Subanguina chilensis sp. n. (Nematoda: Anguinidae), a new leaf-gall nematode parasitizing Nothophagus obliqua, in Chile.

Newly formed and mature foliar galls on leaves of rubble tree, N. obliqua, were dissected to study their relationship with a new gall-inducing Anguinidae nematode species of Subanguina. S. chilensis sp. nov. is unique among the family of Anguinidae by inducing leaf galls in a deciduous tree plant-host and is characterized by mucronate tail tips in both sexes. It is separated from the other species of the genus (particularly from those described as Afrina, a junior synonym of Subanguina) by a combination of characters such as a shorter body in both sexes, position of excretory pore and vulva, shorter male tail, spicules, and gubernaculum. The histopathogenesis of foliar galls induced by Subanguina chilensis sp. nov. in Nothophagus obliqua was examined via serial sections prepared from naturally infected leaves. Nematodes infected the blades of young leaves. Hypertrophy and hyperplasia, mainly of the mesophyllic tissues, resulted in the formation of confluent galls which varied in size from 2 to 8 mm, and were located randomly, proximal to the midribs or secondary leaf veins. Mature galls contained a cavity lined with parenchymatogenous nutritive tissue, comprising intercellular spaces, and actively dividing hypertrophied elongated cells with granular cytoplasm and, in some cases, hypertrophied nuclei and nucleoli. All life stages of the nematode were concentrated in the gall cavity, and in many mature galls, active egg deposition occurred.