Breinlia (Breinlia) bigenera, 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 : 9-10

Breinlia (Breinlia) bigenera sp. nov.

( Figs. 7–20 )

Synonyms. Breinlia (Breinlia) rarum (Johnston & Mawson, 1938) sensu Spratt et al. 1991 , pp. 34, 61–62, 68; sensu Beveridge et al. 1992, p. 367.

New genus Beveridge et al. 1992, p.367.

Type host. Aepyprymnus rufescens (Gray) , (Marsupialia: Potoroidae ).

Other hosts. Onychogalea fraenata (Gould) , O. unguifera (Gould) (Marsupialia: Macropodidae );? Antechinus swainsonii (Waterhouse) (Marsupialia: Dasyuridae ).

Site in host. Peritoneal cavity.

Material examined. Holotype ♂, from Aepyprymnus rufescens Funnel Creek, south of Sarina , Queensland (22 0 18’S, 148 0 57’E), coll: R. Speare, 5.vii 1982, AHC 45844; allotype ♀, AHC 45845; paratypes 1♂, 3♀, AHC 45846.

Other material examined. From A. rufescens . QLD: 3♂, 1♀, ( QM G232510 ) Kunwarara, south of Marlborough (22 0 51’S, 150 0 06’E); 1♀, ( QM G232511 ) Apis Creek Station (23 0 00’S, 149 0 34’E) .

From Onychogalea fraenata ): QLD: 2♂, 1♀, ( AHC 45847) Dingo (23 0 38’S, 149 0 19’E)

From Onychogalea unguifera QLD : 2♂, ( QM G232512 ) Wernadinga Station (18 0 07’S, 139 0 57’E) ; 1♀, ( N1537 ) Bylong Station (20 0 43’S, 143 0 08’E) ; 1♀, ( N4369 ) 9 km W Cloncurry (20 0 42’S, 140 0 30’E)..

From? Antechinus swainsonii VIC : 3♂, 4♀ ( N3205 ) Healesville (37 0 39’S, 145 0 31’E) .

Etymology. The species name derives from bigenera meaning hybrid and referring to morphological features of the new species suggestive of a hybrid between Breinlia (B) dasyuri and B. (B.) dentonensis .

Differential diagnosis. Distinguished from all other species of Breinlia (Breinlia) with the exception of B. (B.) tricondylus , by having the shortest males and females, the shortest right and possibly shortest left spicule and by the characteristic morphology of the gubernaculum, shaped like the top spike of an halberd (or halbert) viewed upside–down. It is distinguished from B. (B.) tricondylus by its longer spicules, the spatulate distal tip of the right spicule characteristic of all other species of the subgenus except B. (B.) petauristae , the characteristic shape of the gubernaculum, shorter muscular and glandular portions of the oesophagus, longer tail of female and with two large fleshy latero-ventral papillae and a small, subterminal dorsal papilla, caudal papillae of the male clustered around the cloacal aperture, adcloacal papillae not double and fused throughout and the microfilaria with a blunt, non-filamentous tail. Only two other species, B. (B.) dasyuri and B. (B.) dentonensis , are known to have caudal papillae clustered around the cloacal opening and microfilariae with blunt, non–filamentous tails. The new species is distinguished from B. (B.) dasyuri from the peritoneal cavity of three species of quoll, Dasyurus spp. by the absence of refractile cuticular bosses in both sexes and from B. (B.) dentonensis from the subcutaneous connective tissue of the grey kangaroo, Macropus giganteus Shaw , and the red kangaroo, M. rufus (Desmarest) by the position of the vulva well posterior to the oesophago–intestinal junction in female worms. It is distinguished from both species by the variable distribution of six to eight cloacal papillae around the cloacal aperture.

Description. General: Short slender nematodes, width almost uniform throughout, females attenuated posteriorly. Oral opening small, rounded. Buccal capsule minute,.with minute ring at its base.. Four pairs of submedian papillae arranged in outer circle of four papillae and inner circle of four slightly smaller papillae. Rectangular, laterally–elongated, cuticular peri–buccal field present, appearing as prominent elevation of cuticle joining bases of papillae of inner circle. Small internolateral papillae located on lateral margin of inner field. Second rectangular, laterally–elongated cuticular peribuccal field present, appearing as prominent elevation of cuticle joining bases of papillae of outer circle. Amphids lateral, large, openings located on prominent raised elevations of cuticle on lateral margin of outer field. Oeosphagus divided into short anterior muscular and long posterior glandular regions, variable in length, particularly the latter. Intestine narrow, especially at oesophago–intestinal junction. Excretory pore distinct. Cuticle with fine narrowly–spaced transverse annulations; rugosities or refractile bosses absent. Lateral cords with 3 columns of nuclei, a narrow central column of widely–spaced, elongate nuclei with prominent nucleoli and wider peripheral columns of single, closely–spaced elliptical nuclei with prominent nucleoli. Spicules unequal, dissimilar. Gubernaculum present, highly characteristic in shape. Lateral alae absent. Phasmids and deirids not observed.

Male: (Holotype measurements presented first in italics followed by 4 paratypes). BL 18.6, 20.0 (16.1–23.3) mm. MW 185, 176 (150–201) in mid–body. NR 212, 214 (195–280). EP 292, 311 (292–344). MO 312, 357 (265– 450). GO 927, 1345 (901–1860). Posterior end coiled helically. LS 187, 204 (161–255); Cal 83, 104 (79–165), Lam 83, 69 (60–73)), Fil 21, 21 (16–30), terminating in fine membranous sheath. RS 119, 116 (113–124)), with spatulate distal extremity. Gub 27, 31 (27–31), characteristically shaped like the top spike of an halberd (or halbert) viewed upside–down. Cloacal papillae 6–8 in number distributed variably around cloacal aperture. Cloacal aperture raised, surrounded by cuticular ring. T 318, 371 (318–427), with two large fleshy latero-ventral papillae, a small dorsal papilla and a large medio-ventral papilla 21 µm anterior to tail tip.

Female: (Allotype measurements presented first in italics followed by 5 paratypes). BL 31.9, 33.6 (29.3–37.5) mm. MW 310, 314 (290–340) in mid–body. NR 201, 221 (212–238). EP 334, 279 (239–318). MO 292, 329 (292– 371). GO 1012, 1223 (1044–1367), oesophago–intestinal junction sometimes hidden by anterior loops of uterus and/or vagina uterina filled with microfilariae. V 2024, 2704 (2305–3143). T 360, 343 (292–383), markedly attenuated, with two large, fleshy latero-ventral papillae and a small, subterminal, dorsal papilla. Phasmids and deirids not observed.

Microfilariae: (Measurement of 10 specimens from blood, mean with range in parentheses). BL 178 (175– 180). MW 6 (5–6) in anterior one third. CS 5 (4–5). NR 45 (42–47). EP 66 (62–69). IN 111 (107–112). AV 153 (149–155). Tail tapering abruptly, terminating bluntly, non–filamentous, nuclear column terminating in 2–3 single nuclei. LNT 6 (5–7). Microfilaria unsheathed.

Measurements of B. (B.) bigenera from? A. swainsonii

Male: BL 14.4 (14.3–14.5) mm. MW 184 (183–188). NR 178 (178). EP 333. MO 263 (255–270). GO 951 (918–994). LS 185 (185), Cal 107 (107), Lam 49 (49) Fil 29 (29). RS 97 (96–98). T 359 (343–377), with two, large, fleshy, latero-ventral papillae, a small, dorsal, subterminal papilla and a large medio-ventral papilla 20 µm anterior to tail tip.

Female: BL 25.5 (24–28) mm. MW 310 (288–331). NR (191 (178–204). EP not observed. MO 258 (214–306. GO 1185 (1118–1326). V 1874 (1424–2384). T. 435 (392–479), with two large, fleshy latero-ventral papillae and one small, subterminal, median, dorsal papilla.

Microfilariae: Microfilariae in utero with short, blunt tails.

Distribution and hosts. Breinlia (B.) bigenera occurs in rufous bettongs and nailtail wallabies in northeastern Queeensland. The specimens from? Antechinus swainsonii remain an enigma. The material came with the? on the label but the author has not been able to ascertain whether the host generic identity was in question or whether the host was an antechinus but the species was in question. Further, it is not clear whether the animal came from the wild in the Healesville region or from captivity in the Healesville Sanctuary. The author suspects the latter because the collector was a veterinarian at the Sanctuary at the time. Furthermore, the Santuary had, at that time, a number of captive Aepyprymnus rufecens . The combination of factors suggests that possibly the record represents an accidental transmission of a parasite which occurs naturally in macropodoid species in northeastern Queensland to an abnormal host, a small dasyurid species which occurs naturally in southeastern New South Wales, Victoria and Tasmania.

Remarks. Breinlia (B.) bigenera can be distinguished from all other species of Breinlia (Breinlia) with the exception of B. (B.) tricondylus from the red–necked wallaby in southern New South Wales, by its short length, short right and possibly left spicule and characteristic morphology of the gubernaculum as outlined in the differential diagnosis provided. There was substantial variability in the lengths of the muscular and especially the glandular oesophagus, particularly in specimens from Onychogalea spp. Similar variation was seen in the lengths of the left spicule, especially the calomus in specimens from nailtail wallabies.

This material was originally suspected to be the elusive Breinlia (Breinlia) rara (see Spratt et al. 1991; Beveridge et al. 1992) described from small subcutaneous nodules of Onychogalea fraenata in Victoria by Johnston and Mawson (1938). The species was recorded under W/L # in error in Spratt et al. (1991) and Beveridge et al. (1992). However, in addition to the difference in tissue locality in the host the new species lacks numerous longitudinally elongate cuticular bosses as described from syntype females by Spratt and Varughese (1975), the oesophagus is shorter, the vulva is well posterior to the oesophago–intestinal junction, the distance from the anus to the tail tip is considerably greater and the male remains unknown.

Figures

FIGURES 7–20. Breinlia (Breinlia) bigenera sp. nov. 7, Cephalic end, apical view. 8, Cephalic end, lateral view. 9, Anterior extremity, male, lateral view. 10, Microfilaria. 11, Right spicule and gubernaculum, lateral view. 12, Distal extremity left spicule, latero-ventral view. 13, Left spicule, lateral view. 14, Vulva, vagina and intestine female, lateral view. 15, Caudal end male, lateral view. 16, Posterior extremity male, latero-ventral view. 17, Cloacal papillae male, ventral view. 18, Caudal end female, lateral view. 19, Caudal extremity female, lateral view. 20, Caudal extremity female, ventral view. Scale bars: Fig. 10 = 20 µm, Fig. 16 = 25 µm, Figs. 7, 8, 11–13, 15, 17, 19, 20 = 50 µm, Figs 9, 14, 18 = 100 µm.