Breinlia (Breinlia) zyzomyos, Spratt, 2011

Spratt, David M., 2011, New records of filarioid nematodes (Nematoda: Filarioidea) parasitic in Australasian monotremes, marsupials and murids, with descriptions of nine new species 2860, Zootaxa 2860 (1), pp. 1-61 : 38-40

Breinlia (Breinlia) zyzomyos sp. nov.

( Figs 69–77 )

Type host. Zyzomys woodwardi (Thomas) (Eutheria: Muridae ).

Other hosts. Zyzomys argurus (Thomas) .

Site in host. Peritoneal cavity.

Material examined. Holotype: ♂, from Zyzomys woodwardi, Mitchell Plateau , Western Australia (14 0 46’S, 125 0 47’E), coll: P.J.A. Presidente 16.vii.1982, holotype ♂, AHC 45877, allotype ♀, AHC 45878, 1♂ posterior half and 3 ♀ paratypes, AHC 45879.

Other material examined. From Zyzomys woodwardi: WA : 1♂, 1♀, ( QM G232533 ), Mitchell Plateau .

From Zyzomys argurus: WA : 1♂, 1♂ anterior ( N1851 ) ; 1♂, 6♀ ( QM G232532 ) 2♂, 2♀ ( AHC 45880) ; 4♀ ( N1853 ) ; 1♂ anterior fragment, 2♀ ( N1957 ) , all Mitchell Plateau.

Etymology. The species is named after the host genus.

Differential diagnosis. Breinlia (B.) zyzomyos from rock rats in northwestern Western Australia is morphologically most similar to B. (B.) beveridgei from whiptail wallabies in northern Queensland, B. (B.) melomyos from a grassland melomys in northwestern W.A, and B.(B.) booliati from murids and a squirrel in southeast Asia. It is distinguished from B. (B.) beveridgei by longer males, the absence of large ear–like cephalic papillae of the outer circle, shorter glandular oesophagus, longer right spicule, broader gubernaculum not appearing to surround the distal tip of the right spicule and the more dense and unrestricted distribution of the longitudinal refractile cuticular bosses in males. It is distinguished from B. (B.) melomyos by longer males and females, absence of a cuticular peribuccal field in en face view, longer left and particularly right spicules, longer glandular oesophagus and tails in males and females terminating with a single pair of subterminal latero–ventral papillae and a larger median terminal one in males rather than two pairs of terminal latero–ventral papillae, and more anterior position of the vulva. It is distinguished from B. (B.) booliati by much shorter females, slightly shorter left and longer right spicule, shorter calomus and longer lamina of left spicule, absence of an area rugosa in males, gubernaculum not shaped like a figure “3” in lateral view, much more anterior position of vulva and generally shorter tails in males and females.

Description. Moderately long nematodes with attenuated extremities. Oral opening small, rounded. Four pairs of submedian papillae arranged in outer circle of four small papillae and inner circle of four smaller papillae. Cuticular peribuccal fields absent. Internolateral papillae absent. Amphids lateral, large, opening at level of outer circle of papillae. Buccal capsule minute, narrow, with small, refractile, ring present at its base. Pharynx divided into short anterior muscular and long posterior glandular regions, variable in lengths. Intestine broad. Excretory pore not observed. Cuticle with fine, transverse annulations, elongate, refractile, cuticular bosses present in males only, commencing approximately 9.5 mm from cephalic end, widely spaced and scattered anteriorly and in mid–body, becoming increasingly dense on ventral surface towards posterior, eventually restricted to ventral surface posteriorly and terminating approximately 2mm from tail tip. Lateral cords with 3 columns of nuclei, a narrow, central column of widely–spaced, elliptical nuclei with prominent nucleoli and wider, peripheral columns of closely– spaced, elliptical nuclei with prominent nucleoli. Spicules unequal, dissimilar. Gubernaculum present. Lateral alae absent. Phasmids and deirids not observed.

Male: (Holotype measurements presented first in italics, followed by one posterior end paratype and 2 others). BL 58, 56 (49–63) mm. MW 292, 259 (212–292) in posterior body. NR 270, 268 (265–270). EP not observed. MP 297, 312 (292–345). GP 1166, 1140 (1060–1140). Posterior end coiled helically. LS 364, 381 (364–395), Cal 156, 177, Lam 94, 94 (83–104), Fil 114, 118 (114–125). RS 160, 177 (160–198), with spatulate distal extremity. Gub 33, 32 (31–33). Cloacal papillae highly variable in number and arrangement; ranging 10–14 in number, 3–4 pre–cloacal and 7–10 post–cloacal. T 540, 581 (540–600), with one pair small subterminal latero–ventral papillae and one larger, median, terminal papilla.

Female: (Allotype measurements presented first in italics, followed by three paratypes and 12 others). BL 129, 103 (55–132) mm. MW 424, 418(212–540). NR 229, 230(159–265). EP not observed. MP 355, 368 (265– 424).

GP 822, 952 (848–1139), pharyngo–intestinal junction sometimes hidden by anterior loops of uterus and/or vagina uterina filled with microfilariae. V 2174, 2826 (2024–4065). T 848 813 (557–1070), terminating in a single, median papilla.

Microfilariae. Unknown.

Measurements of 3 male B. (B.) zyzomyos from Zyzomys argurus . BL 53 (41–61). MW 274 (239–292. NR 266 (239–292. EP not observed. MO 380 (265–451). GO 918 (795–980). LS 325 (314–343), Cal 164 (146–187), Lam 83 (83–94), Fil 78 (73–83). RS 173 (166–181). Gub 33 (31–34). T 562 (520–624).

Measurements of 3 female B. (B.) zyzomyos from Zyzomys argurus . BL 103 (100–105). MW 495 (477– 504). NR 246 (208–292). EP not observed. MO 410 (250–504). GO 1298 (1269–1352). V 1385 (1134–1643). T 860 (752–954).

Distribution and hosts. Breinlia (B.) zyzomyos is known only from rock–rats of the genus Zyzomys in northwestern Western Australia.

Remarks. Breinlia (Breinlia) zyzomyos is most similar to B. (B.) beveridgei from whiptail wallabies in north Queensland, B (B.) melomyos from a grassland melomys in northwestern Western Australia and and B. (B.) booliati from Asian murid and sciurid hosts. It is distinguished from these species under the differential diagnosis provided.

The specimens from Z. argurus differ slightly from those from Z. woodwardi .

Males exhibit a shorter oesophagus, primarily in the glandular portion and a shorter left spicule reflected primarily in the filament; females exhibit a longer oesophagus, primarily in the glandular portion and a much more anterior position of the vulva. These differences are not considered sufficient for specific recognition and here all material from rock rats is placed under B. (B.) zyzomyos . It is noteworthy that many of the specimens from Z. argurus contained host cells adhering to the cuticle of the nematodes, possibly suggesting a less than ideal or perhaps more recent host–parasite relationship.

The microcomplement fixation studies of Watts et al. (1992) supported earlier morphological data and placed Zyzomys in a Mesembriomys clade, including Melomys and Uromys , which contains primarily mesic–adapted species and has radiated widely in Australia ( Watts & Baverstock 1994a). Species of Breinlia have not yet been reported from species of Uromys in Australia or Papua New Guinea ( Smales & Spratt 2008) although Monanema australis occurs in hepatic blood vessels and lymphatics of this host in the Atherton Tablelands region of north Queensland.

Figures

FIGURES 69–77. Breinlia (Breinlia) zyzomyos sp. nov. 69, Cephalic end, apical view. 70, Cephalic end, lateral view. 71, Anterior end female, lateral view. 72, Cuticular ornamentation male, 3.7mm from tail tip, bosses most dense ventrally and posteriorly. 73, Vulva, vagina and uterus of female filled with microfilariae, lateral view. 74, Oesophago-intestinal junction female, lateral view. 75, Posterior end male, lateral view. 76, Caudal extremity male, latero-ventral view. 77, Posterior end female, lateral view. Scale bars: Figs 69, 70, 72,75,76 = 50 µm, Figs 71, 73, 74, 77 = 100 µm.