Maxvachonia chabaudi Mawson 1972

Maxvachonia chabaudi Mawson, 1972 Figs. 1‒3 Small, whitish nematodes. Body cylindrical, maximum width at about region of mid-body. Cuticle with fine transverse striations. Somatic papillae absent. Cephalic end rounded. Oral aperture simple, somewhat triangular, surrounded by 3 small lips, each with inner flanges (Figs. 2B, 3D). Dorsal lip with 1 pair of large double cephalic papillae, subventral lips with single large double cephalic papilla and amphid (Figs. 2B, 3D). Buccal capsule short, with three small teeth-like projections at base (Fig. 1E). Oesophagus divided into anterior indistinct pharynx, cylindrical corpus, narrow isthmus and terminal posterior bulb with valves (Fig. 1A–D). Lateral alae only present in male (Fig. 2A). Nerve ring located at about 1/3‒1/2 of oesophageal length. Excretory pore discoid, situated at anterior to oesophageal bulb (Figs. 1A–D, 3A,B). Deirids not observed. Tail of both sexes conical, with pointed tip (Figs. 1F,K,L, 2C,H, 3F,G). Male (based on two mature specimens): Body 2.07‒2.24 mm long; maximum width 140‒220. Entire oesophagus 261‒338 long (including posterior oesophageal bulb), representing 13‒15% of body length; pharynx + corpus + isthmus 213‒280 long, size of oesophageal bulb 48‒58 × 53‒72. Nerve ring 113‒138 and excretory pore 208‒256 respectively, from anterior extremity. Lateral alae narrow, extending from level of excretory pore to anterior of second precloacal papillae (Figs. 1F, 2A,C,G). Posterior end of body distinctly ventrally curved (Figs. 1F, 2C,G). Spicules slender, equal in length, distal end pointed, 88‒122 long, representing 4.3‒5.4% of body length (Fig. 1F,G). Gubernaculum robust, well-sclerotised, with remarkable lateral processes near the proximal end, slightly longer than spicules, 109‒146 long (Figs. 1F,G, 2F). Caudal papillae 15 pairs in total, arranged as follows: 6 pairs precloacal (first pair lateral, far from others), 3 pairs paracloacal (2 pairs ventral, close to cloaca; 1 pair ventrolateral, far from cloaca) and 6 pairs postcloacal (4 pairs ventrolateral and 2 pairs dorsolateral (Figs. 1F, 2C–H). Single precloacal medio-ventral papilla present (Fig. 2F). Tail 150‒200 long, representing 7.2–8.9% body length (Figs. 1F, 2C,H). One pair of small phasmids located at about posterior 1/3 of tail (near third pair of postcloacal papillae) (Fig. 2H,I). Female (based on 33 mature specimens): Body 7.20‒14.6 mm long; maximum width 180‒400. Entire oesophagus 435‒676 long (including posterior oesophageal bulb), representing 3.6‒8.4% of body length; pharynx + corpus + isthmus 362‒580 long, size of bulb 72‒111 × 72‒111. Nerve ring 163‒300 and excretory pore 314‒483 respectively, from anterior extremity. Lateral alae absent. Vulva transverse slit, vulval lips not protruded, 411‒652 from anterior extremity, at 3.8‒7.3% of body length (Figs. 1A–C, 3A,C). Egg oval, thin-walled, with a small nipple at one side, 50‒80 × 38‒58 (n = 66) (Figs. 1H–J, 3E). Tail 1.50‒3.65 mm long, representing 20.3‒30.3% body length; tip of tail finger-like, covered with numerous nodular protuberances (Figs. 1L,K, 3F,G). Phasmids not observed. H o s t: Marine toad Rhinella marina (Linnaeus) (Anura: Bufonidae). L o c a l i t i e s: Cape Weymouth (-12.61611111, 143.43194444), Mareeba (-17.01861111, 143.47000000), northern Queensland; rural areas surrounding Townsville (-19.38472222, 146.96250000 and -19.38472222, 146.96250000), northern Queensland; Boyne Island (-23.93000000, 151.34777778), central Queensland, Australia. R a t e o f i n f e c t i o n: prevalence 5.1% (33 out of 643 of R. marina specimens were infected), with an intensity of 1–9 (mean 2.7) nematodes. S i t e o f i n f e c t i o n: intestine. Vo u c h e r s p e c i m e n s d e p o s i t e d: two males (HBNU– N-2021A005NL), 33 females (HBNU–N-2021A006NL).Published as part of Ni, Xue-Feng, Barton, Diane P., Chen, Hui-Xia & Li, Liang, 2022, Native species Maxvachonia chabaudi Mawson, 1972 (Nematoda: Cosmocercoidea) found in the invasive marine toad Rhinella marina (Linnaeus) (Anura: Bufonidae) in Australia, pp. 1-7 in Folia Parasitologica (028) (028) 69 on page 4, DOI: 10.14411/fp.2022.028, http://zenodo.org/record/814368