The morphological and molecular identity of Longidorus piceicola Lišková, Robbins & Brown, 1997 from Romania (Nematoda, Dorylaimida)

Abstract

Longidorus piceicola, a new geographical and host record from Romania, was described and illustrated on the basis of two populations originating from a coniferous and a deciduous forest. The main morphological characters of specimens from Romania correspond very well with the type material collected from the soil around Picea abies L. (Slovakia) except for the shorter body and tail. The D2-D3 fragment of 28S rDNA from both populations was amplified and sequenced, and the sequences were identical to L. piceicola sequence from Slovakia. The partial 18S-ITS1-5.8S-ITS2 rDNA regions from one of the populations were sequenced for the first time. The evolutionary relationships between L. piceicola and the closest species L. intermedius based on D2-D3 sequence divergence and single-nucleotide polymorphisms are discussed. Although having very low sequence dissimilarity (0.3–0.9 %) both species have distinct morphology and biology. Longidorus piceicola differs from L. intermedius in having a much longer odontostyle, body, distance anterior end - guide ring, a wider lip region, more ventromedian supplements (11 vs 5–7) in the male, and develops through four rather than three juvenile stages. Furthermore, L. piceicola occurs more frequently in association with conifers, while L. intermedius is found mainly in oak forests.