Breinlia (Breinlia) pseudocheiri ( Spratt & Varughese, 1975 ) Chabaud & Bain, 1976

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 : 26-29

Breinlia (Breinlia) pseudocheiri ( Spratt & Varughese, 1975) Chabaud & Bain, 1976

(Fig. 84)

Dipetalonema pseudocheiri Spratt & Varughese, 1975, pp.60–63 , figs. 122–132, peritonal cavity ( Pseudocheirus peregrinus convolutor ) (as Pseudocheirus convolutor ) Launceston, Tasmania.

Breinlia (Breinlia) pseudocheiri (Spratt & Varughese) Chabaud & Bain, 1976, p. 377 ; Spratt et al. 1991, p. 31, 68.

Type host. ( Pseudocheirus peregrinus convolutor (Schinz) (Marsupialia: Pseudocheiridae ). Other hosts. Pseudocheirus peregrinus cookii (Desmarest) , Pseudocheirus peregrinus peregrinus (Boddaert) , Pseudocheirus occidentalis (Thomas) , Petauroides volans (Kerr) (Marsupialia: Pseudocheiridae ), Trichosurus vulpecula (Kerr) (Marsupialia: Phalangeridae ).

Site in host. Peritoneal and pleural cavities.

Other material examined. From Pseudocheirus peregrinus convolutor: TAS : 1♂, ( N415 ) Launceston ; 4♀, ( N924 ) Caveside , 1♂, 3♀, ( N4578 ), Sidmouth .

From Pseudocheirus peregrinus cookii: VIC : 4♀, ( N1624 ) Marysville State Forest . N SW : 3♂, 4♀, ( N583 ) Nadgee State Forest ; 1♀, ( N5222 ) Taronga Zoo, Sydney .

From Pseudocheirus peregrinus peregrinus: QLD :: 1♂, 4♀, ( N5457 ) Bongaree , Bribie Island .

From Pseudocheirus occidentalis: WA : 1♀, ( N5333 ) Collie ; 1♀, ( N5392 ) Albany .

From Petauroides volans: NSW : 5♂, 5♀, ( AHC 45870) Clyde Mountain ; 2♂ 6♀, ( QM G232523 ) from pleural and peritoneal cavities, 3♀ ( N448 ) , 2♀ ( N796 ) , 1♀ ( N800 ) Nadgee State Forest ; 1♂, 3♀ ( QM G232524 ) , Timbillica State Forest , 1♂, 11♀ ( N1354 ) , Buckenbowra State Forest ,). VIC : 2♂, 8♀ ( N5489 ) Healesville. QLD : 3♀ ( N335 ) Maryborough ; 1♀ ( N1806 ) Mareeba .

From Trichosurus vulpecula: NSW : 2♀, ( N585 ) Nadgee State Forest .

Differential diagnosis. Breinlia (B.) pseudocheiri resembles two species from hosts in Asia and B. dendrolagi and B. (B.) melomyos from hosts in Australia and Papua New Guinea. It is distinguished from B. (B.) tinjili from Rattus tiomanicus in Java by the shorter muscular and glandular portions of oesophagus in males and females, shorter calomus of left spicule (includes segments 1 and 2 of Purnomo & Bangs, 1996), several more cloacal papillae in males, slightly smaller gubernaculum which is not trilobed in lateral view, shorter tail in females and shorter microfilariae with the nuclear column terminating in single row of 3–4 rather than 6–9 elongate nuclei. Breinlia (B.) pseudocheiri is distinguished from B. (B.) sergenti from Nycticebus tardigradus in Calcutta by shorter females, slightly shorter right spicule, shorter calomus and longer filament of left spicule, more posterior position of vulva and shorter tails in males and females. Although B. (B.) pseudocheiri has the same spicule ratio as B. (B.) booliati from Asian hosts, the left spicule of the former is shorter.

It is distinguished from B. (B.) dendrolagi from tree kangaroos in Australia and Papua New Guinea by the much shorter length of males and females and shorter muscular and glandular portions of the oesophagus, slightly longer left and right spicules, longer filament of the left spicule which is surrounded by a membranous sheath, refractile cuticular bosses scattered on the ventral surface of males and females rather than arranged in transverse bands in males only, more numerous cloacal papillae, much more anterior position of the vulva, and the nuclear column of the microfilaria terminating in a single row of 3–4 rather than 9–10 elongate nuclei. Breinlia (B.) pseudocheiri is distinguished from B. (B.) melomyos from the grassland melomys in northwestern Western Australia by the slightly shorter left and slightly longer right spicule, shorter filament of the left spicule, generally longer muscular oesophagus in males and females, a more posterior position of the vulva, a considerably shorter tail in males and females and the presence of cuticular cephalic plates in apical view.

Measurements of specimens from Ps. peregrinus cookii from New South Wales, Ps. peregrinus peregrinus from Queensland, Ps. P. convolutor from Tasmania, Pet. volans from New South Wales and T. vulpecula from New South Wales are presented in Table 2. Cloacal papillae in males from both subspecies of Ps. peregrinus were 11 in number, variable in arrangement and dispersed anterior and posterior to the cloaca. Tail of male with one subterminal ventral papilla and terminating in one pair of latero-ventral papillae and a single median papilla.

Tail of females from both subspecies of Ps. peregrinus terminating in pair of latero-ventral papillae. Measurements of microfilariae from the vagina uterina as follows: BL 230 (223–236). MW 5 (5–6). EV 70 (67–72). Tail filamentous.

Cloacal papillae in males from Pet. volans ranged from 9–14 in number, 4–6 pre– and 4–6 post–cloacal. Tail of male terminating in two pairs latero-ventral papillae, the median pair larger than the lateral pair, and one subterminal dorsal papilla.

Tail of females from Pet. volans terminating in pair of latero-ventral papillae and one small subterminal dorsal papilla. Measurements of microfilariae from vagina uterina as follows: BL 242 (237–244). MW 5 (5–6). CS 7 (6– 8). Nuclear column terminating in single row of 4–5 nuclei. Tail filamentous. LNT 25–29. Microfilaria unsheathed, occurs in blood.

Distribution and hosts. Breinlia (B.) pseudocheiri appears to have a wide geographic distribution among petaurid and pseudocheirid hosts in coastal southeastern Australia. There are two possible records, represented by females only, from the western ringtail possum, Ps. occidentalis and a single record of females from the phalangerid brushtail possum, T. vulpecula .

Remarks. Breinlia (Breinlia) pseudocheiri from ringtail possums of eastern and southwestern Australia and the greater glider in southeastern Australia is most similar to B. (B.) tinjili from the Malaysian field rat from Tinjil Island, southwest Java, Indonesia, B. (B.) sergenti from a lemur in Calcutta, B. (B.) dendrolagi from tree kangaroos in Australia and Papua New Guinea and B (B.) zyzomyos from rock–rats in northwestern Western Australia, It is distinguished from these species under the differential diagnosis provided.

There is a great deal of variation in measurements of this species within a host species, between subspecies of Ps. peregrinus from Victoria and New South Wales, Queensland and Tasmania, and between host species. While a case might be made that material from the greater glider ( Petauroides volans ) represents a different species on the basis of measurements of the left spicule, the position of the vulva and the length of the tail in males and females, these lie between those from ringtails ( Pseudocheirus spp. ) from Tasmania and those from ringtails in New South Wales and Queensland .. The right spicule of specimens from P. volans is shorter than those from subspecies of Ps. peregrinus , the number and distribution of papillae on the male tail are different and the oesophagus in males and females particularly is longer. Nevertheless, I consider these differences insufficient to warrant erection of a new species for the material from P. volans and here consider all to be B. (B.) pseudocheiri , until such time as findings from molecular studies are available.

In the absence of males, the specimens from Ps. occidentalis in Western Australia and T. vulpecula in New South Wales are here tentatively placed in B. (B.) pseudocheiri . This filarioid species has been observed in 11 of 25 Ps. peregrinus examined from Tasmania, Victoria, and New South Wales, in 2 of 2 Ps. occidentalis examined from Western Australia, in 9 of 48 Pet. volans examined from New South Wales and Queensland, in 1 of 7 T. vulpecula examined from southeastern New South Wales and in 0 of 229 T. vulpecula examined from central and western New South Wales, Victoria, Tasmania, South Australia and Queensland.

In a number of instances, nematodes recovered from Ps. peregrinus were surrounded by host cells. In the animal from Bribie Island, the pathology report stated “The brain contains scattered microfilaria (sic) located within blood vessels and in perivascular spaces. Blood vessels have endothelial hypertrophy and mild lymphocytic cuffing. There is also mild meningeal lymphocytic infiltration”. The diagnosis was “mild nonsuppurative meningoencephalitis associated with microfilaraemia”and the pathologist stated “These findings suggest that the microfilarial parasite has some neurotropism.” (Neill Sullivan, pers. comm.). Host cells were not associated with nematodes recovered from P. volans , suggesting that it may be the normal or original host and also suggesting a less than fully adapted host–parasite association in Ps. peregrinus .

Pseudocheirus peregrinus occupies the lower shrub canopy of wattles while P. volans occupies the upper tree canopy of eucalypt and peppermint forests in eastern Australia. Of note, the latter is the habitat of the western ringtail possum, Ps. occidentalis , in WA, the greater glider being restricted to eastern Australia ( Van Dyck & Strahan 2008).