First report and morphological, molecular characterization of Xiphinema chambersi Thorne, 1939 (Nematoda, Longidoridae) in Canada

摘要

A Xiphinema species, new to Canada was recovered from rhizosphere of oak trees in Ontario, Canada. The identity was confirmed with morphological and molecular methods as X. chambersi Thorne, 1939. Female bodies are 2.1–2.4 mm long; odontostyle lengths are 110–118 µm; tail 110–177 µm long, arcuate, elongate-conoid, with hyline region 22-43 µm long. Vagina directed about 30 degrees posteriorly. Reproductive system is monodelphic with ovary reflexed anteriorly, vulva opening at 23–26% of the body. Males were not found. The 18S and ITS1 sequences of this population had 3–4 bp differences (99% identity) and 30 bp differences (97% identity) from two Arkansas populations respectively. The nematode population had three juvenile stages. Some variations of the morphometrics were observed comparing with the other populations. This is the first report of X. chambersi in Canada.