Anguina woodi sp. n. (Tylenchida: Anguinidae) from dune grass, Ehrharta villosa, in South Africa

Abstract

Abstract Anguina woodi sp. n. was found in galls on dune grass, Ehrharta villosa var. villosa, on Milnerton Beach, South Africa. Mature galls varied in colour from purplish to brown and formed elongated to round elevations on the stems, leaf sheaths and, occasionally, the leaf blades. The adult females of Anguina woodi sp. n. are 1.6-2.7 mm long and coiled into a circle or spiral. Adult males were 1.4-2.1 mm long, straight or slightly curved ventrad or dorsad. Second-stage juveniles (J2) were more or less straight with a prominent mucro on the tail. A few larger juveniles, probably J3 and J4, with developing gonads were also found. Morphological, morphometric and molecular analyses showed that Anguina woodi sp. n. is closely related to A. australis Steiner, 1940 and, to a lesser extent, to A. microlaenae (Fawcett, 1938) Steiner, 1940. From A. australis it differs mainly in a slightly longer female stylet (9.5-15.5 vs 8.0-11.1 μm) and wider female head (8.6-11 vs 7.4 μm); a slightly longer male stylet (10.5-12.0 vs 10-11 μm) and longer spicule (33-36 vs 26.5-35.3 μm), and a longer tail (72-96 vs 49-68 μm) and slightly higher c-value (7.3-12 vs 6.1-8.1) in the J2. The mucro on the tail tip of the J2 of A. woodi sp. n. is also more prominent and, on average, longer than the mucro in A. australis (3.3 vs 1.5 μm). Anguina woodi sp. n. differs from A. microlaenae mainly in the appearance of the galls incited (roundish elevations attached to the substrate by a flattened base vs pedunculate galls attached to the substrate by a narrow base), a longer stylet in both females and males (8-9 μm long in females and males of A. microlaenae), body of male curved ventrad or dorsad in A. woodi sp. n. (dorsad in males of A. microlaenae) and female tail in A. woodi sp. n. tapering gradually to a sub-acute tip vs a prominent peg-like process in A. microlaenae. Phylogenetic analysis of the ITS1 sequences of 19 anguinid populations and species using maximum parsimony and maximum likelihood methods revealed that A. woodi sp. n. clustered with high bootstrap support with A. australis. The ITS1-5.8S-ITS2 fragment sequence differed between these species by 20 nucleotides (2.6%). The J2 of A. australis is herein described for the first time and is compared with the J2 of A. woodi sp. n. Phylogenetic relationships of A. woodi sp. n. with other anguinids parasitising grasses are presented.