or less uniform in size.
Male: Body length 2.7–4.5 (3.25) mm, maximum width 80–100.5 (89.9). Cephalic vesicle 42.5–49.5 (46.1) long. Oesophagus 270–400 (345) long; nerve ring, deirids and excretory pore not observed. Bursa asymmetrical, right lobe larger, pattern of rays 2–3; dorsal lobe with dorsal cleft, shorter than laterals. Dorsal ray symmetrical, divided at about 2/3 length, terminal divisions, rays 9, 10 symmetrical; rays 8 arising from dorsal ray at same level, right ray slightly larger; rays 4, 5, 6 with common stem, rays 6 curve posteriorly 4, 5 curve anteriorly, rays 2, 3 diverge distally, recurved ventrally, ray 2 not reaching margin of bursa. Genital cone not prominent. Spicules equal, filiform 310–540 (428) long, tips simple, pointed. Gubernaculum 51–54.5 (52.1) long.
Female: Body length 3.8–4.5 (4.1) mm, maximum width 82.5–105.6 (92.8). Cephalic vesicle 46.2–49.5 (48.1) long, with about 8 annulations. Oesophagus 280–350 (326) long; nerve ring not observed; deirids 240 (1 measurement); excretory pore 240 (1 measurement) from anterior end. Vulva, with prominent lips, opens 125–170 (136.5) from tail tip. Ovejector monodelphic, elements all about same length, vagina 35, 40, vestibule 40, 50, sphincter 40, 45, infundibulum 55 long. Tail reflected ventrally, 20–25 (22.5) long, conical ending in point. Eggs thin shelled, ellipsoidal, 68 by 30.6–39.1, as measured in utero.
Remarks. Following the key of Durette-Desset (1983) the specimens in this study are placed in the subfamily Nippostrongylinae and in the genus Odilia, on the basis of the characters of the synlophe, with an axis of orientation of longitudinal continuous cuticular ridges from ventral right to dorsal left at about 65° to the sagittal plane, the slightly asymmetrical bursa, the division and form of the dorsal ray, and rays 6 approximately equal in size. Following the key of Smales (2005) the species falls closest to Odilia mackerrasae, the only other fully described species having a synlophe with interrupted ventral ridges. Odilia dividua sp. nov, is a larger worm than O. mackerrasae (male length 2.7–4.5 compared with 2.2–2.7) with a longer oesophagus (males 270–400 compared with 190–230), longer mean spicule length (428 compared with 388) but spicules relatively shorter (body length: spicule length ratios 1: 7.6 compared with 1: 6.2) and larger eggs (68 by 31–39 compared with 55–58 by 30–32) (Mawson 1961). Although the synlophes of O. dividua and O. mackerrasae both have 16 ridges on the male midbody, ridges 1, 1’ are not significantly larger than ridges 2, 2’ for O. dividua as they are for O. mackerrasae (see Durette-Desset 1969). Odilia dividua differs from Odilia sp.1 of Hasegawa & Sayfruddin (1995), also with 15–16 ridges in the mid body, in not having the three ridges in the right dorsal field well developed and in having a longer oesophagus (270–400) compared with 240), longer spicules (310–540) compared with 278) and larger eggs (68 by 34.8 compared with 56–59 by 27–30) (Hasegawa & Syafruddin 1995; Hasegawa 1996).
description: Published as part of Smales, L. R., 2014, Gastrointestinal helminths (Cestoda, Chabertiidae and Heligmonellidae) of Pogonomys loriae and Pogonomys macrourus (Rodentia: Muridae) from Papua Indonesia and Papua New Guinea with the description of a new genus and two new species, pp. 92-106 in Zootaxa 3889 (1) on pages 100-101, DOI: 10.11646/zootaxa.3889.1.5, http://zenodo.org/record/224756