A taxonomic revision of filarioid nematodes from Australian marsupials

Abstract

The taxonomic status of filarioid nematodes from Australasian marsupials is reviewed and reassessed. Filarioids are reported from 31 species of marsupial host, distributed in the Dasyuridae, Peramelidae, Phalangeridae and Macropodidae, as well as from two species of eutherian Muridae and one monotreme. Three genera in three subfamilies of the Onchocercidae are recognized. Johnstonema Yeh, 1957 (Splendidofilariinae) is defined for the first time; J. annulipapzllatum (Johnston & Mawson, 1938) is considered a valid species; J. andersoni, sp. nov., and J. woerlei, sp. nov., are described and illustrated and a third new species is described but in the absence of males is not named. Dirofilaria roemeri (Linstow, 1905) (Dirofilariinae) is the only filarioid with a known life history from a marsupial. Breinlia Yorke & Maplestone, 1926 (Onchocercinae) is placed as a synonym of Dipetalonema Diesing, 1861 (emend. Chabaud 1952). D. capilliforme Baylis, 1934, D. dasyuri Johnston & Mawson, 1938, D. dendrolagi (Solomon, 1933), D. johnstoni Mackerras, 1954, D. macropi (Wahid, 1962), D. spelaea (Leidy, 1875), D. robertsi Johnston & Mawson, 1938, D. thylogali Mackerras, 1954, and D. trichosuri (Breinl, 1913) arc redescribed and illustrated. D. boltoni, sp. nov., D. dentonensis, sp. nov., D. rnundayi, sp. nov., D. pearsoni, sp. nov., D. pseudocheiri, sp. nov., and D. venacavincola, sp. nov.,arc described and illustrated, and three possibly new species of Dipetalonema are described but in the absence of males not named. D. lutreoli Mackerras, 1962, is placed as a synonym of D. johnstoni; D. tenue Johnston & Mawson, 1938, and D. australiense Yamaguti, 1961, are regarded as synonyms of D. robertsi. D. rarurn Johnston & Mawson, 1938, is redescribed from female worms only. Females of an unnamed species of Dipetalonema are reported from a monotreme. Filaria dentifera Linstow, 1898, is regarded as a species inquirendae.

Species of Dipetalonema are divided into two categories on the basis of spicule and pharyngeal morphology and the presence or absence of a gubernaculum. Each category is further subdivided into two groups on the basis of cephalic and cuticular structures, distribution of cloaca1 papillae and morphology of the microfilaria.

Keys to the genera of filarioids and to the species of Johnstonema and Dipetalonema from Australasian marsupials are provided.

The evolution of filarioid nematodes is discussed in relation to the evolution of their masupial hosts in Australia and New Guinea.