Nematodes from galls on Myrtaceae. III. Fergusobia from flower bud and stigma galls on Eucalyptus, with descriptions of four new species

Abstract

Four new species of Fergusobia from flower bud galls and a stigma gall on Eucalyptus spp. in Australia are described. Fer-gusobia eugenioidae Davies n. sp. is characterised by having an arcuate, open C or C-shaped parthenogenetic female with a conoid tail, an arcuate to open C-shaped infective female with a hooked tail region and a broadly rounded tail tip, and arcuate or open C-shaped males with angular spicules and short bursa. Fergusobia fasciculosae Davies n. sp. is character-ised by the combination of an arcuate parthenogenetic female with a short, broadly conoid tail, an open C-shaped infective female with a hemispherical tail tip, and J-shaped males with angular spicules and short peloderan bursa. This is the first Fergusobia/Fergusonina association to be described from flower stigma galls. Fergusobia juliae Davies n. sp. is character-ised by the combination of an arcuate to C-shaped parthenogenetic female with a short, broadly conoid tail, a J-shaped in-fective female with a hooked tail region, a cuticular plate around the vulva, and a broadly rounded tail tip, and J-shaped males with angular spicules and short peloderan bursa. Fergusobia morrisae Davies n. sp. has a C-shaped parthenogenetic female with a narrowly conoid tail, an arcuate or J-shaped infective female with most curvature behind the vulva and a short tail with an almost hemispherical tip, and arcuate or J-shaped males with strongly sclerotised, angular spicules and a long peloderan bursa. Other known similar forms of Fergusobia/Fergusonina flower bud galls from Eucalyptus spp. are outlined and the larval shield morphology of their associated mutualistic fly species is discussed where known. An inventory of all known Fergusobia/Fergusonina associations from flower bud galls from Eucalyptus spp. is presented. Molecular analysis of Fergusobia nematodes was inferred from DNA sequencing of 28S rDNA D2/D3 domains and a portion of mitochondrial DNA cytochrome oxidase subunit I (mtCOI). Possible evolutionary relationships are discussed.