Schistonchus molochi sp. n. and S. athertonensis sp. n. (Nematoda: Aphelenchoididae) from Ficus watkinsiana (Moraceae) in Australia

Abstract

Ficus watkinsiana (sub-genus Urostigma, Section Stilpnophyllum) is endemic to Australia, growing in two disjunct populations, one in north-eastern Queensland and the other in south-eastern Queensland and north-eastern New South Wales. Schistonchus molochi sp. n. is described from F. watkinsiana in Queensland, Australia, and differentiated from other species of Schistonchus by a combination of morphological characters including having the excretory pore opening near the nerve ring, a broad head, a large, strongly sclerotised, stylet, a distinct lip sector disc with raised edges, a long post-uterine sac, rose-thorn-shaped spicule, no gubernaculum, three pairs of subventral papillae on the tail (one pair pre-cloacal on the anterior lip, one pair adcloacal on the posterior lip, and one slightly posterior to mid-tail) and bluntly rounded tail tip, and apparent biogeographical range. Presence of the lip sector disc suggests that it is closest to S. macrophylla. Schistonchus athertonensis sp. n. is also described from F. watkinsiana in Queensland and is characterised by a combination of morphological characters, including having the excretory pore opening near the nerve ring, a medium length post-uterine sac, presence of vulval flap in some specimens, rose-thorn-shaped spicule, no gubernaculum, and three pairs of subventral papillae on the tail (one pair adcloacal on the posterior lip, one at three to four-fifths of the tail length and one near the tip), a narrowly rounded tail tip, and apparent biogeographical range. Morphospecies 8, originally collected from F. obliqua, was also collected from F. watkinsiana in Queensland, and S. altermacrophylla was found with it in South Australia. These collections are further evidence of host-switching within Schistonchus.